EarthTalk: Is it true that military sonar exercises
actually kill marine wildlife?
-- John Slocum, Newport, RI
sonar device being lowered into the ocean by an anti-submarine
squadron helicopter. Such devices generate slow-rolling
sound waves topping out at around 235 decibels; the
world‚s loudest rock bands top out at only 130.
Evidence shows that whales will swim hundreds of miles,
rapidly change their depth, and even beach themselves
to get away from the sounds of sonar.
© U.S. Navy
for many whales, dolphins and other marine life, the use
of underwater sonar (short for sound navigation and ranging)
can lead to injury and even death. Sonar systems—first
developed by the U.S. Navy to detect enemy submarines—generate
slow-rolling sound waves topping out at around 235 decibels;
the world’s loudest rock bands top out at only 130.
These sound waves can travel for hundreds of miles under
water, and can retain an intensity of 140 decibels as far
as 300 miles from their source.
rolling walls of noise are no doubt too much for some marine
wildlife. While little is known about any direct physiological
effects of sonar waves on marine species, evidence shows
that whales will swim hundreds of miles, rapidly change
their depth (sometime leading to bleeding from the eyes
and ears), and even beach themselves to get away from the
sounds of sonar.
January 2005, 34 whales of three different species became
stranded and died along North Carolina’s Outer Banks
during nearby offshore Navy sonar training. Other sad examples
around the coast of the U.S. and elsewhere abound, notably
in recent years with more sonar testing going on than ever
before. According to the nonprofit Natural Resources Defense
Council (NRDC), which has campaigned vigorously to ban use
of the technology in waters rich in marine wildlife, recent
cases of whale strandings likely represent a small fraction
of sonar’s toll, given that severely injured animals
rarely make it to shore.
2003, NRDC spearheaded a successful lawsuit against the
Navy to restrict the use of low-frequency sonar off the
coast of California. Two years later a coalition of green
groups led by NRDC and including the International Fund
for Animal Welfare (IFAW), the League for Coastal Protection,
Cetacean Society International, and Ocean Futures Society
upped the ante, asking the federal courts to also restrict
testing of more intense, harmful and far ranging mid-frequency
types of sonar off Southern California’s coastline.
filing their brief, the groups cited Navy documents which
estimated that such testing would kill some 170,000 marine
mammals and cause permanent injury to more than 500 whales,
not to mention temporary deafness for at least 8,000 others.
Coalition lawyers argued that the Navy’s testing was
in violation of the National Environmental Policy Act, the
Marine Mammal Protection Act and the Endangered Species
lower courts upheld NRDC’s claims, but the Supreme
Court ruled that the Navy should be allowed to continue
the use of some mid-frequency sonar testing for the sake
of national security. “The decision places marine
mammals at greater risk of serious and needless harm,”
says NRDC’s Joel Reynolds.
groups are still fighting the battle against the sonar,
lobbying the government to curtail testing, at least during
peacetime, or to at least ramp up testing gradually to give
marine wildlife a better chance to flee affected areas.
“The U.S. Navy could use a number of proven methods
to avoid harming whales when testing mid-frequency sonar,”
reports IFAW’s Fred O'Regan. “Protecting whales
and preserving national security are not mutually exclusive.”
EarthTalk: How does the microwave
compare in energy use, say, to using a gas or electric stove
burner to heat water for a cup of tea?
-- Tempie, Dexter, MI
are a tad more energy-efficient than gas burners,
but about 25 percent less efficient than electric
burners. They can save as much as 80 percent of the
energy needed to cook or warm up food in the oven,
but experts say that the energy used by all methods
of cooking pales in comparison to that used in heating,
cooling and lighting one's home, and in the laundry
© Getty Images
The short answer
is that it depends upon several variables, including the
price of electricity versus gas, and the relative efficiency
of the appliances involved. Typically, though, a microwave
would be slightly more efficient at heating water than the
flame on a gas stove, and should use up a little less energy.
The reason: The microwave’s heat waves are focused
on the liquid (or food) inside, not on heating the air or
container around it, meaning that most if not all of the
energy generated is used to make your water ready.
Given this logic,
it is hard to believe that a burner element on an electric
stovetop would be any better, but an analysis by Home Energy
Magazine found otherwise. The magazine’s researchers
discovered that an electric burner uses about 25 percent
less electricity than a microwave in boiling a cup of water.
That said, the
difference in energy saved by using one method over another
is negligible: Choosing the most efficient process might
save a heavy tea drinker a dollar or so a year. “You’d
save more energy over the year by replacing one light bulb
with a CFL [compact fluorescent lightbulb] or turning off
the air conditioner for an hour—not an hour a day,
one hour at some point over the whole year,” says
consumer advocate Michael Bluejay.
Although a microwave
may not save much energy or money over a stove burner when
heating water, it can be much more energy-efficient than
a traditional full-size oven when it comes to cooking food.
For starters, because their heat waves are concentrated
on the food, microwaves cook and heat much faster than traditional
ovens. According to the federal government’s Energy
Star program, which rates appliances based on their energy-efficiency,
cooking or re-heating small portions of food in the microwave
can save as much as 80 percent of the energy used to cook
or warm them up in the oven.
The website Treehugger.com
reports that there are other things you can do to optimize
your energy efficiency around the kitchen when cooking.
For starters, make sure to keep the inside surfaces of your
microwave oven clean so as to maximize the amount of energy
reflected toward your food. On a gas stovetop, make sure
the flame is fully below the cookware; likewise, on an electric
stovetop, make sure the pan or kettle completely covers
the heating element to minimize wasted heat. Also, use the
appropriate size pan for the job at hand, as smaller pans
are cheaper and more energy-efficient to heat up.
tips for cooking greener, Bluejay reiterates that most of
us will hardly put a dent in our overall energy use just
by choosing one appliance over another. According to his
analysis, for someone who bakes three hours a week the cheapest
cooking method saves only an estimated $2.06/month compared
to the most expensive method.
on cooking methods is not the way to save electricity [at
home],” says Bluejay. “You should look at heating,
cooling, lighting and laundry instead.”
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