The idea that humans can colonize other planets is plausible. You send a thousand smart people to Mars with the right supplies and equipment and they could use it to build a self-sustaining infrastructure that then grows into a community of millions.

The idea that ten billion humans are going to take off in spaceships and abandon the Earth is utterly preposterous. The last human on Earth will die on Earth, not leave it for some other place.

It's weird how we seem to understand exponential growth of technology but have a hard time grasping the exponential build-up of excess greenhouse gases due to the exponential growth of human population and economy.

I wonder how these thousand years might look if currently there have been temperature difference of extremes by 20 degrees, with average already raised by 2.

For example, mass extinction of oceanic ecosystems is due to somewhere around 2050s. Whole oceans will get empty very quickly. http://science.sciencemag.org/content/314/5800/787

Collateral victim count of ~3 trillion yearly deaths of oceanic animals is a big contributor.

We'll see how the world will cope when main oxygen producers disappear.