Goodbye, Cruel World?
This is bad enough as it is, but worse is yet to come.
The ash’s injection into the stratosphere would cause it to darken the sky and cool regional, if not planetwide temperatures. If the eruption is particularly sulfur-rich – an efficient blocker of sunlight – then temperatures would plummet several degrees, to the point where the next few years will lack a summer.
“It’s likely there would be significant cooling for many years,” Poland explains. “But how long it would last, and how much cooling would occur, I can't say. I'm not sure anyone can.”
If the far smaller but highly sulfur-rich eruption of Tambora back in 1815 is any example, a caldera-forming blast at Yellowstone would “alter global weather patterns and have enormous effects on human activity” for many years, according to the USGS.
The paths and timings of monsoons would change. Tropical cycle formation would become far more unpredictable for a while and the spread of waterborne-diseases could take highly erratic paths.
Agriculture would also suffer, which could severely disrupt food supplies. This would add to the overall economic damage, which would be severe: A recent estimate by FEMA of a Yellowstone supereruption put the total US damage at $3 trillion, about 16 percent of the nation’s total GDP. To put that in perspective, that’s $400 million more than was lost during the recent global recession.
The USGS is keen to point out that “scientists at this time do not have the predictive ability to determine specific consequences or durations of possible global impacts from such large eruptions.” Whatever happens, though, it won’t cause civilization to come crashing down.
“It would not mean the end of life on Earth,” Poland tells us. “In fact, this experiment has already been run, yet few people realize it.”
He points to the Toba eruption, one that occurred 74,000 years ago, and one that “was larger than anything that Yellowstone has ever produced.” Evidently, humanity survived that, and “they didn't have the benefit of technology back then!”
Make no mistake though: Another full-on Yellowstone supereruption would be a devastating natural disaster, the type that would cost both livelihoods and lives. However, it cannot be emphasized enough that it’s extremely unlikely to happen in the near-future, if ever.
If it did, it wouldn’t be a civilization-ending event either. It would, however, be one that changes the world for the worse.