EarthTalk: I keep meeting people who say that
human-induced global warming is only theory, that just as
many scientists doubt it as believe it. Can you settle the
-- J. Proctor, London, UK
raft of recent peer reviewed studies -– many
which take advantage of new satellite data -–
back up claims that it is emissions from tailpipes
and smokestacks (and now factory farmed food animals,
which release methane) that are causing global warming.
A growing cadre of so-called "global warming
skeptics," however, denies these connections
and chalk it up to natural cycles.
© Getty Images
“global warming skeptics” are indeed getting
more vocal than ever, and banding together to show their
solidarity against the scientific consensus that has concluded
that global warming is caused by emissions from human activities.
of 800 skeptics (most of whom are not scientists) took part
in the second annual International Conference on Climate
Change—sponsored by the Heartland Institute, a conservative
think tank—in March 2009. Keynote speaker and Massachusetts
Institute of Technology meteorologist Richard Lindzen told
the gathering that “there is no substantive basis
for predictions of sizeable global warming due to observed
increases in minor greenhouse gases such as carbon dioxide,
methane and chlorofluorocarbons.”
skeptics attribute global warming—few if any doubt
any longer that the warming itself is occurring, given the
worldwide rise in surface temperature—to natural cycles,
not emissions from power plants, automobiles and other human
activity. “The observational evidence…suggests
that any warming from the growth of greenhouse gases is
likely to be minor, difficult to detect above the natural
fluctuations of the climate, and therefore inconsequential,”
says atmospheric physicist Fred Singer, an outspoken global
warming skeptic and founder of the advocacy-oriented Science
and Environmental Policy Project.
green leaders maintain that even if some warming is consistent
with millennial cycles, something is triggering the current
change. According to the nonprofit Environmental Defense,
some possible (natural) explanations include increased output
from the sun, increased absorption of the sun’s heat
due to a change in the Earth’s reflectivity, or a
change in the internal climate system that transfers heat
to the atmosphere.
scientists have not been able to validate any such reasons
for the current warming trend, despite exhaustive efforts.
And a raft of recent peer reviewed studies—many which
take advantage of new satellite data—back up the claim
that it is emissions from tailpipes, smokestacks (and now
factory farmed food animals, which release methane) that
are causing potentially irreparable damage to the environment.
wit, the U.S. National Academy of Sciences declared in 2005
that “greenhouse gases are accumulating in Earth’s
atmosphere as a result of human activities, causing surface
air temperatures and subsurface ocean temperatures to rise,”
adding that “the scientific understanding of climate
change is now sufficiently clear to justify nations taking
prompt action.” Other leading U.S. scientific bodies,
including the American Meteorological Society, the American
Association for the Advancement of Science and the American
Geophysical Union have issued concurring statements—placing
the blame squarely on humans’ shoulders.
the Intergovernmental Panel on Climate Change (IPCC), a
group of 600 leading climate scientists from 40 nations,
says it is “very likely” (more than a 90 percent
chance) that humans are causing a global temperature change
that will reach between 3.2 and 7.2 degrees Fahrenheit by
the end of this century.
and Environmental Policy Project; U.S.
National Academy of Sciences; IPCC.
EarthTalk: Are elephant populations stable
-- Reuben Perrin, Hartford, CT
hunting (primarily to obtain ivory) and habitat loss
have combined to cause dramatic declines in the numbers
of both African and Asian elephants. In 1930, there
were between five and 10 million wild African elephants,
plying the entire African continent in large bands.
Today that number is likely less than 500,000. Pictured:
Two African elephants standing face to face in Kenya's
Masai Mara National Reserve.
© Getty Images
Far from it.
The double whammy of poaching (illegal hunting) and habitat
loss has led to a dramatic decline in populations of both
African and Asian elephants in recent decades. In 1930,
there were between five and 10 million wild African elephants,
plying the entire African continent in large bands. Just
60 years later, when they were added to the international
list of critically endangered species, only about 600,000
were scattered across a few African countries. Today that
number is likely less than 500,000.
While Asian elephants
were never as numerous as their African counterparts, their
population numbers have also dropped precipitously, from
an estimated 200,000 a century ago to less than 40,000 today.
Conservationists fear that unless demand dries up for ivory,
and people stop moving into prime elephant habitat, the
world’s largest land mammal could become just a memory
within another hundred years.
Putting an end
to habitat loss may be next to impossible as more and more
people vie for fewer and fewer resources and move out further
into the countryside, so conservationists working to save
elephants tend to concentrate on reducing or eliminating
poaching. While trophy hunting of elephants may have been
big decades ago, today most elephant hunters are after the
ivory in the tusks, which have been a hot commodity across
Asia for years as raw material for highly prized and often
ornate carvings. Despite elephants’ inclusion in Appendix
I of the Convention on International Trade in Endangered
Species (CITES) in 1990—meaning the sale of tusks
and other elephant parts is a violation of international
law—poaching is bigger business than ever, with prices
for ivory rising more than 16-fold in recent years.
such as Tanzania and Kenya, are working hard to hold up
their end of the CITES agreement, hiring patrols of young
men—some of them former poachers themselves—to
monitor local elephant populations and enforce national
and international laws against killing these and other endangered
species. Conservation groups like the African Wildlife Foundation
(AWF) and the Wildlife Conservation Society (WCS) are working
hand-in-hand with local officials to improve elephant habitat
and keep poachers at bay. These organizations hope that
the people in these regions can learn how to bring in revenues
from tourism instead of hunting.
governments are not as committed to the ivory ban, let alone
to following laws imposed by outsiders. Government officials
in Zimbabwe, South Africa and Botswana, for example, argue
that trade in ivory should be regulated, not prohibited.
They maintain that countries that are managing their elephants
well should be allowed to sell ivory in order to pay for
In part to test such waters, the first legal sale of ivory
in a decade took place in October 2008, despite protests
from conservationists. Buyers, mostly from China and Japan,
eagerly snatched up some 100 tons of stockpiled elephant
tusks—no elephants were killed recently or illegally
for the sale—with the proceeds going to groups working
to save the elephant and its habitat. But with the legal
ivory sale has come an uptick in elephant poaching, leaving
conservationists with that “one step forward, two
steps back” feeling.
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