Researchers from the Swiss Federal Institute for Forest, Snow and Landscape Research and the Institute of Science and Technology Austria have issued a dire warning: Multi-year global droughts are becoming increasingly frequent and severe due to climate change, posing significant threats to our ecosystems, agriculture and water resources.
Researchers at the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) and the Institute of Science and Technology Austria (ISTA) have revealed a startling trend: The world is facing increasingly severe and prolonged droughts.
This pattern is detailed in a study published in the journal Science, which was conducted under a WSL-funded EMERGE Project.
Alarming Findings
The study — a comprehensive 40-year global inventory — analyzes meteorological data from 1980 to 2018.
It finds that multi-year droughts have become longer, more frequent and more extreme, covering increasingly vast areas of the globe.
“Each year since 1980, drought-stricken areas have spread by an additional 50,000 square kilometers on average — that’s roughly the area of Slovakia, or the U.S. states of Vermont and New Hampshire put together — causing enormous damage to ecosystems, agriculture and energy production,” Francesca Pellicciotti, a professor at ISTA and the principal investigator of the WSL-funded EMERGE Project, said in a news release.
Historical Context and Current Crisis
Chile stands as a stark example of this grim trend, as it endures a 15-year megadrought — the longest in a millennium. This arid stretch has almost depleted the nation’s water reserves and impacted vital sectors like mining.
However, such droughts are often unnoticed until they visibly affect agriculture or forests. Addressing this gap, the research team also mapped previously overlooked droughts, including one that impacted the Congo rainforest from 2010 to 2018.
“Our method not only mapped well-documented droughts but also shed light on extreme droughts that flew under the radar,” Dirk Karger, a WSL senior researcher and study author, said in the news release.
Impact on Diverse Ecosystems
The study underscores the severe impact these droughts have on various ecosystems. Temperate grasslands, boreal forests and tropical rainforests each respond differently to prolonged dry conditions.
For example, while temperate grasslands show significant immediate damage, boreal and tropical forests may exhibit more complex, delayed effects.
The team’s innovative multi-step analysis tracked vegetation changes using satellite images, revealing that while tropical forests can temporarily buffer against drought, they remain susceptible to long-term damage if water shortages persist.
Boreal forests, conversely, benefit from longer growing seasons due to warming but ultimately face enormous challenges from prolonged drought.
“[I]n the event of long-term extreme water shortages, trees in tropical and boreal regions can die, leading to long-lasting damage to these ecosystems. Especially, the boreal vegetation will likely take the longest to recover from such a climate disaster,” Karger added.
Implications and Future Steps
The findings present an urgent call for action. Current mitigation strategies often treat droughts as seasonal phenomena, missing the mark on addressing the more severe and prolonged nature of megadroughts.
“Currently, mitigation strategies largely consider droughts as yearly or seasonal events, which stands in stark contrast to the longer and more severe megadroughts we will face in the future,” added Pellicciotti. “We hope that the publicly available inventory of droughts we are putting out will help orient policymakers toward more realistic preparation and prevention measures.”
With this crucial data, the researchers aspire to drive policy changes and bolster global preparedness for these escalating environmental crises. Pellicciotti also aims to examine how glaciers might buffer the effects of prolonged droughts through her project