A new report finds 77.6% of the planet's landscapes experienced drier conditions from 1990 to 2020 compared to the previous three decades – and most are now drylands inhospitable to farming, nature and people.
The U.N. Convention to Combat Desertification's report was released on Monday to influence decision-makers at its summit that will wrap up at the end of this week in Riyadh, Saudi Arabia.
The 196 countries and the European Union that belong to the UNCCD – a treaty that took effect in 1996 – are holding their 16th Conference of the Parties, or COP16, to deal with droughts, aridity, and degraded lands.
The report shows that factors such as human-caused climate change and deforestation are increasing aridity, which, unlike droughts that represent a temporary period of low rainfall, brings permanent change.
South Sudan and Tanzania have the largest percentage of land transitioning to drylands, it says, while China has the largest total area shifting from non-drylands into drylands.
“Droughts end. When an area’s climate becomes drier, however, the ability to return to previous conditions is lost," says UNCCD Executive Secretary Ibrahim Thiaw, who points to the report as providing new evidence that our planet faces "an existential threat" affecting billions of people.
"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 says.
Out with humidity, in with aridity
Among the issues at the summit is whether rich nations that benefited from fossil fuel burning should provide more funds to fight drought through the creation of more reservoirs and better forecasting and monitoring. The report recommends the use of drip irrigation, which reduces evaporation, and growing crops that need less water.
People living in drylands doubled to 2.3 billion, or more than a quarter of the global population, over the past three decades. If current trends continue, it says, the models suggest as many as 5 billion people could inhabit drylands by 2100, in a "worst-case" climate scenario.
Areas particularly hard hit are the western United States, Brazil, most of Europe, Asia – especially eastern Asia – and central Africa, the report says.
The other 22.4% of the planet's landscapes that did not experience drier conditions from 1990 to 2020 were instead wetter than usual, including areas in the central U.S., the Atlantic coast of Angola, and Asia-Pacific nations such as Malaysia, Indonesia and the Philippines.
Aridity is expected to continue to rise in the climate-altered future," it says. "No areas are projected to shift from being drylands in the past to humid in the future. Instead, increases in semi-arid and dry subhumid classes are expected for all regions."
