Hydrological impacts in La Plata basin under 1.5ºC, 2ºC and 3ºC global warming above the preindustrial level

MONTROULL, N.; SAURRAL, R.; CAMILLONI, I.

INTERNATIONAL JOURNAL OF CLIMATOLOGY

JOHN WILEY & SONS LTD

Lugar: Londres; Año: 2018

0899-8418

The assessment of regional climate and hydrological impacts at different levels of global-mean temperature increase became vital to guide decision makers and water management planners after the adoption of the Paris Agreement in 2015. With current emission trends close to a pathway of 3°C warming by the end of the present century, this study investigates the projected regional hydrology impacts over La Plata basin (LPB) for the warming thresholds of 1.5°C and 2°C established in Paris and for 3°C above the preindustrial level. We also explore the consequences from following a medium or high-emission Representative Concentration Pathway (RCP) to achieve the different warming targets. In order to determine the possible changes in precipitation, evapotranspiration, runoff and river discharges, we use the VIC distributed hydrology model in combination of bias-corrected GCM outputs from the Inter-Sectorial Impact Model Intercomparison Project phase 2a (ISIMIP). Since the behavior of the hydrometeorological variables are not homogeneous over LPB, we analyzed impacts of the different changes in mean global temperature and RCPs over four sub-basins: Paraguay, Paraná, Iguazú and Uruguay. Overall, most of the changes over the sub-basins suggest moister conditions with increasing temperatures. The comparison of the RCPs indicates that increases in precipitation, evapotranspiration and runoff would be larger under the medium-emission scenario. When the different responses of the various components of the terrestrial water cycle were integrated, results show that variation of annual mean streamflow in all sub-basins range between ±20%. However, in most cases, the sign of the changes highly depend on the RCP chosen to achieve a warming level.