Tag Archive for 'endangered species'

Climate Change Could Wreak Havoc on Drought-Plagued California

Photo retrieved from: www.alternet.org

“Michael Goulden, associate professor of earth system science at the  University of California Irvine, and Roger Bales, director of the  Sierra Nevada Research Institute at the University of California Merced, publish their alarming findings in the  Proceedings of the National Academy of Sciences.

Their research looked not at the long-term projections for precipitation in the US south-west, but simply at the  effect of higher average temperatures on plant growth.

Mountains in many ways mimic hemispheres: just as trees become more stunted at higher latitudes, so they get smaller and less frequent at higher altitudes. Temperature ultimately controls plant growth.

But a projected warming of 4.1°C by 2100 would make a big difference to plant growth in the Arctic tundra and around the present alpine treeline everywhere in the world.

The scientists contemplated snow and rain conditions in the King’s River Basin in the Sierra Nevada range. They looked at how much flows downstream to local communities, and how much goes back into the atmosphere as water vapour. Then they did their sums.

They calculated that the 4.1°C temperature rise in the region would increase the density of vegetation at high elevations, with a 28% increase in evapotranspiration − the process that draws water up through the roots to the leaves, and then releases it as vapour through the pores. And what was true for one river basin, they thought, should be true for the whole area. River run-off could drop by 26%.”

Read more: AlterNet

 

 

Dams Cutting Off 400 Million People From Food and Income

 

Photo: Water is released below the Glen Canyon Dam on the Colorado River.

Water is released below the Glen Canyon Dam on the Colorado River. Photograph by Bill Hatcher, National Geographic

“The world’s dams have allowed cities to sprout in dry lands—but at a steep cost to hundreds of millions of already impoverished people, according to a new report.”

‘Lead author Brian Richter, co-director of The Nature Conservancy’s Global Freshwater Program, knew from previous estimates that 40 to 80 million people have been directly displaced over the past decade by dam and reservoir construction.”

“But he wanted to know how many people living farther downstream had been harmed.”

“Richter and his coauthors used published studies, population estimates and geographic information system (GIS) data to take a look.”

““Our conservative estimate of 472 million suggests that the number of people . . . exceeds by six to twelve times the number directly displaced by these structures,” the authors write.”

“Those affected include downstream fishermen and farmers who have had their lives and livelihoods altered or even destroyed by dams, many of them poor people who may find it hard to adapt. For example, when the Maga Dam and a water diversion scheme went in on Cameroon’s Logone River in 1979, combined hits to floodplain agriculture, fisheries, and other downstream attributes reduced the regional economy by $2.4 million per year, according to the International Union for Conservation of Nature (IUCN)”

This story is part of a special series that explores the global water crisis. For more, visit National Geographic’s Freshwater website