GC23K-17 – The future of the North American carbon cycle – projections and associated climate change


Deborah N Huntzinger
Northern Arizona University
Abhishek Chatterjee
NASA Goddard Space Flight Center
Sarah R Cooley
Ocean Conservancy Inc.
John P Dunne
Geophysical Fluid Dynamics Laboratory
Forrest M. Hoffman (forrest at climatemodeling dot org)
Oak Ridge National Laboratory
Yiqi Luo
University of Oklahoma Norman Campus
David J Moore
University of Arizona
Sara B Ohrel
U.S. Environmental Protection Agency
Benjamin Poulter
Montana State University
Daniel M Ricciuto
Oak Ridge National Laboratory
Maria Tzortziou
City College of New York
Anthony P Walker
Oak Ridge National Laboratory
Melanie A Mayes
Oak Ridge National Laboratory


The Second State of the Carbon Cycle Report (SOCCR-2): Assessing the Last Decades’ Science of the Carbon Cycle across North America and Adjacent Oceans II
Tuesday, December 13, 2016 15:15–15:21
Moscone West 3007


Approximately half of anthropogenic emissions from the burning of fossil fuels is taken up annually by carbon sinks on the land and in the oceans. However, there are key uncertainties in how carbon uptake by terrestrial, ocean, and freshwater systems will respond to, and interact with, climate into the future. Here, we outline the current state of understanding on the future carbon budget of these major reservoirs within North America and the globe. We examine the drivers of future carbon cycle changes, including carbon-climate feedbacks, atmospheric composition, nutrient availability, and human activity and management decisions. Progress has been made at identifying vulnerabilities in carbon pools, including high-latitude permafrost, peatlands, freshwater and coastal wetlands, and ecosystems subject to disturbance events, such as insects, fire and drought. However, many of these processes/pools are not well represented in current models, and model intercomparison studies have shown a range in carbon cycle response to factors such as climate and CO2 fertilization. Furthermore, as model complexity increases, understanding the drivers of model spread becomes increasingly more difficult. As a result, uncertainties in future carbon cycle projections are large. It is also uncertain how management decisions and policies will impact future carbon stocks and flows. In order to guide policy, a better understanding of the risk and magnitude of North American carbon cycle changes is needed. This requires that future carbon cycle projections be conditioned on current observations and be reported with sufficient confidence and fully specified uncertainties.

Forrest M. Hoffman (forrest at climatemodeling dot org)