Stephen Leahy
BROOKLIN, Canada, May 18 (IPS) - Global warming may now be the largest cause
of soaring rates of species extinctions, which threaten the global ecosystems
that sustain life on Earth, scientists say.
The rapidly warming polar regions are a prime example, said Jeffrey McNeely,
chief scientist for IUCN-the World Conservation Union (IUCN). The melting ice
and permafrost are changing the habitat Arctic species need to survive, Mc Neely
told IPS in advance of International Day for Biological Diversity, which falls
on May 22.
''Climate change will simply accelerate habitat loss which already is the
leading threat to species,'' McNeely said from his office in Gland, Switzerland.
The diversity of life on the planet is in steep decline due to habitat
destruction, invasion by non-native species and over-exploitation by humans, and
now climate change is the latest and perhaps greatest threat according to David
King, the British government's chief scientific adviser.
''The warming could take place so quickly that many species will not be able to
adapt quickly enough,'' King wrote in the British journal Birds earlier this
month.
The current rate of species loss is estimated to be 1,000 times faster than at
any time in history. With the expected changes due to climate change, up to 30
percent of all mammal, bird, and amphibian species are in danger of disappearing
by 2050, according to a recent report from the Millennium Ecosystem Assessment.
The assessment is an unprecedented 22-million-dollar study of Earth's life
support systems. Since 2001, some 1,350 experts from 95 countries have compiled
and analysed all available data on 24 of the planet's vital ecosystems and
concluded that 15 are being degraded or used in an unsustainable fashion.
In essence, the assessment finds that life on Earth is unraveling.
The major difference between the lifeless, barren Moon that orbits Earth is the
thin skin of life that covers the latter. Biological diversity refers to the
amazing variety of living things that make up that skin, which scientists call
the biosphere. Between 10 and 100 million multi-celled species make up the
biosphere although only 1.5 million have been identified so far.
With so many species, the loss of a few dozen or even hundreds of exotic
creatures like the Dodo or Tasmanian Tiger, while lamentable, could scarcely be
considered the critical issue of the 21st century.
Yet, that is what the millennium assessment says. Ecosystems that support all
life are being degraded because of the loss of biodiversity.
''The living machinery of the Earth has a tendency to move from gradual to
catastrophic change with little warning,'' states the study.
Of course some species are more important than others. An ecosystem is like a
house of cards: removing some cards -- or in this case, species -- makes the
structure weaker but it remains standing. But remove one or two others, and it
collapses.
''Everything is connected to everything else,'' said Rod Mast, vice president of
the U.S.-based environmental group Conservation International. This
interconnectedness is the fundamental principle of ecology.
''Sea turtles are a keystone species. They help keep coral reefs and beds of sea
grass healthy,'' Mast said in an interview. ''Their eggs are important food
sources for shoreline birds and mammals.''
The extinction of the endangered Leatherback or Kemp's Ridley sea turtles could
have wide-ranging and largely unknown impacts on the ocean ecosystem, he said.
In fact the status of sea turtles worldwide remains unknown. Mast said he hopes
the first global assessment will be completed this year.
Much more is known about forest ecosystems but the full range of services they
provide the planet is under appreciated. For example, forests produce oxygen,
clean water, prevent erosion and flooding, capture excess carbon dioxide, and
provide food and habitat for many species.
Logging all the trees in a forest ends up eliminating many species of plants,
animals, birds, and insects. It also results in a loss of those ecosystem
services for many years, and in some cases permanently because reduced
biodiversity makes it difficult for the forest to recover.
British researchers confirmed this in a study published in the journal Nature
last April. The greater the diversity of species on an island, the higher the
proportion of endemic species on that island they found. In other words,
biodiversity begets biodiversity.
However, more than 15,500 species now face extinction and another 60,000 are
threatened, according to IUCN's 2004 Red List of Threatened Species.
By 2050, the world will be a very different place, said Stuart Pimm, a leading
conservation biologist at Duke University in the U.S. state of North Carolina.
''Vast areas of the tropics that have lost their forests will have the same damn
weeds, bushes and scrawny eucalyptus trees so that you don't know if you're in
Africa or the Americas,'' Pimm said.
''Without its natural diversity the world will be a poorer place. It will be
boring,'' he added.
Perhaps more important will be the loss of services that the natural world
currently provides free of charge.
''Nearby forests provide the clean, untreated drinking water of two the world's
great cities, New York City and Rio de Janeiro,'' Pimm said.
Pricing and paying for nature's ''free'' services like soil formation,
pollination, and water cleaning is difficult but a crucial step in reducing
''our profligate consumption'' added IUCN's McNeely.
World consumption of natural resources has increased by a factor of 16 while the
global population has only increased by a factor of four since 1900, McNeely
said.
''Many of us are convinced that this rate of consumption is not sustainable,''
he added.
In addition to significant reductions in consumption is the need for greater
equity considering that ''over one billion people are officially listed as
obese, while 800 million are under nourished,'' said Pimm. He suggested using
economic tools such as higher taxes on the wealthy and financial incentives to
support conservation of biodiversity.
''We have to stop doing stupid things like subsidising economically and
ecologically damaging activities,'' said Pimm.
''For example the global fish catch is worth about 50 billion dollars at the
dock but government subsidies to the fishing industry amount to 100 billion
dollars.''
Tax subsidies are also behind much of the clear-cut logging that goes on in the
Amazon rainforest and in many other forests, Pimm said.
Over-exploitation of the local environment has led to the extinction of a number
of cultures, said McNeely.
''Although descended from cultures that managed their resources sustainably, it
does not appear that we have learned the lessons from our ancestors very well,''
he said. (END/2005)
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