Aridity crisis: Billions at risk as global drylands expand

Even as dramatic water-related disasters such as floods and storms intensified in some parts of the world, more than three-quarters of Earth’s land became permanently drier (aridity) in recent decades, a new report has revealed.

According to the report dubbed The Global Threat of Drying Lands: Regional and global aridity trends and future projections, if the world fails to curb greenhouse gas emissions, another three per cent of the world’s humid areas will become drylands by the end of this century.

According to the report from the UN Convention to Combat Desertification (UNCCD) some 77.6 per cent of earth’s land experienced drier conditions during the three decades leading up to 2020 compared to the previous 30-year period.

Over the same period, dry lands expanded by about 4.3 million kilometers squared an area nearly a third larger than India, the world’s seventh largest country.

“Most of these areas have transitioned from humid landscapes to drylands, with dire implications for agriculture, ecosystems, and the people living there.” The report reads in part.

In high greenhouse gas emissions scenarios, expanding drylands are forecast across the Midwestern United States, central Mexico, northern Venezuela, north-eastern Brazil, south-eastern Argentina, the entire Mediterranean Region, the Black Sea coast, large parts of southern Africa, and southern Australia.

“This analysis finally dispels an uncertainty that has long surrounded global drying trends. For the first time, the aridity crisis has been documented with scientific clarity, revealing an existential threat affecting billions around the globe.” Ibrahim Thiaw, UNCCD Executive Secretary noted.

“unlike droughts (temporary periods of low rainfall) aridity represents a permanent, unrelenting transformation. Drought end but when an area’s climate becomes drier, the ability to return to previous conditions is lost.  The drier climates now affecting vast lands across the globe will not return to how they were and this change is redefining life on Earth.” He added.

The report points to human-caused climate change as the primary driver of this shift.

Greenhouse gas emissions from electricity generation, transport, and industry and land use changes warm the planet and other human activities warm the planet and affect rainfall, evaporation and plant life, creating the conditions that increase aridity.

“For the first time, the UN is warning that burning fossil fuels is causing permanent drying across much of the world, with potentially catastrophic impacts on water access. As vast areas become more arid, the consequences of inaction grow increasingly dire, making adaptation imperative.” UNCCD Chief Scientist Barron Orr said.

Areas particularly hard-hit by the drying trend include almost all of Europe (95.9 per cent of its land), parts of the western United States, Brazil, parts of Asia (notably eastern Asia), and central Africa.

South Sudan and Tanzania are the nations with the largest percentage of land transitioning to drylands, and China is the country experiencing the largest total area shifting from non-drylands into drylands.

Mediterranean and Southern Europe that were once considered agricultural breadbaskets, are also facing a stark future as semi-arid conditions expand.

By contrast, less than a quarter of the planet’s land (22.4 per cent) experienced wetter conditions, with areas in the central United States, Angola’s Atlantic coast, and parts of Southeast Asia showing some gains in moisture.

According to Thiaw, the overarching trend, however, is clear: drylands are expanding, pushing ecosystems and societies to suffer from aridity’s life-threatening impacts.

This expansion, puts well over 25 per cent of the World’s population in a situation that requires lasting, adaptive solutions. And as the planet continues to warm, report projections in the worst-case scenario suggest up to five billion people could live in drylands by the century’s end, grappling with depleted soils, dwindling water resources, and the diminishment or collapse of once-thriving ecosystems.

“This report underscores the critical need to address aridity as a defining global challenge of our time. Tackling aridity demands a collaborative vision that integrates innovation, adaptive solutions, and a commitment to securing a sustainable future for all.” Narcisa Pricope, co-lead author, professor of geosciences and associate vice president for research at Mississippi State University, USA noted.

Aridity is considered the world’s largest single driver behind the degradation of agricultural systems, affecting 40 per cent of Earth’s arable lands. Rising aridity has been blamed for a 12 per cent decline in gross domestic product (GDP) recorded for African countries between 1990–2015.

Increasing aridity is also expected to play a role in larger and more intense wildfires in the climate-altered future not least because of its impacts on tree deaths in semi-arid forests and the consequent growing availability of dry biomass for burning.

Rising aridity will also exacerbate poverty, water scarcity, land degradation, and insufficient food production, contributing to worsening health outcomes globally. These challenges disproportionately affect vulnerable populations, particularly children and women, leading to higher rates of sickness and death.

“Rising aridity will reshape the global landscape, challenging traditional ways of life and forcing societies to reimagine their relationship with land and water. As with climate change and biodiversity loss, addressing aridity requires coordinated international action and an unwavering commitment to sustainable development.” Andrea Toreti, co-lead author and senior scientist, European Commission’s Joint Research Centre said.

Thiaw reveals that though people think this is something that will happen in future it is already happening with forced migration as one of aridity’s most visible consequences.

As land becomes uninhabitable, families and entire communities facing water scarcity and agricultural collapse often have no choice but to abandon their homes, leading to social and political challenges worldwide.

From the Middle East to Africa and South Asia, millions are already on the move a trend set to intensify in coming decades.

Though the report reveals that one fifth of all land could experience abrupt ecosystem transformations from rising aridity by the end of the century, causing dramatic shifts (such as forests becoming grasslands and other changes) and leading to extinctions among many of the world’s plants, animals and other life, Thiaw says that there is need to integrate aridity metrics into existing drought monitoring systems. This approach would enable early detection of changes and help guide interventions before conditions worsen.

Apart from that, incentivizing sustainable land use systems can mitigate the impacts of rising aridity, particularly in vulnerable regions.

Additionally, investing in water efficiency, building resilience in vulnerable communities, and developing international frameworks and cooperation are also crucial strategies in addressing aridity’s challenges.

“Without concerted efforts, billions face a future marked by hunger, displacement, and economic decline. Yet, by embracing innovative solutions and fostering global solidarity, humanity can rise to meet this challenge. The question is not whether we have the tools to respond it is whether we have the will to act.” Nichole Barger, Chair, and UNCCD Science-Policy Interface noted.

According to Sergio Vicente-Serrano, co-lead author of the report and an aridity expert with Spain’s Pyrenean Institute of Ecology this report’s clarity is a wake-up call for policymakers and shows that tackling aridity demands more than just science. It requires a diversity of perspectives and knowledge systems.

“By weaving indigenous and local knowledge with cutting-edge data, we can craft stronger, smarter strategies to slow aridity’s advance, mitigate its impacts and thrive in a drying world.” Serrano added.