Before we humans came along with our Industrial Revolution and our greenhouse gases, the earth was hurtling towards an intense ice age that could have covered much of the northern hemisphere with deep ice sheets as soon as 10,000 years from now, according to a tentative new study. But that's no reason to thank our lucky stars for global warming, says study coauthor Thomas Crowley:
"We're creating a situation at least as dangerous, only going in the opposite direction" [Wired News].
Climate data shows that complex life evolved on a much warmer "hothouse earth," and that the planet has been gradually cooling for the last 50 million years.
Then, 2.5 million years ago, the climate entered a curious new phase: it started oscillating wildly, see-sawing between interglacial periods with conditions similar to today's and ice ages during which the amount of permanent ice in the northern hemisphere expanded hugely. At ...
