Are we in danger of being erased from the universe? Here we look at the factors that could doom humanity: natural disasters, human-triggered cataclysms, willful self-destruction, and greater forces directed against us.
1. Ecosystem Collapse
Images of slaughtered elephants and burning rain forests capture people’s attention, but the big problem — the overall loss of biodiversity — is a lot less visible and a lot more serious. Billions of years of evolution have produced a world in which every organism’s welfare is intertwined with that of countless other species.At least 30,000 species vanish every year from human activity, which means we are living in the midst of one of the greatest mass extinctions in Earth’s history. Stephen Kellert, a social ecologist at Yale University, sees a number of ways people might upset the delicate checks and balances in the global ecology. New patterns of disease might emerge he says, or pollinating insects might become extinct, leading to widespread crop failure. Or as with the wolves of Isle Royale, the consequences might be something we’d never think of, until it’s too late.
The Earth is getting warmer, and scientists mostly agree that humans bear some blame. It’s easy to see how global warming could flood cities and ruin harvests. More recently, researchers like Paul Epstein of Harvard Medical School have raised the alarm that a balmier planet could also assist the spread of infectious disease by providing a more suitable climate for parasites and spreading the range of tropical pathogens.That could include crop diseases which, combined with substantial climate shifts, might cause famine.
Benny Peiser, an anthropologist-cum-pessimist at Liverpool John Moores University in England, claims that impacts have repeatedly disrupted human civilization. As an example, he says one killed 10,000 people in the Chinese city of Chi’ing-yang in 1490. Many scientists question his interpretations: Impacts are most likely to occur over the ocean, and small ones that happen over land are most likely to affect unpopulated areas. But with big asteroids, it doesn’t matter much where they land. Objects more than a half-mile wide — which strike Earth every 250,000 years or so — would touch off firestorms followed by global cooling from dust kicked up by the impact. Humans would likely survive, but civilization might not.
4. Global pandemics
If Earth doesn’t do us in, our fellow organisms might be up to the task. Germs and people have always coexisted, but occasionally the balance gets out of whack. The Black Plague killed one European in four during the 14th century; influenza took at least 20 million lives between 1918 and 1919; the AIDS epidemic has produced a similar death toll and is still going strong.
From 1980 to 1992, reports the Centers for Disease Control and Prevention, mortality from infectious disease in the United States rose 58 percent. Old diseases such as cholera and measles have developed new resistance to antibiotics. Intensive agriculture and land development is bringing humans closer to animal pathogens. International travel means diseases can spread faster than ever.
5. Global War
Together, the United States and Russia still have almost 19,000 active nuclear warheads. Nuclear war seems unlikely today, but a dozen years ago the demise of the Soviet Union also seemed rather unlikely. Political situations evolve; the bombs remain deadly.
There is also the possibility of an accidental nuclear exchange. And a ballistic missile defense system, given current technology, will catch only a handful of stray missiles — assuming it works at all. Other types of weaponry could have global effects as well. Japan began experimenting with biological weapons after World War I, and both the United States and the Soviet Union experimented with killer germs during the cold war.
6.Robots Take Over
People create smart robots, which turn against us and take over the world. Yawn. We’ve seen this in movies, TV, and comic books for decades. After all these years, look around and still — no smart robots. Yet Hans Moravec, one of the founders of the robotics department of Carnegie Mellon University, remains a believer. By 2040, he predicts, machines will match human intelligence, and perhaps human consciousness. Then they’ll get even better. He envisions an eventual symbiotic relationship between human and machine, with the two merging into “postbiologicals” capable of vastly expanding their intellectual power.
Aliens might want resources from our solar system (Earth’s oceans, perhaps, full of hydrogen for refilling a fusion-powered spacecraft) and swat us aside if we get in the way, as we might dismiss mosquitoes or beetles stirred up by the logging of a rain forest. Aliens might unwittingly import pests with a taste for human flesh, much as Dutch colonists reaching Mauritius brought cats, rats and pigs that quickly did away with the dodo. Or aliens might accidentally upset our planet or solar system while carrying out some grandiose interstellar construction project.
Judaism has the Book of Daniel; Christianity has the Book of Revelation; Islam has the coming of the Mahdi; Zoroastrianism has the countdown to the arrival of the third son of Zoroaster. The stories and their interpretations vary widely, but the underlying concept is similar: God intervenes in the world, bringing history to an end and ushering in a new moral order.
9. Giant solar flares
10.Rogue black holes