Quantcast

NASA Scientists: Future Megadroughts Could Last 30+ Years 'Thanks to Human-Induced Climate Change'

Climate

The drought in California, going into its fourth year, has been in the news, especially since California produces much of the country's food. But a new NASA study, published this week in the journal Science Advances, suggests that the U.S. could be looking at much worse. It predicts multi-decade "megadroughts" of more than 30 years by the end of the 21st century if we don't significantly reduce greenhouse gas emissions.

"Recent droughts such as the ongoing drought in California or the Southwest, or even historical droughts such as the Dust Bowl in the 1930s, these are naturally occurring droughts that typically last several years or sometimes almost a decade," said the study's lead author Ben Cook, a climate scientist at NASA's Goddard Institute for Space Studies and Columbia University's Lamont-Doherty Earth Observatory. "What we're seeing is that with climate change many of these types of droughts will likely last for 20, 30, sometimes even 40 years."

How bad these droughts will get is tied to how much greenhouse gas emissions humans generate in future years. Cook and his colleagues say the current risk of a megadrought is 12 percent. If greenhouse gas emissions stop increasing by the mid-21st century, they project the risk at more than 60 percent in the second half of the 21st century. And if they continue to rise at current rates, the researchers say, there is an 80 percent chance of a megadrought in the Southwest and Central Plains between 2050 and 2099. "Alternatively, if the world were to take aggressive actions to reduce emissions, the model still showed drought but the trends would be less severe," they found.

Cook said this study is more robust than previous research, which used fewer drought indictors and few climate models. This study used 17 different climate models, all of which showed a drier planet "thanks to human-induced climate change," says NASA.

"What I think really stands out in the paper is the consistency between different metrics of soil moisture and the findings across all the different climate models," said climate scientist Kevin Anchukaitis of Woods Hole Oceanographic Institution, who was not involved in the study. "It is rare to see all signs pointing so unwaveringly toward the same result, in this case a highly elevated risk of future megadroughts in the United States."

This is also the first study to compare future drought projections to droughts over the last 1,000 years, using tree-ring information to estimate droughts beyond the last 150 years. The researchers looked at megadroughts of 30-50 years that occurred in North America between 1100 and 1300 and compared them with projected late 21st-century droughts. They found that whether greenhouse gas emissions stop increasing or continue to increase at the current rate, the likelihood of drier conditions and droughts lasting 30 years or more is greater.

"We can't really understand the full variability and the full dynamics of drought over western North America by focusing only on the last century or so," said Cook. "We have to go to the paleoclimate record, looking at these much longer timescales, when much more extreme and extensive drought events happened, to really come up with an appreciation for the full potential drought dynamics in the system."

Megadroughts could require adaptations well beyond anything the U.S. has ever faced. Image credit: NASA

Anchukaitis agreed that comparing medieval-era droughts with projected ones is useful.

"Those droughts had profound ramifications for societies living in North America at the time," he said. "These findings require us to think about how we would adapt if even more severe droughts lasting over a decade were to occur in our future."

Those adaptations would be more challenging than anything we've seen in the past, says Cook.

"The droughts represent events that nobody in the history of the U.S. has ever had to deal with," he said. "Even in the modern era, droughts such as the ongoing droughts in California and the Southwest, these normal droughts act as major stressors on water resources in the region. So we expect that with these much longer droughts, it's going to be even more impactful and cause even more problems for agriculture and ecosystems in the region."

YOU MIGHT ALSO LIKE

California Experiences Worst Drought in 1,200 Years

NASA Satellite Images Reveal Shocking Groundwater Loss in Drought-Stricken California

NOAA Report Misses Link Between California Drought and Human-Caused Climate Change

EcoWatch Daily Newsletter

A verdant and productive urban garden in Havana. Susanne Bollinger / Wikimedia Commons

By Paul Brown

When countries run short of food, they need to find solutions fast, and one answer can be urban farming.

Read More Show Less
Trevor Noah appears on set during a taping of "The Daily Show with Trevor Noah" in New York on Nov. 26, 2018. The Daily Show With Trevor Noah / YouTube screenshot

By Lakshmi Magon

This year, three studies showed that humor is useful for engaging the public about climate change. The studies, published in The Journal of Science Communication, Comedy Studies and Science Communication, added to the growing wave of scientists, entertainers and politicians who agree.

Read More Show Less
Sponsored
rhodesj / Flickr / CC BY 2.0

Cities around the country are considering following the lead of Berkeley, California, which became the first city to ban the installation of natural gas lines in new homes this summer.

Read More Show Less
Rebecca Burgess came up with the idea of a fibersheds project to develop an eco-friendly, locally sourced wardrobe. Nicolás Boullosa / CC BY 2.0

By Tara Lohan

If I were to open my refrigerator, the origins of most of the food wouldn't be too much of a mystery — the milk, cheese and produce all come from relatively nearby farms. I can tell from the labels on other packaged goods if they're fair trade, non-GMO or organic.

Read More Show Less
A television crew reports on Hurricane Dorian while waves crash against the Banana River sea wall. Paul Hennessy / SOPA Images / LightRocket / Getty Images

By Mark Hertsgaard and Kyle Pope

Some good news, for a change, about climate change: When hundreds of newsrooms focus their attention on the climate crisis, all at the same time, the public conversation about the problem gets better: more prominent, more informative, more urgent.

Read More Show Less
Sponsored
U.S. Senators Chris Coons (D-Del.) and Mike Braun (R-Ind.) met with Bill Gates on Nov. 7 to discuss climate change and ways to address the challenge. Senator Chris Coons

The U.S. Senate's bipartisan climate caucus started with just two members, a Republican from Indiana and a Democrat from Delaware. Now it's up to eight members after two Democrats, one Independent and three more Republicans joined the caucus last week, as The Hill reported.

Read More Show Less
EPA scientists survey aquatic life in Newport, Oregon. U.S. Environmental Protection Agency

The U.S. Environmental Protection Agency (EPA) is proposing to significantly limit the use of science in agency rulemaking around public health, the The New York Times reports.

Read More Show Less
A timelapse video shows synthetic material and baby fish collected from a plankton sample from a surface slick taken off Hawaii's coast. Honolulu Star-Advertiser / YouTube screenshot

A team of researchers led by the National Oceanic and Atmospheric Administration didn't intend to study plastic pollution when they towed a tiny mesh net through the waters off Hawaii's West Coast. Instead, they wanted to learn more about the habits of larval fish.

Read More Show Less