Tonight at 9 pm on ABC, “Bob Woodruff explores what might be the worst case scenario for civilization.”

Help Grist raise $25,000 by September 30 to further advance our climate reporting

Hurray for the mainstream media exploring the worst-case scenario aka Hell and High Water! I am very interested in your thoughts on this show — before and after. One of the most commented on posts of this year was “How likely is it that Global Warming will destroy human civilization within the next century?

You can see video excerpts and viewer submissions on what looks to be an excellent website:

Grist thanks its sponsors. Become one.

Experts say over the next hundred years the “perfect storm” of population growth, resource depletion and climate change could converge with catastrophic results….

“If we continue on the business as usual trajectory, there will be a tipping point that we cannot avert,” says John P. Holdren, science advisor to President Obama. “We will indeed drive the car over the cliff“….

“A few hundred years down the line, they’ll look back and say the dark ages began with the twenty-first century,” says E. O. Wilson, an award-winning evolutionary biologist and professor at Harvard University.

Here’s more on the two scenarios the show lays out for humanity’s future:

Grist thanks its sponsors. Become one.

Imagine a world in which cities are abandoned and our population has dropped by 90 percent. A world in which we have wreaked havoc on our delicate ecosystems and nature has begun to reclaim Earth. Once-bustling cities have fallen silent except for the rustle of the wind through the grass and trees that have cracked through the collapsing pavement. Humans have not walked these urban streets for years.

And some people say I’m an alarmist!

Does it seem like the stuff of science fiction? According to the world’s top scientists, it could very well be the legacy we leave our children and grandchildren. They say we are at a turning point, that the choices we make today will determine if the human race, as we know it, will survive.

Imagine our future as two doors. Door No. 1 is our current path, or as the scientists put it, business as usual. If we continue on this trajectory, experts say, over the next 100 years the “perfect storm” of population growth, resource depletion and climate change will converge with catastrophic results. In this scenario the combination of war, famine and disease has the potential to “decimate” the world in less than a hundred years.

Note to ABC: “Decimate” technically means kill every 10th person, but that has changed with popular usage. That said, the ABC scenario is much harsher than mine. Climate change killing every 10th person by 2100 — one billion people — would be a staggering outcome. I personally cannot even conceive of what losing 90% would mean.

“Earth 2100″ takes viewers through door No.1, with the help of a fictional character, Lucy. Born in the year 2009, Lucy guides us through the next century as it may well unfold, if we don’t take drastic measures. With the assistance of some of the world’s foremost scientific experts, she gives us a detailed decade-by-decade countdown to the collapse of society.

But it does not have to be. “Earth 2100″ will conclude by traveling through door No. 2. The clock resets to 2009, and using the same chronology and the same scientists, we leave the viewer with the inspiring story of an alternate future. The experts tell us what actions we must take to survive and describe the world we can create. In this version, Earth in 2100 will be one we would be proud to imagine.

It does not have to be!

UPDATE: This was certainly the best done worst-case scenario mainstream media has ever put in front of the American public. I have a bunch of little quibbles — no one’s going to be abandoning the American suburbs just because gasoline hits $5.50 a gallon, as the show depicts — see “Why I don’t agree with James Kunstler about peak oil and the “end of suburbia.“ Heck, Great Britain has had gasoline costs above seven dollars a gallon for many years and the life goes on. But ABC deserves a lot of kudos for laying out so many realistic threats that humanity faces on the business as usual path.