“The fact is that the planet is changing faster than even pessimists expected: ice caps are shrinking, arid zones spreading, at a terrifying rate. And according to a number of recent studies, catastrophe — a rise in temperature so large as to be almost unthinkable — can no longer be considered a mere possibility. It is, instead, the most likely outcome if we continue along our present course.
Thus researchers at M.I.T., who were previously predicting a temperature rise of a little more than 4 degrees by the end of this century, are now predicting a rise of more than 9 degrees. Why? Global greenhouse gas emissions are rising faster than expected; some mitigating factors, like absorption of carbon dioxide by the oceans, are turning out to be weaker than hoped; and there’s growing evidence that climate change is self-reinforcing — that, for example, rising temperatures will cause some arctic tundra to defrost, releasing even more carbon dioxide into the atmosphere.
Temperature increases on the scale predicted by the M.I.T. researchers and others would create huge disruptions in our lives and our economy. As a recent authoritative U.S. government report points out, by the end of this century New Hampshire may well have the climate of North Carolina today, Illinois may have the climate of East Texas, and across the country extreme, deadly heat waves — the kind that traditionally occur only once in a generation — may become annual or biannual events.”