Emergent constraints on the sensitivity of global land surface runoff to
temperature based on CMIP6 projections
Abstract
Climate change affects the water cycle. Despite the improved accuracy of
simulations of historical temperature, precipitation and runoff in the
latest Coupled Model Intercomparison Project Phase 6 (CMIP6), the
uncertainty of the future sensitivity of global runoff to temperature
remains large. Here, we identify an emergent relationship between the
historical sensitivity of precipitation to temperature change
(1979–2014) and the future sensitivity of runoff to temperature change
(2015–2100), which can be used to constrain future runoff sensitivity
estimates. Using this constraint, we estimate that the uncertainties in
future sensitivity of runoff have been reduced by 7.2 – 12.0%. The
constrained sensitivity of runoff is much larger (36 – 104%) than that
directly inferred from original CMIP6 projections. Our constrained
sensitivities also indicate more extreme wet conditions and fewer dry
conditions. These results suggest that the future global land water
cycle is accelerating and comes with more hydroclimatic extremes than
previously projected