Alfonso FERNANDEZ, Department of Geography, Universidad de Concepción, Chile
Marcelo SOMOS-VALENZUELA, Universidad de la Frontera, Chile
Francisco MANQUEHUAL-CHEUQUE, Universidad de la Frontera, Chile
Among the myriad of mitigation strategies for anthropogenic climate warming, Climatic Geoengineering is one of the most controversial proposals to limit projected trajectories of temperature increase for the rest of the 21st century. Numerical models that evaluate the sensitivity of the climate system to different types of climate engineering include those that simulate the effect of solar radiation management (SRM) in order to attenuate warming by decreasing the incoming shortwave radiation flux, the engine of the global energy balance. While many numerical models indicate that Climatic Geoengineering can limit warming to levels below 1.5º to 2ºC relative to pre-industrial conditions, little is known on the regional effects associated to these mitigation approaches. Here we present results from the analysis G6Solar experiment over the Andes, including impacts on temperature, precipitation, and glacier mass balance. The G6Solar experiment is part of the GeoMIP6, and simulates a climate derived from decadal decreases of the solar radiation influx to the surface. We compare this experiment with the CMIP6 SSP245 and SSP585 scenarios and use a glacier mass balance model forced by these different experiments. Our results show that G6Solar produces cooling along the Cordillera. However, precipitation shows a pattern of drying towards the south, suggesting that there might be unintended impacts of Geoengineering on mountain hydrology, which it is not necessarily better than the SSP245 or SSP585 for glaciers. In fact, the computation of glacier mass balance using G6Solar as model input shows that many glaciers will likewise irremediably shrink, particularly in extratropical areas, even at faster rates than under the SSP585 scenario for some glaciers. In addition to describing these results, in this work we put forward some dynamical arguments to explain the drying trend of the G6Solar. We also discuss implications for policy-making.
Mots clés : Geoengineering|Glacier mass balance|mountain hydroclimate|glacier-climate modeling
A102812AF