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The Foundations of Life Itself Are in Danger |
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By Stephen Leahy*
Around
30 percent of all mammal, bird and amphibian species could disappear
from the planet, reducing the quality of the important ''services''
provided by the world's ecosystems, says the Millennium Ecosystem
Assessment.
BROOKLIN, Canada - Species are going extinct
1000 times faster than any time in history, with up to 30 percent
of all mammal, bird and amphibian species in danger of disappearing,
according to the Millennium Ecosystem Assessment, released Mar.
30.
This accelerated loss of biodiversity on the planet threatens 60
percent of the ecosystems necessary for life, says the 22-million-dollar
study that was begun in 2001, promoted by United Nations Secretary-General
Kofi Annan.
The Millennium Ecosystem Assessment Synthesis Report, involving
1,300 experts from 95 countries, concluded that 15 of 24 of the
ecosystem services that support life on Earth¬¬ are being degraded
or used unsustainably.
An ecosystem is a complex dynamic of plants, animals, microorganisms
and their environment -- water, air, sunlight -- that interact as
a functional unit, and their ''services'' contribute to the reproduction
of life, and include climate regulation.
''Biodiversity underpins ecosystems. Reductions in species reduce
the range and quality of ecosystem services,'' Janet Ranganathan,
director of biological resources at the Washington-based World Resources
Institute, told Tierramérica.
''Ecosystem services are the link between conservation and human
development,'' Ranganathan said.
A forest, for example, provides a wide range ecosystem services,
such as producing oxygen, cleaning water, preventing erosion and
flooding, capturing excess carbon dioxide, and providing habitat
for many other species.
While clearcutting a forest generates income for a few, the loss
of biodiversity -- the trees and other species -- leads to a loss
of ecosystem services for many years, and in some cases permanently,
for many more people.
''With this understanding we can be much more aware of the tradeoffs
involved in converting natural areas,'' said Ranganathan.
The authors of the Millennium Environmental Assessment warn that
the harm from this degradation could grow significantly worse in
the next 50 years.
Already one quarter of the Earth's land surface has been converted
into cropland, grazing land and other food producing areas. Much
of this conversion has been recent. Since 1945 more land was converted
to farmland than in the eighteenth and nineteenth centuries combined,
the report notes
While this conversion provided much needed food, timber, fiber and
fuel, it has also resulted in a ''substantial and largely irreversible
loss in the diversity of life on Earth,'' the report finds.
More than 15,500 species are currently facing extinction and another
60,000 are threatened, according to the IUCN-World Conservation
Union's 2004 Red List of Threatened Species. Although the loss of
a unique individual species that has survived hundreds of thousands
of years is distressing, its role in the web of life may be irreplaceable.
''Reduction in biodiversity weakens the resiliency of ecosystems…
It's not obvious to most people that biodiversity is key to the
provision of ecological services,'' says David Cooper, of the Secretariat
of the Convention on Biological Diversity in Montreal, Canada.
For example, a plantation forest made up of one tree species is
more vulnerable to forest fires than an old-growth forest, Cooper
told Tierramérica.
Removing biologically diverse wetlands in a region will lead to
more flooding because wetlands act as sponges, absorbing excess
water. Wetlands also clean water of pollutants, including those
that are causing the growing number of dead zones along the world
ocean coastlines, he said.
''The valuable services of coral reefs and coastal mangrove forests
became clear during the Indian Ocean tsunami'' in December 2004,
the expert pointed out.
''The living machinery of the Earth has a tendency to move from
gradual to catastrophic change with little warning,'' states the
Millennium Assessment.
However, the measure of biodiversity should not be focused on total
numbers of species, cautions Paul Herbert of the University of Guelph,
in Ontario, Canada. Herbert is on the verge of revealing thousands
of new species thanks to new scientific technique he pioneered called
''DNA barcoding''.
This approach permits the rapid identification of species by examining
particular part of a particular gene that is found in all animal
species. Herbert has already increased the number of bird species
by three percent by correcting previous classification errors.
The scientific community hopes that in 10 years, these and other
techniques will determine whether there are 10 million or 100 million
multi-celled species in existence.
Meanwhile the Earth is undergoing what Herbert calls ''global biotic
change'', which could have a greater impact than climate change
because extinctions cannot be reversed. And those extinctions degrade
ecosystem services, he says.
''We need to start seriously thinking about what kind of quality
of life we want to have on this planet.''
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