ABSTRACT FINAL ID: GC54A-07;

TITLE: Quantifying and Reducing Climate-Carbon Cycle Feedback Uncertainties: Analysis of CMIP5 Earth System Model Feedbacks

SESSION TYPE: Oral

SESSION TITLE: GC54A. Climate Modeling: Analysis of CMIP5 Simulations II

AUTHORS: Forrest M. Hoffman and James Tremper Randerson

INSTITUTIONS:
¹Earth System Science, University of California, Irvine, CA, United States.
²Computational Earth Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, United States.

ABSTRACT BODY: Increasing atmospheric carbon dioxide (CO₂) concentrations, resulting from anthropogenic perturbation of the global carbon cycle, are altering the Earth’s climate. Climate change is expected to induce feedbacks on future CO₂ concentrations and on the climate system itself. These feedbacks are highly uncertain, potentially large, and difficult to predict using Earth System Models (ESMs). In order to reduce the range of uncertainty in climate predictions, model representation of feedbacks must be improved through comparisons with contemporary observations. In this study, we quantify the terrestrial and ocean carbon storage sensitivity to climate and atmospheric CO₂ concentration of ESMs participating in the Climate Model Intercomparison Project Phase 5 (CMIP5) following the methodology of Friedlingstein et al. (2006). In order to evaluate the models’ abilities to capture the 21^st century carbon cycle and to offer possible constraints on the modeled feedback strengths, comparisons with contemporary observations will be made over three different time scales: seasonal to annual, interannual to decadal, and decadal to centennial. A conceptual framework for evaluating climate-carbon cycle feedbacks in global models—employing best-available observational data—will be presented, along with results from application of this framework to CMIP5 model output. Included in the analysis will be prototype model evaluation benchmarks of the carbon cycle being designed for the International Land Model Benchmarking (ILAMB) Project.

http://www.ilamb.org/

KEYWORDS:
[0315] ATMOSPHERIC COMPOSITION AND STRUCTURE / Biosphere/atmosphere interactions,
[0428] BIOGEOSCIENCES / Carbon cycling,
[1615] GLOBAL CHANGE / Biogeochemical cycles, processes, and modeling,
[1627] GLOBAL CHANGE / Coupled models of the climate system .

SPONSOR NAME: Forrest Hoffman