Climate Impacts | Science Matters

No Right to Stable Climate in Our Holocene Epoch

Leszek Marks explains how warming and cooling alternated throughout the last 12,000 years and how our modern period is no different in his paper Contemporary global warming versus climate change in the Holocene. Excerpts in italics with my bolds and added images. H/T No Tricks Zone

Leszek Eugeniusz Marks is a Polish geologist, professor ordinarius, currently at the Warsaw University, Department of Climate Geology; and the Polish Geological Institute-National Research Institute, president of Committee for Quaternary Research of the Polish Academy of Sciences. At present, member of editorial boards of scientific journals Boreas, “Litosfera”, “Geography and Geology”, and Studia Quaternaria.

Abstract

Cyclical climate change is characteristic of the Holocene, with successive warmings and coolings. A solar forcing mechanism has steered Holocene climate change, expressed by 9 cooling phases known as Bond events. There is reliable geological evidence that the temperatures of most warming phases in the Holocene were globally higher or similar to that of the current warming period, Arctic sea ice was less extensive and most mountain glaciers in the northern hemisphere either disappeared or were smaller.
During the African Humid Period in the Early and Middle Holocene, much stronger summer monsoons made the Sahara green with growth of savanna vegetation, huge lakes and extensive peat bogs. The modern warming is part of a climatic cycle with a progressive warming after the Little Ice Age, the last cold episode of which occurred at the beginning of the 19th century. Successive climate projections of the Intergovernmental Panel on Climate Change are based on the assumption that the modern temperature rise is steered exclusively by the increasing content of human-induced CO2 in the atmosphere. If compared with the observational data, these projected temperatures have been highly overestimated.

Overview

This paper presents the current state of knowledge of the climate change in the Holocene. The geological record of the climate change in this epoch has been verified by the results of archaeological, historical and meteorological investigations (Marks, 2016). Determination of the steering forces of modern warming is among the current scientific priorities in the world and, therefore, geological input is an important contribution to the discussion about human impact on the climate.

The current interglacial of the Holocene started 11.7 ka cal BP (Walker et al., 2018), with progressively increasing human impact on the Earth’s environment, especially strong during the past decades (Gibbard et al., 2021). Geological examination of past climate changes is crucial to distinguish the natural and the human-induced factors of the current climate change. The most important climate-steering factor is solar radiation, subjected to cyclical changes caused by the Sun’s activity that supplies with over 99% of the energy that is responsible for the climate of the Earth. Geological reconstructions show that rises and falls in the temperature on the Earth are dependent on the sunspot cycles (Table 1; Easterbrook, 2011; Usoskin et al., 2016; Usoskin,2023), and these in turn respond to the varying magnetic activity of the Sun.

The natural input of solar energy is transformed by different external and internal factors to modulate climate on the Earth. Latitudinal insolation in the Holocene depended on the Earth’s orbital parameters (Milankovič cycles). In comparison with the present values, summer temperatures in the northern hemisphere were higher in the Early and Middle Holocene (Beer, Van Geel, 2008; Beer, Wanner, 2012). Winter temperatures in the southern hemisphere were higher in the Middle Holocene, followed by higher temperatures in the northern hemisphere in the Late Holocene. In the coming 3 ka, lower temperatures are expected everywhere, except for the intertropical zone where higher winter temperatures are expected (Marks, 2016).

The natural rhythm of climate change during the Holocene was disturbed by large volcanic eruptions. Emission of dust into the atmosphere was responsible for a couple of cold events during the Holocene (Shindell et al., 2003). Such eruptions can be detected by concentrations of SO2 in polar ice core records (Zielinski et al., 1994; Castellano et al., 2004). The extent of the vegetation cover had an important, but very complex, effect on the climate (Foley et al., 2003), because the evaporative cooling by a forest mitigated warmings and limited dust mobilisation (Bonan, 2008). The atmospheric CO2 concentration decreased in the Early Holocene and started to increase since 7 ka, being independent of temperature variations (Palacios et al., 2024a). Ocean-atmosphere interchange was the main source of CO2 until the recent decades when the anthropogenic emission of CO2 became significant (Brovkin et al., 2019).

Fig. 1. Climate change in the Holocene, adapted from Palacios et al. (2024a) and modified: warm periods are in yellow and less warm in pale yellow, and cold in blue; Bond Events are after Bond et al. (1997, 2001) and geochronology after Walker et al. (2019).

Climate change after the Holocene Thermal Maximum

The temperature deduced from the oxygen isotope curve in the Greenland ice core GISP2 shows that several warmings occurred after the Holocene Thermal Maximum (Fig. 1; Drake, 2012). These were periods during which great progress in the development of human societies occurred: Late Bronze Age, Roman Warm Period and the MWP. The separating cold Bond Events, named the Iron Age and Dark Ages Cold Periods respectively, were expressed by economic, intellectual and cultural decline. The temperature history since 900 CE was based firstly on the estimated climate history of central England (Lamb, 1977; IPCC, 1990). This showed a distinct warming of ~1.3°C when compared with the LIA (Moberg et al., 2005; D’Arrigo et al., 2006; Mann et al., 2009). This warming was a result of natural processes, because human activity could not have had any significant effect on temperature changes before 1900 CE. The Roman Warm Period (250 BC–450 CE), the MWP (950–1250 CE) and the Modern Warming Period reflect 1000-cycles with high solar radiation (Table 1; Vahrenholt, Lüning, 2014).

Discussion

The claim of the IPCC (2021) that ‘…the latest decade was warmer than any multi-century period after the Last Interglacial, around 125,000 years ago’ ignores all the knowledge about reconstructed temperatures in the Holocene, based on multi-proxy palaeoclimatic data.

Despite the extensive northern ice sheets, the increased summer insolation in the northern hemisphere caused a warming trend from the beginning of the Holocene and lasting until the Middle Holocene (Palacios et al., 2024a). This warming trend was reversed from 6–5 ka onwards, due to decreased summer insolation in the northern hemisphere. Such general warming or cooling trends in the Holocene were interrupted by short periods with opposite and abrupt temperature changes (Fig. 1).

The modern warming represents a part of the cyclical climate change after the LIA, the last cold episode of which occurred at the beginning of the 19th century. The LIA with low temperatures is named the pre industrial period by the advocates of global anthropogenic warming and such an approach helps them to promote the idea that an increased human emission of CO2 (especially in the 20th century) is the only reason for rising temperatures on Earth. They do not bother with the evidence that the mutual time relations of global temperature and contents of CO2 in the atmosphere in 1980–2019 indicate a leading role of temperature, a rise of which was followed in that time by a 6-month delay in the rise of CO2 (Humlum et al., 2012; Koutsoyiannis, Kundzewicz, 2020).

The official curve of the global mean annual temperature anomalies based on regular measurements (https://data.giss.nasa.gov/gistemp/graphs_v4/) overlaps slightly with the temperature projections in reports of the IPCC (1990, 1995, 2001, 2007, 2014, 2021). These IPCC projections were created by climate models, based on the assumption that the modern temperature rise is steered exclusively by the increasing content of human-induced CO2 in the atmosphere while the role of water vapour as the main greenhouse gas is neglected (cf. Hołyst, 2020). Such an approach makes the IPCC-projected temperature highly overestimated if compared with the observational data (Fig. 3). Despite the lockdowns during the Covid-19 pandemic in 2020–2021, connected with large cutbacks in transport, travel, industrial production and energy generation, no reduction in atmospheric CO2 was noted. This fact suggests that the proposed reductions in global energy use would be most probably highly ineffective in limiting the level of atmospheric CO2.

Fig. 3. Global estimates of mean annual temperature anomalies (1880–2023), based on land and ocean data (https://data.giss.nasa.gov/gistemp/graphs_v4/) and temperature projections to AD 2100 in the successive IPCC reports (1990, 1995, 2001, 2007, 2014, 2021)

Conclusions

The Holocene climate change was characterized by cyclical warmings (such as: Holocene Thermal Maximum, Late Bronze Age, Roman Warm Period, MWP) and coolings (Bond Events: including Iron Age Cold Period, Dark Ages Cold Period and LIA). The IPCC claims that current warming is unprecedented in the last 2000 or even the last 125,000 years; this statement is very unconvincing and it is not supported by the geological data. There is good evidence that both in the last 2000 years as well during the Holocene Thermal Maximum, temperatures were higher or broadly similar to the ones in the current warming period, the Arctic sea ice was less extensive and most mountain glaciers (especially in the northern hemisphere) either disappeared or were smaller. Much stronger summer monsoons in the Early and Middle Holocene made the Sahara green with savanna vegetation, huge lakes and extensive peat bogs. The terms ‘the Holocene Thermal Maximum’ and ‘the Holocene Climatic Optimum’ are avoided by the IPCC (2021), and its popularized statements making the current warming look ‘unprecedented’ and therefore ‘unique’ are false and flatten the climate history (cf. Marcott et al., 2013).

The climate is a product of complicated interdependence of many factors that have not been yet sufficiently recognized qualitatively and quantitatively. It is a great scientific challenge that requires an extensive interdisciplinary research. There is a crucial need to make climate science less political and climate policy more scientific.

New England Facing Energy Crisis, Worries About Bugs

Posted on September 22 by Ron Clutz

Linnea Lueken explains the false alarm in her Climate Realism article Climate Change Is Not Causing New England’s ‘Creepy’ Bacteria and Bugs, Boston Globe. Excerpts in italics with my bolds and added images.

The Boston Globe posted an article titled “Climate change is bringing creepy — and dangerous — bacteria, bugs, and viruses to New England,” claiming that global warming is “fueling an increase in bacteria and disease” in New England. The headline and the attached story are highly misleading. For things like mosquito-borne illness, mosquitos carrying diseases previously thrived even in New England in previous centuries, with 20^th century human intervention wiping them out, not temperature changes. Also, bacteria in waterways are a seasonal phenomenon which has always existed.

The Real New England Crisis is Green Agenda Attack on Electricity Supply

Source: granitegeek, Concord Monitor

Daniel Turner explains in his Real Clear Energy article The Green Agenda Turned New England Into an Energy Price Punchline. Excerpts in italics with my bolds and added images.

Fall is here, the leaves are changing, the temperature is dropping and sadly New England families know the routine.

Every month, the electric bill arrives, and it’s larger than the month before. The region pays more for electricity than almost anyone else in America—higher than the national average and, outside of Alaska and Hawaii, higher than anywhere else in the country. This is not a coincidence. It is the inevitable result of politicians who pushed the risky and unreliable green agenda while forcing reliable power plants off the grid.

Here’s an inconvenient history lesson. When Joe Biden took office, electricity in New England cost 20.7 cents per kilowatt-hour. By the time he left, it was more than 28.2 cents. That’s a staggering spike of more than 36% in just four years. Hundreds of dollars gone from family budgets and small businesses every single year. For working households already feeling the squeeze of Biden’s inflation, it can mean the difference between savings and debt, between heating a home and keeping it uncomfortably cold.

October 2022 generation in New England, by fuel source

And the blame is clear. The forced closure of coal, oil, and natural gas plants in the name of “climate progress” is why rates are climbing. In 2022, Massachusetts Senators Elizabeth Warren and Ed Markey traveled to Somerset to celebrate the shutdown of traditional energy plants. They smiled for the cameras, congratulated themselves on a “victory,” and then went back to Washington while families were left to pay the tab.

First came the celebration, but now we see the deflection. Four Democratic senators, including Warren and Markey, recently wrote a letter to the Trump administration suddenly pretending to care about rising electricity bills. It is political theater and nothing more. They didn’t care when they cheered the closures in 2022, and they don’t care now. New England’s families are stuck with the consequences of the green agenda they applauded; they just want to escape the blame.

Project abandoned in 2017 after New York blocked planning and permit processes.

Let’s be clear: This cascade of closures started when Joe Biden was vice president and accelerated under his presidency. Nearly 400 fossil fuel plants have been shuttered across the country since 2010, including almost 300 coal plants. In the Northeast alone, names like Indian Point in New York, Eagle Point in New Jersey, Schiller Station in New Hampshire, and Canal Station in Massachusetts have been crossed off the map. Each closure meant fewer megawatts of reliable power and higher bills for families.

Project abandoned in April 2016

The problem is not complicated. Shutting down affordable, always-on power and replacing it with expensive, intermittent sources like wind and solar leads to higher prices. Add the surge in demand from artificial intelligence data centers, which analysts say could double electricity consumption by 2030, and the consequences are obvious: higher costs, weaker reliability, and a grid at the breaking point.

There is a way out of this crisis, but it requires real action, not pointless blaming. My organization, Power The Future, lays out the steps in our recent report.

♦ First, use the Defense Production Act to treat grid reliability as the national security issue it is, and direct resources to keep critical plants online.
♦ Second, build new fossil fuel plants—modern natural gas and coal facilities that can deliver decades of dependable, affordable power.
♦ Third, halt premature closures until replacement capacity is running, not just promised on paper. And fourth, expand the capacity of existing coal plants, many of which are running below potential thanks to political limits, to quickly add thousands of megawatts back to the grid.

These are not radical ideas. They are common sense. They put working families, not political slogans, at the center of energy policy. They recognize that you cannot run a 21st-century economy on wishful thinking, photo-ops, and subsidies for technology that fails when the wind doesn’t blow, or the sun doesn’t shine.

Too many of New England’s “leaders” in Washington have turned their states into punchlines of America’s power prices. Working families deserve leaders who care more about their constituents’ bills than their standing with environmental activists. They deserve an energy policy grounded in reality, not ideology.

If you want to know who killed affordable power in New England, it wasn’t President Trump and it wasn’t the utility companies. All you need to do is just look at who popped the champagne when the plants closed.

Tropics UAH Temps Cooler August 2025

Posted on September 19 by Ron Clutz

The post below updates the UAH record of air temperatures over land and ocean. Each month and year exposes again the growing disconnect between the real world and the Zero Carbon zealots. It is as though the anti-hydrocarbon band wagon hopes to drown out the data contradicting their justification for the Great Energy Transition. Yes, there was warming from an El Nino buildup coincidental with North Atlantic warming, but no basis to blame it on CO2.

As an overview consider how recent rapid cooling completely overcame the warming from the last 3 El Ninos (1998, 2010 and 2016). The UAH record shows that the effects of the last one were gone as of April 2021, again in November 2021, and in February and June 2022 At year end 2022 and continuing into 2023 global temp anomaly matched or went lower than average since 1995, an ENSO neutral year. (UAH baseline is now 1991-2020). Then there was an usual El Nino warming spike of uncertain cause, unrelated to steadily rising CO2, and now dropping steadily back toward normal values.

For reference I added an overlay of CO2 annual concentrations as measured at Mauna Loa. While temperatures fluctuated up and down ending flat, CO2 went up steadily by ~65 ppm, an 18% increase.

Furthermore, going back to previous warmings prior to the satellite record shows that the entire rise of 0.8C since 1947 is due to oceanic, not human activity.

gmt-warming-events

The animation is an update of a previous analysis from Dr. Murry Salby. These graphs use Hadcrut4 and include the 2016 El Nino warming event. The exhibit shows since 1947 GMT warmed by 0.8 C, from 13.9 to 14.7, as estimated by Hadcrut4. This resulted from three natural warming events involving ocean cycles. The most recent rise 2013-16 lifted temperatures by 0.2C. Previously the 1997-98 El Nino produced a plateau increase of 0.4C. Before that, a rise from 1977-81 added 0.2C to start the warming since 1947.

Importantly, the theory of human-caused global warming asserts that increasing CO2 in the atmosphere changes the baseline and causes systemic warming in our climate. On the contrary, all of the warming since 1947 was episodic, coming from three brief events associated with oceanic cycles. And in 2024 we saw an amazing episode with a temperature spike driven by ocean air warming in all regions, along with rising NH land temperatures, now dropping below its peak.

Chris Schoeneveld has produced a similar graph to the animation above, with a temperature series combining HadCRUT4 and UAH6. H/T WUWT

August 2025 Lower Tropics UAH Temps

With apologies to Paul Revere, this post is on the lookout for cooler weather with an eye on both the Land and the Sea. While you heard a lot about 2020-21 temperatures matching 2016 as the highest ever, that spin ignores how fast the cooling set in. The UAH data analyzed below shows that warming from the last El Nino had fully dissipated with chilly temperatures in all regions. After a warming blip in 2022, land and ocean temps dropped again with 2023 starting below the mean since 1995. Spring and Summer 2023 saw a series of warmings, continuing into 2024 peaking in April, then cooling off to the present.

UAH has updated their TLT (temperatures in lower troposphere) dataset for August 2025. Due to one satellite drifting more than can be corrected, the dataset has been recalibrated and retitled as version 6.1 Graphs here contain this updated 6.1 data. Posts on their reading of ocean air temps this month are ahead the update from HadSST4 or OISST2.1. I posted recently on SSTs July 2025 Ocean SSTs: NH Warms Slightly. These posts have a separate graph of land air temps because the comparisons and contrasts are interesting as we contemplate possible cooling in coming months and years.

Sometimes air temps over land diverge from ocean air changes. In July 2024 all oceans were unchanged except for Tropical warming, while all land regions rose slightly. In August we saw a warming leap in SH land, slight Land cooling elsewhere, a dip in Tropical Ocean temp and slightly elsewhere. September showed a dramatic drop in SH land, overcome by a greater NH land increase. 2025 has shown a sharp contrast between land and sea, first with ocean air temps falling in January recovering in February. Then land air temps, especially NH, dropped in February and recovered in March. Now in July SH ocean dropped markedly, pulling down the Global ocean anomaly despite a rise in the Tropics. SH land also cooled by half, driving Global land temps down despite Tropics land warming.

Note: UAH has shifted their baseline from 1981-2010 to 1991-2020 beginning with January 2021. v6.1 data was recalibrated also starting with 2021. In the charts below, the trends and fluctuations remain the same but the anomaly values changed with the baseline reference shift.

Presently sea surface temperatures (SST) are the best available indicator of heat content gained or lost from earth’s climate system. Enthalpy is the thermodynamic term for total heat content in a system, and humidity differences in air parcels affect enthalpy. Measuring water temperature directly avoids distorted impressions from air measurements. In addition, ocean covers 71% of the planet surface and thus dominates surface temperature estimates. Eventually we will likely have reliable means of recording water temperatures at depth.

Recently, Dr. Ole Humlum reported from his research that air temperatures lag 2-3 months behind changes in SST. Thus cooling oceans portend cooling land air temperatures to follow. He also observed that changes in CO2 atmospheric concentrations lag behind SST by 11-12 months. This latter point is addressed in a previous post Who to Blame for Rising CO2?

After a change in priorities, updates are now exclusive to HadSST4. For comparison we can also look at lower troposphere temperatures (TLT) from UAHv6.1 which are now posted for August 2025. The temperature record is derived from microwave sounding units (MSU) on board satellites like the one pictured above. Recently there was a change in UAH processing of satellite drift corrections, including dropping one platform which can no longer be corrected. The graphs below are taken from the revised and current dataset.

The UAH dataset includes temperature results for air above the oceans, and thus should be most comparable to the SSTs. There is the additional feature that ocean air temps avoid Urban Heat Islands (UHI). The graph below shows monthly anomalies for ocean air temps since January 2015.

In 2021-22, SH and NH showed spikes up and down while the Tropics cooled dramatically, with some ups and downs, but hitting a new low in January 2023. At that point all regions were more or less in negative territory.

After sharp cooling everywhere in January 2023, there was a remarkable spiking of Tropical ocean temps from -0.5C up to + 1.2C in January 2024. The rise was matched by other regions in 2024, such that the Global anomaly peaked at 0.86C in April. Since then all regions have cooled down sharply to a low of 0.27C in January. In February 2025, SH rose from 0.1C to 0.4C pulling the Global ocean air anomaly up to 0.47C, where it stayed in March and April. In May drops in NH and Tropics pulled the air temps over oceans down despite an uptick in SH. At 0.43C, ocean air temps were similar to May 2020, albeit with higher SH anomalies. Now in August Global ocean temps are little changed since SH rose, offsetting NH cooling and Tropics plummenting down to 0.16C from its peak of 1.24C March 2024.

Land Air Temperatures Tracking in Seesaw Pattern

We sometimes overlook that in climate temperature records, while the oceans are measured directly with SSTs, land temps are measured only indirectly. The land temperature records at surface stations sample air temps at 2 meters above ground. UAH gives tlt anomalies for air over land separately from ocean air temps. The graph updated for August is below.

Here we have fresh evidence of the greater volatility of the Land temperatures, along with extraordinary departures by SH land. The seesaw pattern in Land temps is similar to ocean temps 2021-22, except that SH is the outlier, hitting bottom in January 2023. Then exceptionally SH goes from -0.6C up to 1.4C in September 2023 and 1.8C in August 2024, with a large drop in between. In November, SH and the Tropics pulled the Global Land anomaly further down despite a bump in NH land temps. February showed a sharp drop in NH land air temps from 1.07C down to 0.56C, pulling the Global land anomaly downward from 0.9C to 0.6C. In March that drop reversed with both NH and Global land back to January values, holding there in April. In May sharp drops in NH and Tropics land air temps pulled the Global land air temps back down close to February value. In August Tropics land air dropped sharply, down from 0.58C to 0.26C, and NH land also cooled by 0.1C, offset by SH rising, resulting in no change of Global land air temps.

The Bigger Picture UAH Global Since 1980

The chart shows monthly Global Land and Ocean anomalies starting 01/1980 to present. The average monthly anomaly is -0.0, 2for this period of more than four decades. The graph shows the 1998 El Nino after which the mean resumed, and again after the smaller 2010 event. The 2016 El Nino matched 1998 peak and in addition NH after effects lasted longer, followed by the NH warming 2019-20. An upward bump in 2021 was reversed with temps having returned close to the mean as of 2/2022. March and April brought warmer Global temps, later reversed

With the sharp drops in Nov., Dec. and January 2023 temps, there was no increase over 1980. Then in 2023 the buildup to the October/November peak exceeded the sharp April peak of the El Nino 1998 event. It also surpassed the February peak in 2016. In 2024 March and April took the Global anomaly to a new peak of 0.94C. The cool down started with May dropping to 0.9C, and in June a further decline to 0.8C. October went down to 0.7C, November and December dropped to 0.6C. Now in August Global Land and Ocean is down to 0.39C

The graph reminds of another chart showing the abrupt ejection of humid air from Hunga Tonga eruption.

TLTs include mixing above the oceans and probably some influence from nearby more volatile land temps. Clearly NH and Global land temps have been dropping in a seesaw pattern, nearly 1C lower than the 2016 peak. Since the ocean has 1000 times the heat capacity as the atmosphere, that cooling is a significant driving force. TLT measures started the recent cooling later than SSTs from HadSST4, but are now showing the same pattern. Despite the three El Ninos, their warming had not persisted prior to 2023, and without them it would probably have cooled since 1995. Of course, the future has not yet been written.

The Sea is Not Coming to Get You

Posted on September 9 by Ron Clutz

Issues and Insights Editorial Board published Another Crack Appears In The Global Warming Narrative. Excerpts in italics with my bolds and added images.

Al Gore famously warned that sea level rise caused by man’s use of fossil fuels was going to kill us. Barack Obama implied that he had magic powers that would control surging sea levels. A fresh study shows just how dishonest this pair and the many others who did their best to misinform the public have been.

Gore’s 2006 propaganda film told us to beware of sea levels rising by 20 feet, devastating New York and Florida. The uber-narcissistic Obama promised an adoring crowd that his nomination to be the Democratic Party’s 2008 presidential nominee “was the moment when the rise of the oceans began to slow and our planet began to heal.” California Gov. Jerry Brown predicted a little more than a decade ago that collapsing glaciers would submerge both the Los Angeles and San Francisco international airports.

These of course are just three of many examples of alarmists, hacks, globalist busybodies, NASA eggheads, academic ideologues and true believers fear-mongering over sea-level rise.

Obama, no climate refugee he, was later roasted for buying oceanfront compounds in Martha’s Vineyard and Hawaii. The purchases clearly show he didn’t believe what he said – he was just another political hack appealing for votes and hoping to burnish a legacy before he even set foot in the White House.

But how can we know it’s just fear-mongering?

Actual science, not Gore’s junk variety, now tells us that “approximately 95% of the suitable locations” researchers looked at showed “no statistically significant acceleration of the rate of sea level rise.” This “suggests that local, non-climatic phenomena are a plausible cause of the accelerated sea level rise observed at the remaining 5% of the suitable locations.”

“On average,” the European paper says, “the rate of rise projected by the IPCC is biased upward with approximately 2 mm per year in comparison with the observed rate.”

As it turns out:

The majority of the local causes of rapid sea level rise (or drop) appear to be geologic. Tectonic motion explains sudden changes of sea level rise found in a few places. More gradual but rapid rise (or fall) of sea level is mostly caused by glacial isostatic adjustment and in a few isolated cases by an excessive sediment load.

What else do we know about the oceans? It’s been well established that sea levels, like Earth’s climate, have been constantly changing without any human influence.

We acknowledge that we live in an era of rising sea levels, just as we live in a time in which we are escaping the lower temperatures of the Little Ice Age that lasted until the late 19th century, if not, according to some researchers, the early 20th century. But the rise we’re seeing is slow, not remotely catastrophic, and not outside of historical norms (even though the hysterics continue to claim the rise is “accelerating” and is “unprecedented”).

The climate cranks, warming crackpots, and those possessed of Marxphilia won’t be deterred by this or any other scientific evidence. But it’s news that can help persuade larger swaths of voters that the global warming scare is a con. As more Americans learn the truth, the radicals and zealots who perpetuate the fiction will fade into the oblivion they deserve.

See Also

Observed vs. Imagined Sea Levels 2023 Update

Fear Not For Fiji

Surplus Arctic Ice Persists to End of August 2025

Posted on September 2 by Ron Clutz

After a sub-par March maximum, by end of May 2025 Arctic ice closed the gap with the 19-year average. Then in June the gap reopened and in July the melting pace matched the average, abeit four days in advance of average. In mid-August MASIE showed the Arctic ice extent matching the 19-year average. Mid month Arctic ice went above average and remained in surplus, ranging from a high of +231k km2 to +160k km2 at end of August.

During August the average year loses 1.9M km2 of ice extent. MASIE on day 213 was 308k km2 down, and the gap closed steadily, going into surplus on day 230. Note 2020 and 2024 were well below average mid-August. 2024 ended nearly average, while 2020 went down almost off the chart. Meanwhile SII v.4 started August ~400k km2 lower than MASIE, increasing to -690k mid month, before drawing closer to MASIE (-200k km2) on the last reported day 242. More on what happened to SII in footnote.

The regional distribution of ice extents is shown in the table below. (Bering and Okhotsk seas are excluded since both are now virtually open water.)

Region	2025243	Day 243 Ave.	2025-Ave.	2020243	2025-2020
(0) Northern_Hemisphere	5112372	4952249	160123	4345398	766974
(1) Beaufort_Sea	646546	569909	76637	763281	-116735
(2) Chukchi_Sea	400517	284622	115895	212438	188079
(3) East_Siberian_Sea	563058	360155	202902	176996	386062
(4) Laptev_Sea	172574	175114	-2540	1029	171545
(5) Kara_Sea	2579	48983	-46404	23958	-21379
(6) Barents_Sea	0	15952	-15952	0	0
(7) Greenland_Sea	106688	167723	-61035	192361	-85673
(8) Baffin_Bay_Gulf_of_St._Lawrence	61034	27656	33378	5016	56019
(9) Canadian_Archipelago	278943	298169	-19226	273116	5827
(10) Hudson_Bay	8604	20611	-12006	23611	-15007
(11) Central_Arctic	2870279	2982526	-112247	2672903.81	197375

The table shows large surpluses in Eurasian basins Beaufort, Chukchi and E. Siberian, more than offsetting deficits in Central Arctic, Kara and Greenland seas. Hudson Bay is mostly open water at this time of year. 2025 exceeds the average ice extents by 160k km2, or 3%, and is 767k km2 greater than 2020, or nearly 0.8 Wadhams of ice extent.

September monthly average ice extent is considered the annual minimum for climate purposes. Note also that typically the lowest daily value occurs mid September, with a small positive gain between the end of August and end of September.

Why is this important? All the claims of global climate emergency depend on dangerously higher temperatures, lower sea ice, and rising sea levels. The lack of additional warming prior to 2023 El Nino is documented in a post SH Drives UAH Temps Cooler July 2025.

The lack of acceleration in sea levels along coastlines has been discussed also. See Observed vs. Imagined Sea Levels 2023 Update

Also, a longer term perspective is informative:

post-glacial_sea_level

Footnote Regarding SII v.4

NSDIC acknowledged my query regarding the SII (Sea Ice Index) dataset. While awaiting an explanation I investigated further. My last download of the SII Daily Arctic Ice Extents was on July 30, meaning that the most recent data in that file was day 210, July 29. The header on that file was Sea_Ice_Index_Daily_Extent_G02135_v3.

Then on August 1, the downloaded file had the heading Sea_Ice_Index_Daily_Extent_G02135_v4. So it appears that these are now the values from a new version of SII. As I wrote in my query, since March 14 all of the values for Arctic Ice Extents are lower in this new record. The graph above shows the implications for August as an example of estimates from SIIv.4.

In the past, SIIv.3 tracked MASIE with slightly lower values. But with v.4, larger monthly average deficits to MASIE were reported in July 2025 ( -282k km2) and in August (-440k km2).

The change started in January 2025 and will be the basis for future reporting. The logic for this is presented in this document: Sea Ice Index Version 4 Analysis

In June 2025, NSIDC was informed that access to data from the Special Sensor Microwave
Imager/Sounder (SSMIS) onboard the Defense Meteorological Satellite Program (DMSP)
satellites would end on July 31 (NSIDC, 2025). To prepare for this, we rapidly developed version
4 of the Sea Ice Index. This new version transitions from using sea ice concentration fields
derived from SSMIS data as input to using fields derived from the Advanced Microwave
Scanning Radiometer 2 (AMSR2) sensor onboard the Global Change Observation Mission – W1
(GCOM-W1) satellite. On 29 July 2025, we learned that the Defense Department decision to terminate access to DMSP data had been reversed and that data will continue to be available until September 2026.

We are publishing Version 4, however, for these reasons:

• The SSMIS instruments are well past their designed lifespan and a transition to
AMSR2 is inevitable. Unless the sensors fail earlier, the DoD will formally end the
program in September 2026.
• Although access of SSMIS will continue through September 2026, the Fleet
Numerical Meteorology and Oceanography Center (FNMOC), where SSMIS data
from the DMSP satellite are downloaded, made an announcement that “Support
will be on a best effort basis and should be considered data of opportunity.” This
means that SSMIS data will likely contain data gaps.
• We have developer time to make this transition now and may not in the future.
• We are confident that Version 4 data are commensurate in accuracy to those
provided by Version 3.

Oh Climate Change (pop song)

Posted on September 1 by Ron Clutz

https://suno.com/song/41d513c2-cba1-4c0f-b3c0-6197c65426c7?sh=aCPKpJB0WYleREsJ

Red link to website to play song. Text below. H/T Climate Depot

More Evidence Temperatures Drive CO2 Levels, Not the Reverse

Posted on August 30 by Ron Clutz

Robbins, 2025 Figure 2: Global tropic SSTs overlaid onto monthly atmospheric CO2 increases (Mauna Loa)

Kenneth Richard posted a No Tricks Zone article: Another New Study Suggests Most – 80% – Of The Modern CO2 Increase Has Been Natural. Excerpts in italics with my bolds and added images.

CO2 concentration increases are not the cause of rising temperature,
but an effect of rising temperature.

The 2025 paper by Bernard Robbins is Atmospheric CO2: Exploring the Role of Sea Surface Temperatures and the Influence of Anthropogenic CO2. Excerpts in italics with my bolds and added images.

Abstract

Close examination of the small perturbations within the atmospheric CO2 trend, as measured at Mauna Loa, reveals a strong correlation with variations in sea surface temperatures (SSTs), most notably with those in the tropics. The temperature-dependent process of CO2 degassing and absorption via sea surfaces is well-documented, and changes in SSTs will also coincide with changes in terrestrial temperatures, and temperature-dependent changes in the marine and terrestrial biospheres with their associated carbon cycles.

Using SST and Mauna Loa datasets, three methods of analysis are presented that seek to identify and estimate the anthropogenic and, by default, natural components of recent increases in atmospheric CO2, an assumption being that changes in SSTs coincide with changes in nature’s influence, as a whole, on atmospheric CO2 levels. The findings of the analyses suggest that an anthropogenic component is likely to be around 20 %, or less, of the total increase since the start of the industrial revolution.

The inference is that around 80 % or more of those increases are of natural origin, and indeed the findings suggest that nature is continually working to maintain an atmospheric/surface CO2 balance, which is itself dependent on temperature. A further pointer to this balance may come from chemical measurements that indicate a brief peak in atmospheric CO2 levels centred around the 1940s, and that coincided with a peak in global SSTs.

Source: The phase relation between atmospheric carbon dioxide and global temperature OleHumlum, KjellStordahl, Jan-ErikSolheim.

Introduction

Research into the influence SSTs have on changes in atmospheric CO2 includes the work by Humlum et al. (2013). When examining phase relationships, they found a maximum correlation for changes in atmospheric CO2 lagging 11-12 months behind those of global SSTs [1]. A paper by the late Fred Goldberg (2008) noted their correlation by examining El Niño events [2]. He also considered Henry’s law [3] in relation to SSTs, i.e. a temperature-dependent equilibrium between atmospheric CO2 and its solubility in seawater. Spencer (2008) also noted similarities between surface temperature variations with changes in atmospheric CO2 [4].

For the oceans specifically, areas of surface CO2 absorption and degassing are shown in maps provided by NOAA [5] and ESA [6] for example. These maps show that colder sea surfaces towards the poles are net absorbers of CO2 whilst the warmer surface waters of the tropics are net emitters. An analogy often cited is the greater ability of carbonated drinks to retain CO2 at cooler temperatures; this ability drops as the drinks get warmer.

Figure 1: Deseasonalised atmospheric CO2 data (Mauna Loa).

A strong correlation between changes in atmospheric CO2 and SSTs can be readily discerned from the relevant datasets. To illustrate, the upper graph in Fig. 1 plots atmospheric CO2 in parts per million (ppm) as measured at Mauna Loa, Hawaii, since 1982. The data [7] has been ‘deseason-alised’ by NOAA to remove natural annual CO2 cycles.

The similarity between the two traces is striking: short-term fluctuations in CO2 readings at Mauna Loa appear particularly sensitive to tropic conditions (if tropic SSTs are substituted for global SSTs in Fig. 2, the correlation is less strong). Warm tropical seas, with surface temperatures typically around 25-30 oC, cover almost one third of the earth’s surface. The most prominent peaks in the figure coincide with strong El Niño events. Taken at face value, and ignoring any influence from anthropogenic emissions, Fig. 2 suggests that if the tropic SST anomaly dropped to around -1 oC (with related drops globally) then the concentration of CO2 in the atmosphere, as measured at Mauna Loa, would level off.

Robbins, 2025 Figure 2: Global tropic SSTs overlaid onto monthly atmospheric CO2 increases (Mauna Loa)

An important point is that changes in SSTs will coincide with those of terrestrial temperatures, temperature-dependent changes to both terrestrial and marine carbon cycles and, taking into consideration the research by Humlum et al. (2013) who found that changes in atmospheric CO2 followed changes in SSTs, an assumption in the work presented here is that nature’s influence on atmospheric CO2 levels, as a whole, follows on from changes in SSTs.

Discussion

The techniques used in Analyses 1 and 2, aimed at discerning and estimating the human contribution to recent increases in atmospheric CO2, are based on processing of monthly data from both SST and atmospheric CO2 datasets. Using the technique described in Analysis 1, no contribution from human emissions to the measured increases in atmospheric CO2, since 1995, was discerned. Given an approximate 60 % increase in annual human emissions since 1995 this suggests, by itself, that any human contribution to the measured increases is likely to be relatively small compared to nature’s contribution.

For the technique described in Analysis 2, a figure of ~27 ppm was estimated for a possible human contribution out of a total increase of 143 ppm since 1850, equating to around 19 % of the total increase in atmospheric CO2 since the start of the industrial revolution. Thus the results of these two analyses, taken together, suggest that nature appears to account for around 80 % or more of increases in atmospheric CO2 since 1995.

The technique described in Analysis 3 examines the relationship between longer-term trends in SST datasets and atmospheric CO2 measurements. This data analysis goes as far back as the late 1950s, when the ongoing acquisition of atmospheric CO2 measurements began at Mauna Loa. The resulting three graphs show an apparent almost-linear long-term relationship between SSTs and atmospheric CO2. Linear trend lines fitted to these graphs produce gradients of between ~120 and ~145 ppm/ 0C for the three SST datasets examined.

Figure 15: Atmospheric CO2 as a function of global SST trend since 1958

As for anthropogenic CO2, published figures (e.g. GCB data) suggest a roughly linear relationship between cumulative anthropogenic emissions as a function of time, and atmospheric CO2 measurements from Mauna Loa. If it’s reasoned that this mostly accounts for the linear trends as calculated in Analysis 3, this reasoning would not fit with the findings of the first two analysis methods that suggest 80 % or more of recent atmospheric CO2 increases are of natural origin.

Conclusions

Analyses of SST and atmospheric CO2 data, acquired since 1995, produce an estimated atmospheric CO2 increase, possibly attributed to human emissions, of around 20 %, or less, of the total increase since the industrial revolution, thus inferring that around 80 % or more of the increase is of natural origin.

Further data examination points to an almost linear longer-term relationship between SSTs and atmospheric CO2 since at least the late 1950s, and is suggestive of nature working to maintain a temperature-dependent atmosphere/surface CO2 balance. Recent historical evidence of such a balance may come from chemical measurements that indicate a brief peak in atmospheric CO2 levels centred around the 1940s, and that coincided with a peak in global SSTs.

Human emissions of CO2 are about 1/20-th of the natural turnover, and the findings of the analyses presented here suggest that this relatively-small human contribution is being readily incorporated into nature’s carbon cycles as they continually adjust to our constantly-changing climate.

As for surface temperatures, the research by Humlum et al. concluded that changes in atmospheric temperature are an ‘effect’ of changes in SSTs and not a ‘cause’ as some might advocate. And Humlum’s ‘take home’ message from a recent presentation was:

‘What controls the ocean surface temperature, controls the global climate’ [33]. He suggests the sun would be a good candidate, modulated with the cloud cover.

Killer Climate Lawsuit on Shaky Ground

Posted on August 29 by Ron Clutz

Washington Free Beacon reports on shaky case to make climate change a killer First-Of-Its-Kind Lawsuit Blaming Oil Companies for Woman’s Heat-Wave Death Failed to Mention Her Heart Disease. Excerpts in italics with my bolds and added images.

‘The diagnosis and likely treatment for it is highly relevant,’
doctor tells Free Beacon

A first-of-its-kind lawsuit accusing some of the nation’s largest oil companies of causing global warming and therefore causing a Washington woman’s 2021 heat-wave death left out one critical detail: she had been diagnosed with heart disease.

Juliana Leon’s death certificate, obtained by the Washington Free Beacon, shows she had been diagnosed with hypertensive cardiovascular disease, a condition that stems from unmanaged high blood pressure and increases the risks of heart failure and sudden cardiac death. The medical examiner for King County, Wash., determined that the condition contributed to her death, meaning it wasn’t the direct cause of death, but made her more vulnerable to it.

The wrongful death lawsuit Leon’s daughter filed earlier this year against oil companies, however, failed to make a single mention of her underlying condition. It instead focused entirely on the direct cause of death: hyperthermia.

The revelation, which has not been reported until now, is relevant because it could explain why Leon succumbed to the high temperatures that hit the Pacific Northwest in June 2021, according to doctors interviewed by the Free Beacon. And it is important too because of the lawsuit’s potentially wide-reaching impact. If successful, the lawsuit could lead to dozens of similar wrongful death suits and even future criminal homicide prosecutions against the oil industry.

The lawsuit—the first instance of a case attempting to put oil companies on the hook for heat-related wrongful death—is part of a coordinated effort nationwide to use the courts to cripple the oil industry and usher in a green energy transition. Activists say such litigation will hold the industry accountable, while critics say it is designed to bankrupt the industry, something that would have devastating economic impacts.

“The main reasons for hyperthermia under these conditions include medications or skin conditions impairing the ability to sweat. People with hypertensive cardiovascular disease are likely to be taking such medicines,” said Jane Orient, the executive director of the Association of American Physicians and Surgeons and a clinical lecturer at the University of Arizona College of Medicine.

“I think the diagnosis and likely treatment for it are highly relevant,” she continued. “A body temperature as high as 110 is extremely unlikely without impairment in the body’s temperature-regulating mechanism, at least under the circumstances here. Most people will have dehydration, but not heat stroke, during a heat wave. This lady likely had both.”

Jeffrey Singer, a senior fellow at the Cato Institute and the founder of a private surgical practice in Arizona, agreed that the diagnosis could be relevant. Singer told the Free Beacon:

“Having hypertension and its cardiovascular stigmata, depending on severity, might affect a person’s risk of succumbing to hyperthermia. But it’s the hyperthermia that kills,”

Lawyers representing Leon’s estate and daughter did not respond to requests for comment.

Leon died on June 28, 2021, during an extreme heat wave, which ultimately claimed the lives of 100 people in Washington, state data show. According to the wrongful death lawsuit, Leon died in her car after the vehicle’s air conditioning system broke and as outside temperature exceeded 105 degrees Fahrenheit. Her internal temperature rose to 110 degrees Fahrenheit right before she died.

Two weeks earlier, Leon had undergone bariatric surgery, a weight-loss surgery that helps reduce the risk of heart disease and high blood pressure. As a result, she had been on a liquid diet in the two weeks leading up to her death. In fact, Leon died in her car on her drive home from the doctor’s office where she was informed that morning that she may begin to eat soft foods again.

Still, the lawsuit blames seven oil companies for her death, arguing that they knew their products caused global warming decades ago, but continued selling them anyway. The lawsuit states that the 2021 heat wave in the Pacific Northwest wouldn’t have occurred without human-caused global warming.

A study published in the American Meteorological Society’s journal Weather and Forecasting last year found that there is “little evidence” greenhouse gases amplified the heat wave and emphasized that weather forecasts for the event were “highly accurate.” “Global warming may have made a small contribution, but an extreme heat wave, driven by natural variability, would have occurred in any case,” it concluded. Singer told the Free Beacon:

“You don’t need climate change to have a heat wave. Humans have been experiencing heat spells since the beginning of recorded history,”

The Free Beacon reported last week that an environmental group funded by the powerful Rockefeller Family Fund is quietly steering the wrongful death suit. According to legal filings, Leon’s daughter quietly appointed a climate activist to serve as the agent for her deceased mother’s estate. Those documents were authored by lawyers at the Rockefeller-backed Center for Climate Integrity, a nonprofit leading the coordinated, nationwide plan to “drive divestment” from and “delegitimize” the oil industry through litigation.

Beware Claims Attributing Extreme Events to Hydrocarbons

Posted on August 28 by Ron Clutz

RIP. You did good science and for that we are grateful.

Roger Pielke Jr. alerts us to a dangerous development in the IPCC effort claiming loss and damage from using hydrocarbons. His blog article is A Takeover of the IPCC.

The IPCC’s longstanding framework for detection and attribution looks DOA in AR7

Pielke: The Intergovernmental Panel on Climate Change (IPCC) has just released the names of its authors for its seventh assessment report (AR7). The author list for its Chapter 3 — Changes in regional climate and extremes, and their causes — suggests strongly that the IPCC will be shifting from its longstanding focus on detection and attribution (D&A) of extreme events to a focus on “extreme event attribution” (EEA).

The IPCC AR6 was decidedly lukewarm to freezing cold on the notion of EEA, and emphasized the traditional D&A framework. Those days may now be over. World Weather Attribution (WWA) co-founder Frederika Otto has been put in charge of the chapter, along with another academic who focuses on extreme event attribution.

Pielke has a series of articles taking exception to EEA methods and claims. This post is a synopsis of work by Patrick Brown on the same issue, which is likely to be featured by climatists in the days and months ahead.

How Climate Attribution Studies Become Devious and Untrustworthy

Patrick Brown raises the question Do Climate Attribution Studies Tell the Full Story? Excerpts in italics with my bolds and added images, his analysis concluding thusly:

How a cascade of selection effects bias
the collective output of extreme event attribution studies.

Weather and climate extremes—such as high temperatures, floods, droughts, tropical cyclones, extratropical cyclones, and severe thunderstorms—have always threatened both human and natural systems. Given their significant impacts, there is considerable interest in how human-caused climate change influences these extremes. This is the focus of the relatively new discipline of Extreme Event Attribution (EEA).

Over the past couple of decades, there has been an explosion in EEA studies focusing on (or, “triggered by”) some prior notable weather or climate extreme. Non-peer-reviewed reports from World Weather Attribution (e.g., here, here, and here) represent some of the most notable examples of these kinds of analyses, and many similar studies also populate the peer-reviewed literature. The Bulletin of the American Meteorological Society’s “Explaining Extreme Events From a Climate Perspective” annual series compiles such studies, as does the Sabin Center for Climate Change Law, and they are also synthesized in reports like those from the IPCC (IPCC WG1 AR6 Chapter 11.2.3) and the United States National Climate Assessment.

The collective output of these kinds of studies certainly gives the impression that human-caused climate change is drastically changing the frequency and intensity of all kinds of weather extremes. Indeed, Carbon Brief recently published an extensive summary of the science of EEA studies, which begins with the proclamation, “As global temperatures rise, extreme weather events are becoming more intense and more frequent all around the world.”

However, these numbers cannot be taken as an accurate quantification of the influence of climate change on extreme weather because they are heavily influenced by a cascade of selection biases originating from the physical climate system, as well as researcher and media incentives. Identifying and understanding these biases is a prerequisite for properly interpreting the collective output of EEA studies and, thus, what implications they hold for general scientific understanding, as well as political and legal questions.

The large apparent discrepancy between the size of the influence of human-caused climate change on extreme weather reported in EEA studies (like those compiled by Carbon Brief) compared to more comprehensive systematic analyses (like those compiled by the IPCC) can, in large part, be attributed to the many layers of Selection Biases that influence the EEA literature’s collective output.

Selection Bias is a broad term that refers to any bias that arises from a process that selects data for analysis in a way that fails to ensure that data is representative of the broader population that the study wishes to describe.

Selection biases in the context of EEA studies include those associated with the physical climate system itself, those concerning proclivities and incentives facing researchers/journals, and those concerning the proclivities and incentives facing the media. They include

Occurrence Bias is a bias introduced by the physical climate system. Since EEA studies tend to be triggered by extreme events that have actually occurred, there is reason to believe that these studies will disproportionately sample events that are more likely than average to be exacerbated by climate change because the events occurred in the first place. Essentially, extreme events that are more likely to occur under climate change—and thus more likely to be observed—are going to be overrepresented in EEA studies, and extreme events that are less likely to occur under climate change—and thus less likely to be observed—are going to be underrepresented in EEA studies.

The map below illustrates this phenomenon. It shows changes in the magnitude of extreme drought under climate change. Specifically, it shows the fractional change in the intensity of once-per-50-year droughts (as quantified by monthly soil moisture) between a preindustrial and 21st-century run (SSP2-4.5 emissions) of the highly-regarded NCAR CESM2 Climate Model. Blue areas represent locations where the model simulates that extreme droughts become less frequent and intense with enhanced greenhouse gas concentrations, and red areas represent locations where the model simulates that extreme droughts become more frequent and intense with enhanced greenhouse gas concentrations. It is notable that overall, this model simulates that warmingdecreases the frequency and intensity of extreme drought in more locations than it increases it (consistent with soil moistening under warming simulated by other models).

Now, here’s the kicker: The black dots show locations where once-per-50-year droughts actually occurred in the 21st-century simulation and thus represent events that would plausibly trigger EEA studies.

What do you notice about where the dots are compared to where the red is? That’s right; the simulated EEA studies overwhelmingly sample areas where droughts are getting more intense and more frequent by the very nature that those are the types of droughts that are more likely to occur in the warming climate. The result is that the EEA sample is majorly biased: warming decreased the intensity of once-per-50-year droughts by about 1% overall, but it increased their intensity within the EEA sample by 18%!

Thus, if you just relied on the EEA sample, you would come away with an
incorrect impression not only on the magnitude of change in extreme droughts
but also on the sign of the direction of change!

Choice Bias arises when researchers use prior knowledge to choose events for EEA studies that are more likely to have been made more severe by climate change. A clear example of Choice Bias pervading the Carbon Brief database is there have been 3.6 times more studies on extreme heat than there have been on extreme winter weather (205 vs. 57). Another example would be the dearth of EEA studies on extratropical cyclones (the kinds of low-pressure systems with cold and warm fronts that are responsible for most of the dramatic weather outside of the tropics). The IPCC states that the number of extratropical cyclones associated with intense surface wind speeds is expected to decrease strongly in the Northern Hemisphere with warming. Yet, it is relatively rare for EEA attribution studies to be done on these types of systems, which results in an exclusion of this good news from the EEA literature.

Publication Bias could be playing a role, too, where researchers are more likely to submit, and journals are likely to publish studies that report significant effects on salient events compared to studies that find null effects.

From Clark et al., 2023

Finally, the climate reporting media ecosystem is characterized by actors whose explicit mission is to raise awareness of the negative impacts of climate change, and thus, there will be a natural Media Coverage Bias with a tendency to selectively highlight EEA studies where climate change is found to be a larger driver than EEA studies that do not reach such a conclusion. These selection biases are apparent at the aggregate level, but there is also strong evidence of their presence in individual studies.

A more recent specific example suggestive of many of these dynamics is a study, Gilford et al. (2024), titled “Human-caused ocean warming has intensified recent hurricanes”. This study was conducted by three researchers at Climate Central, which summarizes the study’s findings with the following infographic:

From Climate Central press release on Gilford et al. (2024).

Essentially, they claim that climate change is enhancing the intensity of all hurricanes and that the enhancement is quite large: Storms today are calculated to be an entire Category stronger than they would have been in a preindustrial climate.

This is a huge effect, and thus, if it were real, it is reasonable to expect to see clear long-term trends in metrics of tropical cyclone (hurricane) intensity like the accumulated number of major (Category 3+) hurricane days or the accumulated cyclone energy from all tropical cyclones (which is proportional to the square of hurricane windspeed accumulated over their lifetimes). However, any long-term trends in such metrics are subtle at best, both globally and over the North Atlantic.

From Colorado State University Department of Atmospheric Science Tropical Meteorology Project.

So, this is a microcosm of the aforementioned apparent discrepancy between more broad quantifications of changes in extremes and their associated EEA counterparts, and again, I’d argue there are several selection biases at play affecting the production and dissemination of the EEA study.

Let’s start with Choice Bias on methodology. Human-caused warming changes the environment in some ways that work to enhance hurricanes and in other ways that diminish them. The main way that hurricanes are enhanced is via the increase in sea surface temperatures (which provides the fundamental fuel for hurricanes), and the main way that hurricanes are diminished is via changes in atmospheric wind shear and humidity.

The net result of these countervailing factors pulling in opposite directions is that we expect fewer hurricanes overall, but when hurricanes are able to form, they can be stronger than they would otherwise. These factors, though, are small relative to natural random variability, and thus, they are difficult to detect in observations.

However, the Climate Central researchers made the methodological choice
to largely exclude the influence of factors that diminish
hurricane development from the study.

Are these Choice Biases in event type and methodology an accident? There are many reasons to believe they are not.

The research paper itself spells out that the motivation of the study is to “connect the dots” between climate change and hurricanes because “landfalling hurricanes with high intensities—can act as ‘focusing events’ that draw public attention” and that “Increased attention during and in wake of storms creates opportunities for public and private discourse around climate and disaster preparedness.”

Then, there is the extensive media coverage of this study. It was picked up by 134 news outlets and ranked in the 99.95th percentile of research articles (across all journals) of similar age in terms of online attention. Further, it was immediately incorporated into seven Wikipedia articles (likely having high leverage on AI queries, which would make its findings indistinguishable from scientific “fact”). This is affected by the aforementioned Media Coverage Bias, but it is also undoubtedly directly influenced by the efforts of Climate Central, which is explicitly an advocacy organization whose self-described specialty is media placement and dissemination.

The above sheds light on the reasons for certain choice biases in a particular study, but there is plenty of evidence that these selection biases are pervasive in the EEA field. After all, Dr. Myles Allen essentially founded the field with the motivation of answering the question, “Will it ever be possible to sue anyone for damaging the climate?”. This same motivation seems to animate many of the most high-profile scientists in the field today, like Allen’s protege, Dr. Friederike Otto (co-founder and leader of World Weather Attribution). She and her organization are frequently cited as bringing the necessary intellectual authority to credibly sue fossil fuel companies. She states the motivation of her work explicitly:

“Attributing extreme weather events to climate change, as I do
through my work as a climatologist, means we can hold
countries and companies to account for their inaction.”

Given the explicitly stated motivation of those in the EEA field, it is quite reasonable to suppose that there are major selection biases at play, and thus, it is not at all surprising that the collective output of the EEA field would look so different from more broad comprehensive assessments.

Surplus Arctic Ice late August 2025

Posted on August 23 by Ron Clutz

After a sub-par March maximum, by end of May 2025 Arctic ice closed the gap with the 19-year average. Then in June the gap reopened and in July the melting pace matched the average, abeit four days in advance of average. In mid-August MASIE showed the Arctic ice extent matching the 19-year average. Now with a week to go Arctic ice has been above average for the last five days, by over +200k km2 yesterday.

During August the average year loses 1.9M km2 of ice extent. MASIE on day 213 was 308k km2 down, and the gap closed steadily, going into surplus on day 230. Note 2020 and 2024 were well below average mid-August. 2024 ended nearly average, while 2020 went down almost off the chart. Meanwhile SII v.4 started August ~400k km2 lower than MASIE, increasing to 600k km2 yesterday. More on what happened to SII in footnote.