Two-Thirds Of
World's
Resources Used Up
By Tim Radford
31 March, 2005
The
Guardian
The
human race is living beyond its means. A report backed by 1,360 scientists
from 95 countries - some of them world leaders in their fields - today
warns that the almost two-thirds of the natural machinery that supports
life on Earth is being degraded by human pressure.
The study contains
what its authors call "a stark warning" for the entire world.
The wetlands, forests, savannahs, estuaries, coastal fisheries and other
habitats that recycle air, water and nutrients for all living creatures
are being irretrievably damaged. In effect, one species is now a hazard
to the other 10 million or so on the planet, and to itself.
"Human activity
is putting such a strain on the natural functions of Earth that the
ability of the planet's ecosystems to sustain future generations can
no longer be taken for granted," it says.
The report, prepared
in Washington under the supervision of a board chaired by Robert Watson,
the British-born chief scientist at the World Bank and a former scientific
adviser to the White House, will be launched today at the Royal Society
in London. It warns that:
· Because
of human demand for food, fresh water, timber, fibre and fuel, more
land has been claimed for agriculture in the last 60 years than in the
18th and 19th centuries combined.
· An estimated
24% of the Earth's land surface is now cultivated.
· Water withdrawals
from lakes and rivers has doubled in the last 40 years. Humans now use
between 40% and 50% of all available freshwater running off the land.
· At least
a quarter of all fish stocks are overharvested. In some areas, the catch
is now less than a hundredth of that before industrial fishing.
· Since 1980,
about 35% of mangroves have been lost, 20% of the world's coral reefs
have been destroyed and another 20% badly degraded.
· Deforestation
and other changes could increase the risks of malaria and cholera, and
open the way for new and so far unknown disease to emerge.
In 1997, a team
of biologists and economists tried to put a value on the "business
services" provided by nature - the free pollination of crops, the
air conditioning provided by wild plants, the recycling of nutrients
by the oceans. They came up with an estimate of $33 trillion, almost
twice the global gross national product for that year. But after what
today's report, Millennium Ecosystem Assessment, calls "an unprecedented
period of spending Earth's natural bounty" it was time to check
the accounts.
"That is what
this assessment has done, and it is a sobering statement with much more
red than black on the balance sheet," the scientists warn. "In
many cases, it is literally a matter of living on borrowed time. By
using up supplies of fresh groundwater faster than they can be recharged,
for example, we are depleting assets at the expense of our children."
Flow from rivers
has been reduced dramatically. For parts of the year, the Yellow River
in China, the Nile in Africa and the Colorado in North America dry up
before they reach the ocean. An estimated 90% of the total weight of
the ocean's large predators - tuna, swordfish and sharks - has disappeared
in recent years. An estimated 12% of bird species, 25% of mammals and
more than 30% of all amphibians are threatened with extinction within
the next century. Some of them are threatened by invaders.
The Baltic Sea is
now home to 100 creatures from other parts of the world, a third of
them native to the Great Lakes of America. Conversely, a third of the
170 alien species in the Great Lakes are originally from the Baltic.
Invaders can make
dramatic changes: the arrival of the American comb jellyfish in the
Black Sea led to the destruction of 26 commercially important stocks
of fish. Global warming and climate change, could make it increasingly
difficult for surviving species to adapt.
A growing proportion
of the world lives in cities, exploiting advanced technology. But nature,
the scientists warn, is not something to be enjoyed at the weekend.
Conservation of natural spaces is not just a luxury.
"These are
dangerous illusions that ignore the vast benefits of nature to the lives
of 6 billion people on the planet. We may have distanced ourselves from
nature, but we rely completely on the services it delivers."
© Guardian Newspapers Limited 2005