Water: Impacts, Risks, and Adaptation

This chapter breaks with traditional climate change assessments of the water sector by focusing primarily on emerging adaptation activities being pursued by water providers rather than on either the changes to water cycle or impacts and risks to, and vulnerabilities of, human and natural systems. This altered focus occurs because the mandate of this assessment was to identify important new findings since 2009, the date of the last U.S. national assessment on climate change (Karl, Melillo and Peterson 2009). In most cases, the science about water-cycle changes and human and natural system impacts, risks, and vulnerabilities has changed little over the last three years. During this same period, however, numerous adaptation initiatives have been pursued by water managers and providers in the West. These activities are predominantly new, important, and pertinent to this assessment. It is critical to note that these nascent efforts have produced important documents and networks of knowledgeable experts, but few other tangible products or projects.