Originally Posted by addabox
600 million to 20 million years before man, actually. And your chart depicts 10 degree average global temperature shifts occurring over tens of millions of years.
I'll leave it for you to work out how that differs from what we're talking about.
The PermianTriassic extinction event
The PermianTriassic (PTr) extinction event, informally known as the Great Dying, was an extinction event that occurred 251.4 million years ago, forming the boundary between the Permian and Triassic geologic periods. It was the Earth's most severe extinction event, with up to 96 percent of all marine species and 70 percent of terrestrial vertebrate species becoming extinct; it is the only known mass extinction of insects. Because so much biodiversity was lost, the recovery of life on earth took significantly longer than after other extinction events. This event has been described as the "mother of all mass extinctions".
So if this graph is accurate, in it's own "cartoonish" way then the above extinction event coincided with a 1 degree centigrade temperature rise. Oh, and the horizontal scale is ~1.000.000 years/pixel, meaning that the resolution is so course, that we could never obtain meaningful rates of temperature change, which is the subject de jour.
So for example, if we use the current estimate of 0.10 degrees centigrade per decade, which is a low estimate, then for 1,000,000 years, the global temperature will be 0,10 *1,000,000 / 10 = 10,000 degrees centigrade. OK, I'll admit that this won't happen, because well before then, man would become extinct.
So now lets look at a 10 degree centigrade temperature rise based on the range shown in this graph; 10 degrees centigrade / 0.01/year = 1,000 years (or one thousand years). Now that is most certainly doable given a highly industrialized society of ~ 10 billion people and the plentiful supply of fossil fuel in the form of coal.
Now go back to the "cartoon" graph. Do you see anywhere on that graph a rise (or fall) of 10 degrees centigrade occurring in just 0.001 pixels (i. e. 1,000 years)? Do you even see a 10 degree centigrade rise over just one full pixel (i, e, one million years)?
The answer is the same for both, no and no.
We are talking about climate change
are we not? And we are not talking about climate stasis as shown by the 22 degree centigrade climate plateau's, correct?
So to sum it all up in three words it's all about the rate of change
. It is not about what temperature regimes existed in the past, but how rapidly the temperature changes from one extreme to the other. In that regard this "cartoon" graph is virtually useless.