What prompted all the headlines about a hothouse Earth?
We tend to use “ice age” to mean a period where large ice sheets push south to what are now temperate regions. But from a geologist’s perspective, even current conditions are part of an ice age, since large ice sheets exist at the poles. The term provides a contrast to what are called hothouse conditions, which the Earth has experienced for periods that were long enough to entirely melt the poles. The planet hasn’t seen hothouse conditions for over 2.5 million years.
But this week, headlines were full of discussion of a possible return of a hothouse Earth courtesy of climate change. The sudden worries weren’t the product of any new research; instead, they were simply the product of a perspective some researchers had written on our current understanding of the climate, plus some potential risks associated with it. The perspective argued that there are multiple tipping points in the climate, and we can’t rule out shooting past them even if we get emissions under control within a few decades.
Hot hot hot
So how seriously should we view this risk, and why are scientists suddenly talking about it now?