The sun is supposed to last another seven billion years or so (thus we think that lotteries should include 7,000,000,000 as a playable lucky number). However, scientists predict that dramatic—and mostly unavoidable—natural changes in the earth's planetary status will mean the end of life here in another 500 million years.
Those who have discovered the Fountain of Eternal Life and are hoarding it all for themselves will be dismayed to find out their
endless summer will end less than 200 billion days from now. The rest of us limited-lifespan humans recognize that 500 million years is so far into the future that there's no point in worrying about it. But what about unnatural, man-caused changes to earth? Which ones have a more near-term potential to dramatically alter, or even destroy, the ecosystem that supports all life on planet earth? Here are a few of the top threats to consider:
1. Nuclear War — All-out nuclear war could make the planet's ecosystem uninhabitable for millennia. The threat of nuclear terrorism is a subset of this problem and, while clearly a serious problem, it's likely to have an effect locally, not globally. Nuclear-tipped tensions between Russia and the US have eased greatly since their height during the Cuban Missile Crisis in the 1960s, but regional conflicts such as those between India and Pakistan or in the Middle East have go-nuclear potential.
2. Deterioration of the Ozone Layer — Without protection from the sun's harsh UV radiation, plant life would suffer catastrophic losses and, subsequently, so will animal life, including humans. The "hole" in the ozone layer warrants watching.
3. Global Warming — Though the planet's temperature has fluctuated over the eons, never before has man's infrastructure—particularly coastal housing and the farm belts—stood to suffer such abrupt change. Some predict that global warming could raise temperatures enough to reduce the productivity of America's farms to the point that the US would become a net importer of grain instead of a net exporter. Hundreds of millions of years ago, mass extinctions are thought to have occurred because of natural global warming. It could happen again due to human-caused global warming.
4. Degradation of the Web of Life — In some ways, the connections between the different forms of life on earth are robust. Most organisms have a variety of food sources and can withstand some amount of habitat change. But there is a limit, and the continuing chemical insult we're imparting to the land, air and water; the ongoing degradation and loss of habitat; the unprecedented rate of species extinctions—all these things spell trouble. The planet's species and ecosystems, which are all interrelated to some extent—call it the Six Degrees of Everything—are all strands on the global web of life. If one snips too many strands, the web will collapse.
5. Biotech Run Amuck — Hybridization of plants and breeding of animals has been going on for thousands of years. Those efforts, however, were done by natural cross-pollination and cross-breeding. Genetic engineering technology often inserts the genes of one species into completely different types of organisms. The long-term possible effects of these technologies, especially their potential to "escape into the wild" with unknown consequences, have not been well studied. Bioterrorism, especially if employing bioengineered organisms, is another potential problem of large proportion.