OOS 82

Terrestrial Carbon Cycle and Nonautonomous Systems

Modern civilization of humanity is largely driven by uses of fossil fuel energy. However, fossil fuel burning releases carbon dioxide into the atmosphere, likely inducing global warming. The latter, in turn, poses a great threat to the human civilization. To sustain humanity into future generations, we have to improve our understanding of carbon cycles in biosphere, atmosphere, and lithosphere in the Earth system. Carbon cycle research has been primarily done by use of observations through various networks, field and laboratory experiments, and simulation models. Observations characterize regional and global patterns of carbon cycle components on the Earth. Experimental studies directly probe responses of ecosystems to global change. The modeling community has incorporated more and more processes into Earth system models. As a consequence, the Earth system models become increasingly complex and less tractable. Overall, the existing approaches have not led to well-constrained predictions of the terrestrial carbon cycle. It is essential to explore other approaches to study global carbon cycle. Recent research has examined several lines of empirical evidence to show that the terrestrial carbon cycle can be described as a nonautonomous system. That is, the carbon cycle can be expressed by a set of differential equations with their coefficients being modified by nonlinear response functions to external forcing. We have formed a working group, supported by NSF National Institute of Mathematical and Biological Synthesis (NIMBioS) over the past three years, to study the nonautonomous system of the terrestrial carbon cycle. The NIMBioS working group consists of seven mathematicians and seven ecologists. The group has explored a variety of carbon cycle issues using interdisciplinary approaches. The proposed organized oral session (OOS) will present eight talks, seven of which directly stem from research by the working group. To make this symposium broadly interesting to a wide audience, we will have one introductory talk on ecological and mathematical properties of the terrestrial carbon cycle and one introductory talk on nonautonomous systems with applications in ecology. One talk will review applications of the nonautonomous systems theory to different ecological applications. Then we will have two more ecology-oriented talks on mathematical behaviors of nonlinear microbial models and parameter space of carbon cycle models, respectively. Two math-oriented talks are on global attractors and convergences of the nonautonomous carbon cycle systems and residence times of transient pool-flux systems, respectively. One talk is to examine tropical forest dynamics under the nonautonomous systems framework