It's an idea that most of us would rather not face -- that within the next century, life as we know it could come to an end. Our civilization could crumble, leaving only traces of modern human existence behind.
It seems outlandish, extreme -- even impossible. But according to cutting edge scientific research, it is a very real possibility. And unless we make drastic changes now, it could very well happen.
Experts have a stark warning: that unless we change course, the "perfect storm" of population growth, dwindling resources and climate change has the potential to converge in the next century with catastrophic results.
Watch "Earth 2100," a two-hour television event, Tuesday, June 2, at 9 p.m. ET.
In order to plan for the worst, we must anticipate it. In that spirit, guided by some of the world's experts, ABC News' "Earth 2100," hosted by Bob Woodruff, will journey through the next century and explore what might be our worst-case scenario.
But no one can predict the future, so how do we address the possibilities that lie ahead? Our solution is Lucy, a fictional character devised by the producers at ABC to guide us through the twists and turns of what the next 100 years could look like. It is through her eyes and experiences that we can truly imagine the experts' worst-case scenario -- and be inspired to make changes for the better.
For more information on the climate change war game featured in Earth 2100, click HERE.
By 2015, there are expected to be hopeful signs. Experts predict alternative energy solutions that are currently in their infancy will gain momentum. Windmills may sprout up everywhere. Off the coast of Scotland, a sprawling wave farm will harvest renewable energy from the ocean. Vatican City will meet all of its energy needs with solar power. And the U.S. will produce cleaner, more fuel efficient vehicles in accordance with newly unveiled emissions guidelines.
But will it be enough? In 2015, global demand for fossil fuels could be massive and growing, but experts say oil will be harder to find and far more expensive to consume.
"We have no new source of energy on the horizon that's currently capable of being developed on a large enough scale to replace the supply of oil in any near- term framework," says Michael Klare, professor of peace and world security studies at Hampshire College.
If the cost of gasoline skyrockets, few may be able to afford to maintain the lifestyles to which we've grown accustomed. There may be a mass exodus from the suburbs, as driving gas-fueled cars becomes nearly impossible economically. But will that convince us to change our ways?
"Until we have a crisis of some kind, I don't think we're going to be motivated to make the really deep changes in the way we use energy, the technologies we use, the density of our cities, our travel patterns," says Thomas Homer-Dixon, a political science professor and author of "The Upside of Down."
The imagined crises in Lucy's futuristic world come in the forms of earthshaking hurricanes spawned by over-reliance on climate-damaging coal and other nonrenewable resources. What if climate change in our world is actually much closer than we think? Many experts say we have to start seriously reducing greenhouse gas emissions by 2015, or we may pass a point of no return.