The Changing North American Carbon Cycle: Projections, Consequences and Research Priorities

The rise of atmospheric carbon dioxide (CO₂), primarily due to fossil fuel emissions and changes in land cover and land-use, has been dampened by carbon uptake by the oceans and terrestrial biosphere. Uptake of anthropogenic CO₂ has caused documented direct and indirect effects on terrestrial and oceanic systems and processes in different regions of North America. The capacity of these systems to continue to act as carbon sinks, however, is not certain and remains poorly quantified. Over the past two-to-three decades, there has been considerable effort to understand how terrestrial and oceanic systems behave (in response to rising atmospheric CO₂ and changing climate conditions), quantify the dynamics of system responses to environmental change, and project how the ocean and terrestrial carbon cycle will interact with, and influence, future atmospheric CO₂ concentrations and climate. In this presentation, we will summarize key findings related to projected changes to the North American carbon cycle, and the consequences of these changes, as reported in Chapters 17 and 19 of the Second State of the Carbon Cycle Report (SOCCR-2). We will also discuss current knowledge gaps and outline a set of future research priorities, including both monitoring and modeling activities, that are necessary to improve projections of future changes to the North American carbon cycle and address adaptation and resource management decisions.