Oceans Make Climate

April 2026 SSTs Continue to Warm

Posted on by Ron Clutz

The best context for understanding decadal temperature changes comes from the world’s sea surface temperatures (SST), for several reasons:

  • The ocean covers 71% of the globe and drives average temperatures;
  • SSTs have a constant water content, (unlike air temperatures), so give a better reading of heat content variations;
  • A major El Nino was the dominant climate feature in recent years.

Previously I used HadSST3 for these reports, but Hadley Centre has made HadSST4 the priority, and v.3 will no longer be updated.  This February report is based on HadSST 4, but with a twist. The data is slightly different in the new version, 4.2.0.0 replacing 4.1.1.0. Product page is here.

The Current Context

The chart below shows SST monthly anomalies as reported in HadSST 4.2 starting in 2015 through February 2026. A global cooling pattern is seen clearly in the Tropics since its peak in 2016, joined by NH and SH cycling downward since 2016, followed by rising temperatures in 2023 and 2024 and cooling in 2025, now with a steady mild rising in 2026.

Note that in 2015-2016 the Tropics and SH peaked in between two summer NH spikes.  That pattern repeated in 2019-2020 with a lesser Tropics peak and SH bump, but with higher NH spikes. By end of 2020, cooler SSTs in all regions took the Global anomaly well below the mean for this period.  A small warming was driven by NH summer peaks in 2021-22, but offset by cooling in SH and the tropics, By January 2023 the global anomaly was again below the mean.

Then in 2023-24 came an event resembling 2015-16 with a Tropical spike and two NH spikes alongside, all higher than 2015-16. There was also a coinciding rise in SH, and the Global anomaly was pulled up to 1.1°C in 2023, ~0.3° higher than the 2015 peak.  Then NH started down autumn 2023, followed by Tropics and SH descending 2024 to the present. During 2 years of cooling in SH and the Tropics, the Global anomaly came back down, led by Tropics cooling from its 1.3°C peak 2024/01, down to 0.5C in November 2025. That same month, the Global anomaly exactly matched the mean for this period, with all regions converging on that value, lincluding a 5 month drop in NH.  Now in 2026, due to a six-month rise in SH and Tropice, plus NH the last three months, the Global anomaly in April  is matching the value 2 years ago, 04/2024.

Comment:

The climatists have seized on this unusual warming as proof their Zero Carbon agenda is needed, without addressing how impossible it would be for CO2 warming the air to raise ocean temperatures.  It is the ocean that warms the air, not the other way around.  Recently Steven Koonin had this to say about the phonomenon confirmed in the graph above:

El Nino is a phenomenon in the climate system that happens once every four or five years.  Heat builds up in the equatorial Pacific to the west of Indonesia and so on.  Then when enough of it builds up it surges across the Pacific and changes the currents and the winds.  As it surges toward South America it was discovered and named in the 19th century  It iswell understood at this point that the phenomenon has nothing to do with CO2.

Now people talk about changes in that phenomena as a result of CO2 but it’s there in the climate system already and when it happens it influences weather all over the world.   We feel it when it gets rainier in Southern California for example.  So for the last 3 years we have been in the opposite of an El Nino, a La Nina, part of the reason people think the West Coast has been in drought.

It has now shifted in the last months to an El Nino condition that warms the globe and is thought to contribute to this Spike we have seen. But there are other contributions as well.  One of the most surprising ones is that back in January of 2022 an enormous underwater volcano went off in Tonga and it put up a lot of water vapor into the upper atmosphere. It increased the upper atmosphere of water vapor by about 10 percent, and that’s a warming effect, and it may be that is contributing to why the spike is so high.

A longer view of SSTs

To enlarge, open image in new tab.

The graph above is noisy, but the density is needed to see the seasonal patterns in the oceanic fluctuations.  Previous posts focused on the rise and fall of the last El Nino starting in 2015.  This post adds a longer view, encompassing the significant 1998 El Nino and since.  The color schemes are retained for Global, Tropics, NH and SH anomalies.  Despite the longer time frame, I have kept the monthly data (rather than yearly averages) because of interesting shifts between January and July. 1995 is a reasonable (ENSO neutral) starting point prior to the first El Nino.

The sharp Tropical rise peaking in 1998 was dominant in the record, starting Jan. ’97 to pull up SSTs uniformly before returning to the same level Jan. ’99. There were strong cool periods before and after the 1998 El Nino event. Then SSTs in all regions returned to the mean in 2001-2.

SSTS fluctuate around the mean until 2007, when another, smaller ENSO event occurs. There is cooling 2007-8,  a lower peak warming in 2009-10, following by cooling in 2011-12.  Again SSTs are average 2013-14.

Now a different pattern appears.  The Tropics cooled sharply to Jan 11, then rise steadily for 4 years to Jan 15, at which point the most recent major El Nino takes off.  But this time in contrast to ’97-’99, the Northern Hemisphere produces peaks every summer pulling up the Global average.  In fact, these NH peaks appear every July starting in 2003, growing stronger to produce 3 massive highs in 2014, 15 and 16.  NH July 2017 was only slightly lower, and a fifth NH peak still lower in Sept. 2018.

The highest summer NH peaks came in 2019 and 2020, only this time the Tropics and SH were offsetting rather adding to the warming. (Note: these are high anomalies on top of the highest absolute temps in the NH.)  Since 2014 SH has played a moderating role, offsetting the NH warming pulses. After September 2020 temps dropped off down until February 2021.  In 2021-22 there were again summer NH spikes, but in 2022 moderated first by cooling Tropics and SH SSTs, then in October to January 2023 by deeper cooling in NH and Tropics.

Then in 2023 the Tropics flipped from below to well above average, while NH produced a summer peak extending into September higher than any previous year.  Despite El Nino driving the Tropics January 2024 anomaly higher than 1998 and 2016 peaks, following months cooled in all regions, and the Tropics continued cooling in April, May and June along with SH dropping.  After July and August NH warming again pulled the global anomaly higher, September through January 2025 resumed cooling in all regions, continuing February through April 2025, with little change in May,June and July despite upward bumps in NH. Now temps in all regions have cooled  from August through November 2025, followed by a rebound of mild warming in 2026 appears in all regions  through April.

What to make of all this? The patterns suggest that in addition to El Ninos in the Pacific driving the Tropic SSTs, something else is going on in the NH.  The obvious culprit is the North Atlantic, since I have seen this sort of pulsing before.  After reading some papers by David Dilley, I confirmed his observation of Atlantic pulses into the Arctic every 8 to 10 years.

Contemporary AMO Observations

Through January 2023 I depended on the Kaplan AMO Index (not smoothed, not detrended) for N. Atlantic observations. But it is no longer being updated, and NOAA says they don’t know its future.  So I find that ERSSTv5 AMO dataset has current data.  It differs from Kaplan, which reported average absolute temps measured in N. Atlantic.  “ERSST5 AMO  follows Trenberth and Shea (2006) proposal to use the NA region EQ-60°N, 0°-80°W and subtract the global rise of SST 60°S-60°N to obtain a measure of the internal variability, arguing that the effect of external forcing on the North Atlantic should be similar to the effect on the other oceans.”  So the values represent SST anomaly differences between the N. Atlantic and the Global ocean.

The chart above confirms what Kaplan also showed.  As August is the hottest month for the N. Atlantic, its variability, high and low, drives the annual results for this basin.  Note also the peaks in 2010, lows after 2014, and a rise in 2021. Then in 2023 the peak reached 1.4C before declining to 0.9 August 2026.  An annual chart below is informative:

Note the difference between blue/green years, beige/brown, and purple/red years.  2010, 2021, 2022 all peaked strongly in August or September.  1998 and 2007 were mildly warm.  2016 and 2018 were matching or cooler than the global average.  2023 started out slightly warm, then rose steadily to an  extraordinary peak in July.  August to October were only slightly lower, but by December cooled by ~0.4C.

Then in 2024 the AMO anomaly started higher than any previous year, then leveled off for two months declining slightly into April.  Remarkably, May showed an upward leap putting this on a higher track than 2023, and rising slightly higher in June.  In July, August and September 2024 the anomaly declined, and despite a small rise in October, ended close to where it began.  Note 2025 started much lower than the previous year and headed sharply downward, well below the previous two years, then since April through September aligning with 2010. In October there was an unusual upward spike, now reversed down to match 2022 and 2016.  The orange 2026 line continues downward and is visible on top of 2016 purple line, well below the peak years of 2023 and 2024.

The pattern suggests the ocean may be demonstrating a stairstep pattern like that we have also seen in HadCRUT4.

The rose line is the average anomaly 1982-1996 inclusive, value 0.18.  The orange line the average 1982-2025, value 0.41 also for the period 1997-2012. The red line is 2015-2025, value 0.74. As noted above, these rising stages are driven by the combined warming in the Tropics and NH, including both Pacific and Atlantic basins.

Curiosity:  Solar Coincidence?

The news about our current solar cycle 25 is that the solar activity is hitting peak numbers now and higher  than expected 1-2 years in the future.  As livescience put it:  Solar maximum could hit us harder and sooner than we thought. How dangerous will the sun’s chaotic peak be?  Some charts from spaceweatherlive look familar to these sea surface temperature charts.

Summary

The oceans are driving the warming this century.  SSTs took a step up with the 1998 El Nino and have stayed there with help from the North Atlantic, and more recently the Pacific northern “Blob.”  The ocean surfaces are releasing a lot of energy, warming the air, but eventually will have a cooling effect.  The decline after 1937 was rapid by comparison, so one wonders: How long can the oceans keep this up? And is the sun adding forcing to this process?

uss-pearl-harbor-deploys-global-drifter-buoys-in-pacific-ocean

USS Pearl Harbor deploys Global Drifter Buoys in Pacific Ocean

CO2 Warming Rejected on Energetic and Geochemical Grounds (Segalstad)

Posted on by Ron Clutz

The_distribution_of_CO_between_atmospherDownload

Tom Segalstad wrote this paper pointing out major holes in the CO2 Warming belief. You can scroll through the text in the embedded document above, or download the pdf by clicking on the Download button. Below is my excerpted synopsis with my bolds and added images.

1. Introduction

It has recently been created a belief among people that an apparent increase in atmospheric CO2 concentration is caused by anthropogenic burning of fossil carbon in petroleum, coal, and natural gas. The extra atmospheric CO has been claimed to cause global climatic change with a significant atmospheric temperature rise, of 1.5 to 4.5°C in the next decennium (Houghton et al., 1990). This postulate is here discussed and rejected on energetic and geochemical grounds.

2. Heat energy and temperatures

Our relatively high global atmospheric temperature near the surface of the Earth, with an average of 14 to 15°C, is caused by heat-absorbing gases in the atmosphere, mainly H2O vapor. Without the Earth’s atmosphere the surface temperature would be approximately -18°C.

All human activities have been claimed to contribute about 1.3% of this (approx. 2 W/m2 ), while a hypothetic doubling of the atmospheric CO concentration would contribute about 2.6% (approx. 4 W/m2 ) to the present “Greenhouse Effect”. 150 years-long time series of temperature measurements are covering too short time spans to be useful for climate prediction, in order to be used as “evidence” for anthropogenic heating (or cooling). The global mean temperature has risen and fallen several times over the last 400 years, with no evidence of anthropogenic causes, although strong explosive volcanic eruptions have caused periodically colder climates.

It should also be noted that clouds can reflect up to approx. 50 W/m2 and can  absorb up to approx. 30 W/m2 of the solar radiation, making the Earth’s average “Greenhouse Effect” vary naturally within approx. 96 and 176 W/m2 . Hence the anticipated anthropogenic atmospheric CO heat absorption is much smaller than the natural variation of the Earth’s “Greenhouse Effect”.

The oceans act as a huge heat energy buffer; the global climate is primarily governed by the enormous amount of heat stored in the oceans (total mass approx. 1.4 x 10^24 g), rather than the minute amount of heat withheld in the heat-absorbing part of the atmosphere (total mass approx. 1.4 x 10^18 g), a mass difference of one million times. Most of the atmospheric heat absorption occurs in water vapor (total mass approx. 1.3 x 10^19 g), which is equivalent to a uniform layer of only 2.5 cm of liquid water covering the globe, with a residence time of about 9 days.

The total internal energy of the whole ocean is more than 1.6 x 10^27 Joules, about 2000 times larger than the total internal energy 9.4 x 10^23 Joules of the whole atmosphere. Furthermore the cryosphere (ice sheets, sea ice, permafrost, and glaciers; total mass of the continental ice is approx. 3.3 x 10^22 g) plays a central role in the Earth’sclimate as an effective heat sink for the atmosphere and oceans.  With a large latent heat of melting on the order of 9.3 x 10^24 Joules, that hypothetic energy is equivalent tocooling the entire oceans by about 2°C (5.8 x 10^24 J/°C). For comparison, the energy needed to warm the entire atmosphere by 1°C is only 5.1 x 10^21 Joules.

Hence it will be impossible to melt the Earth’s ice caps and thereby increase the sea level just by increasing the heat energy of the atmosphere through a few percent by added heat absorption of anthropogenic CO2 in the lower atmosphere.

3. CO2 measurements in atmosphere and ice cores

Houghton et al. (1990) claim in their section 1.2.5 three evidences that the contemporary atmospheric CO2 increase is anthropogenic: First, CO2 measurements from ice cores show a 21% rise from 280 to 353 ppmv (parts per million by volume) since pre-industrial times; second, the atmospheric CO2 increase closely parallels (sic!) the accumulated emission trends from fossil fuel combustion and from land use changes, although the annual increase has been smaller each year than the fossil CO2 input [some 50% deviation]; third, the isotopic trends of C13 and C14 agree qualitatively (sic!) with those expected due to the CO2 emissions from fossil fuels and the biosphere.

Figure 1.  Concentration of CO2 in air bubbles from the pre-industrial ice from Siple, Antarctica (open squares), and in the 1958-1986 atmosphere at Mauna Loa, Hawaii (solid line): (A) original Siple data without assuming an 83 year younger age of air than the age of the enclosing ice, and (B) the same data after arbitrary “correction” of age of air (Neftel et al., 1985; Friedli et al., 1986; and IPCC 1990).

Jaworowski et al. (1992 a) have presented a number of criticisms regarding the 
methodology of atmospheric CO2 measurements, including spectroscopic instrumental
peak overlap errors (from N2O, CH4 , and CFCs in the air). They also pointed out that the CO2 measurements at current CO2 observatories use a procedure involving a subjective editing (Keeling et al., 1976) of measured data, only representative of a few tenths of percent of the total data. There are also fundamental problems connected with the use of stable carbon isotopes ( C13/ C14) in tree rings for model calculations of earlier  atmospheres’ CO2 concentration, a method which now seems to have been abandoned..  The third evidence, based on carbon isotopes, will be discussed below in Section 5.

4. Chemical laws for distribution of CO2 in nature

Statistically it has been found that the atmospheric CO2 concentration rises after temperature rises (Kuo et al., 1990), and it has been suggested that the reason is that  cold water dissolves more CO2 (e.g. Segalstad, 1990). Hence, if the water temperature  increases, the water cannot keep as much CO2 in solution, resulting in CO2 degassing from the water to the atmosphere. According to Takahashi (1961) heating of sea water by 1°C will increase the partial pressure of atmospheric CO by 12.5 ppmv during
upwelling of deep water. For example 12°C warming of the Benguela Current should increase the atmospheric CO2 concentration by 150 ppmv.

From a geochemical consideration of sedimentary rocks deposited throughout the Earth’s history, and the chemical composition of the ocean and atmosphere, Holland (1984) showed that degassing from the Earth’s interior has given us chloride in the  ocean; and nitrogen, CO2 , and noble gases in the atmosphere. Mineral equilibria have  established concentrations of major cations and H in the ocean, and the CO2 concentration in the atmosphere, through different chemical buffer reactions. Biological
reactions have given us sulphate in the ocean and oxygen in the atmosphere.

Carbon dioxide is an equally important requisite for life on Earth as oxygen. Plants. need CO2 for their living (the photo synthesis), and humans and animals breath out CO2 from their respiration. In addition to this biogeochemical balance, there is also an important geochemical balance. CO2 in the atmosphere is in equilibrium with carbonic acid dissolved in the ocean, which in term is close to CaCO saturation and in equilibrium with carbonate shells of organisms and lime (calcium carbonate; limestone) in the ocean through the a series pf reactions.

If the temperature changes, the chemical equilibrium constant will change, and move the equilibrium to the left or right. The result is that the partial pressure of CO (g) will increase or decrease. The equilibrium will mainly be governed by Henry’s Law: the partial pressure of CO2 in the air will be proportional to the concentration of CO2 dissolved in water. The proportional constant is the Henry’s Law Constant, which is strongly temperature dependent, and lesser dependent on total pressure and salinity.

5. Carbon isotopes in atmospheric CO2

Houghton et al. (1990) assumed for the IPCC model 21% of our present-day atmospheric CO2 has been contributed from burning of fossil fuel. This has been made possible by CO2 having a “rough indication” (sic!) lifetime of 50 – 200 years. It is possible to test this assumption by inspecting the stable C13/ C12 isotope ratio (expressed as δ13Cpdb ) of atmospheric CO2 . It is important to note that this value is the net value of mixing all different CO2 components, and would show the results of all natural and non-natural (i.e. anthropogenic) processes involving CO2.

Segalstad (1992, 1993) has by isotope mass balance considerations calculated the atmospheric CO2 lifetime and the amount of fossil fuel CO2 in the atmosphere. The December 1988 atmospheric CO2 composition was computed for its 748 GT C total mass and δ13C = -7.807‰ for 3 components: (1) natural fraction remaining from the pre-industrial atmosphere; (2) cumulative fraction remaining from all annual fossil-fuel CO emissions (from production data); (3) carbon isotope mass-balanced natural fraction. The masses of the components were computed for different atmospheric lifetimes of CO2 .

Source: Skrable et al. (2022) Despite an estimated 205 ppm of FF CO2 emitted since 1750, only 46.84 ppm (23%) of FF CO2 remains, while the other 77% is distributed into natural sinks/sources. As of 2018 atmospheric CO2 was 405, of which 12% (47 ppm) originated from FF. And the other 88% (358 ppm) came from natural sources: 276 prior to 1750, and 82 ppm since. Natural CO2 sources/sinks continue to drive rising atmospheric CO2, presently at a rate of 2 to 1 over FF CO2. [My snyopsis: On CO2 Sources and Isotopes]

The calculations show how the IPCC’s (Houghton et al., 1990) atmospheric CO2 lifetime of 50-200 years only accounts for half the mass of atmospheric CO2 . However, the unique result fits an atmospheric CO2 lifetime of -5 (5.4) years, in agreement with numerous C14 studies compiled by Sundquist (1985) and chemical kinetics (Stumm & Morgan, 1970). The mass of all past fossil-fuel and biogenic emissions remaining in the current atmosphere was in December 1988 calculated to be -30 GT C or less, i.e. a maximum -4%, corresponding to an atmospheric CO concentration of -14 ppmv. This small amount of anthropogenic atmospheric CO2 probably contributes less than half a Watt/m2 of the 146 W/m “Greenhouse Effect” of a cloudless atmosphere, contributing to less than half a degree C of radiative heating of the lower atmosphere.

The isotopic mass balance calculations show that at least 96% of the current atmospheric CO2 is isotopically indistinguishable from non-fossil-fuel sources, i.e. natural marine and juvenile sources from the Earth’s interior. Hence, for the atmospheric CO2 budget, marine equilibration and degassing, and juvenile degassing from e.g. volcanic sources, must be much more important, and burning of fossil-fuel and biogenic materials much less important, than assumed by the authors of the IPCC model
(Houghton et al., 1990)

6. Conclusions

Water vapor is the most important “greenhouse gas”. Man’s contribution to  atmospheric CO2 from the burning of fossil fuels is small, maximum 4% found by carbon isotope mass balance calculations. The “Greenhouse Effect” of this contribution is small and well within natural climatic variability. The amount of fossil fuel carbon is minute compared to the total amount of carbon in the atmosphere, hydrosphere, and lithosphere. The atmospheric CO2 lifetime is about 5 years. The ocean will be able toabsorb the larger part of the CO2 that Man can produce through burning of fossil fuels. The IPCC CO2 global warming model is not supported by the scientific data. Based on geochemical knowledge there should be no reason to fear a climatic catastrophe because of Man’s release of the life-governing CO2 gas.

The global climate is primarily governed by the enormous heat energy stored in the oceans and the latent heat of melting of the ice caps, not by the small amount of heat that can be absorbed inatmospheric CO2 ; hence legislation of “CO2 taxes” to be paid by the public cannot influence on the sea level and the global climate.

See Also:

CO2 Facts Net Zero Zealots are Hiding from You

March 2026 Mild Warming SSTs Continue

Posted on by Ron Clutz

The best context for understanding decadal temperature changes comes from the world’s sea surface temperatures (SST), for several reasons:

  • The ocean covers 71% of the globe and drives average temperatures;
  • SSTs have a constant water content, (unlike air temperatures), so give a better reading of heat content variations;
  • A major El Nino was the dominant climate feature in recent years.

Previously I used HadSST3 for these reports, but Hadley Centre has made HadSST4 the priority, and v.3 will no longer be updated.  This February report is based on HadSST 4, but with a twist. The data is slightly different in the new version, 4.2.0.0 replacing 4.1.1.0. Product page is here.

The Current Context

The chart below shows SST monthly anomalies as reported in HadSST 4.2 starting in 2015 through February 2026. A global cooling pattern is seen clearly in the Tropics since its peak in 2016, joined by NH and SH cycling downward since 2016, followed by rising temperatures in 2023 and 2024 and cooling in 2025, now with a mild rising in 2026.

 

Note that in 2015-2016 the Tropics and SH peaked in between two summer NH spikes.  That pattern repeated in 2019-2020 with a lesser Tropics peak and SH bump, but with higher NH spikes. By end of 2020, cooler SSTs in all regions took the Global anomaly well below the mean for this period.  A small warming was driven by NH summer peaks in 2021-22, but offset by cooling in SH and the tropics, By January 2023 the global anomaly was again below the mean.

Then in 2023-24 came an event resembling 2015-16 with a Tropical spike and two NH spikes alongside, all higher than 2015-16. There was also a coinciding rise in SH, and the Global anomaly was pulled up to 1.1°C in 2023, ~0.3° higher than the 2015 peak.  Then NH started down autumn 2023, followed by Tropics and SH descending 2024 to the present. During 2 years of cooling in SH and the Tropics, the Global anomaly came back down, led by Tropics cooling from its 1.3°C peak 2024/01, down to 0.6C in September this year. Note the smaller peak in NH in July 2025 now declining along with SH and the Global anomaly cooler as well. In December the Global anomaly exactly matched the mean for this period, with all regions converging on that value, led by a 6 month drop in NH.  Now in 2026 the first 3 months show a mild warming in all regions, in March approximately matching values 3 years ago, 03/2023 before the warming spike.

Comment:

The climatists have seized on this unusual warming as proof their Zero Carbon agenda is needed, without addressing how impossible it would be for CO2 warming the air to raise ocean temperatures.  It is the ocean that warms the air, not the other way around.  Recently Steven Koonin had this to say about the phonomenon confirmed in the graph above:

El Nino is a phenomenon in the climate system that happens once every four or five years.  Heat builds up in the equatorial Pacific to the west of Indonesia and so on.  Then when enough of it builds up it surges across the Pacific and changes the currents and the winds.  As it surges toward South America it was discovered and named in the 19th century  It iswell understood at this point that the phenomenon has nothing to do with CO2.

Now people talk about changes in that phenomena as a result of CO2 but it’s there in the climate system already and when it happens it influences weather all over the world.   We feel it when it gets rainier in Southern California for example.  So for the last 3 years we have been in the opposite of an El Nino, a La Nina, part of the reason people think the West Coast has been in drought.

It has now shifted in the last months to an El Nino condition that warms the globe and is thought to contribute to this Spike we have seen. But there are other contributions as well.  One of the most surprising ones is that back in January of 2022 an enormous underwater volcano went off in Tonga and it put up a lot of water vapor into the upper atmosphere. It increased the upper atmosphere of water vapor by about 10 percent, and that’s a warming effect, and it may be that is contributing to why the spike is so high.

A longer view of SSTs

To enlarge, open image in new tab.

The graph above is noisy, but the density is needed to see the seasonal patterns in the oceanic fluctuations.  Previous posts focused on the rise and fall of the last El Nino starting in 2015.  This post adds a longer view, encompassing the significant 1998 El Nino and since.  The color schemes are retained for Global, Tropics, NH and SH anomalies.  Despite the longer time frame, I have kept the monthly data (rather than yearly averages) because of interesting shifts between January and July. 1995 is a reasonable (ENSO neutral) starting point prior to the first El Nino.

The sharp Tropical rise peaking in 1998 was dominant in the record, starting Jan. ’97 to pull up SSTs uniformly before returning to the same level Jan. ’99. There were strong cool periods before and after the 1998 El Nino event. Then SSTs in all regions returned to the mean in 2001-2.

SSTS fluctuate around the mean until 2007, when another, smaller ENSO event occurs. There is cooling 2007-8,  a lower peak warming in 2009-10, following by cooling in 2011-12.  Again SSTs are average 2013-14.

Now a different pattern appears.  The Tropics cooled sharply to Jan 11, then rise steadily for 4 years to Jan 15, at which point the most recent major El Nino takes off.  But this time in contrast to ’97-’99, the Northern Hemisphere produces peaks every summer pulling up the Global average.  In fact, these NH peaks appear every July starting in 2003, growing stronger to produce 3 massive highs in 2014, 15 and 16.  NH July 2017 was only slightly lower, and a fifth NH peak still lower in Sept. 2018.

The highest summer NH peaks came in 2019 and 2020, only this time the Tropics and SH were offsetting rather adding to the warming. (Note: these are high anomalies on top of the highest absolute temps in the NH.)  Since 2014 SH has played a moderating role, offsetting the NH warming pulses. After September 2020 temps dropped off down until February 2021.  In 2021-22 there were again summer NH spikes, but in 2022 moderated first by cooling Tropics and SH SSTs, then in October to January 2023 by deeper cooling in NH and Tropics.

Then in 2023 the Tropics flipped from below to well above average, while NH produced a summer peak extending into September higher than any previous year.  Despite El Nino driving the Tropics January 2024 anomaly higher than 1998 and 2016 peaks, following months cooled in all regions, and the Tropics continued cooling in April, May and June along with SH dropping.  After July and August NH warming again pulled the global anomaly higher, September through January 2025 resumed cooling in all regions, continuing February through April 2025, with little change in May,June and July despite upward bumps in NH. Now temps in all regions have cooled led by NH from August through December 2025. A mild warming in 2026 appears in all regions January through March.

What to make of all this? The patterns suggest that in addition to El Ninos in the Pacific driving the Tropic SSTs, something else is going on in the NH.  The obvious culprit is the North Atlantic, since I have seen this sort of pulsing before.  After reading some papers by David Dilley, I confirmed his observation of Atlantic pulses into the Arctic every 8 to 10 years.

Contemporary AMO Observations

Through January 2023 I depended on the Kaplan AMO Index (not smoothed, not detrended) for N. Atlantic observations. But it is no longer being updated, and NOAA says they don’t know its future.  So I find that ERSSTv5 AMO dataset has current data.  It differs from Kaplan, which reported average absolute temps measured in N. Atlantic.  “ERSST5 AMO  follows Trenberth and Shea (2006) proposal to use the NA region EQ-60°N, 0°-80°W and subtract the global rise of SST 60°S-60°N to obtain a measure of the internal variability, arguing that the effect of external forcing on the North Atlantic should be similar to the effect on the other oceans.”  So the values represent SST anomaly differences between the N. Atlantic and the Global ocean.

The chart above confirms what Kaplan also showed.  As August is the hottest month for the N. Atlantic, its variability, high and low, drives the annual results for this basin.  Note also the peaks in 2010, lows after 2014, and a rise in 2021. Then in 2023 the peak reached 1.4C before declining to 0.9 August 2026.  An annual chart below is informative:

 

Note the difference between blue/green years, beige/brown, and purple/red years.  2010, 2021, 2022 all peaked strongly in August or September.  1998 and 2007 were mildly warm.  2016 and 2018 were matching or cooler than the global average.  2023 started out slightly warm, then rose steadily to an  extraordinary peak in July.  August to October were only slightly lower, but by December cooled by ~0.4C.

Then in 2024 the AMO anomaly started higher than any previous year, then leveled off for two months declining slightly into April.  Remarkably, May showed an upward leap putting this on a higher track than 2023, and rising slightly higher in June.  In July, August and September 2024 the anomaly declined, and despite a small rise in October, ended close to where it began.  Note 2025 started much lower than the previous year and headed sharply downward, well below the previous two years, then since April through September aligning with 2010. In October there was an unusual upward spike, now reversed down to match 2022 and 2016.  The orange 2026 line continues downward and is visible on top of 2016 purple line, well below the peak years of 2023 and 2024.

The pattern suggests the ocean may be demonstrating a stairstep pattern like that we have also seen in HadCRUT4.

The rose line is the average anomaly 1982-1996 inclusive, value 0.18.  The orange line the average 1982-2025, value 0.41 also for the period 1997-2012. The red line is 2015-2025, value 0.74. As noted above, these rising stages are driven by the combined warming in the Tropics and NH, including both Pacific and Atlantic basins.

Curiosity:  Solar Coincidence?

The news about our current solar cycle 25 is that the solar activity is hitting peak numbers now and higher  than expected 1-2 years in the future.  As livescience put it:  Solar maximum could hit us harder and sooner than we thought. How dangerous will the sun’s chaotic peak be?  Some charts from spaceweatherlive look familar to these sea surface temperature charts.

Summary

The oceans are driving the warming this century.  SSTs took a step up with the 1998 El Nino and have stayed there with help from the North Atlantic, and more recently the Pacific northern “Blob.”  The ocean surfaces are releasing a lot of energy, warming the air, but eventually will have a cooling effect.  The decline after 1937 was rapid by comparison, so one wonders: How long can the oceans keep this up? And is the sun adding forcing to this process?

uss-pearl-harbor-deploys-global-drifter-buoys-in-pacific-ocean

USS Pearl Harbor deploys Global Drifter Buoys in Pacific Ocean

February 2026 NH and Tropic SSTs Warm Slightly

Posted on by Ron Clutz

The best context for understanding decadal temperature changes comes from the world’s sea surface temperatures (SST), for several reasons:

  • The ocean covers 71% of the globe and drives average temperatures;
  • SSTs have a constant water content, (unlike air temperatures), so give a better reading of heat content variations;
  • A major El Nino was the dominant climate feature in recent years.

Previously I used HadSST3 for these reports, but Hadley Centre has made HadSST4 the priority, and v.3 will no longer be updated.  This February report is based on HadSST 4, but with a twist. The data is slightly different in the new version, 4.2.0.0 replacing 4.1.1.0. Product page is here.

The Current Context

The chart below shows SST monthly anomalies as reported in HadSST 4.2 starting in 2015 through February 2026. A global cooling pattern is seen clearly in the Tropics since its peak in 2016, joined by NH and SH cycling downward since 2016, followed by rising temperatures in 2023 and 2024 and cooling in 2025, now with a small bump upward in 2026.

Note that in 2015-2016 the Tropics and SH peaked in between two summer NH spikes.  That pattern repeated in 2019-2020 with a lesser Tropics peak and SH bump, but with higher NH spikes. By end of 2020, cooler SSTs in all regions took the Global anomaly well below the mean for this period.  A small warming was driven by NH summer peaks in 2021-22, but offset by cooling in SH and the tropics, By January 2023 the global anomaly was again below the mean.

Then in 2023-24 came an event resembling 2015-16 with a Tropical spike and two NH spikes alongside, all higher than 2015-16. There was also a coinciding rise in SH, and the Global anomaly was pulled up to 1.1°C in 2023, ~0.3° higher than the 2015 peak.  Then NH started down autumn 2023, followed by Tropics and SH descending 2024 to the present. During 2 years of cooling in SH and the Tropics, the Global anomaly came back down, led by Tropics cooling from its 1.3°C peak 2024/01, down to 0.6C in September this year. Note the smaller peak in NH in July 2025 now declining along with SH and the Global anomaly cooler as well. In December the Global anomaly exactly matched the mean for this period, with all regions converging on that value, led by a 6 month drop in NH.  Essentially, all the warming since 2015 was gone, with a slight warming starting 2026.

Comment:

The climatists have seized on this unusual warming as proof their Zero Carbon agenda is needed, without addressing how impossible it would be for CO2 warming the air to raise ocean temperatures.  It is the ocean that warms the air, not the other way around.  Recently Steven Koonin had this to say about the phonomenon confirmed in the graph above:

El Nino is a phenomenon in the climate system that happens once every four or five years.  Heat builds up in the equatorial Pacific to the west of Indonesia and so on.  Then when enough of it builds up it surges across the Pacific and changes the currents and the winds.  As it surges toward South America it was discovered and named in the 19th century  It iswell understood at this point that the phenomenon has nothing to do with CO2.

Now people talk about changes in that phenomena as a result of CO2 but it’s there in the climate system already and when it happens it influences weather all over the world.   We feel it when it gets rainier in Southern California for example.  So for the last 3 years we have been in the opposite of an El Nino, a La Nina, part of the reason people think the West Coast has been in drought.

It has now shifted in the last months to an El Nino condition that warms the globe and is thought to contribute to this Spike we have seen. But there are other contributions as well.  One of the most surprising ones is that back in January of 2022 an enormous underwater volcano went off in Tonga and it put up a lot of water vapor into the upper atmosphere. It increased the upper atmosphere of water vapor by about 10 percent, and that’s a warming effect, and it may be that is contributing to why the spike is so high.

A longer view of SSTs

To enlarge, open image in new tab.

The graph above is noisy, but the density is needed to see the seasonal patterns in the oceanic fluctuations.  Previous posts focused on the rise and fall of the last El Nino starting in 2015.  This post adds a longer view, encompassing the significant 1998 El Nino and since.  The color schemes are retained for Global, Tropics, NH and SH anomalies.  Despite the longer time frame, I have kept the monthly data (rather than yearly averages) because of interesting shifts between January and July. 1995 is a reasonable (ENSO neutral) starting point prior to the first El Nino.

The sharp Tropical rise peaking in 1998 was dominant in the record, starting Jan. ’97 to pull up SSTs uniformly before returning to the same level Jan. ’99. There were strong cool periods before and after the 1998 El Nino event. Then SSTs in all regions returned to the mean in 2001-2.

SSTS fluctuate around the mean until 2007, when another, smaller ENSO event occurs. There is cooling 2007-8,  a lower peak warming in 2009-10, following by cooling in 2011-12.  Again SSTs are average 2013-14.

Now a different pattern appears.  The Tropics cooled sharply to Jan 11, then rise steadily for 4 years to Jan 15, at which point the most recent major El Nino takes off.  But this time in contrast to ’97-’99, the Northern Hemisphere produces peaks every summer pulling up the Global average.  In fact, these NH peaks appear every July starting in 2003, growing stronger to produce 3 massive highs in 2014, 15 and 16.  NH July 2017 was only slightly lower, and a fifth NH peak still lower in Sept. 2018.

The highest summer NH peaks came in 2019 and 2020, only this time the Tropics and SH were offsetting rather adding to the warming. (Note: these are high anomalies on top of the highest absolute temps in the NH.)  Since 2014 SH has played a moderating role, offsetting the NH warming pulses. After September 2020 temps dropped off down until February 2021.  In 2021-22 there were again summer NH spikes, but in 2022 moderated first by cooling Tropics and SH SSTs, then in October to January 2023 by deeper cooling in NH and Tropics.

Then in 2023 the Tropics flipped from below to well above average, while NH produced a summer peak extending into September higher than any previous year.  Despite El Nino driving the Tropics January 2024 anomaly higher than 1998 and 2016 peaks, following months cooled in all regions, and the Tropics continued cooling in April, May and June along with SH dropping.  After July and August NH warming again pulled the global anomaly higher, September through January 2025 resumed cooling in all regions, continuing February through April 2025, with little change in May,June and July despite upward bumps in NH. Now temps in all regions have cooled led by NH from August through December 2025. A slight warming in 2026 is led by SH and Tropics.

What to make of all this? The patterns suggest that in addition to El Ninos in the Pacific driving the Tropic SSTs, something else is going on in the NH.  The obvious culprit is the North Atlantic, since I have seen this sort of pulsing before.  After reading some papers by David Dilley, I confirmed his observation of Atlantic pulses into the Arctic every 8 to 10 years.

Contemporary AMO Observations

Through January 2023 I depended on the Kaplan AMO Index (not smoothed, not detrended) for N. Atlantic observations. But it is no longer being updated, and NOAA says they don’t know its future.  So I find that ERSSTv5 AMO dataset has current data.  It differs from Kaplan, which reported average absolute temps measured in N. Atlantic.  “ERSST5 AMO  follows Trenberth and Shea (2006) proposal to use the NA region EQ-60°N, 0°-80°W and subtract the global rise of SST 60°S-60°N to obtain a measure of the internal variability, arguing that the effect of external forcing on the North Atlantic should be similar to the effect on the other oceans.”  So the values represent SST anomaly differences between the N. Atlantic and the Global ocean.

The chart above confirms what Kaplan also showed.  As August is the hottest month for the N. Atlantic, its variability, high and low, drives the annual results for this basin.  Note also the peaks in 2010, lows after 2014, and a rise in 2021. Then in 2023 the peak reached 1.4C before declining to 0.9 August 2026.  An annual chart below is informative:

Note the difference between blue/green years, beige/brown, and purple/red years.  2010, 2021, 2022 all peaked strongly in August or September.  1998 and 2007 were mildly warm.  2016 and 2018 were matching or cooler than the global average.  2023 started out slightly warm, then rose steadily to an  extraordinary peak in July.  August to October were only slightly lower, but by December cooled by ~0.4C.

Then in 2024 the AMO anomaly started higher than any previous year, then leveled off for two months declining slightly into April.  Remarkably, May showed an upward leap putting this on a higher track than 2023, and rising slightly higher in June.  In July, August and September 2024 the anomaly declined, and despite a small rise in October, ended close to where it began.  Note 2025 started much lower than the previous year and headed sharply downward, well below the previous two years, then since April through September aligning with 2010. In October there was an unusual upward spike, now reversed down to match 2022 and 2016.  The orange 2026 line continues downward and is visible on top of 2016 purple line.

The pattern suggests the ocean may be demonstrating a stairstep pattern like that we have also seen in HadCRUT4.

The rose line is the average anomaly 1982-1996 inclusive, value 0.18.  The orange line the average 1982-2025, value 0.41 also for the period 1997-2012. The red line is 2015-2025, value 0.74. As noted above, these rising stages are driven by the combined warming in the Tropics and NH, including both Pacific and Atlantic basins.

Curiosity:  Solar Coincidence?

The news about our current solar cycle 25 is that the solar activity is hitting peak numbers now and higher  than expected 1-2 years in the future.  As livescience put it:  Solar maximum could hit us harder and sooner than we thought. How dangerous will the sun’s chaotic peak be?  Some charts from spaceweatherlive look familar to these sea surface temperature charts.

Summary

The oceans are driving the warming this century.  SSTs took a step up with the 1998 El Nino and have stayed there with help from the North Atlantic, and more recently the Pacific northern “Blob.”  The ocean surfaces are releasing a lot of energy, warming the air, but eventually will have a cooling effect.  The decline after 1937 was rapid by comparison, so one wonders: How long can the oceans keep this up? And is the sun adding forcing to this process?

uss-pearl-harbor-deploys-global-drifter-buoys-in-pacific-ocean

USS Pearl Harbor deploys Global Drifter Buoys in Pacific Ocean

January 2026 Ocean SSTs Warm Slightly

Posted on by Ron Clutz

The best context for understanding decadal temperature changes comes from the world’s sea surface temperatures (SST), for several reasons:

  • The ocean covers 71% of the globe and drives average temperatures;
  • SSTs have a constant water content, (unlike air temperatures), so give a better reading of heat content variations;
  • A major El Nino was the dominant climate feature in recent years.

Previously I used HadSST3 for these reports, but Hadley Centre has made HadSST4 the priority, and v.3 will no longer be updated.  This January report is based on HadSST 4, but with a twist. The data is slightly different in the new version, 4.2.0.0 replacing 4.1.1.0. Product page is here.

The Current Context

The chart below shows SST monthly anomalies as reported in HadSST 4.2 starting in 2015 through January 2026. A global cooling pattern is seen clearly in the Tropics since its peak in 2016, joined by NH and SH cycling downward since 2016, followed by rising temperatures in 2023 and 2024 and cooling in 2025, now with a small bump upward.

Note that in 2015-2016 the Tropics and SH peaked in between two summer NH spikes.  That pattern repeated in 2019-2020 with a lesser Tropics peak and SH bump, but with higher NH spikes. By end of 2020, cooler SSTs in all regions took the Global anomaly well below the mean for this period.  A small warming was driven by NH summer peaks in 2021-22, but offset by cooling in SH and the tropics, By January 2023 the global anomaly was again below the mean.

Then in 2023-24 came an event resembling 2015-16 with a Tropical spike and two NH spikes alongside, all higher than 2015-16. There was also a coinciding rise in SH, and the Global anomaly was pulled up to 1.1°C in 2023, ~0.3° higher than the 2015 peak.  Then NH started down autumn 2023, followed by Tropics and SH descending 2024 to the present. During 2 years of cooling in SH and the Tropics, the Global anomaly came back down, led by Tropics cooling from its 1.3°C peak 2024/01, down to 0.6C in September this year. Note the smaller peak in NH in July 2025 now declining along with SH and the Global anomaly cooler as well. In December the Global anomaly exactly matched the mean for this period, with all regions converging on that value, led by a 6 month drop in NH.  Essentially, all the warming since 2015 was gone, with a slight warming starting 2026.

Comment:

The climatists have seized on this unusual warming as proof their Zero Carbon agenda is needed, without addressing how impossible it would be for CO2 warming the air to raise ocean temperatures.  It is the ocean that warms the air, not the other way around.  Recently Steven Koonin had this to say about the phonomenon confirmed in the graph above:

El Nino is a phenomenon in the climate system that happens once every four or five years.  Heat builds up in the equatorial Pacific to the west of Indonesia and so on.  Then when enough of it builds up it surges across the Pacific and changes the currents and the winds.  As it surges toward South America it was discovered and named in the 19th century  It iswell understood at this point that the phenomenon has nothing to do with CO2.

Now people talk about changes in that phenomena as a result of CO2 but it’s there in the climate system already and when it happens it influences weather all over the world.   We feel it when it gets rainier in Southern California for example.  So for the last 3 years we have been in the opposite of an El Nino, a La Nina, part of the reason people think the West Coast has been in drought.

It has now shifted in the last months to an El Nino condition that warms the globe and is thought to contribute to this Spike we have seen. But there are other contributions as well.  One of the most surprising ones is that back in January of 2022 an enormous underwater volcano went off in Tonga and it put up a lot of water vapor into the upper atmosphere. It increased the upper atmosphere of water vapor by about 10 percent, and that’s a warming effect, and it may be that is contributing to why the spike is so high.

A longer view of SSTs

To enlarge, open image in new tab.

The graph above is noisy, but the density is needed to see the seasonal patterns in the oceanic fluctuations.  Previous posts focused on the rise and fall of the last El Nino starting in 2015.  This post adds a longer view, encompassing the significant 1998 El Nino and since.  The color schemes are retained for Global, Tropics, NH and SH anomalies.  Despite the longer time frame, I have kept the monthly data (rather than yearly averages) because of interesting shifts between January and July. 1995 is a reasonable (ENSO neutral) starting point prior to the first El Nino.

The sharp Tropical rise peaking in 1998 was dominant in the record, starting Jan. ’97 to pull up SSTs uniformly before returning to the same level Jan. ’99. There were strong cool periods before and after the 1998 El Nino event. Then SSTs in all regions returned to the mean in 2001-2.

SSTS fluctuate around the mean until 2007, when another, smaller ENSO event occurs. There is cooling 2007-8,  a lower peak warming in 2009-10, following by cooling in 2011-12.  Again SSTs are average 2013-14.

Now a different pattern appears.  The Tropics cooled sharply to Jan 11, then rise steadily for 4 years to Jan 15, at which point the most recent major El Nino takes off.  But this time in contrast to ’97-’99, the Northern Hemisphere produces peaks every summer pulling up the Global average.  In fact, these NH peaks appear every July starting in 2003, growing stronger to produce 3 massive highs in 2014, 15 and 16.  NH July 2017 was only slightly lower, and a fifth NH peak still lower in Sept. 2018.

The highest summer NH peaks came in 2019 and 2020, only this time the Tropics and SH were offsetting rather adding to the warming. (Note: these are high anomalies on top of the highest absolute temps in the NH.)  Since 2014 SH has played a moderating role, offsetting the NH warming pulses. After September 2020 temps dropped off down until February 2021.  In 2021-22 there were again summer NH spikes, but in 2022 moderated first by cooling Tropics and SH SSTs, then in October to January 2023 by deeper cooling in NH and Tropics.

Then in 2023 the Tropics flipped from below to well above average, while NH produced a summer peak extending into September higher than any previous year.  Despite El Nino driving the Tropics January 2024 anomaly higher than 1998 and 2016 peaks, following months cooled in all regions, and the Tropics continued cooling in April, May and June along with SH dropping.  After July and August NH warming again pulled the global anomaly higher, September through January 2025 resumed cooling in all regions, continuing February through April 2025, with little change in May,June and July despite upward bumps in NH. Now temps in all regions have cooled led by NH from August through December 2025.

What to make of all this? The patterns suggest that in addition to El Ninos in the Pacific driving the Tropic SSTs, something else is going on in the NH.  The obvious culprit is the North Atlantic, since I have seen this sort of pulsing before.  After reading some papers by David Dilley, I confirmed his observation of Atlantic pulses into the Arctic every 8 to 10 years.

Contemporary AMO Observations

Through January 2023 I depended on the Kaplan AMO Index (not smoothed, not detrended) for N. Atlantic observations. But it is no longer being updated, and NOAA says they don’t know its future.  So I find that ERSSTv5 AMO dataset has current data.  It differs from Kaplan, which reported average absolute temps measured in N. Atlantic.  “ERSST5 AMO  follows Trenberth and Shea (2006) proposal to use the NA region EQ-60°N, 0°-80°W and subtract the global rise of SST 60°S-60°N to obtain a measure of the internal variability, arguing that the effect of external forcing on the North Atlantic should be similar to the effect on the other oceans.”  So the values represent SST anomaly differences between the N. Atlantic and the Global ocean.

The chart above confirms what Kaplan also showed.  As August is the hottest month for the N. Atlantic, its variability, high and low, drives the annual results for this basin.  Note also the peaks in 2010, lows after 2014, and a rise in 2021. Then in 2023 the peak reached 1.4C before declining to 0.9 last month.  An annual chart below is informative:

Note the difference between blue/green years, beige/brown, and purple/red years.  2010, 2021, 2022 all peaked strongly in August or September.  1998 and 2007 were mildly warm.  2016 and 2018 were matching or cooler than the global average.  2023 started out slightly warm, then rose steadily to an  extraordinary peak in July.  August to October were only slightly lower, but by December cooled by ~0.4C.

Then in 2024 the AMO anomaly started higher than any previous year, then leveled off for two months declining slightly into April.  Remarkably, May showed an upward leap putting this on a higher track than 2023, and rising slightly higher in June.  In July, August and September 2024 the anomaly declined, and despite a small rise in October, ended close to where it began.  Note 2025 started much lower than the previous year and headed sharply downward, well below the previous two years, then since April through September aligning with 2010. In October there was an unusual upward spike, now reversed down to match 2022 and 2016.  An orange dot on the left axis represents the value of 0.71C for January 2026

The pattern suggests the ocean may be demonstrating a stairstep pattern like that we have also seen in HadCRUT4.

The rose line is the average anomaly 1982-1996 inclusive, value 0.18.  The orange line the average 1982-2025, value 0.41 also for the period 1997-2012. The red line is 2015-2025, value 0.74. As noted above, these rising stages are driven by the combined warming in the Tropics and NH, including both Pacific and Atlantic basins.

Curiosity:  Solar Coincidence?

The news about our current solar cycle 25 is that the solar activity is hitting peak numbers now and higher  than expected 1-2 years in the future.  As livescience put it:  Solar maximum could hit us harder and sooner than we thought. How dangerous will the sun’s chaotic peak be?  Some charts from spaceweatherlive look familar to these sea surface temperature charts.

Summary

The oceans are driving the warming this century.  SSTs took a step up with the 1998 El Nino and have stayed there with help from the North Atlantic, and more recently the Pacific northern “Blob.”  The ocean surfaces are releasing a lot of energy, warming the air, but eventually will have a cooling effect.  The decline after 1937 was rapid by comparison, so one wonders: How long can the oceans keep this up? And is the sun adding forcing to this process?

uss-pearl-harbor-deploys-global-drifter-buoys-in-pacific-ocean

USS Pearl Harbor deploys Global Drifter Buoys in Pacific Ocean

December 2025 All Ocean SSTs Cool to Mean

Posted on by Ron Clutz

The best context for understanding decadal temperature changes comes from the world’s sea surface temperatures (SST), for several reasons:

  • The ocean covers 71% of the globe and drives average temperatures;
  • SSTs have a constant water content, (unlike air temperatures), so give a better reading of heat content variations;
  • A major El Nino was the dominant climate feature in recent years.

Previously I used HadSST3 for these reports, but Hadley Centre has made HadSST4 the priority, and v.3 will no longer be updated. I’ve grown weary of waiting each month for HadSST4 updates, so the July and August reports were based on data from OISST2.1.  This dataset uses the same in situ sources as HadSST along with satellite indicators. Now however, the US government is shut down and updates to climate datasets are likely to be delayed.  Reminds of what hospitals do when their budgets are slashed: They close the Maternity Ward to get public attention.

This December report is based again on HadSST 4, but with a twist. The data is slightly different in the new version, 4.2.0.0 replacing 4.1.1.0. Product page is here.

The Current Context

The chart below shows SST monthly anomalies as reported in HadSST 4.2 starting in 2015 through December 2025. A global cooling pattern is seen clearly in the Tropics since its peak in 2016, joined by NH and SH cycling downward since 2016, followed by rising temperatures in 2023 and 2024 and cooling in 2025.

Note that in 2015-2016 the Tropics and SH peaked in between two summer NH spikes.  That pattern repeated in 2019-2020 with a lesser Tropics peak and SH bump, but with higher NH spikes. By end of 2020, cooler SSTs in all regions took the Global anomaly well below the mean for this period.  A small warming was driven by NH summer peaks in 2021-22, but offset by cooling in SH and the tropics, By January 2023 the global anomaly was again below the mean.

Then in 2023-24 came an event resembling 2015-16 with a Tropical spike and two NH spikes alongside, all higher than 2015-16. There was also a coinciding rise in SH, and the Global anomaly was pulled up to 1.1°C in 2023, ~0.3° higher than the 2015 peak.  Then NH started down autumn 2023, followed by Tropics and SH descending 2024 to the present. During 2 years of cooling in SH and the Tropics, the Global anomaly came back down, led by Tropics cooling from its 1.3°C peak 2024/01, down to 0.6C in September this year. Note the smaller peak in NH in July 2025 now declining along with SH and the Global anomaly cooler as well. In December the Global anomaly exactly matched the mean for this period, with all regions converging on that value, led by a 6 month drop in NH.  Essentially, all the warming since 2015 is now gone.

Comment:

The climatists have seized on this unusual warming as proof their Zero Carbon agenda is needed, without addressing how impossible it would be for CO2 warming the air to raise ocean temperatures.  It is the ocean that warms the air, not the other way around.  Recently Steven Koonin had this to say about the phonomenon confirmed in the graph above:

El Nino is a phenomenon in the climate system that happens once every four or five years.  Heat builds up in the equatorial Pacific to the west of Indonesia and so on.  Then when enough of it builds up it surges across the Pacific and changes the currents and the winds.  As it surges toward South America it was discovered and named in the 19th century  It iswell understood at this point that the phenomenon has nothing to do with CO2.

Now people talk about changes in that phenomena as a result of CO2 but it’s there in the climate system already and when it happens it influences weather all over the world.   We feel it when it gets rainier in Southern California for example.  So for the last 3 years we have been in the opposite of an El Nino, a La Nina, part of the reason people think the West Coast has been in drought.

It has now shifted in the last months to an El Nino condition that warms the globe and is thought to contribute to this Spike we have seen. But there are other contributions as well.  One of the most surprising ones is that back in January of 2022 an enormous underwater volcano went off in Tonga and it put up a lot of water vapor into the upper atmosphere. It increased the upper atmosphere of water vapor by about 10 percent, and that’s a warming effect, and it may be that is contributing to why the spike is so high.

A longer view of SSTs

To enlarge, open image in new tab.

The graph above is noisy, but the density is needed to see the seasonal patterns in the oceanic fluctuations.  Previous posts focused on the rise and fall of the last El Nino starting in 2015.  This post adds a longer view, encompassing the significant 1998 El Nino and since.  The color schemes are retained for Global, Tropics, NH and SH anomalies.  Despite the longer time frame, I have kept the monthly data (rather than yearly averages) because of interesting shifts between January and July. 1995 is a reasonable (ENSO neutral) starting point prior to the first El Nino.

The sharp Tropical rise peaking in 1998 is dominant in the record, starting Jan. ’97 to pull up SSTs uniformly before returning to the same level Jan. ’99. There were strong cool periods before and after the 1998 El Nino event. Then SSTs in all regions returned to the mean in 2001-2.

SSTS fluctuate around the mean until 2007, when another, smaller ENSO event occurs. There is cooling 2007-8,  a lower peak warming in 2009-10, following by cooling in 2011-12.  Again SSTs are average 2013-14.

Now a different pattern appears.  The Tropics cooled sharply to Jan 11, then rise steadily for 4 years to Jan 15, at which point the most recent major El Nino takes off.  But this time in contrast to ’97-’99, the Northern Hemisphere produces peaks every summer pulling up the Global average.  In fact, these NH peaks appear every July starting in 2003, growing stronger to produce 3 massive highs in 2014, 15 and 16.  NH July 2017 was only slightly lower, and a fifth NH peak still lower in Sept. 2018.

The highest summer NH peaks came in 2019 and 2020, only this time the Tropics and SH were offsetting rather adding to the warming. (Note: these are high anomalies on top of the highest absolute temps in the NH.)  Since 2014 SH has played a moderating role, offsetting the NH warming pulses. After September 2020 temps dropped off down until February 2021.  In 2021-22 there were again summer NH spikes, but in 2022 moderated first by cooling Tropics and SH SSTs, then in October to January 2023 by deeper cooling in NH and Tropics.

Then in 2023 the Tropics flipped from below to well above average, while NH produced a summer peak extending into September higher than any previous year.  Despite El Nino driving the Tropics January 2024 anomaly higher than 1998 and 2016 peaks, following months cooled in all regions, and the Tropics continued cooling in April, May and June along with SH dropping.  After July and August NH warming again pulled the global anomaly higher, September through January 2025 resumed cooling in all regions, continuing February through April 2025, with little change in May,June and July despite upward bumps in NH. Now temps in all regions have cooled led by NH from August through December 2025.

What to make of all this? The patterns suggest that in addition to El Ninos in the Pacific driving the Tropic SSTs, something else is going on in the NH.  The obvious culprit is the North Atlantic, since I have seen this sort of pulsing before.  After reading some papers by David Dilley, I confirmed his observation of Atlantic pulses into the Arctic every 8 to 10 years.

Contemporary AMO Observations

Through January 2023 I depended on the Kaplan AMO Index (not smoothed, not detrended) for N. Atlantic observations. But it is no longer being updated, and NOAA says they don’t know its future.  So I find that ERSSTv5 AMO dataset has current data.  It differs from Kaplan, which reported average absolute temps measured in N. Atlantic.  “ERSST5 AMO  follows Trenberth and Shea (2006) proposal to use the NA region EQ-60°N, 0°-80°W and subtract the global rise of SST 60°S-60°N to obtain a measure of the internal variability, arguing that the effect of external forcing on the North Atlantic should be similar to the effect on the other oceans.”  So the values represent SST anomaly differences between the N. Atlantic and the Global ocean.

The chart above confirms what Kaplan also showed.  As August is the hottest month for the N. Atlantic, its variability, high and low, drives the annual results for this basin.  Note also the peaks in 2010, lows after 2014, and a rise in 2021. Then in 2023 the peak reached 1.4C before declining to 0.9 last month.  An annual chart below is informative:

 

Note the difference between blue/green years, beige/brown, and purple/red years.  2010, 2021, 2022 all peaked strongly in August or September.  1998 and 2007 were mildly warm.  2016 and 2018 were matching or cooler than the global average.  2023 started out slightly warm, then rose steadily to an  extraordinary peak in July.  August to October were only slightly lower, but by December cooled by ~0.4C.

Then in 2024 the AMO anomaly started higher than any previous year, then leveled off for two months declining slightly into April.  Remarkably, May showed an upward leap putting this on a higher track than 2023, and rising slightly higher in June.  In July, August and September 2024 the anomaly declined, and despite a small rise in October, ended close to where it began.  Note 2025 started much lower than the previous year and headed sharply downward, well below the previous two years, then since April through September aligning with 2010. In October there was an unusual upward spike, now reversed down to match September 2025.

The pattern suggests the ocean may be demonstrating a stairstep pattern like that we have also seen in HadCRUT4.

The rose line is the average anomaly 1982-1996 inclusive, value 0.18.  The orange line the average 1982-2025, value 0.41 also for the period 1997-2012. The red line is 2015-2025, value 0.74. As noted above, these rising stages are driven by the combined warming in the Tropics and NH, including both Pacific and Atlantic basins.

Curiosity:  Solar Coincidence?

The news about our current solar cycle 25 is that the solar activity is hitting peak numbers now and higher  than expected 1-2 years in the future.  As livescience put it:  Solar maximum could hit us harder and sooner than we thought. How dangerous will the sun’s chaotic peak be?  Some charts from spaceweatherlive look familar to these sea surface temperature charts.

Summary

The oceans are driving the warming this century.  SSTs took a step up with the 1998 El Nino and have stayed there with help from the North Atlantic, and more recently the Pacific northern “Blob.”  The ocean surfaces are releasing a lot of energy, warming the air, but eventually will have a cooling effect.  The decline after 1937 was rapid by comparison, so one wonders: How long can the oceans keep this up? And is the sun adding forcing to this process?

uss-pearl-harbor-deploys-global-drifter-buoys-in-pacific-ocean

USS Pearl Harbor deploys Global Drifter Buoys in Pacific Ocean

Slam Dunk: Δtemp Drives Δco2, Ocean Biochemistry at Work

Posted on by Ron Clutz

Peter Smith explains in his Quadrant article Shunned by Sanctitudinous Science.  Excerpts in italics with my bolds and added images.  Synopsis of Ivan Kennedy paper follows later.

When coffeeing with a group of conservative friends as I do on Fridays, one of our number, Professor Emeritus Ivan Kennedy, said something to the effect that there were no scientific alternative theories to the IPCC’s explanation of global warming except for his.

I was taken aback. Surely, even within my limited knowledge, William Happer (Princeton) and Richard Lindzen (MIT) hypothesise that the effect of CO2 on warming progressively declines. Nobel Prize winner Dr John Clauser hypothesises that reflective cumulus clouds created by water vapour, engendered by modest warming, act as a thermostat to keep global temperatures down. You can read about it here if you wish. So what is going on?

Let me start by dismissing the canard that global warming is an invention. Sure, maybe the so-called ‘homogenisation’ of past land and sea temperature data has artificially steepened the warming record since the 1940s. But, for all that, the NOAA satellite data since the end of 1979 shows that the temperature in the sub-troposphere has trended up by about 0.7⁰C between December 1979 and December 2024. As this data has been compiled by Roy Spencer and John Christy (sceptical scientists) at the University of Alamba in Huntsville, we can safely assume it is trustworthy.

So the climate has warmed. Now should come the scientific fun.
Competing theories jostling to best explain the data. No such fun.
Blaming exploitative Western man has proved to be a sacrosanct hypothesis.

Sacrosanctity and science don’t mix. Many past theories propounded by scientific giants have eventually failed the test: Ptolemy’s geocentric theory of the solar system; Aristotle’s theory of gravity, even Newton’s. Yet a tenuous theory of the climate concocted by relative mediocrities, which hasn’t come close to accurately predicting global temperatures, is holy writ. Risible, except that political and celebrity buy-in is undoing progress wherever it results in the replacement of reliable with unreliable energy. Think of Australia as a quintessential case study.

Happily, despite powerful and well-funded forces out to cancel dissenters, maverick scientists keep on stirring the pot. Which brings me back to Prof. Kennedy and his collaborators. Their hypothesis can be found here. In lay terms it goes like this:

The increased concentration of CO2 in the atmosphere since the 1960s has been caused by warming not the reverse. Other things equal, emissions by mankind of CO2 are all absorbed by the land (hence the greening) and by the oceans. Thus, on this account, there is no material net increase of CO2 in the atmosphere from fossil fuel emissions. Ergo, such emissions cannot be the cause of warming. It is true that warming has occurred, and that atmospheric CO2 has risen. The underlying chain of events is as follows.

Warming, perhaps through solar activity, promotes the precipitation of calcium carbonate (limestone) in surface sea water, absorbing CO2 from the atmosphere in the process. In turn, the absorbed CO2, magnified by calcium carbonate precipitation, acidifies surface sea water. The acidification then results in the emission of CO2 into the atmosphere in autumn and winter. This emission of CO2 is greater than the absorption, precisely because of the continuing acidification in the warming water.

In the end we see increased atmospheric CO2 and warming.
It is easy to draw the wrong conclusion. Indeed, the IPCC has done so.

I see the point about Kennedy’s hypothesis being singularly different from other alternative hypotheses. Lindzen’s and Happer’s hypothesis, and Clauser’s, embrace the foundational proposition of the received theory, albeit in muted form. Namely, that man-made CO2 is adding to atmospheric CO2, thereby having a greenhouse effect. Kennedy’s hypothesis does not embrace that proposition.

Whether Kennedy is right (or Lindzen and Happer or Clauser) is by the way. Alternative hypotheses are in the skeptical scientific tradition of searching for theories which better explain the facts than does the received theory. That is particularly important in this case. The received theory is upending life as we know it, while being shielded from rival theories by money, politics and pseudo-religiosity.

The paper by Ivan Kennedy et al. is A Thermal Acid Calcification Cause for Seasonal Oscillations in the Increasing Keeling Curve . Synopsis below with excerpts in italics with my bolds and added images.

Abstract:

Why do atmospheric carbon dioxide levels rise and fall seasonally measured on Mauna Loa? This study explores the thermal acid-calcification (TAC) hypothesis, suggesting that seasonal temperature shifts in surface seawater trigger acid pH-driven CO₂ emissions caused by calcification. Using oceanographic data, we modeled how temperature affects dissolved inorganic carbon including CO₂, bicarbonate, and carbonate.

Our findings reveal that warming waters absorb atmospheric CO2 by promoting calcium carbonate formation, acidifying seawater and boosting CO₂ release to the atmosphere in late autumn and winter, when atmospheric CO₂ becomes highest. The model predicts a net annual CO₂ rise of 2 ppmv, driven by calcification rather than land-based processes. Seasonal pH swings of 0.04 units corroborate this mechanism. The TAC hypothesis indicates that continued ocean warming, not just fossil fuels, contribute to rising CO₂ levels, calling for deeper investigation into marine carbon dynamics.

The Keeling Curve for atmospheric pCO2 in parts per million by volume

Fig. 1. The Keeling curve of atmospheric CO2 partial pressure at 3200 m on Mauna Loa, Hawaii. Data from Dr. Pieter Tans, NOAA/ESRL and Dr.Ralph Keeling, Scripps Institution of Oceanography.CC BY-SA

The very stuff of plant life on Earth in photosynthesis as well as in the structural basis of all living creatures, we are told by the United Nations Intergovernmental Panel on Climate Change (IPCC) (2) that the continuing rise of CO2 in the Keeling curve shown in Figure 1 now threatens global catastrophe from global warming. Such a paradoxical contrast for good and bad lacks credibility, given the longevity of life on Earth.

Transfers of CO2 out of the ocean surface in winter versus that entering in summer

We propose that a quasi-equilibrium exists between a falling pH value in surface water, favoring CO2 emisssion. Falling pH values in the surface water of the oceans have been an enigma, invisible to scientific view until recently after the year 2000. Our logic is supported in our articles (3, 4) where we describe the basis for the thermal acid-calcification (TAC) hypothesis, also using data cited from others. Acidic calcification is thermodynamically favored in warming surface seawater, particularly in northern oceans in spring and summer with shallow mixing zones and higher temperature ranges. This raises the fugacity or potential pressure of CO2 in seawater to its peak value in summer when the pCO2 in air is minimal, causing its forceful emission into air in the next autumn reaching a maximum pCO2 in late winter (Fig. 1, seasonal variation insert). 

Fig. 2. Thermal acid-calcification model for seasonal and longer-term generation of the Keeling curve. The Thermal model (3), showed calcification is favored by increase in temperature giving decreasing pH values in summer, reversing in cooler conditions to more alkaline pH in winter. Note that precipitation of CaCO3 in spring to summer removes CO32- that is replaced from HCO3 – with more acidity, provided by absorption of CO2 from air up to October. However, as the pH falls the steady state concentration of [CO2} increases favoring photosynthesis.

Acid calcification is essential for phytoplankton

Any process of strong acidification of surface seawater will raise the concentration of carbon dioxide as [CO2] available to phytoplankton for photosynthesis. Bicarbonate cannot be a direct substrate for photosynthesis although the presence of the enzyme carbonic anhydrase speeds up its interconversion with CO2. Our published modeling analysis confirmed that CaCO3 precipitation is strongly favored by warmer temperatures (Table 1). Indeed, all the reaction equilibria in seawater are displaced to the right in Figure 2 acidifying the water, although the equilibrium between CO2 concentration and pCO2 in air favors a lower concentration [CO2} in water in summer, compared to winter, when it is greatest. Our results even confirmed that the formation of CaCO3 as calcite is predicted to increase in summer as water becomes warmer (Table 1b).

Thus, we can expect more limestone formation in summer if the carbonate concentration reaches a sufficient level, favored by added warming. The decline in average pH values in surface seawater to about 8.05 from pH 8.20 could explain the increased pCO2 in the atmosphere of 140 ppmv since 1800 as a matter of dynamic equilibrium. Caused by calcification, this would require a simultaneous equivalent deposition of limestone as sediment, though only an increase of about 10 μmoles per kg of surface seawater, or a net 1 mg per kg each year. This is a key prediction for experimental testing of the TAC hypothesis.

This fully reversible calcification equation moves towards acidification in summer and reverses to alkalinization in winter. The psi factor is a variable function of the range of seasonal changes in temperature. However, the greatest thermodynamic potential to emit CO2 in seawater by acidification of bicarbonate (HCO3-) is when the pH value is lowest, the conversion of bicarbonate to CO2 generating the greatest difference between CO2 fugacity in seawater and that in air in midsummer in northern hemisphere waters. The seasonal variation near Mauna Loa in atmospheric pCO2 is about 6 ppmv whereas the long term increase in the Keeling curve year by year is one third of this, about 2 ppmv suggesting that in spring and summer the CO2 absorbed in about 2 ppmv, less than that emitted in autumn and winter.

Fig. 5. Rates per square meter in global carbon cycling between land water, the atmosphere, and the ocean, illustrating the pH-acidification hypothesis. Emissions and absorptions shown are average moles per square meter of the Earth, for a mixing ratio of 420 ppmv in 2021 shown in the central column bridging land and ocean. The land acidification values are derived elsewhere (11), assuming photosynthesis is equal to respiration. The terrestrial area of Earth is 1.48×1014 m-2 , the ocean’s area is 3.62×1014 m2 , 5.101 x1014 m2 in total., represented as a mean value in the central air column.

Discussion

Limestone as a product of calcification is regarded as a biogeochemical product, given that phytoplankton and other marine organisms enhance its rate of production, if nutrients are available (3). In particular, the extracellular carbonic anhydrase apparently speeds the reversible dehydration of CO2, forming bicarbonate and hydrated hydrogen ions (H+) controlling pH. This article emphasizes that the reversible dehydration of CO2 in surface seawater allowing transfer between aqueous and gaseous phases is most rate limiting of all, that carbonic anhydrase may even assist in autumn and winter, transferring CO2 to the atmosphere.

More significantly for managing climate change, if fossil fuel emissions are being largely absorbed by sequestration into the ocean surface and by ‘greening’ photosynthesis on land and in the ocean (11), the implications of this aspect of the TAC hypothesis for carbon-zero policies and renewable energy are profound.

The thermal acid-calcification hypothesis predicts that global warming
acidifies the ocean surface by increasing calcification causing
pCO2 to increase, independently of fossil emissions.

Furthermore, this represents a striking illustration of the Le Chatelier principle, the carbon cycle on Earth responding intelligently to changing climate. The hope that carbon dioxide removal as sequestration (14), either biologically, chemically or geologically, by burial after capture, will prove futile. 

The uncertainty of the current IPCC paradigm regarding climate change and the role of fossil emissions of CO2 in warming is large, lacking scientific evidence. A plausible alternative hypothesis offered here as the true cause of the increasing Keeling curve needs to be investigated urgently. This new model would still give predictively increasing emissions from the ocean in the complete absence of fossil fuel emissions because the acidification from calcification is purely a function of surface warming, from whatever cause.

See Also

Yearend 2025, Cooling Temperatures Reducing CO2 Rise

Key Point

Changes in CO2 follow changes in global temperatures on all time scales, from last month’s observations to ice core datasets spanning millennia. Since CO2 is the lagging variable, it cannot logically be the cause of temperature, the leading variable. It is folly to imagine that by reducing human emissions of CO2, we can change global temperatures, which are obviously driven by other factors.

OISST Updates: Ocean SST Cooling Confirmed

Posted on by Ron Clutz

The best context for understanding decadal temperature changes comes from the world’s sea surface temperatures (SST), for several reasons:

  • The ocean covers 71% of the globe and drives average temperatures;
  • SSTs have a constant water content, (unlike air temperatures), so give a better reading of heat content variations;
  • A major El Nino was the dominant climate feature in recent years.

Recently I posted on SST data from HadSST4 since the US shutdown stopped other SST sources. Now OISST is back online, so this report is based on data from OISST2.1.  This dataset uses the same in situ sources as HadSST along with satellite indicators.  Importantly, it produces daily anomalies from baseline period 1991-2020.  The data is available at Climate Reanalyzer (here).  Product guide is (here).  The charts and analysis below is produced from the current data.

The Current Context

The chart below shows SST monthly anomalies as reported in OISST2.1 starting in 2015 through October 2025.  A global cooling pattern is seen clearly in the Tropics since its peak in 2016, joined by NH and SH cycling downward since 2016, followed by rising temperatures in 2023 and 2024 and cooling in 2025.

Note that in 2015-2016 the Tropics and SH peaked in between two summer NH spikes.  That pattern repeated in 2019-2020 with a lesser Tropics peak and SH bump, but with higher NH spikes. By end of 2020, cooler SSTs in all regions took the Global anomaly well below the mean for this period.  A small warming was driven by NH summer peaks in 2021-22, but offset by cooling in SH and the tropics, By January 2023 the global anomaly was again below the mean.

Then in 2023-24 came an event resembling 2015-16 with a Tropical spike and two NH spikes alongside, all higher than 2015-16. There was also a coinciding rise in SH, and the Global anomaly was pulled up to 0.6°C in 2023, ~0.2° higher than the 2015 peak.  Then NH started down autumn 2023, followed by Tropics and SH descending 2024 to the present. During nearly 2 years of cooling in SH and the Tropics, the Global anomaly came back down, led by Tropics cooling the last 22 months from its 0.9°C peak 2024/01 down to 0.26C in October this year. SH and NH also cooled Sept./Oct. pulling the Global anomaly down to 0.42C, just 0.1C above the average for this decadal period.

Comment:

The climatists have seized on this unusual warming as proof their Zero Carbon agenda is needed, without addressing how impossible it would be for CO2 warming the air to raise ocean temperatures.  It is the ocean that warms the air, not the other way around.  Recently Steven Koonin had this to say about the phonomenon confirmed in the graph above:

El Nino is a phenomenon in the climate system that happens once every four or five years.  Heat builds up in the equatorial Pacific to the west of Indonesia and so on.  Then when enough of it builds up it surges across the Pacific and changes the currents and the winds.  As it surges toward South America it was discovered and named in the 19th century  It iswell understood at this point that the phenomenon has nothing to do with CO2.

Now people talk about changes in that phenomena as a result of CO2 but it’s there in the climate system already and when it happens it influences weather all over the world.   We feel it when it gets rainier in Southern California for example.  So for the last 3 years we have been in the opposite of an El Nino, a La Nina, part of the reason people think the West Coast has been in drought.

It has now shifted in the last months to an El Nino condition that warms the globe and is thought to contribute to this Spike we have seen. But there are other contributions as well.  One of the most surprising ones is that back in January of 2022 an enormous underwater volcano went off in Tonga and it put up a lot of water vapor into the upper atmosphere. It increased the upper atmosphere of water vapor by about 10 percent, and that’s a warming effect, and it may be that is contributing to why the spike is so high.

A longer view of SSTs

To enlarge, open image in new tab.

The graph above is noisy, but the density is needed to see the seasonal patterns in the oceanic fluctuations.  Previous posts focused on the rise and fall of the last El Nino starting in 2015.  This post adds a longer view, encompassing the significant 1998 El Nino and since.  The color schemes are retained for Global, Tropics, NH and SH anomalies.  Despite the longer time frame, I have kept the monthly data (rather than yearly averages) because of interesting shifts between January and July. 1995 is a reasonable (ENSO neutral) starting point prior to the first El Nino.

The sharp Tropical rise peaking in 1998 is dominant in the record, starting Jan. ’97 to pull up SSTs uniformly before returning to the same level Jan. ’99. There were strong cool periods before and after the 1998 El Nino event. Then SSTs in all regions returned to the mean in 2001-2.

SSTS fluctuate around the mean until 2007, when another, smaller ENSO event occurs. There is cooling 2007-8,  a lower peak warming in 2009-10, following by cooling in 2011-12.  Again SSTs are average 2013-14.

Now a different pattern appears.  The Tropics cooled sharply to Jan 11, then rise steadily for 4 years to Jan 15, at which point the most recent major El Nino takes off.  But this time in contrast to ’97-’99, the Northern Hemisphere produces peaks every summer pulling up the Global average.  In fact, these NH peaks appear every July starting in 2003, growing stronger to produce 3 massive highs in 2014, 15 and 16.  NH July 2017 was only slightly lower, and a fifth NH peak still lower in Sept. 2018.

The highest summer NH peaks came in 2019 and 2020, only this time the Tropics and SH were offsetting rather adding to the warming. (Note: these are high anomalies on top of the highest absolute temps in the NH.)  Since 2014 SH has played a moderating role, offsetting the NH warming pulses. After September 2020 temps dropped off down until February 2021.  In 2021-22 there were again summer NH spikes, but in 2022 moderated first by cooling Tropics and SH SSTs, then in October to January 2023 by deeper cooling in NH and Tropics.

Then in 2023 the Tropics flipped from below to well above average, while NH produced a summer peak extending into September higher than any previous year.  Despite El Nino driving the Tropics January 2024 anomaly higher than 1998 and 2016 peaks, following months cooled in all regions, and the Tropics continued cooling in April, May and June along with SH dropping.  After July and August NH warming again pulled the global anomaly higher, September through January 2025 resumed cooling in all regions.  The descending sawtooth in all regions continued through Sept./Oct.

What to make of all this? The patterns suggest that in addition to El Ninos in the Pacific driving the Tropic SSTs, something else is going on in the NH.  The obvious culprit is the North Atlantic, since I have seen this sort of pulsing before.  After reading some papers by David Dilley, I confirmed his observation of Atlantic pulses into the Arctic every 8 to 10 years.

Contemporary AMO Observations

Through January 2023 I depended on the Kaplan AMO Index (not smoothed, not detrended) for N. Atlantic observations. But it is no longer being updated, and NOAA says they don’t know its future.  So I find that ERSSTv5 AMO dataset has current data.  It differs from Kaplan, which reported average absolute temps measured in N. Atlantic.  “ERSST5 AMO  follows Trenberth and Shea (2006) proposal to use the NA region EQ-60°N, 0°-80°W and subtract the global rise of SST 60°S-60°N to obtain a measure of the internal variability, arguing that the effect of external forcing on the North Atlantic should be similar to the effect on the other oceans.”  So the values represent SST anomaly differences between the N. Atlantic and the Global ocean.

The chart above confirms what Kaplan also showed.  As August is the hottest month for the N. Atlantic, its variability, high and low, drives the annual results for this basin.  Note also the peaks in 2010, lows after 2014, and a rise in 2021. Then in 2023 the peak reached 1.4C before declining to 0.9 last month.  An annual chart below is informative:

Note the difference between blue/green years, beige/brown, and purple/red years.  2010, 2021, 2022 all peaked strongly in August or September.  1998 and 2007 were mildly warm.  2016 and 2018 were matching or cooler than the global average.  2023 started out slightly warm, then rose steadily to an  extraordinary peak in July.  August to October were only slightly lower, but by December cooled by ~0.4C.

Then in 2024 the AMO anomaly started higher than any previous year, then leveled off for two months declining slightly into April.  Remarkably, May showed an upward leap putting this on a higher track than 2023, and rising slightly higher in June.  In July, August and September 2024 the anomaly declined, and despite a small rise in October, ended close to where it began.  Note 2025 started much lower than the previous year and headed sharply downward, well below the previous two years, then since April through September aligning with 2010, with an upward bump in October 2025.

The pattern suggests the ocean may be demonstrating a stairstep pattern like that we have also seen in HadCRUT4.

The rose line is the average anomaly 1982-1996 inclusive, value -0.25.  The orange line the average 1982-2025, value -0.014 also for the period 1997-2012. The red line is 2015-2025, value 0.32. As noted above, these rising stages are driven by the combined warming in the Tropics and NH, including both Pacific and Atlantic basins.

Curiosity:  Solar Coincidence?

The news about our current solar cycle 25 is that the solar activity is hitting peak numbers now and higher  than expected 1-2 years in the future.  As livescience put it:  Solar maximum could hit us harder and sooner than we thought. How dangerous will the sun’s chaotic peak be?  Some charts from spaceweatherlive look familar to these sea surface temperature charts.

Summary

The oceans are driving the warming this century.  SSTs took a step up with the 1998 El Nino and have stayed there with help from the North Atlantic, and more recently the Pacific northern “Blob.”  The ocean surfaces are releasing a lot of energy, warming the air, but eventually will have a cooling effect.  The decline after 1937 was rapid by comparison, so one wonders: How long can the oceans keep this up? And is the sun adding forcing to this process?

uss-pearl-harbor-deploys-global-drifter-buoys-in-pacific-ocean

USS Pearl Harbor deploys Global Drifter Buoys in Pacific Ocean

October 2025 Ocean SST Cools to Mean

Posted on by Ron Clutz

The best context for understanding decadal temperature changes comes from the world’s sea surface temperatures (SST), for several reasons:

  • The ocean covers 71% of the globe and drives average temperatures;
  • SSTs have a constant water content, (unlike air temperatures), so give a better reading of heat content variations;
  • A major El Nino was the dominant climate feature in recent years.

Previously I used HadSST3 for these reports, but Hadley Centre has made HadSST4 the priority, and v.3 will no longer be updated. I’ve grown weary of waiting each month for HadSST4 updates, so the July and August reports were based on data from OISST2.1.  This dataset uses the same in situ sources as HadSST along with satellite indicators. Now however, the US government is shut down and updates to climate datasets are likely to be delayed.  Reminds of what hospitals do when their budgets are slashed: They close the Maternity Ward to get public attention.

So this October report is based again on HadSST 4, but with a twist. The data is slightly different in the new version, 4.2.0.0 replacing 4.1.1.0. Product page is here.

The Current Context

The chart below shows SST monthly anomalies as reported in HadSST 4.2 starting in 2015 through October 2025. A global cooling pattern is seen clearly in the Tropics since its peak in 2016, joined by NH and SH cycling downward since 2016, followed by rising temperatures in 2023 and 2024 and cooling in 2025.

Note that in 2015-2016 the Tropics and SH peaked in between two summer NH spikes.  That pattern repeated in 2019-2020 with a lesser Tropics peak and SH bump, but with higher NH spikes. By end of 2020, cooler SSTs in all regions took the Global anomaly well below the mean for this period.  A small warming was driven by NH summer peaks in 2021-22, but offset by cooling in SH and the tropics, By January 2023 the global anomaly was again below the mean.

Then in 2023-24 came an event resembling 2015-16 with a Tropical spike and two NH spikes alongside, all higher than 2015-16. There was also a coinciding rise in SH, and the Global anomaly was pulled up to 1.1°C in 2023, ~0.3° higher than the 2015 peak.  Then NH started down autumn 2023, followed by Tropics and SH descending 2024 to the present. During 2 years of cooling in SH and the Tropics, the Global anomaly came back down, led by Tropics cooling from its 1.3°C peak 2024/01, down to 0.6C in September this year. Note the smaller peak in NH in July 2025 now declining along with SH and the Global anomaly cooler as well. In October the Global anomaly nearly matched the mean for this period

Comment:

The climatists have seized on this unusual warming as proof their Zero Carbon agenda is needed, without addressing how impossible it would be for CO2 warming the air to raise ocean temperatures.  It is the ocean that warms the air, not the other way around.  Recently Steven Koonin had this to say about the phonomenon confirmed in the graph above:

El Nino is a phenomenon in the climate system that happens once every four or five years.  Heat builds up in the equatorial Pacific to the west of Indonesia and so on.  Then when enough of it builds up it surges across the Pacific and changes the currents and the winds.  As it surges toward South America it was discovered and named in the 19th century  It iswell understood at this point that the phenomenon has nothing to do with CO2.

Now people talk about changes in that phenomena as a result of CO2 but it’s there in the climate system already and when it happens it influences weather all over the world.   We feel it when it gets rainier in Southern California for example.  So for the last 3 years we have been in the opposite of an El Nino, a La Nina, part of the reason people think the West Coast has been in drought.

It has now shifted in the last months to an El Nino condition that warms the globe and is thought to contribute to this Spike we have seen. But there are other contributions as well.  One of the most surprising ones is that back in January of 2022 an enormous underwater volcano went off in Tonga and it put up a lot of water vapor into the upper atmosphere. It increased the upper atmosphere of water vapor by about 10 percent, and that’s a warming effect, and it may be that is contributing to why the spike is so high.

A longer view of SSTs

To enlarge, open image in new tab.

The graph above is noisy, but the density is needed to see the seasonal patterns in the oceanic fluctuations.  Previous posts focused on the rise and fall of the last El Nino starting in 2015.  This post adds a longer view, encompassing the significant 1998 El Nino and since.  The color schemes are retained for Global, Tropics, NH and SH anomalies.  Despite the longer time frame, I have kept the monthly data (rather than yearly averages) because of interesting shifts between January and July. 1995 is a reasonable (ENSO neutral) starting point prior to the first El Nino.

The sharp Tropical rise peaking in 1998 is dominant in the record, starting Jan. ’97 to pull up SSTs uniformly before returning to the same level Jan. ’99. There were strong cool periods before and after the 1998 El Nino event. Then SSTs in all regions returned to the mean in 2001-2.

SSTS fluctuate around the mean until 2007, when another, smaller ENSO event occurs. There is cooling 2007-8,  a lower peak warming in 2009-10, following by cooling in 2011-12.  Again SSTs are average 2013-14.

Now a different pattern appears.  The Tropics cooled sharply to Jan 11, then rise steadily for 4 years to Jan 15, at which point the most recent major El Nino takes off.  But this time in contrast to ’97-’99, the Northern Hemisphere produces peaks every summer pulling up the Global average.  In fact, these NH peaks appear every July starting in 2003, growing stronger to produce 3 massive highs in 2014, 15 and 16.  NH July 2017 was only slightly lower, and a fifth NH peak still lower in Sept. 2018.

The highest summer NH peaks came in 2019 and 2020, only this time the Tropics and SH were offsetting rather adding to the warming. (Note: these are high anomalies on top of the highest absolute temps in the NH.)  Since 2014 SH has played a moderating role, offsetting the NH warming pulses. After September 2020 temps dropped off down until February 2021.  In 2021-22 there were again summer NH spikes, but in 2022 moderated first by cooling Tropics and SH SSTs, then in October to January 2023 by deeper cooling in NH and Tropics.

Then in 2023 the Tropics flipped from below to well above average, while NH produced a summer peak extending into September higher than any previous year.  Despite El Nino driving the Tropics January 2024 anomaly higher than 1998 and 2016 peaks, following months cooled in all regions, and the Tropics continued cooling in April, May and June along with SH dropping.  After July and August NH warming again pulled the global anomaly higher, September through January 2025 resumed cooling in all regions, continuing February through April 2025, with little change in May,June and July despite upward bumps in NH. Now temps in all regions are cooling August and September 2025.

What to make of all this? The patterns suggest that in addition to El Ninos in the Pacific driving the Tropic SSTs, something else is going on in the NH.  The obvious culprit is the North Atlantic, since I have seen this sort of pulsing before.  After reading some papers by David Dilley, I confirmed his observation of Atlantic pulses into the Arctic every 8 to 10 years.

Contemporary AMO Observations

Through January 2023 I depended on the Kaplan AMO Index (not smoothed, not detrended) for N. Atlantic observations. But it is no longer being updated, and NOAA says they don’t know its future.  So I find that ERSSTv5 AMO dataset has current data.  It differs from Kaplan, which reported average absolute temps measured in N. Atlantic.  “ERSST5 AMO  follows Trenberth and Shea (2006) proposal to use the NA region EQ-60°N, 0°-80°W and subtract the global rise of SST 60°S-60°N to obtain a measure of the internal variability, arguing that the effect of external forcing on the North Atlantic should be similar to the effect on the other oceans.”  So the values represent SST anomaly differences between the N. Atlantic and the Global ocean.

The chart above confirms what Kaplan also showed.  As August is the hottest month for the N. Atlantic, its variability, high and low, drives the annual results for this basin.  Note also the peaks in 2010, lows after 2014, and a rise in 2021. Then in 2023 the peak reached 1.4C before declining to 0.9 last month.  An annual chart below is informative:

Note the difference between blue/green years, beige/brown, and purple/red years.  2010, 2021, 2022 all peaked strongly in August or September.  1998 and 2007 were mildly warm.  2016 and 2018 were matching or cooler than the global average.  2023 started out slightly warm, then rose steadily to an  extraordinary peak in July.  August to October were only slightly lower, but by December cooled by ~0.4C.

Then in 2024 the AMO anomaly started higher than any previous year, then leveled off for two months declining slightly into April.  Remarkably, May showed an upward leap putting this on a higher track than 2023, and rising slightly higher in June.  In July, August and September 2024 the anomaly declined, and despite a small rise in October, ended close to where it began.  Note 2025 started much lower than the previous year and headed sharply downward, well below the previous two years, then since April through September aligning with 2010. Now in October there was an unusual upward spike.

The pattern suggests the ocean may be demonstrating a stairstep pattern like that we have also seen in HadCRUT4.

The rose line is the average anomaly 1982-1996 inclusive, value 0.18.  The orange line the average 1982-2025, value 0.40 also for the period 1997-2012. The red line is 2015-2025, value 0.68. As noted above, these rising stages are driven by the combined warming in the Tropics and NH, including both Pacific and Atlantic basins.

Curiosity:  Solar Coincidence?

The news about our current solar cycle 25 is that the solar activity is hitting peak numbers now and higher  than expected 1-2 years in the future.  As livescience put it:  Solar maximum could hit us harder and sooner than we thought. How dangerous will the sun’s chaotic peak be?  Some charts from spaceweatherlive look familar to these sea surface temperature charts.

Summary

The oceans are driving the warming this century.  SSTs took a step up with the 1998 El Nino and have stayed there with help from the North Atlantic, and more recently the Pacific northern “Blob.”  The ocean surfaces are releasing a lot of energy, warming the air, but eventually will have a cooling effect.  The decline after 1937 was rapid by comparison, so one wonders: How long can the oceans keep this up? And is the sun adding forcing to this process?

uss-pearl-harbor-deploys-global-drifter-buoys-in-pacific-ocean

USS Pearl Harbor deploys Global Drifter Buoys in Pacific Ocean

September 2025 Ocean SST Cooling

Posted on by Ron Clutz

The best context for understanding decadal temperature changes comes from the world’s sea surface temperatures (SST), for several reasons:

  • The ocean covers 71% of the globe and drives average temperatures;
  • SSTs have a constant water content, (unlike air temperatures), so give a better reading of heat content variations;
  • A major El Nino was the dominant climate feature in recent years.

Previously I used HadSST3 for these reports, but Hadley Centre has made HadSST4 the priority, and v.3 will no longer be updated. I’ve grown weary of waiting each month for HadSST4 updates, so the July and August reports were based on data from OISST2.1.  This dataset uses the same in situ sources as HadSST along with satellite indicators. Now however, the US government is shut down and updates to climate datasets are likely to be delayed.  Reminds of what hospitals do when their budgets are slashed: They close the Maternity Ward to get public attention.

So this September report is based again on HadSST 4, but with a twist. The data is slightly different in the new version, 4.2.0.0 replacing 4.1.1.0. Product page is here.

The Current Context

The chart below shows SST monthly anomalies as reported in HadSST 4.2 starting in 2015 through September 2025. A global cooling pattern is seen clearly in the Tropics since its peak in 2016, joined by NH and SH cycling downward since 2016, followed by rising temperatures in 2023 and 2024 and cooling in 2025.

Note that in 2015-2016 the Tropics and SH peaked in between two summer NH spikes.  That pattern repeated in 2019-2020 with a lesser Tropics peak and SH bump, but with higher NH spikes. By end of 2020, cooler SSTs in all regions took the Global anomaly well below the mean for this period.  A small warming was driven by NH summer peaks in 2021-22, but offset by cooling in SH and the tropics, By January 2023 the global anomaly was again below the mean.

Then in 2023-24 came an event resembling 2015-16 with a Tropical spike and two NH spikes alongside, all higher than 2015-16. There was also a coinciding rise in SH, and the Global anomaly was pulled up to 1.1°C in 2023, ~0.3° higher than the 2015 peak.  Then NH started down autumn 2023, followed by Tropics and SH descending 2024 to the present. During 2 years of cooling in SH and the Tropics, the Global anomaly came back down, led by Tropics cooling from its 1.3°C peak 2024/01, down to 0.6C in September this year. Note the smaller peak in NH in July 2025 now declining along with SH and the Global anomaly cooler as well. Presently the Global anomaly is only slightly above the mean for this period

Comment:

The climatists have seized on this unusual warming as proof their Zero Carbon agenda is needed, without addressing how impossible it would be for CO2 warming the air to raise ocean temperatures.  It is the ocean that warms the air, not the other way around.  Recently Steven Koonin had this to say about the phonomenon confirmed in the graph above:

El Nino is a phenomenon in the climate system that happens once every four or five years.  Heat builds up in the equatorial Pacific to the west of Indonesia and so on.  Then when enough of it builds up it surges across the Pacific and changes the currents and the winds.  As it surges toward South America it was discovered and named in the 19th century  It iswell understood at this point that the phenomenon has nothing to do with CO2.

Now people talk about changes in that phenomena as a result of CO2 but it’s there in the climate system already and when it happens it influences weather all over the world.   We feel it when it gets rainier in Southern California for example.  So for the last 3 years we have been in the opposite of an El Nino, a La Nina, part of the reason people think the West Coast has been in drought.

It has now shifted in the last months to an El Nino condition that warms the globe and is thought to contribute to this Spike we have seen. But there are other contributions as well.  One of the most surprising ones is that back in January of 2022 an enormous underwater volcano went off in Tonga and it put up a lot of water vapor into the upper atmosphere. It increased the upper atmosphere of water vapor by about 10 percent, and that’s a warming effect, and it may be that is contributing to why the spike is so high.

A longer view of SSTs

To enlarge, open image in new tab.

The graph above is noisy, but the density is needed to see the seasonal patterns in the oceanic fluctuations.  Previous posts focused on the rise and fall of the last El Nino starting in 2015.  This post adds a longer view, encompassing the significant 1998 El Nino and since.  The color schemes are retained for Global, Tropics, NH and SH anomalies.  Despite the longer time frame, I have kept the monthly data (rather than yearly averages) because of interesting shifts between January and July. 1995 is a reasonable (ENSO neutral) starting point prior to the first El Nino.

The sharp Tropical rise peaking in 1998 is dominant in the record, starting Jan. ’97 to pull up SSTs uniformly before returning to the same level Jan. ’99. There were strong cool periods before and after the 1998 El Nino event. Then SSTs in all regions returned to the mean in 2001-2.

SSTS fluctuate around the mean until 2007, when another, smaller ENSO event occurs. There is cooling 2007-8,  a lower peak warming in 2009-10, following by cooling in 2011-12.  Again SSTs are average 2013-14.

Now a different pattern appears.  The Tropics cooled sharply to Jan 11, then rise steadily for 4 years to Jan 15, at which point the most recent major El Nino takes off.  But this time in contrast to ’97-’99, the Northern Hemisphere produces peaks every summer pulling up the Global average.  In fact, these NH peaks appear every July starting in 2003, growing stronger to produce 3 massive highs in 2014, 15 and 16.  NH July 2017 was only slightly lower, and a fifth NH peak still lower in Sept. 2018.

The highest summer NH peaks came in 2019 and 2020, only this time the Tropics and SH were offsetting rather adding to the warming. (Note: these are high anomalies on top of the highest absolute temps in the NH.)  Since 2014 SH has played a moderating role, offsetting the NH warming pulses. After September 2020 temps dropped off down until February 2021.  In 2021-22 there were again summer NH spikes, but in 2022 moderated first by cooling Tropics and SH SSTs, then in October to January 2023 by deeper cooling in NH and Tropics.

Then in 2023 the Tropics flipped from below to well above average, while NH produced a summer peak extending into September higher than any previous year.  Despite El Nino driving the Tropics January 2024 anomaly higher than 1998 and 2016 peaks, following months cooled in all regions, and the Tropics continued cooling in April, May and June along with SH dropping.  After July and August NH warming again pulled the global anomaly higher, September through January 2025 resumed cooling in all regions, continuing February through April 2025, with little change in May,June and July despite upward bumps in NH. Now temps in all regions are cooling August and September 2025.

What to make of all this? The patterns suggest that in addition to El Ninos in the Pacific driving the Tropic SSTs, something else is going on in the NH.  The obvious culprit is the North Atlantic, since I have seen this sort of pulsing before.  After reading some papers by David Dilley, I confirmed his observation of Atlantic pulses into the Arctic every 8 to 10 years.

Contemporary AMO Observations

Through January 2023 I depended on the Kaplan AMO Index (not smoothed, not detrended) for N. Atlantic observations. But it is no longer being updated, and NOAA says they don’t know its future.  So I find that ERSSTv5 AMO dataset has current data.  It differs from Kaplan, which reported average absolute temps measured in N. Atlantic.  “ERSST5 AMO  follows Trenberth and Shea (2006) proposal to use the NA region EQ-60°N, 0°-80°W and subtract the global rise of SST 60°S-60°N to obtain a measure of the internal variability, arguing that the effect of external forcing on the North Atlantic should be similar to the effect on the other oceans.”  So the values represent SST anomaly differences between the N. Atlantic and the Global ocean.

The chart above confirms what Kaplan also showed.  As August is the hottest month for the N. Atlantic, its variability, high and low, drives the annual results for this basin.  Note also the peaks in 2010, lows after 2014, and a rise in 2021. Then in 2023 the peak reached 1.4C before declining to 0.9 last month.  An annual chart below is informative:

Note the difference between blue/green years, beige/brown, and purple/red years.  2010, 2021, 2022 all peaked strongly in August or September.  1998 and 2007 were mildly warm.  2016 and 2018 were matching or cooler than the global average.  2023 started out slightly warm, then rose steadily to an  extraordinary peak in July.  August to October were only slightly lower, but by December cooled by ~0.4C.

Then in 2024 the AMO anomaly started higher than any previous year, then leveled off for two months declining slightly into April.  Remarkably, May showed an upward leap putting this on a higher track than 2023, and rising slightly higher in June.  In July, August and September 2024 the anomaly declined, and despite a small rise in October, ended close to where it began.  Note 2025 started much lower than the previous year and headed sharply downward, well below the previous two years, then since April through September aligning with 2010.

The pattern suggests the ocean may be demonstrating a stairstep pattern like that we have also seen in HadCRUT4.

The rose line is the average anomaly 1982-1996 inclusive, value 0.18.  The orange line the average 1982-2025, value 0.41 also for the period 1997-2012. The red line is 2015-2025, value 0.69. As noted above, these rising stages are driven by the combined warming in the Tropics and NH, including both Pacific and Atlantic basins.

Curiosity:  Solar Coincidence?

The news about our current solar cycle 25 is that the solar activity is hitting peak numbers now and higher  than expected 1-2 years in the future.  As livescience put it:  Solar maximum could hit us harder and sooner than we thought. How dangerous will the sun’s chaotic peak be?  Some charts from spaceweatherlive look familar to these sea surface temperature charts.

Summary

The oceans are driving the warming this century.  SSTs took a step up with the 1998 El Nino and have stayed there with help from the North Atlantic, and more recently the Pacific northern “Blob.”  The ocean surfaces are releasing a lot of energy, warming the air, but eventually will have a cooling effect.  The decline after 1937 was rapid by comparison, so one wonders: How long can the oceans keep this up? And is the sun adding forcing to this process?

uss-pearl-harbor-deploys-global-drifter-buoys-in-pacific-ocean

USS Pearl Harbor deploys Global Drifter Buoys in Pacific Ocean