WHAT'S BIODIVERSITY WORTH?

Many people might think, "What's biodiversity done for me today?" Answer: lots.

In my previous article, I pointed out that half of all medicines, drugs and other pharmaceuticals are manufactured from startpoint materials from wild species, especially plants. The commercial value of all these products is estimated at $20 billion per year in the United States alone.

Now for some specific examples. The bark of a yew tree in the U.S. Pacific Northwest contains a biocompound, taxol, which damages cancer cells unaffected by other drugs. Taxol could help at least 100,000 Americans with breast, lung and ovarian cancers. All plant-derived anti-cancer drugs save 30,000 lives in the United States each year, with economic benefits amounting to billions of dollars (yes, billions) in terms of lives saved, suffering relieved, morbidity reduced and worker productivity maintained. Suppose that until the year 2050 there is an extinction every two years of one plant species with medicinal or pharmaceutical potential. The cumulative retail-market loss from each such extinction will amount to $12 billion for the United States alone.

So much for a few wild species and their value. What of the other species? Most products in question come from plants, and there are 300,000 species out there. So far we have used only a tiny proportion of them, and that is after scientists have analyzed only 5,000 or so. There's a long way to go before we make full use of nature's pharmacopeia.

Next, consider the scope for new foods from wild species. During the course of human history we have utilized around 300 plant species as major sources of food. Yet the Earth contains at least another 75,000 edible plants. Of this cornucopia of plant foods, only about 150 have ever been cultivated on a large scale, and a mere 20 produce 90% of our food. We are essentially using the same limited number of plant species that have served humankind for millennia. All our modern crops are confined to particular environments, meaning that many potential food-producing areas are left unexploited. What if we could draw on additional plant species that could serve as crops in environments that are e.g. too dry or too saline for conventional agriculture?

There are numerous instances of underexploited food plants with proven potential. For instance, Aborigines in Australia have used scores of plants, especially fruits and bulbs, as food. They favor certain yams that are well adapted to dry conditions, opening up the possibility that crossbreeds with established forms of yams could allow this important crop to be extended to several further regions. Another dryland plant, the yeheb-nut bush of Somalia grows prolific bunches of pods that contain seeds the size of peanuts (though they taste more like cashew nuts), making a nutritious food that Somalis prefer to staples such as corn and sorghum. In addition, the yeheb's foliage supplies tasty fodder for livestock. Being adapted to arid environments, the yeheb could assist semi-desert dwellers in many parts of the world, including the western United States. It is being brought back from the very verge of extinction in the wild through domestication efforts in Somalia.

Similarly, a marine plant from the west coast of Mexico, known as eelgrass, produces grain that the Seri Indians grind into flour. This plant opens up the prospect that we could use the seas to grow bread. Many other little-known crops have exceptional potential, such as the amaranth, a grain crop of the Andes.

Perhaps the most promising category of wild foods comprises vegetables. The main center investigated to date is Southeast Asia, where at least 300 vegetable species have been used in native cultures, about 80 of them still growing only in the wild in forest habitats. A second center is the highlands of Ethiopia, where leafy grass vegetables prove a promising source of plant protein, yielding as much as alfalfa or soybean. When considering the potential of these Ethiopian vegetables, we should recall that a single wild species of the same genus has provided us, through plant breeding, with cabbage, kale, broccoli, cauliflower and brussel sprouts.

Especially pertinent is the winged bean, a vegetable native to the island of New Guinea. The vine-like plant contains far more protein than potato, cassava and several other crops that serve as principal sources of food for hundreds of millions of people. In fact it offers a nutritional value equivalent to soybean. Its capacity to match the soybean might remind us that the United States grew sporadic patches of the soybean for at least a century before the plant was finally upgraded into a widespread crop, until today it is the premier protein crop in the world, flourishing in dozens of temperate-zone countries. As a result of genetic improvement, the winged bean is now upgrading the diets of hundreds of millions of people in more than fifty countries.

Many other leafy food plants are important on a local scale while remaining unknown elsewhere. At least 1650 of them in tropical forests are reputed to contain roughly as much protein as legumes. They also feature some five to ten times more calcium than legumes and fruits, from two to six times as much iron, and ten to 100 times more carotene (a yellow pigment in the green chlorophyll). In addition, these leafy vegetables often contain as much vitamin C as the best fruits, together with an abundance of Vitamin A.

There's still more to the story. The term biodiversity does not apply to species alone, even though that is how many people view it. Properly understood, biodiversity includes subspecies and other sub-units such as species' populations. It also includes all living processes, known technically as ecosystems. The latter supply us with a huge variety of environmental services, and they do it for free. Such services range from soil formation and pollution dissipation to watershed functions and climate regulation. Reader, try your hand at being an ecologist and figure out the many other services we enjoy every day.

In the mid-1990s an international team of ecologists and economists estimated the value of these services worldwide, coming up with a total of $33 trillion per year. Contrast that with the global economy at that time, $29 trillion per year. Global natural product is greater than global national product.

Now for the sub-units of species, especially their populations, i.e. large groups of individual creatures living apart from other populations. It is these rather than species that provide us with our daily services, particularly the local services (a large flock of birds in New Jersey might be the same species as a large flock in California, but they exist as separate populations). It is estimated that there are roughly 2.2 billion populations on Earth, by contrast with perhaps 10 million species. Unfortunately these populations are thought to be going extinct at a rate of roughly 43,000 per day, which is proportionately far faster than we are losing species.

Upshot: we shall pay a heavy price as we cause the biotic holocaust to continue. A prime way to confront the problem is to slow the still surging growth in human numbers and thus relieve humans' pressures on wildlife habitats. In the United States, which has the fastest population growth rate among all developed nations, women are now having an average of 2.1 children, whereas during the 1970s it was only 1.8. Hey, what's happening out there?

Norman Myers is an internationally renowned scientist and a Fellow of Oxford University. He is the author of numerous books, the most recent being "Perverse Subsidies: How Misused Tax Dollars Harm the Environment and the Economy". He was a Senior Advisor to the International Conference on Population and Development. He has worked on population issues with United Nations agencies, USAID, and many non-governmental organizations.