A far greater man-made threat to the natural world from humanity is a all out nuclear war. That threat has receded from imminent global threat in 1962-1989 to merely “possible” or “regional” threats in the post 1989 world. However, I would argue that nuclear weapons still pose one of the greatest threats to the long term survival of the natural world. An asteroid hitting Earth is also possibly a preventable extinction level event.

This doesn’t diminish the threat to the natural world by climate change. But I think the greater threat, as with global nuclear or asteroid, is that humanity would cease to exist. Thus, I think Klaatu framed the question incorrectly. If a good portion of the natural world dies and the oceans rise, we will be the species that is losing our food supply and habitat.

Harming the natural world harms humanity’s long term survival. It’s in our own interest to fix the climate change problem. As the book, the World Without Us illustrates, nature can heal itself really quickly if given as chance.

And all of this assumes we’ll even have fossil fuels in large quantities to burn in 100 years….