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Tropical Rain Forests and the World Atmosphere

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Public awarness of the advancing destruction of tropical forest habitats has grown in recent years, as has the scientific understanding of the complexity of these diverse and fragile ecosystems and the importance of their contribution to the global atmosphere. Current research demonstrates that the role of tropical forests in maintaining the equilibrium of the atmosphere may be far greater than previously believed and that the accelerating rate forest destruction may have profound implications for atmospheric budgets of N2O, CH4, CO2, and important trace gases. Large-scale deforestration may also have serious and unforeseen effects on climate and hydrology.rnNew techniques such as remote sensing have made posible accurate evaluations of the rate of destruction of tropical rain forests. The results are alarming: Norman Myers, in Chapter 2, estimates that 200,000 square kilometers of this biome are being deplated each year from a total area of less than 10 million square kilometers.rnThis volume, the result of a American Association for the Advancement of Science (aaas) symposium organized to explore the ramifications of tropical deforestration, emphasizes the relationship of biosphere to troposphere, aiming to set tropical forest ecology in the context of the global ecosystem. Case studies illustrate our increasing knowledge of these important habitats and the urgency of finding ways to perseve them. Diagnoses are accompanied by prescriptions for the future policies.rnFew places on earth on earth seem more distant from the temperate-zone, city-dweller than the tropical rain forests. Yet events transpiring in that remote biome are fixing, perhaps unalterably, the prospects for mankind.rnAs we ought to know from the composition of our own bodies, we are more air than dust, atmospheric gases and vapors compose 90% of the substance of the biosphere, by weight and volume, taking up in living tissue no more than pinches of other elements from the litosphere. In the exchange of gases and vapors between the interpenetrating biosphere and atmosphere, tropical rain forests play a role much larger than their acreage in ration to the whole. As Michael B. McElroy and Steven C. Wofsy show in their contribution to this volume, fully half of the nitrous oxide, nearly half of the carbon monoxide, and a quarter of the methane released into the atmosphere emanate from the metabolism tropical rain forests. To that metabolism human activity is contributing in mounting proportion.rnMore than half of the flux of carbon monoxide from tropical rain forests comes from the clearling and burning that is reducing their acreage all around the world. Carbon monoxide, methane, and nitrous oxide are of interest because they are catalysis of the reactions in the upper atmosphere that are tending to thin out the life-shielding ozone layer. The burning and decay of the tropical biomass now injects also as much carbon dioxide into the atmosphere as the burning of fossil fuels in the industrial nations of the Northern Hemisphere. By opaquing the infra-red window in the sky, the increasing concentration of this gas is blocking the re-radiation of the sun's heat from the earth. The destabilizing of the climate worldwide thretened by this development offers the ultimate argument for the necessity of nuclear power, put forward so compellingly elsewhere by Gorge M. Woodwell.rnThus the outlook for temperate-zone city-dwellers and for their grandchildren is inextricably linked to the disappearance of the rain forests. The improverishment of the life in the mid-latitudes and the extinction of plant and animal communities not yet named and catalogued might otherwise by regarded as a local event to be regretted outside only by taxonomiests. Ghillean T. Prance develops, however, the poignance of this event. For the rain forests and for systematic biology he argues furthermore that the world economy will someday have to regret the loss of many plants of use to the indigeneous peoples and of unrealized economic promise for a growing world population.rnEneas Salati and his colleagues exhibit another consequences of the disappearance of the rain forests that may reach into the world outside. In the upper Amazone therain forest recycles the rains brought onto the continent from the Atlantic Ocean by the easterly trade winds. For the region as a whole, transpiration and evaporation supply fully half the rainfall, in basins with high forest cover, all but 20% of the local rainfall. The drought attendanton the disappearance of the Amazon rain forest, 30% of the land area of the 20 degree equatorial belt, can change the energy balance governing the planetary atmospheric circulation system. Associated with the deforestration of the Congo and the saharization-sahelization of equatorial Africa, this prospect urgently invites the cooperative international study necessary to raise the priority for preventative action before it is too late.rnIn relation to these ongoing and impending events, the fortunate denizens of the Northern Hemisphere are not only innocent bystanders, they are accomplices as well. Norman Myers shows that the rain forest in Latin America is losing 20,000 hectares a year to the extension of pasture for beef cattle. This is a consequence of the vertical integration of the marketing of hamburgers by fast-food chains in the United States that has been redusing traffic in the country's supermarkets. The persisting colonial relationship between the North and South has larger consequences. All around the 20 degree equatorial belt, from Africa, across the Amazon valley, through the Archipelago of the Southwest Pacific into Africa again, forest farmers" are clearing nearly 200

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Ketersediaan

090101004

634.0.91 PRA t

My Library

Tersedia

Informasi Detil

Judul Seri

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No. Panggil

634.0.91 PRA t

Penerbit

Westview Press, Inc. : United States of America., 1986

Deskripsi Fisik

xxi, 105 p.

Bahasa

English

ISBN/ISSN

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Klasifikasi

634.0.91 PRA t

Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

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Subyek

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Info Detil Spesifik

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Pernyataan Tanggungjawab

as George M. Woodwell shows

Versi lain/terkait

Lampiran Berkas

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