Advancing the Science of Climate Change: The National Academies Press 2010

Skimming the chapter on Freshwater Resources of the book, Advancing the Science of Climate Change, by the National Research Council of the National Academies, the reader realizes the inconclusiveness of the research and need for "better data and modeling as well as a better understanding of both the impacts of climate change and the role of water governance on water resources" (p. 200). In the review of precipitation--its frequency, intensity, storminess-- and snowpack, glaciers, and snowmelt, the authors acknowledge some documented trends. The United States has experienced approximately a 5 percent increase in precipitation during the past five years, with wetter occurrences in the Northeast and drier occurrences in the Southwest.

Indefinite conclusions result on the subject of hurricane intensity and climate change, although scientists have noticed changes in intensity (e.g., Katrina). Scientists have documented decreases in snow cover. In the United States, declines of snow pack happen more acutely in areas of lower elevation in the mountains of the Northwest and California. Increases in temperatures cause snow pack to decrease in spring "resulting in reduced later-summer stream flows" (p. 204). Globally, scientists observe shrinkage of glacier systems, with consequences of "reductions in river flows during dry seasons and lost water resources for the hundreds of millions of people who rely upon glacier-fed rivers worldwide" (p. 204).

Considering surface and groundwater, surface water trends mirror trends in precipitation, which, as noted above, experienced increases over the immediate past in the United States. Evapotranspiration, a factor in surface water runoff, lacks longitudinal data to measure water loss to the atmosphere. Insufficient data exists on the impact of climate change on groundwater levels. Water managers in dry areas of the United States have resorted to increases of ground water withdrawals to meet public demand and recharge projects to replenish declining supplies. The authors mentioned factors that complicate an assessment, "inconsistent regulation of groundwater and surface water from state to state, and the lack of readily available legal mechanisms to link ground and surface water management--even where they are physically linked" (p. 206).

In their discussion of drought, the authors cited the Palmer Drought Severity Index, which from the period of 1870 to 2002 measured that areas of dryness doubled globally from the beginning of the study to its end. The inconclusiveness of precipitation and evapotranspiration data and the inconsistency of soil moisture information make modeling drought difficult. The authors concluded, "this uncertainty in future soil moisture projections leads to uncertainties about ecosystem dynamics and projections of agricultural productivity, and thus present a challenge for farmers, natural resource managers, and others trying to plan adaptation measures" (p. 2006). Equally as vague and understood are predictions of water quality from climate change, despite predictions of the growth of algae from warmer water temperatures and increases of salinity due to infiltration of seawater on freshwater.

Before listing a number of topics for future research, the authors addressed the maintenance and restoration of aging infrastructure, which would transmit and distribute potable water to the public during the period of climate change. Governance theories to assist in framing policies for planning include the Integrated Water Resources Management and Adaptive Management. The first focuses on "reforming broader institutional structures of water governance including decentralization, integration, participatory collaborative management, and social learning" (p. 207). Adaptive management, according to these authors, stressed flexibility. Even these frameworks require further study, the authors argued.

This prepublication copy is subject to change and can be found at http://www.nap.edu/catalog.php?record_id=12782