Abstract
We investigate hydrology during a past climate slightly warmer than the
present: the Last Interglacial (LIG). With daily output of
pre-industrial and LIG simulations from eight new climate models we
force hydrological model PCR-GLOBWB, and in turn hydrodynamic model
CaMa-Flood. Compared to pre-industrial, annual mean LIG runoff,
discharge, and 100-year flood volume are considerably larger in the
Northern Hemisphere, by 14%, 25% and 82%, respectively. Anomalies are
negative in the Southern Hemisphere. In some boreal regions, LIG runoff
and discharge are lower despite higher precipitation, due the higher
temperatures and evaporation. LIG discharge is much higher for the
Niger, Congo, Nile, Ganges, Irrawaddy, Pearl, and lower for the
Mississippi, Saint Lawrence, Amazon, ParanĂ¡, Orange, Zambesi, Danube,
Ob. Discharge is seasonally postponed in tropical rivers affected by
monsoon changes. Results agree with published proxies on the sign of
discharge anomaly in 15 of 23 sites where comparison is possible.