Environmental Engineering Reference
In-Depth Information
Not everyone buys into the notion of “climate change.” But
change
is
happening. Spring already comes earlier than it did
a century ago; at least from Mother Nature's point of view. “In New
England and Canada, the maple sap from trees is running two
weeks earlier than a century ago,” says Dellapenna. “That's nature's
way of adapting to climate change.”
Earth's water cycle—evaporation and precipitation—has accel-
erated, too, increasing the amount of water feeding into the world's
oceans, according to a new study by NASA and university research-
ers. The study, published in the Proceedings of the National
Academy of Sciences, found that “18 percent more water fed into
the world's ocean from rivers and melting polar ice sheets in 2006
than in 1994,” with an average annual increase of 1.5 percent.
“That might not sound like much—1.5 percent a year—but
after a few decades, it's huge,” said Jay Famiglietti, University of
California-Irvine Earth system science professor and investigator
on the study, when the study was published in October 2010. “In
general, more water is good. But . . . not everybody is getting more
rainfall, and those who are may not need it. What we're seeing is
exactly what the Intergovernmental Panel on Climate Change pre-
dicted—that precipitation is increasing in the tropics and the Arctic
Circle with heavier, more punishing storms. Meanwhile, hundreds
of millions of people live in semiarid regions, and those are
drying up.”
17
Infrastructure woes.
“Our dams, aqueducts, and water systems
were built for yesterday's climate, not tomorrow's,” says Gleick.
“Tomorrow's climate will be different. We don't know the extent to
which that infrastructure will be able to handle the changes that are
coming.”
Among potential infrastructure problems are reservoirs built
the wrong size and in the wrong locations to capture enough water
during runoff and wet times to serve the nation's needs in dry
times, experts agree.
“Under prior climate conditions, our dam system stored ade-
quate water for summer needs. But existing reservoir capacity isn't
enough to capture the added runoff in what now is late winter, but
by the end of the century, in terms of temperature, will be well into
spring,” Dellapenna says.
