Climate health costs bug-borne ills, killer heat
Tree-munching beetles, malaria-carrying mosquitoes and deer ticks
that spread Lyme disease are three living signs that climate change is
likely to exact a heavy toll on human health.
These pests and others are expanding their ranges in a warming world,
which means people who never had to worry about them will have to start.
And they are hardly the only health threats from global warming. The
Lancet medical journal declared in a May 16 commentary: "Climate change
is the biggest global health threat of the 21st century."
Individual threats range from the simple to the very complex, the
Lancet said, reporting on a year-long study conducted with University
College London.
As the global mean temperature rises, expect more heat waves. The
United Nations Intergovernmental Panel on Climate Change projects 25
percent more heat waves in Chicago by the year 2100; Los Angeles will
likely have a four-to-eightfold increase in the number of heat-wave days
by century's end.
These "direct temperature effects" will hit the most vulnerable
people hardest, according to the U.S. Environmental Protection Agency,
especially those with heart problems and asthma, the elderly, the very
young and the homeless.
The EPA has declared that carbon dioxide, a powerful greenhouse gas.
is a danger to human health and welfare, clearing the way for possible
regulation of emissions.
At the same time, the U.S. Congress is working on a bill that would
cap emissions and issue permits that could be traded between companies
that spew more than the limit and those that emit less.
People who live within 60 miles (97 km) of a shoreline, or about
one-third of the world's population, could be affected if sea levels
rise as expected over the coming decades, possibly more than 3 feet (1
metre) by 2100. Flooded homes and crops could make environmental
refugees of a billion people.
As it becomes hotter, the air can hold more moisture, helping certain
disease-carriers, such as the ticks that spread Lyme disease, thrive,
the EPA said.
A changing climate could increase the risk of mosquito-borne diseases
like malaria, dengue fever, yellow fever and various viral causes of
encephalitis. Algae blooms in water could be more frequent, increasing
the risk of diseases like cholera. Respiratory problems may be
aggravated by warming-induced increases in smog.
Other less obvious dangers are also potentially devastating.
Pine bark beetles, which devour trees in western North America will
be able to produce more generations each year, instead of subsiding
during winter months. They leave standing dead timber, ideal fuel for
wildfires from Arizona to Alaska, said Paul Epstein of the Center for
Health and the Global Environment at Harvard University.
Other insects are spreading in the United States, and while immediate
protection is possible, the only real solution is to curb climate
change, Epstein said in a telephone interview.
"You can tuck your pants into your socks and be very vigilant, but
ultimately, if we don't stabilize the climate, it's going to continue to
increase ... infectious diseases," Epstein said.
Carbon dioxide emissions, from coal-fired power plants, steel mills
and petroleum-fueled cars, trucks and boats, among other sources, do
more than modify climate, Epstein said. They also stimulate ragweed,
some pollen-bearing trees and fungi, extending the spring and fall
allergy and asthma seasons. It is hard to quantify the potential
financial cost of U.S. climate-change-related health problems, said Dr.
Chris Portier of the U.S. National Institute of Environmental Health
Sciences. WASHINGTON, (Reuters) |