EARTH'S TOP ENVIRONMENTAL PROBLEMS
part 2

In my last article (Pop!ulation Press, Jan/Feb 2003) I presented the human problems of overpopulation, overconsumption, poverty and global warming. Now let's look at the environmental impacts of these problems.

Biodepletion aka Mass Extinction of species

Forget the word biodiversity, what's important is biodepletion. According to 80% of biodiversity experts, we are into the opening phase of a mass extinction of species. We are losing thousands and more likely tens of thousands of species every year (only a few eliminated outright, the rest consigned to "doomed to die" status because of inadequate habitat for long-term survival). This rate is thousands and more likely tens of thousands more than in the prehistoric past. Within our children's lifetimes we could well bid adieu to roughly half of all the ten million species that share this planet with us (though they might think we are not so hot at sharing). That would make for the biggest mass extinction since the demise of the dinosaurs and associated species 65 million years ago. Sure, evolution will one day generate replacement species to match today's in numbers and variety--but that will take several million years, maybe twenty times longer than humans have been humans.

That much is agreed. Not so clear is how to set conservation priorities. We do not have enough resources-funds, skills, etc-to save all species under threat, and the problem is getting worse rapidly. So we must decide what comes first. One way is to focus on "biodiversity hotspots": areas that (a) feature exceptional concentrations of endemic species (i.e. found nowhere else), and (b) face exceptional threat of habitat destruction. Some 25 hotspots contain the last remaining habitats of 35-45% of all species on land, in localities that have lost an average of 88% of their original vegetation . Safeguarding the hotspots at an annual cost of $500 million (total conservation spending today, $6 billion per year) would knock a big hole in the mass extinction crisis. The amount raised for hotspots thus far is $650 million over twelve years, a long way from what is needed, but the largest sum ever assigned to a single conservation activity.

Tropical Deforestation

Closely related to mass extinction is tropical deforestation. These forests are the most exuberant celebration of nature that has ever graced the face of the planet. They occupy only 5% of Earth's land surface, about the same as the United States, yet they contain well over half of all species. They share another unique tribute: they are being eliminated faster than any other ecological zone. We have already lost half of these forests, and the rest are disappearing at a rate that may leave little within just a few decades.

Two thirds of deforestation is due to small-scale farmers who, finding themselves landless in, for example, southern and eastern Brazil, feel they have no alternative but to pick up machete and matchbox and head off towards Amazonia. The same applies in several other parts of Latin America, also in tropical Africa and Asia. To relieve the pressures from these displaced farmers, we need broad-scope measures such as population planning, relief of poverty, and a host of other measures on the part of the global community-again with leadership from the United States.

Forests supply material goods that extend far beyond timber and other wood products. They include wild fruits, latexes, essential oils, exudates, waxes, tannins, dyes and medicinals, with an on-site worth of roughly $90 billion a year. The net present value of medicinal products, including anti-cancer drugs and improved contraceptives, is estimated at a minimum of $420 billion.

As for the forests environmental services, the value of India's forest services just in regulating river flows are roughly assessed at $72 billion a year. To replace the carbon storage function of tropical forests with respect to global warming could cost as much as $3.7 trillion. When we consider all uses of the forests, both direct and indirect, Mexico's forests are worth $32 per hectare per year, Costa Rica's forests $60, and Panama's forests over $200.

Topsoil Loss

We are losing 25 billion tonnes of topsoil to erosion per year. To put the figure in perspective, consider that it is enough in principle to grow sufficient grain to make up the diets of malnourished people totalling 700 million (all hungry people total 820 million). Minimum economic costs, in terms of additional fertilizer needed to offset loss of natural plant nutrients, totals $400 billion per year (in the United States, at least $200 per person).

Key question: why isn't more done to tackle the problem? Partial answer: perception. A crop field losing 20 tons per hectare per year is losing half of its fertility within 20 years, but only 5mm off the soil horizon. Which farmer is going to notice that?

By the year 2050 we may well have run out of oil supplies (if we haven't weaned ourselves off it already). By that time too, we may be near to running out of topsoil. We shall find other sources of energy, but no one has yet devised an alternative to topsoil.

Water Shortages

Global fresh water use tripled during the four decades 1950-1990, and demand is expected to double again during the two decades 1991-2010. At least half a billion people today are short of water, yet already we divert three-fifths of all available freshwater for human use and most convenient supplies have been grossly over-used. In the United States, farmers are taking water from the Ogallala aquifer underlying the great wheat states at rates averaging forty times that of natural replenishment. By 2025 some three billion people worldwide are forecast to be living in water stressed areas.

In 90 developing countries with 40% of the world's population, the problem sorely limits their economic prospects. At least 80% of developing-nation disease, or four billion cases per year, is due to lack of clean water for household use, and six million deaths per year stem from water-related diseases such as malaria, cholera, schistosomiasis, yellow fever and especially diarrhoea. All water-related diseases are estimated to levy a cost of $125 billion a year through workdays lost to sickness. This contrasts with the cost of $50 billion a year to supply both water and sanitation facilities; and it is two and a half times more than government subsidies that foster wasteful and inefficient use of water.

So pressing is the problem that it could eventually precipitate violent conflict, mainly because of water stocks that straddle international frontiers. Of 214 major river basins around the world, three-quarters are shared by two countries and one quarter by three to ten countries. Almost half of Earth's land surface is located within international river basins, supporting 40% of the world's population, and nearly 50 countries have more than three-quarters of their territory within such areas.

A large part of the problems listed above are due to the sheer pressure of rising human numbers. All the mores a pity: it's much cheaper to slow population growth than to undo the ravages of climate change, extinction, deforestation, water shortages and topsoil loss. To reiterate a basic fact: there are approximately 130 million couples in developing countries who simply don't want any more children. They have thought about it, they have discussed it, they have decided, but they lack the contraceptive hardware to put their wish into practice. Were we to supply them with family planning facilities, we could reduce the ultimate global population by as much as one billion. The cost for a rich-world taxpayer, in line with government pledges, would be the equivalent of a beer every second month.

Let's, as they say, just do it.

Norman Myers, world renowned British scientist, is the creator of the idea of biologically rich, but at risk, "hotspots." He is a Fellow of Oxford University, England.