World' Resources in 'Critical Condition'
By Tim Radford, Science editor
Posted on Guerilla News Network March 30th, 2005
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
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
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.”