Climate Change And Land Use Affect Water System
September 26, 2012

Earth’s Water System Could Be Affected By Land Use, Climate Change And Ecosystems

April Flowers for - Your Universe Online

We don't yet understand the how the connections between water sustainability and hydrologic processes will be affected by climate change, but to better this understanding, the National Science Foundation (NSF) has teamed up with the United States Departments of Agriculture's National Institute of Food and Agriculture (NIFA). The collaboration has awarded grants totaling almost $27 million through the Water Sustainability and Climate (WSC) program.

NSF's Directorates for Geociences, Engineering, and Social, Behavioral & Economic Sciences support the WSC grants, which fall under the Science, Engineering and Education for Sustainability investment.

"Among the most urgent challenges facing the world today is ensuring the adequate supply and quality of water, especially in light of burgeoning human needs and climate variability and change," says Marge Cavanaugh, NSF acting assistant director for Geosciences.

"Whereas the water imperative is global, WSC recognizes that water availability and quality issues must be examined at local scales where most water decisions are made," says Cavanaugh. "That's why WSC projects are placed-based, and each examines how global and regional climate changes are playing out in terms of water balance at the local scale."

There are three categories of awards from WSC. Category 1 awards are for workshop planning grants, Category 2 grants cover observatories and modeling, and Category 3 grants are for modeling.

"Water is a critical component to the success of American agriculture, yet there is a lack of understanding of how climate variability, land use and other environmental factors affect the water supply," says Sonny Ramaswamy, director of NIFA. "These projects will allow us to better understand water sustainability and allow our producers and rural communities to prepare for future changes."

The goal of these projects, which include studies of Rocky Mountain pine beetles, Los Angeles' water supply and the Sierra Nevada snowpack, is the understanding and prediction of the interactions of Earth's water system with climate change, land use, ecosystem function and services, and the built environment.

More than four million acres of forest in Colorado and Wyoming are dying, for example. The Rocky Mountain pine beetle seems to be the main culprit. This is a species of bark beetle native to the woodlands of western North America. The recent summer droughts and mild winters have exacerbated the infestation of beetles, which may turn out to be the largest insect blight in North American history.

Dead trees line up like falling forest soldiers, highlighting the stunning effects of this infestation. However, they are only the tip of the problem; the invisible changes to the watersheds in the Rocky Mountains may be a longer lasting legacy.

Another study will be conducted in Los Angeles, which lies in a semi-arid region and relies on centralized redistribution for its water supply. To support agricultural and urban needs, water is transported hundreds of miles from mountain to city. However, water allocations from the mountain sources are declining because of drought, over-extraction and competing water needs.

Water resources management plans in arid and semi-arid regions worldwide are based on the assumption that the snowpack that accumulates in winter holds the majority of water that will be used. This snowpack melts, replenishing reservoirs whose supplies are meted out to satisfy human consumption.

This is especially true in California's Sierra Nevada range, a remote and sparsely populated area that supplies water and power for millions of people. The question is if the Sierras will be able to continue to sustain that supply in the years to come.

There is a lot of water on the Earth, but only 2.5 percent of it is fresh water, with 98.8 percent of that locked away in ice or hidden in groundwater. Less than 0.3 percent is in lakes, rivers and the atmosphere.

What better management techniques can we develop to predict and assure water availability for future generations given the ways that the water cycle has been altered by climate change and direct human intervention?

A holistic approach to the water cycle and water resource processes, the feedbacks in a water system, and the vulnerability and resilience of water systems to climate and human changes is needed to find the proper answers.

Water systems are comprised of drainage basins and their physical, chemical and biological constituents, including water networks, ecosystems, the built environment, the oceanic and atmospheric systems that govern evaporation and precipitation in the basin and the source water bodies and terminal lakes or seas into which the water flows.

WSC researchers will attempt to study the entire water system with an integrative, systems science approach to create an analysis that will lead to the improved understanding, prediction and management of water resources.

"Earth has approximately 1,386 million cubic kilometers of water, most of which is the saltwater of oceans and seas," says Cavanaugh.

"What decisions will we make about the rest, the freshwater that's 'technically' available to us? Those decisions are for societies to make, and water sustainability researchers are working through WSC to fully inform those complex decisions."