Blue water tradeoffs with ecosystems in a CO2-enriched climate
Abstract
Present and future freshwater availability and drought risks are physically tied to the competing responses of surface vegetation to increasing CO2, which includes radiative and plant physiological forcing, as well as their consequences for plant phenology, water use efficiency, and CO2 fertilization. Because Earth system models (ESMs) have increased their sophistication in representing the coupling among biogeochemical and biogeophysical processes at the land surface, projected linkages among ecosystem responses to CO2 and blue water (runoff) can be explored. A detailed analysis of the Western US demonstrates that CO2- and radiatively-induced vegetation growth drives projected decreases in soil moisture and runoff in the NCAR CESM LENS, creating a curious pattern of colocated 'greening' and 'drying.' Here we explore these responses at the global-scale and the consequences of such vegetation-driven drying on blue water availability for people. We present a simple metric that quantifies the tradeoff that occurs between ecosystems and blue water and link their occurrence to changes in daily-scale precipitation extremes, plant functional types, and changes in leaf areas. These results have implications for blue water availability for people and raise important questions about model representations of vegetation-water responses to high CO2.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMGC34B..03M
- Keywords:
-
- 1630 Impacts of global change;
- GLOBAL CHANGE;
- 1803 Anthropogenic effects;
- HYDROLOGY;
- 1812 Drought;
- HYDROLOGY;
- 4329 Sustainable development;
- NATURAL HAZARDS