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 in recent decades, and the UN scientists warn that large parts of southern Africa could get worse in the high greenhouse gas emissions scenarios.
Some 77.6% of Earth’s land experienced drier conditions during the three decades leading up to 2020 compared to the previous 30-year period, according to the landmark report from the UN Convention to Combat Desertification (UNCCD).
Over the same period, drylands expanded by about 4.3 million km2 – an area nearly a third larger than India, the world’s 7th largest country – and now cover 40.6% of all land on Earth (excluding Antarctica).
In recent decades some 7.6% of global lands – an area larger than Canada – were pushed across aridity thresholds (i.e. from non-drylands to drylands, or from less arid dryland classes to more arid classes).
Most of these areas have transitioned from humid landscapes to drylands, with dire implications for agriculture, ecosystems, and the people living there.
And the research warns that, if the world fails to curb greenhouse gas emissions, another 3% of the world’s humid areas will become drylands by the end of this century.
The report, The Global Threat of Drying Lands: Regional and global aridity trends and future projections, was launched at the 16th conference of UNCCD’s nearly 200 Parties in Riyadh, Saudi Arabia (COP16), the largest UN land conference to date, and the first UNCCD COP to be held in the Middle East, a region profoundly affected by impacts from aridity.
“This analysis finally dispels an uncertainty that has long surrounded global drying trends,” says Ibrahim Thiaw, UNCCD Executive Secretary. “For the first time, the aridity crisis has been documented with scientific clarity, revealing an existential threat affecting billions around the globe.”
“Unlike droughts—temporary periods of low rainfall—aridity represents a permanent, unrelenting transformation,” he adds. “Droughts end. When an area’s climate becomes drier, however, 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.”
The report by UNCCD Science-Policy Interface (SPI) — the UN body for assessing the science of land degradation and drought — points to human-caused climate change as the primary driver of this shift. Greenhouse gas emissions from electricity generation, transport, 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.
Global aridity index (AI) data track these conditions and reveal widespread change over the decades. According to the data, Central Africa and parts of Asia: Biologically megadiverse areas are experiencing ecosystem degradation and desertification, endangering countless species.
The overarching trend, however, is clear: drylands are expanding, pushing ecosystems and societies to suffer from aridity’s life-threatening impacts.
The report names South Sudan and Tanzania as nations with the largest percentage of land transitioning to drylands, and China as the country experiencing the largest total area shifting from non-drylands into drylands.
For the 2.3 billion people – well over 25% of the world’s population – living in the expanding drylands, this new normal requires lasting, adaptive solutions. Aridity-related land degradation, known as desertification, represents a dire threat to human well-being and ecological stability.
And as the planet continues to warm, report projections in the worst-case scenario suggest up to 5 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.
Forced migration is 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.
Report marks a turning point
For years, documenting the rise of aridity proved a challenge, the report states. Its long-term nature and the intricate interplay of factors such as rainfall, evaporation, and plant transpiration made analysis difficult. Early studies produced conflicting results, often muddied by scientific caution.
The new report marks a turning point, leveraging advanced climate models and standardized methodologies to deliver a definitive assessment of global drying trends, confirming the inexorable rise of aridity, while providing critical insights into its underlying drivers and potential future trajectory.
Recommendations
The report offers a comprehensive roadmap for tackling aridity, emphasizing both mitigation and adaptation. Among its recommendations:
Strengthen aridity monitoring
Integrate aridity metrics into existing drought monitoring systems. This approach would enable early detection of changes and help guide interventions before conditions worsen. Platforms like the new Aridity Visual Information Tool provide policymakers and researchers with valuable data, allowing for early warnings and timely interventions. Standardized assessments can enhance global cooperation and inform local adaptation strategies.
Improve land use practices
Incentivizing sustainable land use systems can mitigate the impacts of rising aridity, particularly in vulnerable regions. Innovative, holistic, sustainable approaches to land management are the focus of another new UNCCD SPI report, Sustainable Land Use Systems: The path to collectively achieving Land Degradation Neutrality, available at https://bit.ly/3ZwkLZ3. It considers how land-use at one location affect others elsewhere, makes resilience to climate change or other shocks a priority, and encourages participation and buy-in by Indigenous and local communities as well as all levels of government. Projects like the Great Green Wall—a land restoration initiative spanning Africa—demonstrate the potential for large-scale, holistic efforts to combat aridity and restore ecosystems, while creating jobs and stabilizing economies.
neondohenry@yahoo.com