Dr. Peter Thornton studies the interactions of land ecosystems with all other components of the Earth's climate system, including biogeochemical and physical land-atmosphere feedbacks, and interactions with human systems. His research spans spatial scales from organisms to the global Earth system, and involves model development, model evaluation against observations and experimentation, and model applications to discover emergent properties of ecosystems. A special focus of his research is the coupling of carbon, water, and energy cycles with the biotic and abiotic cycling of nutrients such as nitrogen and phosphorus which limit growth and metabolism of plants and microbes. Other primary research topics include the influence of disturbance on biogeochemistry-climate system feedbacks, model evaluation and uncertainty quantification, and biometeorology.
Exploring the dynamics of land carbon sinks under strong climate change mitigation scenarios
P. THORNTON, D. RICCIUTO, X. SHI, J. FIELD, D. MCCOLLUM
Oak Ridge National Laboratory, One Bethel Valley Rd., Oak Ridge, TN 37831
We used the U.S. Department of Energy Exascale Earth System Model (E3SM) to explore land carbon sinks and their changes over space and time over the 21st century, under strong mitigation scenarios with significant overshoot and drawdown of atmospheric CO 2 concentrations. We examined the influence of changing CO 2 concentration on land carbon sink fertilization, and the interactions of these dynamics with land use and land cover change. We used the GCAM multisector dynamics model to estimate future scenarios, and evaluated consistency of climate feedbacks assumed by GCAM and those estimated prognostically with E3SM. We found that global land carbon uptake responds to drawdown concentration scenario with a variety of time lags related to carbon storage in woody pools and slowly cycling soil organic matter pools. Net land uptake is nearly neutral through the 21st century under an overshoot and drawdown scenario.