Synthesis and Assessment Product (SAP) 4.2: Thresholds of Climate Change in Ecosystems

This report is one in a series of 21 Synthesis and Assessment Products (SAPs) produced between 2004 and 2009 by the U.S. Climate Change Science Program, aimed at providing current assessments of climate change science in the U.S. to inform public debate, policy, and operational decisions. This SAP reviews threshold changes in North American ecosystems that are potentially induced by climate change and addresses the significant challenges these threshold crossings impose on resource and land managers.

As defined in this report, an ecological threshold is the point at which there is an abrupt change in an ecosystem quality, property, or phenomenon, or where small changes in one or more external conditions produce large and persistent responses in an ecosystem. The report provides an overview of ecological thresholds and where they are most likely to occur. It also identifies those areas where research is most needed to improve the understanding of these thresholds and suggests potential actions that land and resource managers could use to improve the resilience of the resources they manage to climate change.

Publication Date: January 2009

Authors or Affiliated Users:

  • Daniel B. Fagre
  • Collen W. Charles
  • Craig D. Allen
  • Charles Birkeland
  • Stuart F. Chapin III
  • Peter M. Groffman
  • David A. McGuire
  • Patrick J. Mulholland
  • Debra P.C. Peters
  • Daniel D. Roby

Related Organizations:


Resource Category:

Resource Types:

  • Assessment
  • Climate science


  • Air temperature
  • Drought
  • Invasive species and pests
  • Permafrost melt
  • Precipitation changes
  • Water supply
  • Water temperatures
  • Wildfires

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