Feeling upbeat? Enough of that: Planet Earth is undergoing a sixth mass extinction that will likely annihilate the human race unless we can curb the trend, scientists say. According to a new paper, the current rate of species extinction outpaces the natural rate far more than anyone knew, NBC News reports. The analysis "employed better knowledge" of Earth's natural extinction rate, the Guardian reports, upping the number from one extinction per million species annually to two extinctions. It then compared that to a current extinction rate that study authors consider conservative. Presto, they got a rate since 1900 that's eight to 100 times worse than the natural one. "We were very surprised to see how bad it is," says study leader Gerardo Ceballos. "This is very depressing."
"If it is allowed to continue, life would take millions of years to recover, and our species itself would disappear early on," says Ceballos. But nations can reverse the crisis—which has been linked to deforestation, industrialization, and other human factors—by conserving threatened species and lowering pressures on their populations, the paper says. So far critics seem to buy the paper's basic math but doubt that species extinction will continue at this high rate for centuries. "It is likely the problem will decline rapidly because most countries will be rich and care much for the natural world," writes one environmentalist. Earth has seen five other mass extinctions, including one 443 million years ago that killed off 83% of sea life, and the most recent, which wiped out the dinosaurs 66 million years ago, the Telegraph notes. (Read more mass extinction stories.)