Climate Change Will Impact Global River Flow,
Scientists Warn
ScienceDaily (Oct. 13, 2007) — A global analysis of the potential effect of
climate change on river basins indicates that many rivers impacted by
dams or extensive development will require significant management
interventions to protect ecosystems and people, according to an article
published in the online version of Frontiers in Ecology and the
Environment.
"As a result of damming and development, major rivers worldwide have
experienced dramatic changes in flow, reducing their natural ability to adjust to
and absorb disturbances," said lead author Dr. Margaret Palmer, Director of the
University of Maryland Center for Environmental Science Chesapeake Biological
Laboratory. "Given expected changes in global climate and water needs, this
could lead to serious problems for both ecosystems and people."
In their analysis, the authors project river discharge under different climate and
water withdrawal scenarios and combine this with data on the impact of dams on
large river basins. The results are presented in global maps illustrating potential
changes in discharge and water stress for dam-impacted and free-flowing basins.
The projections indicate that every populated basin in the world will experience
changes in river discharge -- some are expected to have large increases in flood
flows while other basins will experience water stress such that there is not
enough water to meet human needs. For example, by the 2050's, mean annual
river discharge is expected to increase by about 20 percent in the Potomac and
Hudson River basins but to decrease by about 20 percent in Oregon's Klamath
River and California's Sacramento River.
The magnitude of the changes is used to identify basins likely and almost certain
to require proactive or reactive management intervention. The study also finds
that nearly one billion people live in areas likely to require action and
approximately 365 million people live in basins almost certain to require action.
Specific, proactive restoration, rehabilitation, and management actions are
recommended to enhance the resilience of riverine ecosystems and minimize
impacts. These efforts will minimize risks to ecosystems and people and may be
less costly than reactive efforts taken only once problems have arisen. Proactive
actions include stormwater and sediment management, channel reconfiguration,
dam removal, land acquisition and riparian management.
"This report calls attention to significant risks facing many of the world's major
rivers and those people who live near or depend on them for water or food," said
Palmer. "Many of these risks could be reduced dramatically if proactive
management measures are implemented now. It's now up to the world's political
leaders to decide whether or not to step forward and put in place programs
designed to minimize the impacts we may see on our ecosystems and people."
The article, "Climate change and the world's river basins: anticipating
management options," is coauthored by authors from the United States, Sweden,
Germany and Australia. This work was supported by the U.S. Environmental
Protection Agency Global Climate Change Program, the Swedish Research
Council and the Swedish Research Council Formas, Land and Water Australia,
Water CRC Australia, the DFG--German Research Foundation and the
International Water and Climate Dialogue.