I expect a number of my readers are objecting to my claim that global warming is accelerating.
“Look,” they might say, “you’ve drawn a conclusion based on only two sample time periods, and you’ve only been able to show a gradual, linear rising trend for each of them. You’ve haven’t shown any evidence for an exponential curve !”
|Well, yet’s it’s true, I only presented the evidence that it appears that there is a linear (straight) rising trend in global average temperature in the periods 1970 to 2011 and 1915 to 1945. And show that the rising trend is steeper in the period 1970 to 2011 than in the period 1915 to 1945.
What I have not yet done is give a bit of perspective. You see, in historical, geological terms, recent temperature rises are on the steep part of an exponential curve – so steep and so sharp that they appear to be in a straight line.
From where we are now, our perspective is that the temperature rise looks like a straight line – a gradual change. But if you step back and see the bigger picture you will see that what looks like a straight line slanted to rise is the upper part of a very steep upward moving curve – the almost vertical part of an exponential.
So now we come to the justly famous Hockey Stick, because it is still competely unrivalled, and has been repeatedly vindicated, as the best reconstruction of temperatures over the last thousand years.
What my simple charts do is merely map the data from a couple of short sections of the steepest part of the curve, to show that the steepness of the curve has increased more towards the vertical. The temperatures are shooting up – becoming yet more vertiginous :-
My claim that global warming is accelerating is perfectly justified from this perspective – and this speeding up of global warming is directly attributable to rising atmospheric greenhouse gas emissions – most of which are manmade.