JUL 30, 2019 2:16 PM PDT

Our past megadroughts, and what's to come

Do you think the droughts we suffer from now are bad? Centuries ago the American Southwest was plagued with approximately twelve megadroughts that each lasted for decades. From the 9th century throughout the 15th century these droughts took over local climate – but what caused them? Scientists from Columbia University's Lamont-Doherty Earth Observatory aim to answer that question in new research published recently in the journal Science Advances. They hope that their findings will help us better understand the risk that megadroughts pose for our future in our warming planet.

The scientists on the study reconstructed aquatic climate data from the Paleo Hydrodynamics Data Assimilation product and looked at estimates of radiative forcing in order to determine three interacting causes behind the megadroughts. (Radiative forcing refers to when the Earth absorbs more sunlight than it radiates back into space. Both radiative forcing and ocean temperatures were found to be significant factors in triggering the megadroughts of the past.)

The authors reported the following three factors as triggers for megadroughts: “unusually frequent and cold central tropical Pacific sea surface temperature (SST) excursions in conjunction with anomalously warm Atlantic SSTs and a locally positive radiative forcing.”

The authors say that the first factor, unusually frequent and cold central tropical Pacific sea surface temperatures, refers to La Niña events, and is thought to be more than twice as important in causing the megadroughts. An increase seen in heat as a result of high radiative forcing caused greater evaporation, which was exacerbated by warm conditions in the Atlantic.

Are megadroughts lurking in our future? Photo: Pixabay

Although the information the team gathered is more precise than previous studies, the future of megadroughts in our changing climate is still uncertain. A lot of it will depend on future El Niño and La Niña activity, of which there are still poor models, explain the authors. But, they caution, glocal warming sure won’t make the situation better.

"Because you increase the baseline aridity, in the future when you have a big La Niña, or several of them in a row, it could lead to megadroughts in the American West," commented lead author Nathan Steiger, a Lamont-Doherty Earth Observatory hydroclimatologist. Steiger and his team hopes to continue their investigation of past megadroughts in order to prepare us better for what may lie ahead.

Sources: Science Daily, Science Advances

About the Author
  • Kathryn is a curious world-traveller interested in the intersection between nature, culture, history, and people. She has worked for environmental education non-profits and is a Spanish/English interpreter.
You May Also Like
AUG 11, 2020
Microbiology
A New Microbe is Discovered in an 'Unnatural' Environment
AUG 11, 2020
A New Microbe is Discovered in an 'Unnatural' Environment
While we can exert a degree of control over our surroundings, we still share the world and our bodies with microbes.
SEP 29, 2020
Earth & The Environment
Using native wild species to improve crop breeding and production
SEP 29, 2020
Using native wild species to improve crop breeding and production
New research from the University of Portsmouth and Royal Botanic Gardens, Kew, highlights the concern that global farmin ...
OCT 05, 2020
Earth & The Environment
The rising concern of aerosol particles
OCT 05, 2020
The rising concern of aerosol particles
A study from Colorado State University scientists provides insight into the resiliency of aerosol particles, particles f ...
OCT 14, 2020
Earth & The Environment
That's not really how atolls form...
OCT 14, 2020
That's not really how atolls form...
A study published this month in the Annual Review of Marine Science challenges the accuracy of Darwin’s theor ...
NOV 04, 2020
Plants & Animals
Scientists Rediscover "Lost" Chameleon Species in Madagascar
NOV 04, 2020
Scientists Rediscover "Lost" Chameleon Species in Madagascar
Voeltzkow’s chameleon was recently rediscovered after disappearing for more than 100 years. According to an articl ...
NOV 24, 2020
Genetics & Genomics
Cracking the Code of a Locust Swarm
NOV 24, 2020
Cracking the Code of a Locust Swarm
With a reputation for destruction that goes back to ancient Egypt, locust swarms are once again a major problem for some ...
Loading Comments...