Drivers of Future Northern Latitude Runoff Change

Figures & data

Table 1. Description of model simulations.

Simulation	Description
ALL	Reference simulation with all runoff drivers included: CO2 + non-CO2 radiative forcing; vegetation-CO2 physiological forcing; direct effect of sulphate aerosols and historical land cover change.
GG	Effect of CO2 and non-CO2 greenhouse gas forcing alone*
V-CO2	Effect of vegetation-CO2 physiological forcing alone*
AER	Effect of direct sulphate aerosol forcing alone*
LCC	Effect of historical land cover change alone*
*Effect of single driver calculated as the difference between a simulation without this process and the reference simulation ALL.

Fig. 1 Simulated global trend in a) continental runoff, b) land temperature, c) precipitation over land, and d) evaporation over land, in response to the drivers ALL, GG, V-CO₂, LCC and AER.

Fig. 2 Simulated northern latitude trend in a) continental runoff, b) land temperature, c) precipitation over land, and d) evaporation over land, in response to the drivers ALL, GG, V-CO₂, LCC and AER. The region shown here covers all river basins that drain into the North Atlantic and Arctic oceans north of 45°N latitude and between 105°W and 90°E longitude, as indicated by the shaded box in Fig. 3.

Fig. 3 Spatial distribution of precipitation–evapotranspiration (P–E) change between 1800 and 2100, in response to each driver: a) ALL simulation; b) greenhouse gas forcing; c) vegetation physiological forcing; d) aerosol forcing; and e) land cover change. The grey bounding box represents our selected northern latitude region.

Fig. 4 Simulated trends in a) the Atlantic Meridional Overturning Circulation (AMOC), b) surface ocean temperature changes and c) surface ocean salinity changes in response to drivers ALL, GG, V-CO₂, LCC and AER. Surface ocean temperature and salinity values are averaged over the North Atlantic and Arctic oceans, north of 45°N latitude and between 105°W and 90°E longitude.