Nearly 30% of Earth’s Land Is in Drought—and It’s Getting Dryer
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US Scholars Find Hope in Collaboration and Innovation as the Danger Grows
Some environmental concerns seem further away than others, but few are as immediately alarming as drought.
The impact on humans can be devastating. From a lack of drinking water and dying crops to the spread of diseases, there are few areas of human suffering that drought does not touch. Indeed, a global assessment by the United Nations Convention to Combat Desertification and the National Drought Mitigation Center found that over a 30-year period, extreme drought events directly affected 1.83 billion people worldwide.
And there is no question that the danger posed by drought is growing. A study led by researchers at Beijing Normal University and published in Nature Reviews Earth & Environment found that nearly 30% of the Earth's land surface was gripped by drought, while the Organisation for Economic Co-operation and Development (OECD) reported that 37% of global land has experienced “significant soil moisture loss” since 1980, with droughts being responsible for 34% of disaster-related deaths.
The Real Causes of Drought
But what causes drought, and is it simply a case of “not enough rain”?
"Scientifically, drought is a deficit in water availability relative to what is normal or needed for a given place and time," said Dr. Amir AghaKouchak, an internationally recognized expert on drought based at the University of California, Irvine.
"It can begin with below-normal precipitation, but it often becomes more complex as it affects soil moisture, rivers, reservoirs, groundwater, ecosystems, agriculture, and human water supplies," he said.
In other words, drought is not just a weather event but a disruption in what AghaKouchak calls the "water balance." While a lack of rain is the most obvious culprit, poor water management is a critical issue that he said can "turn a dry period into a crisis" or even create drought-like conditions when rainfall is near normal.
AghaKouchak told The Earth & I: "If we overallocate rivers, drain reservoirs too aggressively, expand water demand beyond sustainable limits, or fail to protect groundwater, then the system becomes vulnerable even without a major rainfall deficit."
"If we overallocate rivers, drain reservoirs too aggressively, expand water demand beyond sustainable limits, or fail to protect groundwater, then the system becomes vulnerable even without a major rainfall deficit."
He noted this is closely related to the concept of "anthropogenic drought," where human activities—such as water withdrawals, land-use changes, water diversion, the overbuilding of dams, or inefficient management—cause or intensify drought impacts.
While we mostly equate water in nature with rainfall, groundwater—water buried beneath the Earth’s surface—is another primary source, particularly in drier parts of the globe. Pumping too much of it out can play a major role in causing drought. This underground water supply is an asset that AghaKouchak likens to a "water savings account."
"During dry periods," he said, "we often rely on it as a backup when rainfall, rivers, or reservoirs are not enough. But when we pump groundwater faster than aquifers can naturally recharge, we are spending more water than we are saving or receiving as income."
Over time, he said this leads to a form of "water bankruptcy."
"Water tables decline, wells go dry, pumping becomes more expensive, land can subside, and rivers and wetlands that depend on groundwater can lose flow," he explained, adding that in many regions, groundwater depletion shows that drought risk is not only about climate, but also about whether human water use exceeds the long-term capacity of the system.
Mitigation Measures
Despite the increasing threats of drought, work has been done to successfully mitigate some of its challenges.
Dr. Elizabeth Koebele is an environmental governance researcher at the University of Nevada who works extensively on the Colorado River Basin. She noted that in the western US, the municipal sector has made major strides in adapting to drought risk.
"In many cities across the Colorado River Basin, water use has essentially become decoupled from population growth over the last few decades, meaning that adding more people does not increase water use proportionately," Koebele said.
"In many cities across the Colorado River Basin, water use has essentially become decoupled from population growth over the last few decades, meaning that adding more people does not increase water use proportionately.”
She pointed out that in Las Vegas, for example, the population has grown by over 800,000 residents in the last 25 years, yet overall consumptive water use has decreased by nearly 30%.
"This is largely due to indoor water efficiency improvements," she said. "Nearly half of all water is used inside homes, casinos, hotels, etc. Thanks to efficiency upgrades, about 99% of this water is captured, recycled, and returned to the reservoir that supplies the city’s water."
While outdoor water use is often harder to reduce, Las Vegas has taken strong measures to remove water-intensive turf and transition regional landscaping. As a result, Nevada has reduced its reliance on the strained Colorado River by 40%.
However, Koebele warned that drought response is significantly more challenging in other sectors, such as agriculture. In the Colorado River Basin, approximately 80% of consumptive water use occurs in agriculture.
While the challenges posed by drought show no signs of lessening, both experts agree that societies can take proactive technological and policy measures to reduce long-term impacts. From a policy and planning perspective, Koebele hopes that future drought impacts can be minimized through continued partnerships and collaboration across different sectors and geographies.
"For example," she said, "inland areas in need of water may partner with coastal areas to invest in desalination technology. Cities may jointly fund water recycling efforts that mutually benefit their entire region. Agricultural users may engage in programs to conserve and lease water to others in times of need."
She added that designing such programs and policies to actually produce the intended outcomes was “perhaps the most pressing challenge” in the basin, concluding “it will require governance reform alongside an infusion of funding at multiple levels.”
Technology as a Solution
Alongside policy and planning, technology is also a pillar on which many hopes for tackling drought are pinned. And while AghaKouchak cautions that no single technology will completely solve water insecurity, he said several approaches can still provide significant benefits. This includes things such as better monitoring via satellites, sensors, and predictive models that can reveal emerging risks much earlier.
He highlights managed aquifer recharge—which stores water underground during wet periods for use during dry periods—as a prime example. He also highlighted water reuse, stormwater capture, leakage reduction, demand management, and more flexible reservoir operations as vital methods for making modern infrastructure resilient.
He added: "The most promising strategies are those that combine technology with better governance and water demand management, because water security depends as much on decisions and institutions as on infrastructure."
A New Normal
With rising temperatures now increasingly viewed as a "new normal" by climate experts, it is clear that drought will continue to have far-reaching impacts on the global population.
They warn that technology alone will not ride to the rescue. Instead, a combination of infrastructure tools and modified human behaviors will be required to ensure that where there is water, not a single drop is wasted.
*Mark Smith is a journalist and author from the UK. He has written on subjects ranging from business and technology to world affairs, history, and popular culture for the Guardian, BBC, Telegraph, and magazines in the United States, Europe, and Southeast Asia.
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