Healthy soil and sustainable growing

["Tradingpost" <tradingpost@gilanet.com>]

The state of the world? It is on the brink of disaster
http://news.independent.co.uk/world/science_technology/story.jsp?story=62466
7
30 March 2005

An authoritative study of the biological relationships vital to  
maintaining life has found disturbing evidence of man-made degradation.  
Steve Connor reports


  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.