OK, once more, the rate of change is an important factor. Yes, climate has always changed but usually at a much slower rate which allows for biological accommodation. When rapid change has occurred, major extinction events happen, the worst one being the Permian in which some 95% of terrestrial species and 70 % of marine species disappeared, and that was over a time period of about 20,000 years (http://news.mit.edu/2011/mass-extinction-1118). Compare that to the rate of change we are seeing now occurring over a period of maybe 200 years which is unequivocally driven by human activity (https://en.wikipedia.org/wiki/File:T_comp_61-90.pdf). That’s change at a rate 100 times faster that the Permian Great Dying.
Bottom line: If we don’t change our activities we’re gonna be toast—literally.
(Sigh)
OK, once more, the rate of change is an important factor. Yes, climate has always changed but usually at a much slower rate which allows for biological accommodation. When rapid change has occurred, major extinction events happen, the worst one being the Permian in which some 95% of terrestrial species and 70 % of marine species disappeared, and that was over a time period of about 20,000 years (http://news.mit.edu/2011/mass-extinction-1118). Compare that to the rate of change we are seeing now occurring over a period of maybe 200 years which is unequivocally driven by human activity (https://en.wikipedia.org/wiki/File:T_comp_61-90.pdf). That’s change at a rate 100 times faster that the Permian Great Dying.
Bottom line: If we don’t change our activities we’re gonna be toast—literally.