Drylands Could Cover 40% of Earth by 2100, Study Finds

Scientists warn that Earth's drylands could expand to cover over 40 percent of the planet's land area by 2100, according to a new study in Environmental Research Letters. This expansion threatens to aggravate water scarcity, ecosystem degradation, and desertification in formerly more humid regions. The researchers used updated climate modeling and a CO2-modified aridity index, finding drylands covered about 38.58 percent of Earth's land from 1994-2023. Rising carbon dioxide levels may slow this expansion by reducing plant transpiration, a factor many previous studies neglected. Projections for 2071-2100 range from 39.31 to 40.28 percent coverage depending on emissions scenarios. The top estimate represents an increase of 2.37 million square kilometers, roughly the size of Algeria. Australia is projected to face the most pronounced dryland changes this century, followed by Brazil, with parts of Africa also experiencing widespread shifts.