In an effort to bring awareness to a variety of environmental issues, the Sustainable Earth, Energy and Environmental Systems speaker series highlights issues involving climate change and natural resources. The “Water — Impacts of Climate Change and Solutions” lecture was presented yesterday by Prof. Rebecca Schneider, natural resources.

The discussion focused on the growing problem of freshwater scarcity. A 1997 report by Population Action International estimated that “by 2050, about 4.4 billion people of the world’s projected 10 billion people will suffer from chronic water shortages.”

Schneider noted that direct human influences and global climate changes were both main components of the problem.Drink up ... before it’s all gone: Prof. Rebecca Schneider, natural resources, speaks about water use management in Phillips Hall yesterday.

“We’ve hardened the [earth’s] surface, compacted it,” Schneider said. The man-made parking lots, roadways and rooftops prevent rainfall from seeping into the soil and becoming life-sustaining groundwater: a source of freshwater that steadily feeds into the streams and rivers, maintaining healthy water levels for days, weeks and months after the initial rainfall.

The demands on the freshwater supply for purposes essential to civilized daily life exhaust the water reserves. Such demands include irrigation, hydroelectric/hydrothermal power, flood control and wastewater disposal. “All of these [demands] are happening simultaneously and have an impact on the same water sources,” Schneider said as she highlighted the various stresses on the limited water supply.

Additionally, rivers dammed for reservoirs and water storage cause harmful changes in the hydrologic regime (cycles of high and low water levels) that destroy dependent organisms and ecosystems, she said. They also pose a barrier to fish migration and withhold nutrient-rich sediment, preventing the downstream enrichment of the section of the stream cut off by the dam.

Wasteful irrigation practices constituted another factor through which people deplete the amount of available freshwater. The presentation noted that irrigation accounts for 70 percent of the world’s water consumption and that 50 percent of the water taken from the source never reaches the crop. For instance, gravity-fed and sprinkler irrigation, though a low-cost option, allow a sizable amount of evaporation to occur.

Climate change has also played a hand in the decreasing water supply. Mountain glacial melting, especially in the Himalayas, Alps, Rockies, Peruvian Andes and parts of Africa has reduced downstream summer river flow, which serves as a key resource for many countries. “The reason this is so critical is because the summer flow [of these glaciers] provided water to millions of people,” Schneider said.

The discussion, however, also identified areas where our systems of water usage could be improved. Water scarcity, named as a crisis in management by the 4th world water forum, could be improved with a more conscientious framework of ‘sustainable’ water resource management.

Schneider suggested that “watersheds [are] the way to think about how much water we have to work with.” Watersheds were defined as areas that share a general source of water, or as Schneider explained, “most of the world’s countries belong to some [common] basin, some ‘bowl.’”

Furthermore, Schneider stressed the need for compromise between the modern demands for irrigation, dams and other important uses of water and the future need to preserve the dependent organisms and ecosystems. New technology, such as geographic information system mapping, tracer studies and groundwater and runoff models could keep people informed about how much water they draw from the source. Most importantly, modern communication “[accelerates] information exchange, building collaboration and peer oversight.”

Attending the lecture were a number of interested students and faculty members.

Casey Hagg ’12 thought that the lecture brought “awareness, and a lot of interesting, important statistics.”

The subject of the lecture specifically attracted engineers for whom the topic was very relevant.

“I’m an environmental engineer and watched a documentary on the subject, so I found this to be very interesting,” Eoyssa Dixon ’12 said.