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The
State Of The World?
It Is On The Brink Of Disaster
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An
authoritative study of the biological relationships
vital to maintaining life has found disturbing evidence
of man-made degradation.
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by
Steve Connor, March 30, 2005
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Planet
Earth stands on the cusp of disaster and people should no longer
take it for granted that their children and grandchildren will
survive in the environmentally degraded world of the 21st century.
This is not the doom-laden talk of green activists but the considered
opinion of 1,300 leading scientists from 95 countries who will
today publish a detailed assessment of the state of the world
at the start of the new millennium.
The report
does not make jolly reading. The academics found that two-thirds
of the delicately-balanced ecosystems they studied have suffered
badly at the hands of man over the past 50 years.
The dryland
regions of the world, which account for 41 per cent of the earth's
land surface, have been particularly badly damaged and yet this
is where the human population has grown most rapidly during
the 1990s.
Slow
degradation is one thing but sudden and irreversible decline
is another. The report identifies half a dozen potential "tipping
points" that could abruptly change things for the worse,
with little hope of recovery on a human timescale.
Even
if slow and inexorable degradation does not lead to total environmental
collapse, the poorest people of the world are still going to
suffer the most, according to the Millennium Ecosystem Assessment,
which drew on 22 national science academies from around the
world.
Walt
Reid, the leader of the report's core authors, warned that unless
the international community took decisive action the future
looked bleak for the next generation. "The bottom line
of this assessment is that we are spending earth's natural capital,
putting such 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," Dr Reid said.
"At
the same time, the assessment shows that the future really is
in our hands. We can reverse the degradation of many ecosystem
services over the next 50 years, but the changes in policy and
practice required are substantial and not currently under way,"
he said.
The assessment
was carried out over the past three years and has been likened
to the prestigious Intergovernmental Panel on Climate Change
- set up to investigate global warming - for its expertise in
the many specialisms that make up the broad church of environmental
science.
In summary,
the scientists concluded that the planet had been substantially
"re-engineered" in the latter half of the 20th century
because of the pressure placed on the earth's natural resources
by the growing demands of a larger human population.
"Over
the past 50 years, humans have changed ecosystems more rapidly
and extensively than at any time in human history, largely to
meet rapidly growing demands for food, fresh water, timber and
fibre," the reports says.
The full
costs of this are only now becoming apparent. Some 15 of the
24 ecosystems vital for life on earth have been seriously degraded
or used unsustainably - an ecosystem being defined as a dynamic
complex of plants, animals and micro-organisms that form a functional
unit with the non-living environment in which the coexist.
The scale
of the changes seen in the past few decades has been unprecedented.
Nearly one-third of the land surface is now cultivated, with
more land being converted into cropland since 1945 than in the
whole of the 18th and 19th centuries combined.
The amount
of water withdrawn from rivers and lakes for industry and agriculture
has doubled since 1960 and there is now between three and six
times as much water held in man-made reservoirs as there is
flowing naturally in rivers.
Meanwhile,
the amount of nitrogen and phosphorus that has been released
into the environment as a result of using farm fertilisers has
doubled in the same period . More than half of all the synthetic
nitrogen fertiliser ever used on the planet has been used since
1985.
This
sudden and unprecedented release of free nitrogen and phosphorus
- important mineral nutrients for plant growth - has triggered
massive blooms of algae in the freshwater and marine environments.
This is identified as a potential "tipping point"
that can suddenly destroy entire ecosystems. "The Millennium
Assessment finds that excessive nutrient loading is one of the
major problems today and will grow significantly worse in the
coming decades unless action is taken," Dr Reid said.
"Surprisingly,
though, despite a major body of monitoring information and scientific
research supporting this finding, the issue of nutrient loading
barely appears in policy discussions at global levels and only
a few countries place major emphasis on the problem.
"This
issue is perhaps the area where we find the biggest 'disconnect'
between a major problem related to ecosystem services and the
lack of policy action in response," he said.
Abrupt
changes are one of the most difficult things to predict yet
their impact can be devastating. But is environmental collapse
inevitable?
"Clearly,
the dual trends of continuing degradation of most ecosystem
services and continuing growth in demand for these same services
cannot continue," Dr Reid said.
"But
the assessment shows that over the next 50 years, the risk is
not of some global environmental collapse, but rather a risk
of many local and regional collapses in particular ecosystem
services. We already see those collapses occurring - fisheries
stocks collapsing, dead zones in the sea, land degradation undermining
crop production, species extinctions," he said.
Between
1960 and 2000, the world population doubled from three billion
to six billion. At the same time, the global economy increased
more than six-fold and the production of food and the supply
of drinking water more than doubled, with the consumption of
timber products increasing by more than half.
Meanwhile,
human activity has directly affected the diversity of wild animals
and plants. There have been about 100 documented extinctions
over the past century but scientists believe that the rate at
which animals and plants are dying off is about 1,000 times
higher than natural, background levels.
"Humans
are fundamentally and to a significant extent irreversibly changing
the diversity of life on earth and most of these changes represent
a loss of biodiversity," the Millennium Ecosystem Assessment
says.
The distribution
of species across the world is becoming more homogenous as some
unique animals and plants die out and other, alien species are
introduced into areas in which they would not normally live,
often with devastating impact.
For example,
the Baltic Sea contains 100 non-native species, of which about
one-third come from the Great Lakes of North America. Meanwhile,
a similar proportion of the 170 non-native species found in
the Great Lakes come from the Baltic.
"In
other words, the species in any one region of the world are
becoming more similar to other regions.... Some 10 to 30 per
cent of mammals, birds and amphibians are currently threatened
with extinction. Genetic diversity has declined globally, particularly
among cultivated species," the report says.
Agricultural
intensification, which brought about the green revolution that
helped to feed the world in the latter part of the 20th century,
has increased the tendency towards the loss of genetic diversity.
"Currently 80 per cent of wheat area in developing countries
and three-quarters of all rice planted in Asia is now planted
to modern varieties," the report says. Dr Reid said that
the authors of the assessment were most worried about the state
of the earth's drylands - an area covering 41 per cent of the
land surface and home to a total of two billion people, many
of them the poorest in the world.
Drylands
are areas where crop production or pasture for livestock is
severely limited by rainfall. Some 90 per cent of the world's
dryland regions occur in developing countries where the availability
of fresh water is a growing problem.
One-third
of the world's people live in dryland regions that have access
to only 8 per cent of the world's renewable supply of water,
the scientists found. "We were particularly alarmed by
the evidence of strong linkages between the degradation of ecosystem
services in drylands and poverty in those regions," Dr
Reid said.
"Moreover,
while historically, population growth has been highest in either
urban areas or the most productive ecosystems such as cultivated
lands, this pattern changed in the 1990s and the highest percentage
rate of growth is now in drylands - ecosystems with the lowest
potential to support that growth.
"These
problems of ecosystem degradation and the harm it causes for
human well-being clearly help set the stage for the conflict
that we see in many dryland regions including parts of Africa
and central Asia," he said.
Poor
people living in dryland regions are at the greatest risk of
environmental collapse. Many of them already live unsustainably
- between 10 and 20 per cent of the soil in the drylands are
eroded or degraded.
"Development
prospects in dryland regions of developing countries are especially
dependent on actions to slow and reverse the degradation of
ecosystems," the Millennium Assessment says.
So what
can be done in a century when the human population is expected
to increase by a further 50 per cent?
The board
of directors of the Millennium Assessment said in a statement:
"The overriding conclusion of this assessment is that it
lies within the power of human societies to ease the strains
we are putting on the nature services of the planet, while continuing
to use them to bring better living standards to all.
"Achieving
this, however, will require radical changes in the way nature
is treated at every level of decision-making and new ways of
co-operation between government, business and civil society.
The warning signs are there for all of us to see. The future
now lies in our hands," it said.
Asked
what we should do now and what we should plan to do over the
next 50 years, Dr Reid replied that there must be a fundamental
reappraisal of how we view the world's natural resources. "The
heart of the problem is this: protection of nature's services
is unlikely to be a priority so long as they are perceived to
be free and limitless by those using them," Dr Reid said.
"We
simply must establish policies that require natural costs to
be taken into account for all economic decisions," he added.
"There
is a tremendous amount that can be done in the short term to
reduce degradation - for example, the causes of some of the
most significant problems such as fisheries collapse, climate
change, and excessive nutrient loading are clear - many countries
have policies in place that encourage excessive harvest, use
of fossil fuels, or excessive fertilisation of crops.
"But
as important as these short-term fixes are, over the long term
humans must both enhance the production of many services and
decrease our consumption of others. That will require significant
investments in new technologies and significant changes in behaviour,"
he explained.
Many
environmentalists would agree, and they would like politicians
to go much further.
"The
Millennium Assessment cuts to the heart of one of the greatest
challenges facing humanity," Roger Higman, of Friends of
the Earth, said.
"That
is, we cannot maintain high standards of living, let alone relieve
poverty, if we don't look after the earth's life-support systems,"
Mr Higman said.
"Yet
the assessment hasn't gone far enough in specifying the radical
solutions needed. At the end of the day, if we are to respect
the limits imposed by nature, and ensure the well-being of all
humanity, we must manage the global economy to produce a fairer
distribution of the earth's resources," he added.
The Tipping
Points To Catastrophe
New Diseases
As population
densities increase and living space extends into once pristine
forests, the chances of an epidemic of a new infectious agent
grows. Global travel accentuates the threat, and the emergence
of Sars and bird flu are prime examples of diseases moving from
animals to humans.
Alien
Species
The introduction
of an invasive species - whether animal, plant or microbe -
can lead to a rapid change in ecosystems. Zebra mussels introduced
into North America led to the extinction of native clams and
the comb jellyfish caused havoc to 26 major fisheries species
in the Black Sea.
Algal
Blooms
A build
up of man-made nutrients in the environment has already led
to the threshold being reached when algae blooms. This can deprive
fish and other wildlife of oxygen as well as producing toxic
substances that are a danger to drinking water.
Coral
Reef Collapse
Reefs
that were dominated by corals have suddenly changed to being
dominated by algae, which have taken advantage of the increases
in nutrient levels running off from terrestrial sources. Many
of Jamaica's coral reefs have now become algal dominated.
Fishing
Stocks
Overfishing
can, and has, led to a collapse in stocks. A threshold is reached
when there are too few adults to maintain a viable population.
This occurred off the east coast of Newfoundland in 1992 when
its stock of Atlantic cod vanished.
Climate
Change
In a
warmer world, local vegetation or land cover can change, causing
warming to become worse. The Sahel region of North Africa depends
on rainfall for its vegetation. Small changes in rain can result
in loss of vegetation, soil erosion and further decreases in
rainfall.
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