Ecosystem Thresholds and Climate Tipping Points: Implications for Policymakers

In response to this question, a project was developed jointly by the H. John Heinz III Center for Science, Economics, and the Environment, the Joint Global Change Research Institute, and The Nature Conservancy, entitled "Understanding the Consequences of Thresholds in Global Change and Their Implications for Decision-Making." The project promotes understanding of the physical, natural, and social dynamics that underlie ecological thresholds in order to better inform ongoing adaptation measures and response options across scales of decision-making. Our panel will focus on the work of this important initiative and its draft report, which is based on the first of a series of meetings that took place in 2006. Case studies presented at the meeting included impacts on the critical ecosystems of the American Rockies and Alaska such as: drought in the Colorado River Basin; bark beetles in Western Canada; and forest die-off and die-back in the West. Our speaker panel included Ecothresholds Project participants and other experts.

The Ecothresholds Project envisions workshops and conferences to engage resource managers and practitioners to explore responses to threshold effects that challenge the condition of ecosystem services and the foundation of a range of natural resource management practices. Creating a dialogue between this project and policymakers will help ensure that the major strategic questions being addressed by this project will be incorporated into the federal policy debate on climate change.

On September 20, 2007, the Environmental and Energy Study Institute (EESI) held a congressional briefing about the impacts climate change is having on ecosystems, in particular those changes that are rapid, large, and potentially irreversible. We now have evidence that there may be thresholds that, once crossed, will present serious coping challenges to humans. This raises a major strategic challenge in the climate policy debate before this Congress: What concentrations of greenhouse gases in the atmosphere might lead to environmentally, socially and economically unacceptable impacts?