Question iv): Sensitivity of precipitation change and sea ice retreat
Greenhouse gas increases enhance the contrast between wet and dry regions (if moving with seasons and variability), while the response to explosive volcanic eruptions reduces the contrast (Polson et al., GRL 2017; Schurer et al., ERL 2020). The latter is detectible in the response in longterm streamflow data (Iles and Hegerl, Nature Geoscience 2015). Hence we showed that the embattled ‘wet gets wetter, dry gets drier’ paradigm is a useful paradigm to characterise and quantify future rainfall changes, although only if accounting for the movement of rainfall regions with seasons, and changes in atmospheric circulation. Observed monsoon changes showed a strong detectable contribution from aerosols (Undorf et al., JGR 2018) We have also contributed a new sea ice dataset that avoids some of the infilling of the early 20th century sea ice retreat with climatological mean values, in collaboration with the UK Met Office.