Riccardo Liguori A UN report, presented during the COP16 on desertification taking place in Riyadh, confirms the advance of global aridity. Land degradation threatens agriculture, water resources, health and socio-economic stability. In 2020, 2.3 billion people lived in drylands, double the number in 1990
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A powerful message has emerged in Riyadh, Saudi Arabia until December 12 from COP16: our planet is becoming drier—and at an accelerating pace.
According to a report by the UN Science-Policy Interface, an agency tasked with providing policymakers with reliable scientific insights, 40% of the Earth’s land surface is now classified as arid. This figure has risen from 37.5% three decades ago, illustrating the trend toward increasingly dry climates. In the early 1990s, three-quarters of the planet’s surface had already witnessed growing dryness. Today, an additional 1.66 million square miles-an area larger than Canada-has been affected.
It isn’t restricted to conventionally “desert-like” regions, either. Among the most distressing of these results emerging from the study is how aridity is spreading in the temperate zones of the world. Europe is one of the most sensitive regions, particularly the Mediterranean part. About 96 percent of the continent shows a drier climate compared to previous times.
Drought or aridity?
It is important to make a distinction between drought and aridity. Drought is temporary, whereas aridity reflects a stable and long-term climatic shift. Ibrahim Thiaw, the Executive Secretary of the UNCCD, underlines that aridity offers no way back: once an area gets arid, it is very hard to reverse the process. The causes are different, but human-induced global warming is one of the main drivers. Rising temperatures accelerate evaporation, reducing soil moisture and degrading ecosystems over time.
“Unlike droughts, which are temporary periods of low rainfall, aridity represents a permanent and relentless transformation,” Thiaw explained. “Droughts end. But when an area’s climate becomes drier, it loses the ability to revert to its previous conditions. The drier climates now affecting vast regions globally will not return to what they once were, and this change is redefining life on Earth.”
The numbers tell the story
The effects of aridity are profound across various sectors, with agriculture being the most immediate victim. According to the UNCCD, 40% of the world’s arable land is already impacted. Future projections are grim: global agricultural yields for key crops like corn, wheat, and rice are expected to decline by millions of tons in the coming decades. In Africa, reduced rainfall and soil degradation could slash maize harvests by 50% by 2050.
The impact ripples into economic stability from the realms of food security. Drought and aridity can seriously cripple the GDP of affected nations, thereby threatening rural livelihoods, food supplies, and social stability.
A drier world also implies a water-scarce world. Before the close of this century, more than two-thirds of the world’s land surface is expected to have less water stored. Such a scarcity can cause cascading catastrophes related to health, diseases related to malnutrition, and poor sanitation. Whole communities could have to relocate due to more ‘hospitable’ climes. In 2020, there were 2.3 billion people living in arid regions, twice the number from 1990. A further doubling is forecast for 2100, again likely fueling migratory flows and geopolitical tensions.
COP16: a call to action
COP16 intends to give priority to acting against desertification. The report of the UN Science-Policy Interface discussed in Riyadh outlines a way toward solutions-but time is running out. It calls for enhanced monitoring systems, better agricultural practices, more investment in water efficiency, and increased international cooperation. Reduction of greenhouse gas emissions is key, as well as protection of intact ecosystems, restoration of degraded ones, and sustainable management of water.
For decades, scientists across the world have warned that increasing greenhouse gas emissions are fueling global warming. But now, for the very first time, a scientific panel within the United Nations warns that burning fossil fuel is driving permanent drying on large portions of the earth and can have disastrous results in the access to water that can push people and nature towards disastrous tipping points,” said Barron Orr, Chief Scientist of UNCCD. “As large swaths of the globe get drier, the costs of inaction get worse. Adaptation is no longer a choice—it’s a necessity.”
