Colección: La Educación
Número: (115) II
Trends and Problems
A short tour of the most urgent environmental and development problems can clarify how badly fresh thinking is needed. Different nations worry about different problems, but some generalizations can be made. Island nations find the prospect of sea-level rise most worrisome, for obvious reasons: low-lying island nations (and, indeed, the coastal areas of continents) could eventually be obliterated if the worst global warming forecasts are borne out. Air pollution and water supplies are of most concern in Latin America, the most urbanized continent in the developing world. In Latin America and the Caribbean, the local despoiling of valuable natural resources such as coastal fisheries, soils, and tropical forests gets the most attention, while the United States and Canada tend to focus on such global problems as climate change, deforestation, and the loss of species and habitat. Joint action by North and South can help on both fronts.
The trends are ominous (WRI et al. 1990; 1992). Air pollution is damaging forests, crops, lakes, and rivers in many nations. Clouds over several mountains in the Eastern United States are as acid as lemon juice, and 20 percent of the red spruce in the mountains of New England have succumbed to smog over the past decade (MacKenzie 1989). Air pollution plagues many of the worlds great cities too. In Mexico City, for instance, a 1988 study showed that a high fraction of the newborns had blood lead levels high enough to damage their neurological and motor skills development (Rothenberg et al. 1989). Nearly half of U.S. citizens live in areas where air quality standards are regularly violated (MacKenzie 1989).
Land degradation is a serious problem in many parts of the world. Harmful agricultural practices such as overgrazing, overcultivation, and overuse of chemicals and irrigation water have degraded 1.2 billion hectares of farmlandan area larger than China and India combinedsince World War II (Oldeman et al. 1990). In the United States, farm run-off is the largest source of pollution (Faeth et al. 1991). In 69 developing countries, per capita food production has been declining since 1980, largely due to land degradation (FAO 1991). Soil losses inevitably follow when land ill-suited for agriculture is turned into pasture or cropland. In Costa Rica, for instance, where steep slopes and heavy rainfall make 60 percent of the land suitable only for forests, only 40 percent still has forest cover. Between 1970 and 1989, cattle pasture, for which only 8 percent of the land is suited, spread over 35 percent of the countrys territory. As a result, an estimated 2.2 billion tons of soil was eroded during that period, enough to cover the city of San José with 12 meters of dirt (Solórzano et al. 1991). Soil loss, with its direct implications for agricultural production and nutrition, is a phenomenon known in all continents.
Marine pollution is a growing problem in many regions. Oil spills get most of the press, but they have actually declined by 60 percent since 1981 (UNEP 1992). Raw sewage and silt are todays two main culprits. Most sewage is treated in Canada and the United States, but only 2 percent is treated in Latin America (UN ECLAC 1976). The UN Global Environmental Monitoring Service reports that 10 percent of monitored rivers in 59 countries are contaminated, mostly by sewage (UNEP 1992).
And then, looming over all, are such global environmental problems as greenhouse warming and the loss of forests and species. For scientists, the question is no longer whether the earth will heat up, but how much and how soon. Theres a widespread scientific consensus that the atmospheric buildup of greenhouse gases will warm the earth by from 1.5 to 3 degrees Centigrade over the next century, ushering in adverse changes in climate, weather, and sea levels the world over (IPCC 1992).
A few degrees may not sound like much, but for perspective remember that in the depths of the last ice age, the world was only five degrees Centigrade cooler than it is nowand that a few degrees is the predicted rise in the global average temperature. Temperatures at the middle latitudesthe American Great Plains, for instanceare expected to rise twice the global average. If rainfall patterns change the way that climate models now predict, the combination of higher temperatures and less rain could turn U.S. grain belts into dustbowls reminiscent of the 1930s. One should also bear in mind that the few degrees the Earth is expected to warm in the 21st century is only the beginning: theres no end in sight until some unknown number of decades after humanity stops changing the composition of the atmosphere, thanks to the long time-lag built into the process by the vast mass of the oceans.
The linked problems of deforestation and loss of species are also high on any rational global agenda. Around the world, about 17 million hectares of tropical forestsan area slightly smaller than Uruguayare being felled each year, up 50 percent since 1980 (FAO 1991). In Latin America, Brazil has lost the largest area of forest, and Central America has the highest deforestation rates, but both are moving to curb deforestation. Since tropical forests are home to more than half the Earths species, deforestation is the main force behind a loss of species unmatched for 65 million years, although the degradation of species-rich habitats such as wetlands and coral reefs also plays a role. The United States has lost more than half its wetlands, and its old-growth forests in the Pacific Northwest have been reduced to just 13 percent of their original extent (UNEP 1992). In contrast, Latin America, which has 57 percent of the worlds remaining tropical forest, still has nearly half its land in forest cover (Gradwohl and Greenberg 1988). However, deforestation continues apace, especially in Brazil, Colombia, Mexico, and Ecuadorand the vast majority of the trees cleared are burned or left to rot. Countries such as El Salvador, Haiti, and Barbados are virtually stripped of trees.
The loss of habitats and species has profound ethical implicationsand economic costs as well. Deforestation dims the developing worlds prospects for economic development and relieving poverty, but it has other costs too. The water we drink, the air we breathe, our fertile soils, and our productive seas are all products of healthy biological systems. Wetlands, for instance, provide such ecological services as flood control, fish production, and pollution absorption for freeservices that are costly if not impossible to replicate once the ecosystem in question has been destroyed. As plant and animal species die out, so do untold options for medical and agricultural advances that humanity will someday desperately need. As just one biomedical example, consider the yew tree that grows in the Pacific Northwest: though treated as trash by loggers of old-growth forests, this tree has now been found to contain a substance useful in treating cancer. Or consider the costs to agriculture of declining genetic diversity: Last year, the genetic similarity of Brazils orange trees opened the way for the countrys worst outbreak of citrus canker. Similarly, the Irish potato famine in 1846 and the Soviet wheat crop loss in 1972 both stemmed from reductions in genetic diversity (WRI et al. 1992).
Disturbingly, environmental problems feed on each other to an extent that only time will tell. Deforestation, soil degradation, and other kinds of habitat loss release carbon dioxide and thereby enhance the natural greenhouse effect (though far less than fossil fuel use does). In turn, an enhanced greenhouse effect is expected to drive up temperatures, changing the earths climate in ways that will amplify habitat and species loss. Depletion of the stratospheric ozone layer also threatens habitats and crops and other living things with outcomes that will be experienced before they can be precisely calculated. To protect the ozone layer, most nations have agreed to eventually ban the most damaging substances under the Montreal Protocol, which also sets up a fund through which industrial-country signatories will help developing-country ones meet the expense of phasing out ozone-destroying chemicals.
A more immediate tragedy is the vicious circle of environmental degradation and poverty that plagues much of the developing world. The worlds poorest billion people suffer the most from exhausted cropland, pollution, lack of wood for cooking and heating, malnutrition, and waterborne disease. To eke out a living, many are compelled to cut down forest tracts or overuse marginal lands, undermining the natural resource base on which the future depends. Since 1960, the number of poor people has risen 50 percent in Latin America and the Caribbean (Latin American and Caribbean Commission on Development and Environment 1990), while falling 50 percent in Canada (Stats Canada 1991). The number of people living below the official poverty line in the United States in 1992 is almost the same as it was in 1964 (Rich 1992). The human costs of poverty are appalling: 40 percent of the households in Latin America and the Caribbean do not consume the minimum calories considered necessary for subsistance, and 68 percent of the regions housing is inadequate (Latin American and Caribbean Commission on Development and Environment 1990). The richest fifth of Mexicos population has a life expectancy 20 years longer than the poorest fifth (UNDP 1991). Less than half the population has access to safe drinking water in Bolivia, Haiti, El Salvador, and Paraguay (UNDP 1991).
Todays environmental and development problems are rooted in the phenomenal growth of the human enterprise during the twentieth century. Since 1950, world population has doubled, the world economy has quadrupled, and pollution has permeated everything from the groundwater to the stratosphere. For the first time, human impacts have grown so vast that they are disturbing the planetary systems that support life.
All of these problems are closely interlinked and deadly serious. They cut across sectors and regions. They cannot be addressed issue by issue or by a small groups of nations acting alone. For instance, the United States and Canada can no more protect the earths climate without the cooperation of Latin American and Caribbean countries than these countries can revive their flagging economies without debt relief, investment, and development assistance from their neighbors to the North. Nor can this long list of problems be solved by modest efforts in the face of the likely doubling of world population and quintupling of world economic activity in the lifetime of todays children.