Biological collapse is now underway worldwide and only unprecedented effort will curtail the massive wave of extinctions. Furthermore, climate change from carbon dioxide emissions is likely to accelerate the demise of many forms of life. Although species are disappearing most rapidly from the world's tropical forests, biological diversity is diminishing all over the globe.
The top priority for halting the loss of biological diversity -- the ecosystems, species, and genes that together constitute life on earth -- will be the protection of wildlands, those areas so far minimally degraded by human activities, Ryan concludes. But the pervasive nature of the problem and the imminent threat of global warming mean that parks and reserves alone cannot do the job.
Biological diversity is no luxury. Like every species, ours is intimately dependent on others for its well-being. An adult frog can eat its own weight in insects daily; diminishing frog populations in India have been linked to higher rates of malaria in West Bengal, and pest damage to crops in Maharashtra State. Species-rich tropical forests provide hundreds of millions of rural people with food, health care, raw materials, and cash income.
Governments and communities around the world have taken steps to stem the erosion of life. Today, national parks and other protected areas cover nearly five percent of the earth's land surface, and wilderness areas (many maintained by indigenous people) cover as much as a third of the planet's land.
The efforts of indigenous people, both to protect sacred lands and to sustain diversity in production systems, have likely been more effective than their modern counterparts in conserving life's variety. The world's healthy ecosystems are found predominantly in areas under indigenous control. But many traditional management systems are unraveling as cultures erode and national governments confiscate or privatize resources held by communities.
A top priority for biological conservation, whether in parks, village woodlots, or farms, is to recognize the vital role of local people. Restoring some degree of local control over resources is probably the only way that vast areas in the tropics can be 'managed' at all. Governments claim ownership of 80 percent of the world's remaining mature tropical forests, but only by sharing management responsibility with the millions of people living in or near the forests do governments have any hope of controlling the forests' exploitation.
Government-owned reserves whose commercial resources are managed by local dwellers are no substitute for strictly protected areas. But these and other programs of sustainable commercial use of ecosystems can help conserve diversity if ecological limits are observed and if political reforms ensure the basic human rights of rural people. In Brazil, as in many parts of the world, to speak up for the environment is literally to put one's life in danger.
Limiting the amount of the planet we dominate, and tolerating diversity more in the places we do dominate, will entail tackling two of the most intractable forces in the modern world: galloping per-capita consumption and rapid population growth. No conservation strategy, however ingenious, can get around the fact that the more resources one species consumes, the fewer are available for all the rest.