'Mass extinction has started'

May 13, 1992

An unprecedented biological collapse has begun 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.

So concludes Life Support: Conserving Biological Diversity, a new report by the Worldwatch Institute, a Washington DC-based policy research organisation.

"Although species are disappearing most rapidly from the world's tropical forests", says John C. Ryan, author of the report, "biological diversity is diminishing all over the globe".

The top priority for halting the loss of biodiversity — the ecosystems, species, and genes that together constitute life on earth — will be the protection of areas so far minimally degraded by human activities, Ryan concludes. But parks and reserves alone cannot do the job.

"Only if biodiversity becomes a central concern in our mainstream economic activities as well as our protected areas", Ryan says, "will we avoid squandering our biological inheritance." Among the report's findings:

  • Three-fourths of the world's bird species are declining in population or threatened with extinction.

  • Amphibians (frogs, salamanders and related species) are declining worldwide.

  • In Indonesia, 1500 local varieties of rice have disappeared in the past 15 years. Nearly three-fourths of the rice grown today descends from a single plant.

  • In the United States, about 3000 plants, nearly one in every eight native species, are considered in danger of extinction. More than 700 are likely to disappear in the next 10 years.

Industrial nations have decimated their wetlands: Italy, New Zealand and California have all destroyed more than 90% of their wetlands.

"Without immediate reductions of greenhouse gas emissions, however, the impacts of global warming will probably make the world's current biological collapse pale in comparison", finds Ryan. Rapidly rising temperatures will overwhelm many

species' and ecosystems' ability to adapt.

Biological diversity is no luxury. "Like every species, ours is intimately dependent on others for its well-being", writes Ryan. For example, 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.

American oysters, once so numerous in the United States' Chesapeake Bay that they could filter all its water every three days, have declined in population by 99% since 1870.

Today, national parks and other protected areas cover nearly 5% 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. But these figures can be misleading, Life Support notes.

"Most of the world's remaining wildlands, and most of its protected areas, are deserts and tundra", says Ryan, "and many of the world's parks exist largely on paper." Destructive activities, such as mining or large-scale tourism, are often encouraged within protected areas, while outside forces, from air pollution to landless farmers, often pose even greater threats.

"Restoring some degree of local control over resources is probably the only way that vast areas in the tropics can be 'managed' at all", Ryan writes. Governments claim ownership of 80% 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.

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.

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