Kathleen Miller and David Yates

OBJECTIVES:

The purpose of this project was to produce a succinct, educational report (Primer) for use by the drinking water utility industry outlining the current state of scientific understanding regarding the potential impacts of global climate change on water utilities, including impacts on water supply, demand, and relevant water quality characteristics.

BACKGROUND:

There is a great deal of misunderstanding surrounding the subject of climate change, often leading to profound confusion regarding its potential impacts on natural resource systems and public well-being. Well-intentioned but misguided attempts by the media to call attention to the prospect of climate change have left much of the public with the impression that the Earth's climate system is either poised at the brink of cataclysmic change or that global climate change is a myth that they can safely ignore. Neither of those extreme views provides useful guidance to anyone attempting to make informed decisions about the management of climate-sensitive resources.

HIGHLIGHTS:

The project drew upon extensive scientific literature, providing a sound overview of the current understanding of climate change (both natural and human caused) and its impacts on water resources. A project workshop allowed participants from the science and water provider communities to share information and develop contacts. Workshop participants provided guidance on industry concerns, recent climate impacts on urban water providers, and vulnerabilities to prospective climate changes. Participants provided advice on how to make the Primer scientifically accurate and useful to water utility managers. The authors worked with representatives of 11 of the participating utilities to develop case studies for the Primer.

APPROACH:

The project involved four main phases:

1. Production of a preliminary draft of the Primer, focusing on scientific aspects

2. A workshop to gather input from industry and science participants and to evaluate, augment, and refine the draft Primer

3. Production of the final Primer

4. Production of a supplementary CD-ROM, including extensive additional reference materials

Insights from participating utilities and from the water management literature provided the basis for the report's discussion of vulnerabilities, assessment options, and planning approaches. The participating utility representatives provided case study information and reviewed the document to ensure that the lessons they had learned from their climate-related experiences, and from their efforts to assess climate change impacts, would be adequately communicated to their industry peers.

RESULTS/FINDINGS:

The final report includes a summary of the relevant science that explains the linkages between climate change and the hydrologic cycle and outlines what is known and unknown about future changes in regional hydrologic conditions. The report also describes the implications of climate change for water utilities and discusses planning and response strategies.

In particular, the report demonstrates that the global hydrologic cycle will be intensified by the warmer global average temperatures that will result from continued accumulation of greenhouse gases in the atmosphere. Warming will lead to increases in global average annual precipitation, heavier individual precipitation events, and perhaps longer dry spells between precipitation events. Evapotranspiration and storm tracks will also change. In other words, increased global precipitation does not necessarily imply increased water availability at the regional level. In fact, model simulations indicate potentially large reductions in annual and seasonal runoff in many regions. Water quality impacts are likely to result from the increased incidence of heavy rainfall/runoff events, as well as from wildfire impacts on watersheds and saltwater intrusion into coastal aquifers. While some regional hydrologic changes are clear, including earlier snowmelt, declining glaciers, and sea level rise, significant uncertainties remain.

IMPACT:

This project will help municipal water providers approach planning with a realistic grasp of the nature of the risks posed by climate change. Specifically, the Primer provides a comprehensive overview of issues that water utility managers will confront as they attempt to assess, and plan for, the impacts of climate change. It also provides case studies contributed by water utilities at the forefront of the North American and European industries. These cases identify vulnerabilities and response options, and help to make climate change comprehensible to water utility managers by providing examples of actual utility impacts similar to those expected to result from continued climate warming. The case studies also show utility managers how to approach planning for climate change by providing real-world examples of efforts to incorporate consideration of climate change in ongoing planning activities.

MULTIMEDIA:

The report package includes a supplementary CD-ROM, which contains an electronic copy of the Primer with clickable links to reference materials, including an extensive annotated bibliography, links to useful web resources, and visualizations of climatic processes. It also includes copies of the workshop presentations.

RESEARCH PARTNER:

University Corporation for Atmospheric Research (UCAR)

PARTICIPANTS:

Eleven utilities from the United States, the United Kingdom, Canada, and the Netherlands contributed case study materials or photos.