Journal
GLOBAL CHANGE BIOLOGY
Volume 28, Issue 16, Pages 4794-4806Publisher
WILEY
DOI: 10.1111/gcb.16214
Keywords
drought; drylands; gross primary production (GPP); soil moisture; vapor pressure deficit; warming
Funding
- National Aeronautics and Space Administration [80NSSC19K1335, 80NSSC20K1805]
- National Science Foundation [2131853]
- Strategic Environmental Research and Development Program [RC18-1322]
- U.S. Department of Agriculture [58-0111-17-013, 58-3050-9-013]
- University of Iowa
- Office Of The Director
- OIA-Office of Integrative Activities [2131853] Funding Source: National Science Foundation
Ask authors/readers for more resources
Earth's ecosystems are facing increasing threats from hot drought, which can have significant impacts on the carbon cycle. Through a natural experiment, it was found that hot drought leads to a significant reduction in gross primary production (GPP), with both meteorological and hydrological factors playing a role. Future increases in air temperature and vapor pressure deficit may lead to more frequent and intense hot droughts, exacerbating the reduction in GPP caused by drought.
Earth's ecosystems are increasingly threatened by hot drought, which occurs when hot air temperatures coincide with precipitation deficits, intensifying the hydrological, physiological, and ecological effects of drought by enhancing evaporative losses of soil moisture (SM) and increasing plant stress due to higher vapor pressure deficit (VPD). Drought-induced reductions in gross primary production (GPP) exert a major influence on the terrestrial carbon sink, but the extent to which hotter and atmospherically drier conditions will amplify the effects of precipitation deficits on Earth's carbon cycle remains largely unknown. During summer and autumn 2020, the U.S. Southwest experienced one of the most intense hot droughts on record, with record-low precipitation and record-high air temperature and VPD across the region. Here, we use this natural experiment to evaluate the effects of hot drought on GPP and further decompose those negative GPP anomalies into their constituent meteorological and hydrological drivers. We found a 122 Tg C (>25%) reduction in GPP below the 2015-2019 mean, by far the lowest regional GPP over the Soil Moisture Active Passive satellite record. Roughly half of the estimated GPP loss was attributable to low SM (likely a combination of record-low precipitation and warming-enhanced evaporative depletion), but record-breaking VPD amplified the reduction of GPP, contributing roughly 40% of the GPP anomaly. Both air temperature and VPD are very likely to continue increasing over the next century, likely leading to more frequent and intense hot droughts and substantially enhancing drought-induced GPP reductions.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available