One of the most urgent challenges facing the world today is ensuring the adequate supply and quality of water in light of burgeoning human needs and climate variability and change.

Despite water's importance to life on Earth, there are major gaps in understanding water availability and quality, as well as the effects of a changing and variable climate, and of human activities, on the water system.

To help find new answers to one of the most pressing problems of the millennium, the National Science Foundation (NSF) and the U.S. Department of Agriculture's National Institute for Food & Agriculture (NIFA) have made 26 awards totaling $25 million in their joint Water Sustainability and Climate (WSC) program. This year's awards are the third set in the program.

"Water is the lifeblood of Earth's environment," says Tom Torgersen, lead NSF WSC program officer. "Knowledge of the flow and function of water is paramount to understanding how humankind's activities interact with and alter our environment. The mounting pressures of population increases, land use changes, and climate change underscore the need to understand the role of water."

The WSC program's goal is to understand and predict interactions among Earth's water system and climate change, land use (including agriculture, managed forests and rangeland systems), the "built environment" and ecosystems around the world.

"Agriculture in the U.S. is dependent on the availability and quality of water; however, a number of factors, including climate and the environment, could have a significant effect on our nation's water resources, which, in turn, has consequences for farmers, livestock producers, forest and rangeland managers and rural economies," said NIFA director Sonny Ramaswamy.

"These grants are critically important to our understanding of how the water system is affected by external factors, which ultimately helps farmers and rural communities prepare for future challenges," he added.

Topics addressed by this year's awards include the effects of climate change on agriculture-water systems; water quality and supply in two tropical nations, Ecuador and China; effects of agricultural decision-making and adaptive management on food security; water sustainability in a snow-fed arid river system; land-use and hydrology in the Panama Canal watershed, and decision processes, climate change and water resources in the agricultural Midwest.