Woes Of Warming
Arctic To Echo Worldwide Via Birds
By Alister Doyle
12 November, 2004
Planetark.com
The
decline of migratory birds due to an accelerating Arctic thaw may also
disrupt the delicate ecosystems of their far-flung winter homes from
Africa to South America, experts said this week.
"Birds adapted
to the high Arctic tundra are especially at risk," Hans Meltofte
of Denmark's National Environmental Research Institute told Reuters
at a conference reviewing an eight-nation report on global warming's
impact in the Arctic.
In the long term, global warming is likely to let forests grow further
north in the Arctic, squeezing the tundra breeding grounds of shorebirds
- like curlews, sandpipers or red knots - into a narrowing belt bounded
by the Arctic Ocean.
The report says
the Arctic is heating twice as fast as the rest of the globe and that
the warming "will have implications for biodiversity around the
world because migratory species depend on breeding and feeding grounds
in the Arctic."
Several hundred
million birds migrate every year thousands of km (miles) to the Arctic
to breed, largely because the chill region is almost free of egg-eating
predators. They spend the Arctic winter in places from Patagonia to
Mauritania.
"The bar-tailed
godwit can fly from Alaska to New Zealand with no stops," Meltofte
said. Populations already rise and fall according to the availability
of food in the build-up to the giant flight, lasting almost a week.
"The birds
don't want to go to the Arctic but they have to go to breed," Meltofte
said. "Imagine if two million shorebirds stayed and laid eggs on
the ground in Mauritania. The chicks would be eaten by the crows, gulls
or jackals."
Any decline in bird
populations due to disruptions in the Arctic will affect ecosystems
in the south.
In the shorter term,
however, a warmer Arctic may help some bird species by making food,
such as insects for chicks, more available. One survey showed 12 percent
of Arctic shorebird species were growing in numbers, 42 were stable
and the rest falling.
The gray plover
is among those gaining while the spoon-billed sandpiper of eastern Siberia
is endangered.
Birds may be able
to fly so far because few parasites live in the chill Arctic or in the
salty tidal flats they favor during winter. Higher temperatures might
spread parasites.
"Birds have
this amazing ability to build muscle without training. All mammals need
hard training to build muscles, birds do it naturally, all by hormones,"
Meltofte said.
The Arctic report
blames emissions of heat-trapping gases from burning fossil fuels for
rising temperatures and says the Arctic is warming quickly because dark
water and ground, once uncovered, absorb more heat than snow or ice.