FROM STOCKHOLM TO JOHANNESBURG
(Source: United Nations)
There might be debate about the precise extent of the problem, the timescales involved, the most effective solution. On the over-arching issue, however, a clear majority of the world's scientific experts are in agreement: Our natural environment is in trouble. And the trouble is getting worse as each year passes.
They argue that global climate change, pollution of water, land and air, loss of habitat, diminution of natural resources and species extinction, all are the result of human activity, all are accelerating, and all are inexorably making our world a more difficult, less accommodating place in which to live.
The statistics are plentiful, and alarming. According to the United Nations Environmental Programme (UNEP), 15 million hectares of tropical rainforest - an area the size of England and Wales - is being lost each year to the logging industry.
It says 12,000 cubic kilometres of water worldwide are dangerously polluted - more than the total amount of water contained in the world's 10 largest river basins - and 11,000 species of animal and plant are under threat of extinction, a level not seen since the age of the dinosaurs.
Most worrying of all, many scientists say the 6.6 billion metric tonnes of carbon dioxide our factories, transport systems and power stations pump into the atmosphere annually are having a potentially catastrophic effect on the earth's climate, increasing global warming and leading to ever more extreme weather events.
"Most scientists agree that we will be experiencing serious environmental problems within the next few decades, and that those problems will need careful management," says Dr. Heike Langenberg, Physical Science Editor for Nature magazine.
While there is broad consensus on the need for action, however, there is also awareness that a "stop the world I want to get off" philosophy is simply not practical in the modern industrial age.
In developing countries in particular, environmental degradation is, to a greater or lesser extent, an inevitable by-product of economic growth - growth that is essential if those countries are ever to alleviate the poverty in which a majority of their citizens exist.
The question facing the world's governments, businesses and Green groups is thus not simply how best to tackle the world's growing environmental crisis, but how to do so in a manner that does not at the same time hamstring national economies, especially those of the world's poorest nations.
In short, as we move into the 21st Century, how - if at all - can the human race achieve the goal of sustainable development?
Concern about our environment is not a new thing. Theories about the damaging effects of climate change have been around for the last 200 years.
Green legislation, albeit in the broadest sense of the term, was being enacted as long ago as the medieval period (in 1273, for instance, in order to improve air quality, Edward l of England decreed that anyone who burned coal in London should be hung.)
If its intellectual roots go back a long way, however, and in particular to such 19th Century pioneers as Henry David Thoreau, Gifford Pinchot, George Perkins Marsh and John Muir, it was not until the second half of the 20th Century that a concerted global environmental movement started to emerge, and the world's governments began to take seriously the issues that movement was championing.
"The 1972 United Nations Stockholm Conference is generally seen as the watershed," says Dr. Andy Gouldson, an environmental expert at the London School of Economics.
"There were regional initiatives before that, but it was essentially Stockholm that started the whole environmental ball rolling."
The conference was the first of its kind to unequivocally acknowledge that human activity was seriously damaging the world's natural environment, and to propose a series of measures - both national and global - to try and tackle the problem. As its final Declaration read:
"A point has been reached in history when we must shape our actions throughout the world with a more prudent care for their environmental consequences."
In the same year, four young scientists at the Massachusetts Institute of Technology produced a controversial report titled "The Limits To Growth," using computer models to smash the long-held assumption that the Earth's resources could support limitless economic growth and population expansion.
Their findings caused a sensation, selling 12 million copies and, coming hot on the heels of Stockholm, added weight to calls for an urgent global strategy to safeguard the environment.
In the 30 years since those two landmark events there have been a succession of conferences, summits and initiatives aimed at building on the foundations laid in 1972.
The 1992 U.N. Conference on Environment and Development in Rio de Janeiro, the 1997 Kyoto Protocol, and the 2002 Johannesburg World Summit on Sustainable Development have all sought to highlight the problems facing our natural environment, and to implement measures to try to alleviate those problems.
Their remit has covered everything from the provision of clean drinking water to the protection of endangered species, the disposal of domestic waste to the promotion of lead-free petrol.
Above all they have sought to address the problem of global warming and climate change, considered by most experts to be the defining environmental issue of our age, and the one that presents the greatest challenge to the goal of sustainable development.
The science of global warming is complex and contentious. There are some, most notably the controversial Danish academic Bjorn Lomborg, who maintain the phenomenon is far less of a problem than many are claiming.
"I don't think we have a problem with global warming," says Bonner Cohen, a senior research fellow with the right-wing U.S. think-tank The National Centre for Public Policy Research.
"It is a purely hypothetical problem, a theory whose validity has yet to be determined. Temperatures today are well within standard variations."
Such opinions, however, are very much in the minority. There might be argument about specific details, but the majority of the world's scientific community agree that emissions of man-made greenhouse gases, particularly carbon dioxide from the burning of fossil fuels, are leading to an inexorable warming of the earth's atmosphere, and that this in turn is causing potentially disastrous changes in global climate patterns.
"It is incontrovertible that the burning of fossil fuels is altering the chemistry of the atmosphere," says Dr. Greg Marland of the Carbon Dioxide Information Analysis Centre, "And there is pretty compelling evidence that that is causing climate change."
The effects of climate change are already apparent, with increasing incidence of floods, storms, droughts, water shortages and rising sea levels, phenomena that are expected to grow in severity over the course of the next century, and which are likely to hit the world's poorest countries hardest.
"Africa is the prime example," says Nick Nuttall of the United Nations Environment Programme. "The continent accounts for only 3 percent of all global warming emissions, yet it suffers the most from the effects of global warming because its countries don't have the finance or infrastructure to combat those effects."
Dr. Rajendra Pachauri, chair of the U.N.'s Intergovernmental Panel on Climate Change, concurs. "The impacts of climate change fall disproportionately on the poor. Farmers in tropical and sub-tropical countries are dependent on rains. Variations in rainfall and increased frequency of extreme weather conditions could make the lot of peasants far more difficult than it is currently," he says.
The 1997 Kyoto Protocol was an ambitious attempt to get to grips with the problem, committing the world's 38 largest industrialised countries to specific targets for reducing their 1990 levels of greenhouse gas emissions. Thus the U.S., which has 4 percent of the world's population, yet is responsible for 25 percent of all global carbon emissions, agreed to cut those emissions by 7 percent, Britain by 12.5 percent and Germany by 21 percent.
At the same time, poorer countries such as India and China, both of which are set to become major polluters over the next 30 years, were given a moratorium on reducing greenhouse gases to allow their economies to develop and grow.
Despite its good intentions, however, the initiative is already in trouble.
America withdrew from the Protocol in March 2001, and although Russia's recent decision to ratify the treaty means that it will still come into force - to be legally binding it needs to be ratified by countries that together were responsible for at least 55 percent of the total 1990 greenhouse gas emissions - there are those who argue that even if it does, that will still not be enough to slow, let alone halt or reverse, the global warming bandwagon.
"It's a huge problem and something needs to be done," says Marland, "But the truth is that if I was ruler of the world I just wouldn't know where to start. The whole thing is so mixed up with our lifestyles and aspirations and patterns of energy use. There's just no obvious fix to all of this."
Many are urging drastic action to combat global warming. Green groups in particular insist that what is required is nothing less than a complete conceptual shift in the way we go about our lives and business.
"I think the idea of trying to balance environmental and economic goals is the wrong way of looking at things," says Tony Juniper, Executive Director of Friends of the Earth. "We are creating the false impression that we can continue the economic strategies we have adopted in the past to take us into the future.
"The shift is more fundamental than balancing. What we need to do is to look at the economy differently, not as something we just leave to its own devices but as a way of achieving our social and environmental goals."
Others are looking to technology to provide a solution. Much scientific work is currently being done on Carbon Capture and Storage (CCS), a system of collecting waste carbon dioxide and, rather than putting it into the atmosphere, instead pumping it deep into the earth or into underground aquifers where it would be dissolved in the water.
More radical have been suggestions that, rather than controlling our energy systems, we should instead be trying to control our climate. Thus the idea has been floated of positioning reflectors in space that, rather like giant Venetian blinds, could be used to lessen the amount of incoming radiation and thus balance the earth's climate.
Both scenarios, however - grass-roots lifestyle change and cutting-edge technology - bring with them their own problems.
With the former, any measures that significantly effect jobs, wages and economic stability tend to be vigorously resisted not simply by governments and large corporations, but also by the average person in the street, something that is as true in the developing world as it is in the developed.
In Delhi, for instance, over 100,000 people took to the streets in November 2000 to protest a Supreme Court decision to shut-down and re-locate polluting factories, claiming that such a move would cost them their livelihoods.
Technology likewise, creates as many difficulties as it solves. According to a recent US Department of Energy report, the energy required to operate an effective Carbon Capture and Storage system would double the electricity costs of the power plants that implemented it (not to mention the potential environmental hazards of slow-leakage of carbon dioxide through the soil).
Similarly, those technologies that seek to reduce mankind's dependence on fossil fuels can themselves have a significant environmental knock-on effect.
In India, for instance, hydro-electric power is seen by many as a way of easing the country's reliance on coal-based power stations. The generation of hydro-electicity, however, requires the building of large dams, and this is opposed by Green groups because of the damage such dams cause to biodiversity, and the necessity of re-locating large numbers of people.
"For a country that is starved of electricity, and has significant hydro-electric potential, this is a source of energy we should be harnessing," says Preety Bandari, an ecology expert at the TERI School of Advanced Studies in Delhi. "The whole hydro-electric issue has been retarded, however, by the environmental lobby's opposition."
As Greg Marland puts it: "I have a mantra - Fix, change, tinker or cope. Fix the current energy system, change the current energy system, tinker with the climate system, or cope with the changes that come about as a result of global warming.
"My feeling is that we're going to end up doing a lot of coping."
But it is not all bad news. If global warming remains, for the present at least, a seemingly intractable issue, advances are being made in other areas.
"The world is clearly far more aware of environmental issues than it was 30 years ago," says Nick Nuttall of the UNEP. "If you look at Europe, the US and a lot of other developed countries they have taken great strides environmentally."
Around the world a whole plethora of initiatives, some driven by national governments, most originating at a local government or community level, are helping to improve the environment and preserve it for future generations.
To give just two out of tens-of-thousands of examples. In Brazil the Municipality of Porto Allegre has launched the Guaiba Lives Programme, involving the local community and public authorities in an ambitious scheme to clean up Guaiba Lake, upon which Porto Allegre depends for its water supply.
New sewage treatment plants have been built, a water treatment facility installed, environmental education classes set up and shanty-dwellers along the lakeshore resettled. The result has been a dramatic improvement in the lake's water quality and biodiversity.
In the U.S., meanwhile, Xerox has pioneered the concept of the "backtrack" factory. Rather than simply throwing out Xerox products when they have reached their sell-by date, the company's clients can now return those products to the factory for updating, thus cutting waste and conserving resources.
"This is a key corporate philosophy for us," says David Millican, Head of Communications at Xerox UK. "It's not just for philanthropic reasons. It makes sound business sense as well."
While such schemes are helping to improve the environment, however, they are, in the end, just a drop in the ocean.
"Even in the developed world, while there are clear signs of improvement, most of the consumption and production patters that cause environmental problems have stayed the same, or if anything intensified," says Nick Nuttall.
"We still have a very long way to go."