Less than 4% of dryland areas are projected to desertify despite increased aridity under climate change

Abstract

Abstract Drylands have low biological productivity compared to non-drylands, making many human activities within them sensitive to long-term trends. Trends in the Aridity Index over several decades indicate increasing aridity in the drylands, which has been linked to increasing occurrence of desertification. Future projections show continued increases in aridity due to climate change, suggesting that drylands will expand. In contrast, satellite observations indicate an increase in vegetation productivity. Given the past inconsistency between the Aridity Index changes and observed vegetation changes, the future evolution of vegetation productivity within the drylands remains an open question. Here we used a data driven approach to show that increasing aridity in drylands won’t lead to a general loss of vegetation productivity. Most of the global drylands are projected to see an increase in vegetation productivity due to climate change through 2050. The aridity index will not be a good indicator of drylands in future climates. We found a broad boost to dryland vegetation productivity due to the carbon dioxide (CO2) fertilization effect that is negated by climate changes in at most 4% of global drylands to produce desertification. These regions include parts of north-east Brazil, Namibia, western Sahel, Horn of Africa and central Asia.