From Tallbloke’s Talkshop
May 7, 2023 by tallbloke
Old monkeyface emailed me to say: No, not five years of planetary existence! We have only five years left before the climate emergency unravels entirely.
How do I get to that prediction? We all know how hard predictions are, especially about the future. Well, I base it all on the fundamental observation that the planet has cycles and whether we understand them or not those cycles are going to carry on cycling, and we really should just get used to it.
Now radiative physics is pretty straightforward, but the whole climate emergency is based on a substantial amplification of the modest (and probably beneficial) warming that the recent increase in carbon dioxide concentrations has allegedly contributed to. And the climate klaxons are blaring full blast because people seem to believe that the earth (which has been around a while) is teetering on the edge of countless precipices. Should we cross this threshold, or that limit, they tell us, we will plunge over the edge into a hothouse world.
Personally, I’m a tad more concerned that we slip into another ice age, mini or major; that would be much more damaging to the human race and more difficult to adapt to than a warmer world. But let’s examine one of those precipices in a bit more detail.
We are always being told that the Arctic is the canary in the coal mine, so let’s poke that canary and see if it is chirping happily away or if it is about to take over from the infamous parrot in a Monty Python sketch.
The first chart I have prepared is my version of one that the good folks at the Polar Science Center publish on a regular basis. Here is their version, you can get it at this URL: http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/
The references to the relevant paper is here: Schweiger, A., R. Lindsay, J. Zhang, M. Steele, H. Stern, Uncertainty in modeled arctic sea ice volume, J. Geophys. Res., doi:10.1029/2011JC007084, 2011
PIOMAS stands for Pan-Arctic Ice Ocean Modelling and Assimilation System and the chart above shows the sea ice volume anomaly that they calculate based upon satellite observations. It is all good work, and I don’t doubt their data at all, but I think there is a better way to look at it. Here is my version of their chart.
What’s the difference? Well not a lot, what I do slightly differently is that I add the average September minimum to the monthly anomaly, the reason for doing that is that it gives you a slightly more intuitive number and when it gets to zero that is when you would have an ice-free arctic in September. Looks like we need to get our skates on if we want to pirouette at the North Pole, as by 2035 there won’t be a floe, a polar bear, or a canary, in sight.
The coefficient of determination (or R squared value) is very high at 89%, so obviously this relationship is almost perfect. By the way my yellow bar is two standard deviations either side of the linear relationship and hardly any points lie outside that band.
But there is another way of looking at this dataset. What if, instead of a simple linear relationship, we contemplated a cyclic system? How good a match could we get to that model? Here I have tried a 65 year cycle, and, what do you know, the coefficient of determination is even better at 92%.
Well which is the right model? Here is the thing, we won’t have to wait until 2035 to know which model is the more representative, we will know within five years. I’ve plotted out the linear doom-mongers projection and my more optimistic cyclic projection on the same chart and by 2028 we will know whether the Arctic has stabilised and started to recover or we are well on the way to climate oblivion.
Up to now, it was beyond our ken to really tell the difference. Of course, the match to the cyclic system is better than a linear system, but the data all fell into both bands pretty well.
The final data point in this series, April 2023, is more consistent with a cyclic system than a linear model, but by 2028 those bands will have entirely deviated one from the other, and whether the data falls in one band or the other will tell us if the world’s climate is controlled by the carbon dioxide knob, or if natural cycles dominate.
I’m pretty confident that it will be the cycles. You see 1979 when the satellite records start was a pretty cold year. Here is a Science News cover from 1975 catastrophising about a coming ice age, which in truth really is something to worry about.
But rather than headlines let’s look at some data. Here is the Atlantic Multi-decadal Oscillation index from 1860 to January 2023. I have added a curve which averages the previous five years and the five years before that on a declining weighting. I got this data here: https://psl.noaa.gov/data/timeseries/AMO/
Let’s add on the sea ice data and see if we can spot a correlation.
Nothing to see here folks, move on, move on.
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