With all the concerns about global warming and climate change one might ask the question, "Why don't species just adapt?" Don takes the devil's advocate position and discusses this with Yael.   D: Yael, we know global warming is bad, right? I mean, the temperature of the air on the Earth's surface is projected to increase at a rate more rapid than any temperature change that has taken place in the last ten thousand years.

Y: Yep--the forecast is pretty grim.

D: So my question is: Why can't species simply adapt to these changes? I mean, they've had to adapt to climate change in the past.

Y: Well, for starters, thanks to ecosystem changes due to agriculture and deforestation and pollution, many species are already weakened to begin with. Plus, in the past, climate change has happened slowly enough that many species had enough time to shift the locations where they grow and reproduce. But the current projected rate of surface temperature change would require for plants to move at a rate of 3.5 miles per year.

D: That's not that bad.

Y: It is if you consider that the fastest plant species only migrate at the rate of 1.3 miles a year.

D: Wow. But that's just plants. What about animals?

Y: It's a problem if their food source doesn't move with them. And it doesn't help that all of the different ways we use land means that the Earth is pretty much a mosaic of different ecosystems rather than larger, contiguous habitats.

D: Oh, so even if a species is able to migrate quickly enough, it has nowhere to go and nothing to eat.

Y: Yep. So you see, Don, the Earth's species simply don't have enough time and resources to adapt to such rapid climate change, and that's why many aren't expected to survive if global warming continues at its currently projected rate.