In the fable of Snow White, the evil step-mother asked her hand mirror: “Who is the fairest in the land?” The mirror on the wall always flattered her, but this mirror did not. As we all know, the hand mirror told the truth, the queen was angry and people had to suffer.
We expect mirrors to tell the truth, to show us the objective reality. That is why it is amusing at the carnival sideshow to gaze into mirrors that make normal people look obese or like a beanpole, or otherwise distort one’s appearance.
This post is about what Arctic Ice Extent looks like in the mirrors available to the public.
If you wonder what is happening with Arctic Ice, the first (and maybe only) depiction you encounter will look like this:
I call this The Incredibly Shrinking Ice Mirror, because it is certainly scary (Death Spiral comes to mind). Ice is obviously going to hell in a hand-basket. Once your fright abates, you might wonder about the scale or how much ice is measured. And you might notice this is about September; other months of the year are excluded from view.
You wouldn’t know from this chart that scary looking 2012 had one of the higher March maximums and on average was not so far out. But that wouldn’t be as exciting.
Just for fun, let’s make a mirror from the same dataset, just one month later. I call this The Incredibly Persisting Ice Mirror.
You won’t find this one on the Internet because it is politically incorrect and pretty boring. But it is just as valid as Mirror #1. It is showing a very slow, unalarming decline with something unusual in 2007, but recovering after that.
Is it a distortion? Absolutely, it is incomplete in the same way as Mirror #1, but gives the opposite impression, just by choosing a different month. But at least this one informs your impression with the actual monthly average extents in M km2 (no anomalies or %s).
There are more informative pictures of Arctic Ice dynamics if you look for them. For example, there is this presentation of the complete dataset:
I call this The Bird’s Eye Ice Mirror because you can see the big picture from the satellite passive microwave sensors: the full range of annual variation, the actual measured extents and averages. Note the trend line looks much more like October than September. Is there a reason September is preferred?
As I have pointed out there are other views of ice extent patterns, such as this:
Let’s call it the The Navigator’s Eye Ice Mirror because it is the accumulation of the ice extents you could expect to observe at sea level from buoys or from the deck of a ship operating in the Arctic region (source: MASIE ice charts).
Of course, there are other mirrors trying in their own ways to tell us about Arctic Ice.
Here’s two Magnifying Ice Mirrors, giving you closeups of what is happening with the ice:
Let’s not forget The Rear-view Ice Mirrors showing that there were ice observations long before the satellite record started in 1979.
Figure 16-3: Time series of April sea-ice extent in Nordic Sea (1864-1998) given by 2-year running mean and second-order polynomial curves. Top: Nordic Sea; middle: eastern area; bottom: western area (after Vinje, 2000). IPCC Third Assessment Report
We know as a fact of life that any mirror contains some distortion or bias, even those trying to tell the truth. So it is wise to look at several of them, and pay attention to the frames, before concluding what is happening. Be sure to have a chuckle when you pass by Mirror #1. Although setting energy policies and investing billions of research dollars based on that distortion is not amusing.
Some commentators wondered whether the statistics are affected by icebreakers. I don’t know, but there is evidence of a Norwegian icebreaker in operation:
Reblogged this on Climate Collections.
Great fun. Worth emphasising a lot.
With climate mirrors you may get some smoke as well 😉
Or the fog of the climate wars.
Nice post Ron. You should follow up wiith a look at Antarctic ice too.
I prefer to look at the record from 1979 (and the record for all the months is on the FTP site) rather than the record from 2006, as the latter is way too short. To remove the effect of seasonality, one could even plot 12 graphs – one for each month. I prefer to use a y-axis that does not cover a range that is wider than the range of values, which you do in your ‘NH Arctic Ice Extent October’ graph, as that tends to under-estimate the variation. Trend lines (as in your first graph) can be helpful here. I don’t know what software you use, but they are very easy to plot in Exvel.
Richard, Mirror 2 is intentionally misleading, only in the opposite way than the first one. Mirror 3 is an honest one.
Also the y scale on Mirror 2 is appropriate since it must cover the full range of outcomes: all the way from the highest observed value to ice-free conditions. Wadham’s prediction this summer of 1M km2 can be located on the scale and compared to actual observations.
Thanks, that’s a good point.
Reblogged this on WeatherAction News.
I kind of liked the Icebreaker……:-)…pg
No telling how Nordic seas numbers have accounted for this over the decades.
Maybe there should some adjustments. :>)
Putting alarmist hype into perspective is always a good thing. The only thing real about the alarmists is that they are really wrong.
I understood the comment on WUWT about the block of time being chosen so everyone is looking at the same thing. I am going to say it again here – how do we know that the block of time – 1980 – 2010 – is relative to the actual average extent of sea ice? I actually can accept satellite data as being something that you can measure, if you will, to determine the extent, but any time prior to that leaves the extent in mystery – you can’t fly over the entire amount in 24 hours, as an example, to have a “picture” of what it looks like to estimate it. And prior to planes, you couldn’t honestly do more than “guess” at what it might be. Yet we treat the period of 1980-2010 as if the average of those 30 years exactly reflects historical ice extent. Like so many things we use, including proxies, we do NOT know squat, we are guessing, which, after all, is all a proxy really is – a guess. To actually program how man is supposed to live from this day on based on what we KNOW, is like deciding how to live your life after 35 based on a 20 minute period of a day when you were 12 years old. Worse still, there are those that are deciding how you are to live your life after 35 based on 20 minutes of their friend’s dreams at age 12. Sounds ridiculous on the face of it, and it is ridiculous in actuality. Science calculates a lot, guesses more, and knows damn near next to nothing, but it sure is sure!
My response Tom is: Yes we are too short of data to be sure of very much. When it comes to sea ice, there are charts of observations going back before the 20th century. Limited in scope, but observations none the less.