It sounds like a simple question, and you might assume that the answer is either “Yes” of “No”, but the truth is that neither answer is correct.
I very much like the way that Tom Chivers has described it in the Telegraph …
Imagine you have a big fairground Wheel of Fortune thing, with the numbers one to 10 on it and an arrow at the bottom which shows the winning number. If you spin it 100 times, you’d expect to see the number 10 come up roughly 10 times. Then you put a small weight on the number 10, and spin it again. Say it lands on the 10. Did the weight cause the 10 to come up? What does that mean? It might have landed on a 10 anyway.
But if you spin it another 100 times, and find that instead of getting the 10 about 10 times, you see it 50 times, you can say with confidence that the added weight has caused the statistical change. It’s meaningless to ask, of each individual spin, what “caused” it – the different factors, like how hard you spun it, how well the axle is greased, etc, all contribute. But over the longer term, you can observe the changes in probability, and see the effect that the weight is having on average.
Yes indeed, tempting as it might be to claim that Sandy was a result of global warming, it is just not like that, “Sandy” type events will happen anyway.
It is always a good sign when somebody makes the observation “it’s not as simple as that…”. Indeed not, we know that man-made climate change is real, there is no doubt about that, but putting your finger on a specfic weather event and attempting to claim “Ah ha, climate change” is something that you can’t do because there are too many other factors in the mix, weather is both complex and also very chaotic, so freak extreme events will happen.
Where Climate Change does emerge is when you start to look at the longer term trends.
Some Nice Climate Change Stats
Here are a couple of nice charts that really do sum it all up. First we have one that shows how some present the data, and then shows you what the data actually tells us.
It beautifully illustrates how it is possible to utilize a smaller snippet of data to make a very misleading claim, and then contrasts it with what is actually going on. The above comes from www.skepticalscience.com Yes, almost the same name as mine, but not me, its a very rich source of good solid climate change information. There the above is explained …
Average of GISS, NCDC, and HadCRUT4 monthly global surface temperature anomalies from January 1970 through August 2012 (green) with linear trends applied to the timeframes Jan ’70 – Oct ’77, May ’77 – Dec ’85, Jan ’86 – June ’94, Nov ’94 – Dec ’00, Jan ’01 – Aug ’12 (blue) and Jan ’70 – Aug ’12 (red).
There is also an Arctic Sea Ice chart that illustrates the same pattern …
Once again, we can see what is really going on, in fact so much ice has melted, it is rather hard to dispute that now. The above is described as..
NSIDC September Arctic sea ice extent (blue diamonds) with “recovery” years highlighted in red, vs. the long-term sea ice decline fit with a second order polynomial, also in red
The climate scientists no longer doubt the reality of man made climate change, it is very very real and is indeed happening, that is what the data tells us.