et al.  conclude that during 1999-2015, trends of vegetation production reversed globally, and in drylands, showing extensive declines. Thus, while overall greening has occurred, this trend now appears to be declining. Analyses of vegetation, soil, and physical characteristics of over 50,000 sample points in drylands around the world indicate that aridification causes ecological degradation at three successive thresholds: vegetation decline at Al = 0.56, soil disruption at Al = 0.3 and loss of plant cover at Al = 0.2 . Drylands nevertheless show different dynamics depending on the index used and the variables assessed.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report