Nature's Warnings to the Johannesburg Summiteers

Jeffrey D. Sachs Professor of economics and Director of the Earth Institute Columbia University Project Syndicate

Nature's awesome powers have been on frightening display lately. As world leaders gather in Johannesburg to discuss global environmental threats, many parts of the planet are battered by floods, droughts, harvest failures, massive forest fires, and even new diseases. Man's relationship to nature is a theme as old as our species, but that relationship is changing in complex ways. The most important result of the Johannesburg Summit should be a recognition that more scientific research and much more global cooperation is needed.

Floods and droughts have been scourges from ancient times, yet the frequency, size, and economic impact of these disasters has grown in recent years. Insurance claims against natural disasters rose to unprecedented levels during the 1990s, suggesting that the social costs of environmental upheavals have intensified. Climate shocks such as the fierce El Nino of 1997- 1998 played a major role in recent economic upheavals. Indonesia and Ecuador, among other countries, succumbed to financial crises in 1997-1998 that were linked (in part) to agricultural crises caused by the severe El Nino.

Part of the growing climate effect results from our sheer numbers. Largely as a result of technological successes in the past 200 years, the human population has grown seven-fold since 1800, from around 900 million in 1800 to more than six billion people today, crowding humanity into vulnerable spots throughout the world.

More than two billion of the world's six billion people live within 100 kilometers of a coastline, and so are vulnerable to ocean storms, flooding, and rising sea levels due to global warming. Hundreds of millions more live in fragile habitats on the steep slopes of mountains, or in semi-deserts, or in rain-fed regions where crops fail regularly when rain doesn't arrive.

Human beings are also changing the environment everywhere, often in ways that make societies more vulnerable. This is especially the case in impoverished countries. The increasing population density in rural Africa, with its intensification of farming, is leading to massive soil depletion. When drought comes to Southern Africa, as it has this year, tens of millions of impoverished peasant families struggle for survival.

Because African poverty contributed to the uncontrolled spread of AIDS, the combination of climate shocks and epidemic disease is devastating. Millions of AIDS orphans in Southern Africa live with grandparents too old and weak to produce food or to secure it. Because of the onset of the El Nino, it's likely that the drought will continue into the coming year.

The most remarkable feature of these environmental changes is that they are not limited to local environments. For the first time in human history, human society is undermining the environment at the global scale, through climate change, extinctions, and degraded ecosystems.

Man-made global warming, caused mainly by fossil-fuel burning in rich countries, may well be a factor in the frequency and severity of major droughts, floods, and tropical storms. The frequency and intensity of the El Nino cycle in the past 25 years may also be the result of global warming. China's heavy floods in recent years are partly the result, it seems, of the excessive melting of mountain snows on the Tibetan Plateau, which was caused by higher temperatures.

These growing environmental risks are complex. The effects of environmental change may occur only after many years and may be felt halfway around the world. Or the effects may be indirect. Land use changes, say, can amplify the spread of infectious diseases by changing the mix of species or the ways that animals and humans interact.

Politicians are inept at handling such problems, so environmental risks continue to grow without adequate changes in public policy. When disasters hit (such as this year's droughts or floods), politicians cannot be held accountable for mistakes made over the course of many decades.

The summit in Johannesburg can draw the world's attention to these pressing problems. Even if the summit produces few specific results, it can make a difference if three demands are made of the summiteers:

* we should insist that the world's politicians recognize the overwhelming scientific evidence that points to the major environmental perils humanity faces;

* we should press these leaders to invest more public money in basic environmental research and in the development of new technologies to address environmental risks. For example, investments in research on alternative energy systems that can limit global warming are vital;

* third, we should insist that our politicians agree to greater international environmental cooperation, lest the neglectful and shortsighted policies within each nation end up destroying the global ecosystem.