Decline in terrestrial water recharge with increasing global temperatures

Since 1901, global temperatures have risen by 0.89 °C, seriously impacting precipitation patterns and flow peaks. However, few assessments of changes in global water balance have been conducted. Here we investigate the effect of rising temperatures on water recharge for 31 major river basins across the world using satellite derived terrestrial water storage. We find reductions in Relative Recharge (indicative of the Terrestrial Water Recharge (TWR)) with increasing temperature in 23 of the 31 basins, with 12 basins showing significant reductions (at 90% confidence level). The possible explanation is that increase in temperature reduces the relative recharge due to increased evapotranspiration and reduced snow accumulation. Thus, in a future warmer climate, even an unchanged precipitation would lead to diminished recharge than expected, with reductions in precipitation expected to exacerbate it further. Large-scale changes in recharge would subsequently influence vegetation growth. Reduction in TWR showed clear association with diminished vegetation growth in majority of the river basins analyzed, adding further confirmation to the hypothesis being assessed.