We are already in the midst of a mass extinction event. The regularity with which new or threatened extinctions are announced – from the white rhinoceros to the lemur – is staggering. The background rate of extinction is 150-200 species a day. This is “biological annihilation”. Mass extinction is not new, but its speed is. The last such event took around 60,000 years. Now it’s happening in real time.
And there are accelerators built in to this crisis. The Arctic is already gone. By 2040, the ice will have melted for good. That entails the loss of species, not least of the polar bear. But it also means less solar radiation deflected, further warming the planet.
This is one reason why the crisis is far worse than we think. Paleoclimatologists have shown that past warming episodes show that there are mechanisms which magnify its effects, not represented in current climate models from the Intergovernmental Panel on Climate Change to the Paris Accords. The agreed “carbon budget”, even if anyone was adhering to it, will not keep temperatures within two degrees of the pre-industrial average.