Currently — May 20, 2022

The weather, currently.

The first big East Coast heat wave of the summer is underway, with 100°F (37.8°C) possible from Miami to Boston over the next few days. This will be one of the most intense heat waves ever recorded in the month of May across the eastern US, with numerous record high temperatures already recorded from Texas across the Deep South and up the East Coast this weekend. Boston is expected to reach 97°F (36.1 degrees C) on Sunday—which would tie the hottest temperature ever measured in the month of May.This kind of weather is more than 30 degrees F (17 degrees C) hotter than long term averages for mid-May, and extremely unlikely to occur without the added global heating of climate change caused by burning fossil fuels. The National Weather Service has tips on how to stay safe during heat waves.

—Eric Holthaus

What you need to know, currently.

As a heatwave sweeps across the nation, Denver is set to see some significant snowfall this weekend, with temperatures dropping from the 90s to the low 30s. Snow in late-May is unusual, but not alarming — nothing compared to 1816, which is known as the Year Without a Summer.

In April of 1815, Mount Tambora — a volcano in present-day Indonesia, that had been dormant for 200 years — erupted, sending a plume of ash the size of Australia into the sky and causing a volcanic winter. The ground froze in July and August, snow fell in June, crops and livestock died off — causing widespread famine. According to the New England Historical Society, farmers, who had already shorn their sheep for the summer, tried to tie their wool back onto them, to no avail.

Allegedly, the founder of the Old Farmer’s Almanac, Robert Thomas, had mistakenly printed copies predicting a cold, snowy July that year. Upon discovering his mistake, he had the copies destroyed — only to be vindicated by the volcanic winter.

The basic principles behind volcanic winters are what have inspired researchers to look into certain kinds of geoengineering—namely shooting aerosols into the atmosphere, that would block the sun and effectively mimic the effects of a volcanic eruption.

The risks to geoengineering are manifold, however. Although it may succeed in cooling the climate temporarily, geoengineering is not an argument against reducing emissions and could very well end up worsening the situation.

Alan Robock, a climatologist at Rutgers University outlined some of the risks in a 2016 paper, including ocean acidification, widespread drought and famine, and rapid warming if stopped (once you stop shooting aerosols into the atmosphere, the planet warms faster than if you’d done nothing at all.)

“So far geoengineering research concludes that there is no safe Plan B,” Robock writes. “And provides enhanced support for mitigation and adaptation.”

—Rebecca McCarthy