Impacts of anthropogenic emission change scenarios on U.S. water and carbon balances at national and state scales in a changing climate

The U.S. water supply and carbon sequestration are increasingly threatened
by future climate change and air pollution. This study
investigates the ecohydrological responses to the individual and combined
impacts of climate change and anthropogenic emission changes at
two spatial scales by coupling a regional online-coupled meteorology and
chemistry model (WRF-Chem) and a water balance model (WaSSI). Combined
effects of climate change and anthropogenic emission changes in
2046-2055 relative to 2001-2010 over the US enhance hydrological cycle and
carbon sequestration. However, a drying trend occurs in the central and
part of the western U.S. Climate change is projected to dominate the
ecohydrological changes in most regions. Anthropogenic emission changes
under 2001-2010 climate conditions cools down inland water resource
regions with 0.01~0.15℃, moisturizes the east and dry the west U.S. More
stringent anthropogenic emission control enhances precipitation and
ecosystem production in the east and west but has an opposite
trend in the central U.S. The ecohydrological modeling in California and
North Carolina based on 4-km resolution meteorological data in
2050 and 2005 shows varying changes in magnitudes and spatial
patterns compared to results based on 36-km resolution meteorological
data. Projected changes in air pollutant emissions may accelerate climatic
warming in coastal areas and the state of New Mexico and decrease
precipitation, runoff, and carbon sequestration in part of the western
U.S. Strategies to address future possible problems such as heatwaves,
water stress, and ecosystem productivity should consider the varying
interplay between air quality control and climate change at
different spatial scales.