Of course, as the climate changes today — much more quickly than it has in the past — the question again is how life will adapt to a warmer world. Though the PNAS study doesn’t make any projections, other research has — and it doesn’t paint a pretty picture. It’s difficult to get a firm idea of how wildlife might adapt — or not — to rapid climate change, which makes it hard to project actual numbers of extinctions in a warmer world. The PNAS study shows that temperature change in the past has led to changes in species diversity; when it comes to man-made global warming though, we’re embarking on an unplanned experiment without a control group.
The good news — of sorts — is that the earth has experienced massive climate change and massive species die-off through its 4.5 billion-year history, and every time, life eventually bounces back. Climate change — even drastic climate change — isn’t new for the planet. But something else is: us. The earth has never seen a species as numerous or as demanding as the modern Homo sapiens, spread to every corner of the world, using up resources and transforming the planet through agriculture, mining and deforestation. Science looks to the past to try to understand the future, but nothing like us has ever happened to the earth before.