Deforestation in Amazonia is eliminating wild genepools of many crop-plants. Wild or spontaneous populations of at least 50 perennial crops are at risk, including the Rubber tree and Cacao, as well as several crops emerging from relative obscurity, such as Peach-palm (which is now being planted extensively for palmito production), Annatto (which produces a natural red dye), and Brazil-nut.

Forest resources in tropical Asia are purportedly destroyed by shifting cultivators and spontaneous settlers as well as farmers in planned settlements for the purposes of expansion of agricultural land, land speculation, commercial crop cultivation, livestock ranching, logging, and manufacturing of paper and various industrial goods.

Generally speaking, the fragile and highly-coveted coastal regions of the world badly need integrated land-and water-use planning to reconcile their multiple functions, including that of terrestrial and marine conservation. Properly designed and managed, coastal Biosphere Reserves could constitute a most useful tool for this purpose. Ideally, they would pay equal attention to conservation requirements on the land side and on the marine side, keeping particularly in mind the impact of land-based activities on the marine side. On the land side, consideration should be given not only to the type of ecosystems to be included, but also to land-use in coastal plains and to coastal landscapes. On the marine side the precise place of traditional activities, such as various forms of fishing, will have to be appreciated. Fig. 5 suggests a very idealized zonation pattern for a hypothetical Biosphere Reserve where the above considerations have been kept in mind.

The International Tropical Timber Organization (ITTO), an increasing number of citizens and foresters, and the vast majority of environmentalists, must surely realize that most current use of tropical moist forest is unsustainable. The environmental services of tropical forest, and the biodiversity which it harbours — the world's richest source — is being lost so rapidly that consumer boycotts and other trade constraints aim to reduce the rate of irreversible damage but have so far proved little-effective. On one hand, tropical moist deforestation benefits exceedingly few people, and then only ephemerally. On the other hand, such deforestation permanently impoverishes, deracinates, or sickens, millions of people, impairs local or global environmental services, and exacerbates global environmental risks. The World Resources Institute ranks logging as one of the top causes leading to deforestation.

The need for an integrated approach to ecological conservation and natural resource development is becoming widely recognized as environmental and social problems become more and more acute with human population pressures and depletion of resources. While a number of academic programmes addressing environmental problems have been operating for several decades, comprehensive approaches that integrate conservation with development issues are only just beginning to occur. These innovative, cross-disciplinary problem-solving approaches still face a number of traditional constraints to successful programme development. Obstacles occur in every major aspect of academia — including structure, communication, reward systems, research, curriculum, and evaluation.

The major anthropogenic sources of heat pollution in 1989 have been identified, and the ultimate heat generated has been calculated. Those sources include the combustion of fossil fuels and of biomass, nuclear fission, and the burning of forests. The total rate of heat generated from such sources for the world as a whole, 16 to 26 TW, is compared with a very approximate estimate of the heat retained at the Earth's surface, 291 TW, resulting from decreased radiative heat-loss due to increased concentration of atmospheric CO2. However, heat pollution may be more important than the ratio of about 5 to 9% would appear to indicate. It is a direct process producing heat at the surface of the globe, not subject to moderating feedback mechanisms, and is expected to be most pronounced at land-based sites marking centres of high industrial and other human developments. On the other hand, global warming due to increased atmospheric CO2 is an indirect process that is dependent on many factors, not all of which are known or measured — such as the extensive smoke-clouds resulting from the forest fires in Amazonia. Compared with preindustrial times, the rate of heat pollution has grown by a factor of more than forty.

The natural environments of the South Pacific islands are degrading rapidly. The region suffers one of the highest rates of species extinction in the world, and has probably the world's highest proportion of endangered species per unit land-area. Most island ecosystems in the South Pacific are totally unprotected, and many are rapidly diminishing in area or at least deteriorating in quality. The practice of conservation through conventional forms of protected areas has been ineffective in Pacific countries, having been applied in ignorance or denial of traditional practices or tenurial arrangements when such traditional patterns are often crucial to the maintenance of South Pacific cultures. Only approaches to conservation which embrace the multiple and subsistence uses of natural resources by island communities are having success.

The issue of fuel-wood is often presented as problematical within the context of population pressures and poverty. However, the case of Java, noted for its extremely high human population density (830 people/km2) and its rural poverty, shows that agro-forestry-based fuel-wood production can sustainably meet the bulk of the annual demand of 90 million m3. Fuel-wood for household consumption is collected from gardens in or near the village of its use. Industrial users account for 10% of the demand and are supplied mainly by traders, the Javan Forest Service, and tree-crop estate managers.

Most marine ecosystems present priorities for conservation which are different from, but no less urgent than, those of terrestrial systems. These priorities relate to understanding and regulating human use and impact within the large scale, and the high but variable degree of connectivity of marine systems. The identification and preservation of remnant examples of marine ecosystems, otherwise destroyed by human activity, is generally less of an issue than it is for terrestrial conservation. As a consequence, the needs of marine conservation are not readily addressed by models developed for terrestrial ecosystems, which are based on excluding or severely limiting human access in managed areas. An exception is the philosophy of the Biosphere Reserve, developed as part of the UNESCO Man and the Biosphere Programme. This appears particularly appropriate to marine environments, as it focuses on managing human activities and impacts within the sustainable capacity of the ecosystem.

This analysis of population growth and environmental changes in Central and Eastern Kenya illustrates two models of the interactions of population and resources: (1) the classical neo-Malthusian model that relates population growth to conservation of natural resources but ultimate degradation, and (2) the proposition that population growth induces intensified agricultural production and environmental conservation.

Protests and legal challenges have marked the past seven years of geothermal energy development in Hawaii. Environmentalists seeking to block geothermal development in Hawaiian rain-forests have used legal and civil disobedience tactics to delay development. These are the types of actions which the Hawaii State Legislature sought to avoid when it passed the State's Geothermal Subzone Act in 1983.

Lake Naivasha is an important freshwater resource for Kenya's foreign-currency-earning agriculture and tourism, and for water-supply. It has always experienced extensive water-level fluctuations as a consequence of irregular rainfall patterns that are affected by continental-scale climatic events, and its communities — particularly of aquatic plants — were adapted to these changes.

The shallow Lake Hornborga in southern Sweden has been used by Man for more than 9,000 years, primarily for fishing and hunting but latterly also for cattle-grazing and hay-making. The water-level of the Lake has varied considerably during climatically different periods of time. Changes between dry and wet periods have caused different vegetation-types to predominate, but have probably also effectively counterbalanced a tendency to become overgrown. During the last two centuries the water-level of the Lake has been lowered intentionally five times. Originally, the aim was to counteract spring flooding, but later the reason was to obtain more arable land. The Lake is, however, most famed for its abundance and diversity of bird-life, which is dependent on the local hydrological regime, vegetation, and land-use.

The indicators and the sampling process worked out well at Ranthambhore, and they are probably appropriate for comparable areas elsewhere. However, significant human pressure is not always limited to cutting and grazing. Collecting of certain minor forest products may be a problem in some places, and a suitable indicator must then be found.

As a poor, developing country, Egypt faces a wide variety of pollution and other environmental problems associated with poverty. In this essay are reviewed the most severe environmental problems currently facing Egypt, as well as the range of policies which the government has assayed in order to manage them. Some of the widespread environmental problems are growing acute. Water pollution is seen as serious, and many new factories are being built without sufficient pollution control. There are real threats to agricultural productivity and public health. While many new institutional and legal steps have been undertaken in the last 7 years, most have failed to curb effectively mounting environmental stresses in the country. A rare counter-example is Mediterranean water quality, which is being helped by activation of UNEP's Mediterranean Action Plan.

Mathematical models predict that a nuclear war could cause widespread reductions in light intensity and temperature. To assess the possible impact of these reductions on lowland tropical rain-forests, we exposed seedlings of three species of the family Moraceae to various combinations of day and night conditions under reduced light. The species represent three stages in tropical rain-forest succession: Cecropia obtusifolia is an early-successional pioneer, Trichospermum mexicanum is a mid-successional tree, and Brosimum alicastrum is a late-successional tree of mature-phase forests.

The minimum total breeding seabird biomass in the Australian Antarctic Territory was estimated to be 9,971.1 t, dominated by Emperor Penguins, 3,863 t (38.7%) and Adélie Penguins, 5,825 t (58.4%). The 5° sector between 75°E and 80°E, in south-east Prydz Bay, held 35% of the total AAT seabird biomass. Prydz Bay has been shown to be an area of high productivity, and the concentration of seabird biomass in this area reflects the high biomass of prey species and the availability of nesting habitat in the Vestfold Hills, a large ice-free area adjacent to Prydz Bay. Activities associated With research stations are believed to be the only factors that have impacted on breeding seabird populations to date, but minerals activities, tourism and support facilities, and a Krill fishery, are future conservation issues that will have an impact on this major concentration of seabird biomass in East Antarctica.

There is mounting evidence of global climate change. Analysis of near-surface temperatures over land and oceans during the past 130 years shows marked warming during the first half of this century, with relatively steady temperatures thereafter to the mid-1970s and rapid warming occurring during the 1980s. Of further significance is the fact that the warmest decade in the record is that of the 1980s, with some of the most pronounced warming occurring in the lower latitudes which include the wider Caribbean region. In the context of this study, the important consequences of this warming are the potential impacts associated with rising sea-level and the increased frequency, intensity, and seasonality, of tropical storms due to thermal expansion of the oceans, melting of land-based ice-sheets and glaciers, and local geological parameters. Within the wider Caribbean, rates of relative sea-level rise have been recently estimated at around 2.5 mm/yr. Also, meteorological changes are evident with the occurrence of unusually intense storms such as Hurricane Gilbert in 1988. Rising sea-level coupled with meteorological changes present the potential for increased coastal erosion, loss of wetlands, disappearance of special habitats such as mangroves, and destruction of coral-reef communities. These potential impacts may have a significant influence on future land-use and development practices that could alter the economic growth and development of the region not least through curtailment of tourism.

Nature-based tourism is one of the few economic uses of natural areas that is compatible with protection of the environment and its wildlife. With more than 100 national parks and other conservation areas in Thailand, and a diverse tropical fauna and flora, Nature tourism has tremendous potential for expansion. Although seldom designed to do so, Nature tourism can provide significant income to targeted villages near the borders of national parks, and hence help to reduce illegal exploitation of park resources by local inhabitants.

The ability of global agricultural systems to supply sufficient food for our rapidly-growing human population is becoming constrained by physical and economic limits to traditional means of agricultural expansion. Pests consume or ruin a staggering proportion of crops and, in general, have not been satisfactorily controlled through the ‘broadcast’ application of pesticides.