Amazon faces unexpected pressures

March 1, 2002 - From 7,000 feet, the jungle below looks like a vast, green ocean. On this clear day, it stretches in all directions as far as the eye can see. This is the Amazon basin, the largest intact stretch of tropical forest remaining in the world. From up here it looks pristine. But on the ground, things are more complicated.

When you hear about the Amazon, the news usually isn't good. With the slogan "Land without people for people without land," the Brazilian government has sought to use the jungle to absorb thousands of the nation's poor. These forests have been under assault for decades as farmers clear the land for crops and cattle, and logging companies search for prime lumber. It was the plight of the Amazon that galvanized the environmental movement of the early 1990's, culminating in the 1992 Rio Earth Summit.

The part of the southern Amazon below our airplane has managed to survive relatively intact, thanks largely to the efforts of the Kaiapo, an indigenous group who have fiercely defended their lands against encroachment from logging and mining companies, and ranchers. The Kaiapo want to protect the forests and their traditional practices and knowledge. More than a decade ago, they convinced me to help them start a research station here. Since then, the station has catalogued species of frogs, insects and plants never before recorded by science. We still have much to learn from this land, and its people.

Our plane touches down at the village of Aukre, population 300. On the ground, not much has changed since my first visit in 1988. The children are still healthy and curious and the surrounding forest appears to be thriving. But the Amazon's troubles aren't limited to the forest fringes. Even in this remote place, most of the mahogany trees have been removed. And new studies show that pollution from slash and burn agriculture in one part of the Amazon can harm pristine areas far away.

At the meeting of the American Association for the Advancement of Science in Boston last week, researchers from Brazil's Universidade de Sao Paulo told delegates that over half the Amazon rain forest is being damaged by air pollution. The problem is that burning forests are generating so much smoke and soot that they are actually blocking sunlight in some areas, cooling land temperatures by as much as three degrees Celsius.

Smoke contains fine particles that drift in the air. Some particles absorb the sun's rays, others reflect light back into space. Both reduce the amount of solar radiation reaching the earth's surface - in some areas of the Amazon by up to 40 per cent - which significantly reduces plant photosynthesis. In addition, burning trees and brush produces gases which, combined with sunlight, create ground-level ozone - a pollutant that can drift long distances and harm plant life. The Brazilian researchers say that these pollutants could be having a profound impact on large areas of the Amazon rainforest, and because the Amazon is such a powerful engine for global climate, may even be affecting worldwide weather patterns.

For the Kaiapo, air pollution may be the least of their immediate concerns. Thirteen years ago, the Brazilian government wanted to dam a river in the area, flooding a large portion of the jungle. The Kaiapo fought the project and, with some outside help, it was shelved. But a similar plan with a new name has recently surfaced, and the Kaiapo may once again have to defend their forest.

Before I fly out, I have the opportunity to go fishing on the river. It's rainy season and the water is high, but using fruit as bait, we quickly catch several fish. It is this simple way of life that the Kaiapo want to protect. The land may be vast and their numbers small, but given the incredible life diversity found here and the importance of the Amazon to the global hydrologic and carbon cycles, the best interests of the Kaiapo may also be our own.

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