Читать книгу Harmony: A New Way of Looking at Our World - Tony Juniper - Страница 16

The term ‘ecosystem services’ has begun to be used more and more in environmental and conservation circles and is even beginning to penetrate the language of international treaties. It is a concept that has been central to some of my recent work, including efforts to encourage the world to see how vital the rainforests are to the very survival of many millions of people, which I will explain in more detail later.

OVERLEAF: Monteverde Cloud Forest, Costa Rica. Because of the almost constant cloud induced moist air, the trees are festooned with bromeliads, mosses and other epiphytes. This large reserve is widely regarded as one of the most outstanding wildlife sanctuaries in the Americas. It protects more than 400 species of birds, including 30 hummingbirds, and over 100 species of mammals.

Although perhaps rather an off-putting term, ecosystem services is one of great importance, for it succinctly sums up the wide range of benefits that people derive from properly functioning natural systems. In many respects the advantages provided by Nature are like giant utilities, and indeed include services that are instantly recognizable as such, for example the provision and purification of water.

A film sequence put together by NASA from satellite images and shown to me recently demonstrates the idea admirably. From a vantage point in space, it shows the annual pattern of cloud formation over rainforests. As the trees and other vegetation breathe and grow, so they exhale water vapour. Around twenty billion tonnes of water are released every day by the Amazon rainforests alone, and this condenses into great swirls of white cloud that then produce rain. Not only does the moisture fall back on to the forest, it also travels. Rain clouds generated by the Amazon rainforest help to water crops across a wide swath of South America, including the vast grain lands of Southern Brazil. Some of this moisture also falls over the grain fields of the prairies of North America. And these rainforests even help to water crops and replenish wetlands across North Africa and Southern Europe. One expert described to me how it is rather like a system of ‘flying rivers’ that move moisture around the skies, all driven ultimately by the rainforests themselves.

The statistics are truly staggering. For example, it has been estimated that an area of rainforest trees is able to evaporate into the atmosphere eight to ten times the amount of water that comes from an equivalent patch of ocean. Perhaps even more breathtaking is the fact that the energy needed to match the daily evapotranspiration (basically the release to the air of water from vegetation) of the Amazon basin’s rainforests is about the same as would come from the world’s largest hydroelectric dam working on full power for some 135 years.

Water is essential for our economic well-being, not only enabling crops to grow but also providing the lifeblood of cities and industry everywhere. And remember, in order to produce one kilo of beef it takes fifteen tonnes of water. Just one cup of coffee requires around 140 litres. It is a simple relationship: without the forests there is less water; with less water there is less food.

One of the major challenges that will confront humankind during the present century will be how to match our needs for fresh water with the limited, and in some cases, dwindling supplies that will be available. Urbanization, ever more intensive farming, the never-ending desire for more and more economic growth, and the inexorable increase in the global population will all lead to greater demand at a time when climate change will be causing some areas to have less water. In these circumstances, making every effort we possibly can to maintain sources of rain, especially the rainforests, should be the top priority for the age we live in, and yet the destruction goes on.

Sprinkler sprays water on crops, Palouse, Washington, USA. In addition to cheap oil and gas, modern farming relies on vast quantities of fresh water. Demand for water is rising fast, especially in agriculture. Food security is at risk because of potential water shortages.

And of course it is not only for water that we rely on Nature. Natural systems recycle our organic wastes; soil nutrients are replenished by an unimaginably vast army of microbes and fungi; we rely on insects for the pollination of crops; coral reefs and mangroves protect coastal areas from tidal surges and act as nurseries for the oceanic fisheries that help feed our cities; we rely on trees to help cool the air and the climatic conditions that sustain food production. There is also emerging science that tells us about the vast benefit gained from the storage of organic material in soils. This is not to mention what Nature does to nurture the human spirit, inspiring art and literature and embodying intrinsic values – although I have to say that in many societies today this is something that seems to lie increasingly near the limits of human comprehension.

We also tend to forget that for 3.5 billion years Nature has been working as a vast nonstop chemical laboratory. As a result, an incredible diversity of complex compounds has been produced. There is a tendency for chemists these days to spend more time in the laboratory than in the forests, in search of new potentially useful molecules, and yet there are many substances that because of their complexity will never be identified by experimental methods alone. For example, I recently learned about a species of frog discovered in Australia that had a particularly odd life cycle. Once they had laid their eggs and the male had fertilized them, the females swallowed the eggs so that the tadpoles might hatch and develop in the relative safety of the stomach. On reaching a certain stage these were expelled into the outside world to complete their development. When I learned about this particular means of reproduction I understood why these creatures had the rather odd name of gastric-brooding frogs.

In order to complete such a life cycle, various ingenious adaptations had evolved, including a chemical shield used by the tadpoles. When they were studied it was found that they secreted substances that inhibited the digestive processes and prevented the adult frog’s stomach emptying. This capability is of great interest in designing future drugs and treatments for human peptic ulcer disease – a condition that causes misery to more than 25 million people in the USA alone. However, research could not continue because these frogs suddenly became extinct, in part as a result of the destruction of their forest and stream habitats. The miraculous chemicals that enabled the tadpoles to develop inside their mothers’ stomachs and that might have taken millions of years to evolve – the chemicals that could have provided more effective peptic ulcer treatments – are now gone for ever. We will never know what they were or how they worked.

One group of animals that appears to be especially rich in potentially useful compounds is cone snails. These predatory creatures live on tropical reefs and in mangrove forests, mostly in the South Pacific region. There are about 700 different species and each is believed to manufacture 100–200 different peptide toxins to coat the paralyzing harpoons they use for hunting. Although only about six species and about 100 toxins out of a possible 140,000 have been studied in any detail, it seems that they offer the enormous potential of providing the basis of future painkillers and treatments for epilepsy. Some scientists believe that cone snails may contain more useful medical compounds for humans than any other group of creatures on Earth. And yet they, too, are under threat because coral reefs are being eroded by development, pollution and climate change, and also because mangrove forests are being cleared to make way for shrimp farms and other coastal developments.

Marbled cone shell. The deadly poisons produced by this and other cone shells could provide major medical benefits, but only if we prevent the extinction of these remarkable creatures.

What astonishes me is how all these arguments still seem to count for little in our ever more industrialized and urban societies. It seems that because of our mastery of science and technology we have convinced ourselves that we can somehow outflank Nature, to base all that we do on our technology and industry alone. Perhaps it is finally time to recognize what I have been saying now for a very long time: that changes to the climate and the destruction of Nature are not first and foremost environmental or ‘green’ issues: they are hard economic facts and matters that sit at the heart of how we ensure human wellbeing. For example, in relation to farming it should be a cause of great concern that we increasingly rely on ever more extreme forms of monoculture and have come to depend complacently upon a tiny handful of species to produce much of our food. In these circumstances it is evidently tempting for some to believe that we have successfully isolated ourselves from the need to conserve biodiversity. After all, according to the United Nations’ Food and Agriculture Organization, only some twelve plant species provide about three-quarters of our food supply and only fifteen mammal and bird species supply more than 90 per cent of global livestock production. However, these statistics exclude the fact that the productivity of these few species relies on hundreds of thousands of others – to recycle nutrients, to enable pollination, convert atmospheric nitrogen, to produce rainfall, control pests and facilitate the transfer of nutrients between soils and plants. Without all this, our handful of domesticated animals and plants would be useless. We must realize that our food is produced by a whole system, not just isolated elements. Again, the impression that we have somehow bypassed Nature is just that, an impression; and what I desperately hope the world will wake up to is that it is a very dangerous one. The evidence available provides us with ample warning of the likely consequences of continuing to live out of balance with Nature, which is why I believe one of the most profound failures of our present way of thinking is seen in the realm of economics.