If Gaia is dying then chances are that is is by indigenous causes.

How inflated does our collective ego have to be for us to imagine that we have the capability to inflict any damage whatsoever comparable to that of the Siberian comet/asteroid of the early 20th century or the Yucatan peninsula comet/asteroid impact that wiped out the dinosaurs 65 million years ago?

Even the eruption of Krakatoa in the late 19th century, a single natural event, had more global impact than we could possibly muster if we ran all of our vehicles and factories at once whilst simultaneously triggering every nuclear device in the world today.

Come on guys, get real.

This planet, as is commonly known, has experienced numerous and more horrific environmental changes than we could ever survive or even imagine. This precedes any human impact, real or imagined, on our environment.

However, anyone with the merest hint of awareness knows that the our race has a limited time in which to develop a means of colonising host planets if we have the determination required to secure the future of our descendants.

The alternative is that our species, along with 99% or more of all others here, will join our unwritten and forgotten ancestors. This, despite Hollywood, scaremongers and sci-fi writers, seems unlikely to come about over the next week, day, month, year, decade or even century or so, and therefore we do have a comfort zone of time in which our technos can or may organize our escape.   

Our immediate concern, as current front-runners in the food chain on Earth, relates only to our ability to adapt to the changes promised in the immediate future. With our proven ingenuity this should not be an insurmountable problem.

Reincarnation is both a separate issue and an irrelevance to humanists like myself.

The concept of mass extermination of our fellow humans by pandemic or world war, two 'saving' possibilities embraced by an earlier poster, was an antiquated view when I heard it first in the 1950s and shows, at best, a limited imagination and, at worst, a solution acceptable only to those without future or progeny.

That my children, grandchildren or great-grandchildren should die in such a futile sacrifice would be not only unacceptable but unthinkable.

When we have left this planet it may freeze, boil, or just stumble along in its own way, unaware and uncaring that we have been here or that we have left.   

Man, IMO, will merely have 'abode his hour or two'.