Some analysts believe that the impact of a surging global population should be addressed before it's too late, others believe nothing is wrong and nothing needs to be done.

By Ed Stoddard

REUTERS

JOHANNESBURG

Life on the planet and the ills that plague it will be marked on Earth Day today with "green events" planned by governments and activists around the globe.

But as the 32nd Earth Day is commemorated today ahead of a huge UN summit on poverty, development and the environment -- to be held in Johannesburg later this year -- there is no "green consensus" on the state of the planet's health.

Scientists, writers, think-tanks and pressure groups are deeply divided over the fate of the world's ecosystems. The forecasts range from the apocalyptic to the relentlessly upbeat.

Some scenarios are nightmarish: states go to war over scarce supplies of fresh water, deserts expand as fertile soil is depleted, and tropical island paradises vanish beneath the waves as polar ice-caps melt because of global warming.

Others envision a better life for all as human ingenuity heals nature's wounds and economic growth lifts hundreds of millions of people out of gut-wrenching poverty.

Governments disagree over what strategies are needed.

The EU has bound itself legally to the Kyoto treaty on cutting the pollution blamed for global warming, which the United States has rejected on cost grounds -- opening up one of the biggest diplomatic rifts in the industrialized world.

Coming anarchies ...

A walk down the mean streets of the mega-cities of the developing world such as Lagos or Jakarta, with their creaking infrastructure, open sewers, limited supplies of clean water and soaring populations, will do little to boost faith in the future.

Many analysts link environmental problems, such as urban decay and overcrowding in poor countries, to crime and to threats to national and global security.

In February 1994, Robert D. Kaplan wrote a famous essay in The Atlantic Monthly entitled "The Coming Anarchy: How Scarcity, Crime, Overpopulation, Tribalism, and Disease are Destroying the Social Fabric of the Planet."

"... in Africa and the Third World," Kaplan writes, "man is challenging nature far beyond its limits, and nature is now beginning to take its revenge."

According to Kaplan, social ills and conflict in coming years will often be rooted in environmental problems.

"It is time to understand the environment for what it is: the national-security issue of the early twenty-first century," he asserts.

"The ... impact of surging populations, spreading disease, deforestation and soil erosion, water depletion, air pollution, and, possibly, rising sea levels in critical, overcrowded regions like the Nile Delta and Bangladesh -- developments that will prompt mass migrations and, in turn, incite group conflicts -- will be the core foreign policy challenge."

Kaplan sees environmental disputes fusing with ethnic and historical ones, creating instability along the Danube river between former Communist states such as Romania and Slovakia.

"A war could erupt between Egypt and Ethiopia over Nile River water," he writes.

Much of what Kaplan says draws on the writing of Thomas Homer-Dixon, an influential University of Toronto professor who has linked water shortages in China, population growth in sub-Saharan Africa and other ecological challenges to conflict.

... and what about coming prosperities?

Some scholars look at the evidence and snort "nonsense."

Bjorn Lomborg, a Danish statistician, has caused waves among academics and activists with his book The Skeptical Environmentalist: Measuring the Real State of the World.

"The air in the developed world is becoming less, not more, polluted; people in the developing countries are not starving more, but less," he writes.

Lomborg argues that pressure groups such as Greenpeace have hijacked the environmental debate, promoting "doom and gloom" scenarios that have little basis in reality when carefully measured and scrutinized.

He points out, for example, that the air in London is cleaner today than it was in 1585, when cheap coal with a high sulphur content was used in private households.

Water as a source of conflict?

Doubtful, argues Lomborg, who cites one study of 412 international crises between 1918 and 1994 that found only seven had water as even a partial cause.

Declining forests?

"Globally, forest cover has remained remarkably stable over the second half of the twentieth century ... global forest cover increased from 30.04 percent of the global land area in 1950 to 30.89 percent in 1994."

Mixed legacies

The temperate forests of North America and Europe have expanded over the past 40 years, while far more biologically diverse tropical rain forests are disappearing -- though Lomborg says not at the pace claimed by many.

The reasons for both deforestation and reforestation are many and the impact on humanity has been mixed.

In the Baltic states of Latvia and Estonia, for example, the forests almost doubled in size between the end of World War II and the collapse of the Soviet Union in 1991, while neighboring Lithuania's grew by around 50 percent.

But this was because the Soviet authorities ruthlessly collectivized agriculture and deported hundreds of thousands of peasants to Siberia in the 1940s and 1950s, leaving empty farms that were eventually reclaimed by the surrounding wilderness.

Mass extinctions

There is also great debate about the pace and extent of species loss, with Lomborg saying that we will lose about 0.7 percent of all species over the next 50 years -- a conclusion hotly disputed by many.

Some scientists claim that we are on the verge of the greatest extinction since the dinosaurs died off 65 million years ago, with tens of thousands of species threatened, because of habitat destruction, global warming and pollution.

Certainly, the prospects for many animals look grim, even if for some they have improved substantially in recent years.

Elephants were killed across Africa at a terrifying rate for the ivory in their tusks in the 1970s and 1980s before a global ban on the ivory trade stemmed the slaughter, allowing populations to stabilize and in some countries rebound again.

Africa's white rhinos were almost extinct a century ago but now number several thousand and their numbers are climbing.

But the few hundred mountain gorillas left on the lush, volcanic hills that form the border of Rwanda, Uganda and the Congo may not last long in the face of political instability and pressure on their habitat from soaring local populations.

Earth Day was founded in 1970 in the United States by Gaylord Nelson, a Senator from Wisconsin, to promote conservation and environmental issues.

More than three decades later, the jury is out on the state of the planet, and only the future will determine if the prophets of doom or the Lomborgs are right.