March 30, 2012, San Francisco, CA – When Jason Gurdak says climate change is going underground, he means it literally.
March 30, 2012, San Francisco, CA – When Jason Gurdak says climate change is going underground, he means it literally.
Gurdak, assistant professor of geosciences at San Francisco State University, is co-editor of a new
book by a United Nations-sponsored group of scientists that explores the
effect of climate change on underground water sources, an issue that
Gurdak says has been overlooked by many scientists and policymakers.
As precipitation becomes less frequent due to climate change,
lake and reservoir levels will drop and people will increasingly turn
to ground water for agricultural, industrial and drinking water needs, he
said.
"It is clear that ground water will play a critical role in
society's adaption to climate change," said Gurdak, who has studied the
High Plains aquifer in the Midwest extensively.
Ground water already accounts for nearly half of all drinking water
worldwide, but recharges at a much slower rate than aboveground sources
and in some cases is nonrenewable. As more people tap into
groundwater, they may not realize that they are relying on an
unsustainable resource.
"Once the water tables have been dropping a couple of feet every
year, as they are in some places, it's kind of too late for water to
recharge in a way that we can use," he said.
Gurdak was one of the principle editors of Climate Change Effects
on Groundwater Resources, a book released in December that is the
result of a global ground water initiative by the United Nations
Educational, Scientific, and Cultural Organization (UNESCO).
Though few ground water regulations and conservation measures are
in place in much of the world, the scientists who contributed to the
book hope to change that. The book contains policy recommendations that
Gurdak is taking before international policymakers this week at the
March 12-17 World Water Forum in Marseille, France.
The impacts of climate change on ground water vary widely depending
on the type of climate region. In temperate coastal regions like the
Bay Area, saltwater intrusion is a major threat. When sea levels rise,
saltwater could begin seeping into underground freshwater sources,
tainting their use for drinking water and irrigation. Wetlands, a
crucial regulator of groundwater quality and water levels, may also
start to dry up.
Although ground water is not the primary water source in the Bay
Area – water is piped in from Hetch Hetchy and other reservoirs – ground water is vital in the Central Valley and other parts of the state.
"In many ways, California is leading the way in developing
solutions," Gurdak said. "Artificial recharge, managed storage and
recovery projects and low impact development around the state will
become more important for many local water systems to bank excess water
in aquifers."
But Gurdak said that conservation starts with educating future
generations about where their resources come from and how limited they
may be.
"Day to day we don't see where our water comes from, we just turn
on the tap and it's there and it's clean," he said. "But just like with a
carbon footprint, you can calculate your water footprint."
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