Abstract
In a warmer world, the hydrological cycle will change in intensity and
in its geographic behaviour. This, in turn, will change patterns of
river flood and the risk associated with them. The Last Interglacial
(LIG; 125,000 years ago) is the most recent instance of climate warmer
than today - especially in the high northern latitudes-, sea level was
higher, ice sheets were smaller and monsoons were stronger. We use daily
output from multi-century LIG simulations of an ensemble of paleoclimate
models, and study how global precipitation patterns and extremes
deviate from the preindustrial climate. We validate these results by
comparing them with the first compilation, to our knowledge, of global
LIG precipitation patterns. Successively, we use the daily temperature
and precipitation from the paleoclimate models to drive two global
hydrological models (PCR-GLOBWB and CWATM), and simulate river
discharges at 5-30’ resolution. With this, we force a hydrodynamic
model, CaMa-Flood, and produce floods maps for different return periods.
At the end of this model cascade, we look into what would happen if a
climate similar to the LIG were to materialize in the coming decades: we
combine the flood maps with maps of exposure through vulnerability
relationships, and to calculate the risk that floods may pose to future
people and assets.