SHADES OF FALLEN ANGELS:

The findings from a team of American climate experts suggest that were it not for greenhouse gases produced by humans, the world would be well on the way to a frozen Armageddon.

Scientists have traditionally viewed the relative stability of the Earth’s climate since the end of the last ice age 10,000 years ago as being due to natural causes, but there is evidence that changes in solar radiation and greenhouse gas concentrations should have driven the Earth towards glacial conditions over the last few thousand years.

What stopped it has been the activity of humans, both ancient and modern, argue the scientists.

Heh. Whole story here.

UPDATE: I believe that this is the paper described above. Make of it what you will — except that if what you want to make is a perversely delightful thesis for a science fiction novel, well, it’s already been done. And though I think I’ve mentioned this before, you can read Fallen Angels for free at (where else) the Baen Free Library.