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If the biologists are right, then the decline in seafood catch per person, which started in 1989, will persist for as long as population growth continues. Those born shortly before 1950 have enjoyed a doubling in seafood availability per person, whereas those born in recent years can expect to see a halving of the catch per person during their lifetimes. The beginning of the new millenium marks the turning point in oceanic fisheries, a shift from abundance to one where preferred species become scarce, seafood prices rise, and the conflicts among countries for access to fisheries multiply.

Although the yield data are not as those for oceanic fisheries, the world`s range lands cover roughly twice the area of croplands, supplying most of the beef and mutton eaten worldwide. Unfortunately, as with fisheries, overgrazing is now the rule, not the exception. Sustaining future yields of meat, and in some cases milk as well, and providing livelihoods for ever – growing pastoralist populations will put even more pressure on already deteriorating range lands. Yet another of our basic support systems is being overwhelmed by continuously expanding human needs.

Biodiversity and Climate Change

Perhaps the best single indicator of the Eart`s health is the declining number of species with which we share the planet. Throughout most of the evolutionary history of life, the number of plant and animal species has gradually increased, giving us the extraordinarily rich diversity of life today. Unfortunately, we are now in the early stages of the greatest decimation of plant and animal life in 65 million years.

Of the 242,000 plant species surveyed by the World Conservation Union – IUCN in 1997, 14 percent, or some 33,000 are threatened with extinction. Some 7,000 are in immediate danger of extinction and another 8,000 are vulnerable to extinction. The principal cause of plant extinction is habitat destruction, often in the form of land clearing for agriculture and ranching, for housing construction, or for the drainage of wetlands for agriculture and construction. Large – scale species migration – propelled by growing trade – is compounding that threat, as is climate change, which could eliminate whole ecosystems in the decades ahead.

The status of animal species is equally worrisome. Of the 9,600 bird species that populate the Earth, two-thirds are now in decline, while 11 percent are threatened with extinction. A combination of habitat alteration and destruction, over – hunting, and the introduction of exotic species is primarily responsible. Of the Earth`s 4,400 species of mammals, of which we are but one, 11 percent are in danger of extinction. Another 14 percent are vulnerable to extinction if recent trends continue. Of the 24,000 species of fish that occupy the oceans and freshwater lakes and rivers, one-third are now threatened with extinction.

The globalization of recent decades is also reducing the diversity of life on Earth. Mushrooming trade and travel have broken down ecological barriers that existed for millions of years, allowing thousands of species – plants insects, and other creatures – to invade distant territories, often driving native species to extinction and disrupting essential ecological processes. Recent "bioinvasion" have forced the abandonment of more than one million hectares of cropland in South America and devastated the fisheries of East Africa`s Lake Victoria.