Peatland-dominated boreal ecoregions at risk of drying in a warmer climate
Abstract
The response of evapotranspiration (ET) to future climate warming is of critical importance to the global water cycle, land surface energy balance, and ecosystem carbon cycling. While a warming climate is expected to lead to increasing atmospheric demand for water (through higher vapour pressure deficit [VPD]), its impact on ET and water availability remains poorly understood for many ecosystems including those of the boreal biome. The vast boreal biome is a mosaic of forest, peatland, and lake ecosystems with more accumulated carbon than currently stored in the atmosphere. Utilizing a pan-boreal ET dataset obtained from 90 eddy covariance flux tower sites, we show that boreal peatland ET increases more than forest ET in response to increasing VPD. We also show that by the end of the 21st century, increases in growing season ET are expected to exceed changes in projected growing season precipitation in many peatland-dominated boreal ecoregions such as the Hudson Bay Lowlands and the Western Siberian Taiga. Decreasing water availability during the growing season will likely decrease regional runoff, cause shifts in vegetation composition, and potentially induce peatland carbon emissions to the atmosphere through enhanced decomposition and fire.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.B22D..03H
- Keywords:
-
- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0426 Biosphere/atmosphere interactions;
- BIOGEOSCIENCES;
- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 0438 Diel;
- seasonal;
- and annual cycles;
- BIOGEOSCIENCES