The Ecothresholds Project
Understanding thresholds in global change and their implications for decisionmaking

The Heinz Center's ecothresholds initiative arose from a major strategic challenge in the public debate about global environmental change -- what concentrations of greenhouse gases in the atmosphere might lead to environmentally, socially and economically unacceptable impacts? The Framework Convention on Climate Change (FCCC) takes one approach to this problem: avoiding "dangerous anthropogenic interference" and "allowing ecosystems to adapt." But these phrases implicitly assume that the influences of climate change are likely to be gradual, and that there will be substantial time for natural resources to adapt or for managers to cope with change.

The current state of the science suggests that something quite different may be in the offing. The Intergovernmental Panel on Climate Change (IPCC) and other assessments of possible impacts now agree on two important points. One is that there is already well-documented evidence of the biological and ecological consequences of climate change -- in the behavior of migratory birds, in corals bleached from the influence of warming ocean temperatures, in the loss of glaciers to warming air temperatures, and in the loss of sea grass beds to sea level rise. The second is that ecological systems may not in fact change gradually.

Modeling studies and the historical record both suggest that changes in ecosystems can be rapid, large, and sometimes irreversible, i.e. there may well be thresholds that, once crossed, will present serious coping challenges to humans. Moreover, as suggested in a recent National Academy of Sciences (NAS) workshop on "Understanding and Responding to Multiple Environmental Stresses," dealing with threshold responses that may lead to sudden and dramatic change in societal or environmental structure and function will also require that we develop ways to proceed with decision-making despite the many uncertainties associated with thresholds.

In light of these challenges, a central goal of the ecothresholds initiative is to promote understanding of the physical, natural, and social dynamics that underlie ecological thresholds in order to best inform ongoing adaptation measures and response options across scales of decision-making.

Broadly, the initiative is intended to:

• Enhance collaboration among government, business, academia and environmental NGO's to identify key issues that arise from abrupt changes in ecological systems
• Initiate long-term engagement among the sectors and stakeholders to find workable ways to cope with threshold changes in natural, managed, and socio-economic systems; and
• Initiate a larger discussion about acceptable levels of greenhouse gases necessary to mitigate those threshold changes that cannot be addressed through management actions.

To accomplish this goal, The Heinz Center, in collaboration with The
Nature Conservancy and the Joint Global Change Research Institute, will
be hosting a series of meetings to develop a framework for relating and
understanding threshold dynamics (particularly related to global changes
in climate, land use, etc.) in the context of decision-making and
resource management.