Drylands cover 40% of the global terrestrial surface and provide important
ecosystem services. While drylands as a whole are expected to increase in
extent and aridity in coming decades, temperature and precipitation forecasts
vary by latitude and geographic region suggesting different trajectories for
tropical, subtropical, and temperate drylands. Uncertainty in the future of
tropical and subtropical drylands is well constrained, whereas soil moisture
and ecological droughts, which drive vegetation productivity and composition,
remain poorly understood in temperate drylands. Here we show that, over the
twenty first century, temperate drylands may contract by a third, primarily
converting to subtropical drylands, and that deep soil layers could be
increasingly dry during the growing season. These changes imply major shifts
in vegetation and ecosystem service delivery. Our results illustrate the
importance of appropriate drought measures and, as a global study that focuses
on temperate drylands, highlight a distinct fate for these highly populated
areas