The Ninth World Conservation Lecture*

Environmental Deterioration, Biodiversity and the Preservation of Civilisation Paul Ehrlich

PAUL EHRLICH** Center for Conservation Biology, Stanford University, Stanford, California 94305, USA

Tactics and Strategy

May I start by discussing the difference between tactics and strategy in conservation, a subject of prime importance for both the World Wide Fund for Nature ( W W F ) and my own Center for C o n s e r v a t i o n B i o l o g y (CCB) at S tanford University in California, An example of tactics is the fieldwork being carried out by CCB and other conservat ion groups~ in conjunct ion with the Costa Rican authorities, in the vicinity of La Amis tad Nat iona l Park. This is the b igges t national park in Costa Rica, occupying much of the southern part of the country and continuing, in effect, across the border into Panama, where a contiguous park has also been established. In La Amistad, the conservationists are trying to find ways of doing 'quick and dirty' surveys of areas of greatest biological diversity. Why 'quick and dirty'? Because there simply is not time to be slow and methodical. These surveys will be used to des ign pat terns of explo i ta t ion and non- exploitation for the parks and their immediate surroundings so that the local people can be

* The World Conservation Lecture is an annual event organised by the World Wide Fund for Nature, United Kingdom, to draw attention to the World Conservation Strategy. This lecture was presented in London on 22 April, 1991. The lecture is also available in booklet form from the Public Relations Department, WWF-UK, Panda House, Weyside Park, Godalming, Surrey GU7 1XR.

integrated into the conservation process. In tropical countries, it is neither possible nor

desirable to simply draw a line on a map and say "This is a Reserve. Everybody keep out." We wanted to find out which areas could still be used for hunting or for high-grade timber harvesting, and whether buffer zones in non-park areas could be designed to help preserve biodiversity within the park. The CCB are attempting something which is rarely done at present, but which will become necessary everywhere in the future - that is to monitor what is going on, to find out what is happening to the flora and fauna as human activities increase in the park and its vicinity. Most national parks in the United States, for example, were not designed originally to preserve biodiversity, and even now it is not known in detail how they are doing in that respect (although enough is known to say that it is insufficient).

The Costa Rica project is an example of developing effective conservation tactics: where to establish reserves, how to manage them, and how to be sure they are protecting biodiversity. But what of the strategies? This means looking at the entire g lobal eco log ica l s i tua t ion - the connections between the various elements of the human p r e d i c a m e n t that are leading to a

** Professor Paul Ehrlich is the Bing Professor of Population Studies at Stanford University.

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deterioration in the life-support systems of the planet. The need for effective strategies is now well recognised by the WWF, and can be illustrated by the following example.

Suppose you could establish a beautiful nature reserve based on a good knowledge of where the biological resources are, with an excellent plan of how the local people can exploit some areas but not others, how they can make money from eco-tourism, and so forth, coupled with a good monitoring system to make sure that the whole thing is working. Then you allow carbon dioxide and other greenhouse gases to accumulate in the atmosphere to the point where dramatic changes occur. Unfortunately, the animals and plants in the reserve are adapted to a previous climate. Their fate is sealed, either because they cannot adapt fast enough to keep pace with the climatic changes, or because they cannot migrate out of the reserve due to the human activities which have effectively created a barrier around it. Despite the excellent tactical planning, the reserve is worthless because it is no longer possible to preserve the biological resources inside it.

To emphasise this argument, there is no point in saving a coastal marsh if the sea level is going to rise fast enough to destroy it, no matter how effective the electric fence around the perimeter. The essence of the strategic problem for humanity is that the scale of our activities is too large. That is the basic problem, and it is one we simply cannot avoid dealing with any longer.

It took about four billion years for life to evolve to its present luxuriant diversity. Human beings (of any kind) have been around only a few million years, Modem Homo sapiens expanded in a few millennia from a population of a few million to two billion in about 1932, the year i n which I, Paul Ehrlich, was born. By the time my wife Anne and I wrote The Population Bomb in 1968 there were 3.5 billion human beings, and the total was rising by roughly 70 million a year. At that time, many people said we should not worry because science and technology would make it possible to feed, house, educate and offer a good quality of life to five, ten, even twenty billion human beings. Others, including ourselves, argued that it would be more prudent to take proper care of 3.5 billion people before boasting about how easy it was to do the same for much greater numbers. But the arguments fell on deaf ears.

Super-Consumers There are now 5.4 billion people and the rate of increase has risen to 95 million a year. This annual increase is the equivalent of the combined populations of Britain, Ireland, Iceland, Belgium, Denmark, Norway, Finland and Sweden.

In 1968 there were perhaps 1.0 billion people leading a decent life and about 2.5 billion leading a life that nobody in a country like Britain would consider acceptable. Now the figures are 1.1 billion and 4.3 billion respectively. Interestingly enough, you can find the same kind of imbeciles running around today saying not to worry, that with the aid of science and technology we can take good care of many billions more. Yet we have not even come close to taking care of 5.4 billion.

I find it appalling that in 1992 there will be 5.5 billion human beings. That means that 2.0 billion will have been added since The Population Bomb was written. To put it another way, as many people will have been added in those 24 years as were alive on the planet when I was born. To me that is a stunning number. We have roughly sextupled the impact of human beings on the life- support system of the planet in my lifetime.

The impact of a population can be estimated by multiplying its size by its degree of affluence, or consumption per person, and by a 'technology factor' (the technology used to produce each unit of consumption). By way of an example, the United States may be described as the most over-populated country on Earth. We Americans have the highest impact on the planet because we are a gigantic country, with over a quarter of a billion people. We are extreme super-consumers, and we have a relatively sloppy use of technology. One reason for this is that the United States is not energy-efficient. American cars are 'gas guzzlers' and petrol costs considerably less than bottled water.

The average American baby bom today will have an adverse effect on the global environment that is 50 times greater than that of an average baby born in Bangladesh. For a British baby the comparable figure would be about 30 times. You in Britain are vastly over-populated too by the same standards.

Loss of Biodiversity

Human activities have expanded to the point where the global life-support systems under-

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pinning civilisation are threatening to collapse and take civilisation with them. I would cite the increased rate of destruction of tropical moist forests, which is now about 1.9 percent a year, compared with 1.0 percent in 1980. This is very discouraging in terms of the health of the planet because half or more of the world's biodiversity is to be found in these forests. And there will only be inaccessible fragments o f them left in 20-30 years time unless serious efforts are made right away to stop the destruction.

Unfo r tuna te ly , when cons ide r ing the s ign i f i cance o f es t imates about the loss of biodiversity, I believe some very good scientists have made some very foolish statements on the subject, In essence, they maintain that since we cannot be sure how much tropical forest is being lost, and since we do not know exactly where all this biodiversity is located, then we should not worry so much. Maybe the rate of loss is less than present estimates. There is a feeling among some scientists that if you cannot be 95 or 99 percent sure, then you should not say anything. It would be unscientific to do so.

This approach may be correct in some areas of science, but when the survival of our planet in any recognisable form is at stake, it makes those who take this view look like fools rather than scientists. The essence of science is learning how to make decisions in the face of uncertainty. Sc ience neve r proves anyth ing , and the probabil i ty levels that you accept in making decis ions have to be related to the kind of decisions involved. For example, imagine you were all going to dinner together in a restaurant. If I told you there was a one in ten chance that you would get botulism there and die, you would probably choose somewhere else to have dinner.

As a more s ignif icant i l lustration of our subject, consider the famous debate between the American climatologist, Stephen Schneider, and a statistician about the probability of a catastrophic climate change occurring in the next 50 or 100 years. Schneider thought the probability was high, the s tat is t ic ian thought it was low. Finally, Schneider asked the statistician to put a figure on his probability estimate. He answered "50:50". Schneider said that was what he thought too. The statistician had been taught that if it was not 95 percent or more, it was not significant. Personally, I would say that if an event is likely to bring c iv i l i sa t ion to an end, then 50:50 is very significant indeed.

Returning to the loss of biodiversity, it does

not make any real difference if the tropical forests were disappearing at a rate of 1.9 percent a year or 1.0 p e r c e n t - or only 0.5 percent. That is still catastrophic. And when a scientist with a capital 'S ' says, "Well maybe we are panicking too much, maybe the situation isn't so bad", this allows the press to conclude that concerns about biodiversity are not really significant. Ordinary people then start to relax, when actually the problem is clearly catastrophic - and known to be catastrophic by anybody who has any kind of field experience in the tropics.

The loss of biodiversi ty was just one of several surprises that have occurred since the publication of The Population Bomb in 1968. Those surprises are, with minor exceptions, very unpleasant. Acid precipitation, for example, was known about but not cons ide red to be a widespread, global problem. But by the 1970s it became clear that acid deposition was a very serious problem indeed for aquatic systems. More recently, it has become a significant threat to forests as well, a long with o ther serious consequences.

The Ozone Layer

Ozone depletion was another unpleasant surprise. I recall the famous remark of a US government official: "Who cares? What good is the ozone layer? We'll just have to put on more suntan lotion". That official was obviously not aware there was no life at all on land until the time, about 425 million years ago, when enough ozone had built up in the atmosphere to screen out the UV-B radiation which is lethal to life. Destroying the ozone layer would increase human skin cancer rates, but also would have a dramatic impact on biodiversity and agriculture because of the effects of increased UV-B radiation on plants, insects and many other organisms.

Humanity has probably been saved from the worst effects of ozone depletion thanks to a series of serendipitous discoveries. One of the most significant of these was by Joe Farman, of the British Antarctic Survey, who used land-based instruments to measure the ozone concentration above Antarctica. He found it was only about half of what it should have been. This caused near-panic in the American scientific community, because they had sophist icated satellite data showing that everything was fine in Antarctica. What had happened? It turned out that whoever had written the computer program for analysing

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the sateUite data had decided that any figure for ozone depletion greater than 10 percent was a mistake and should be ignored. So the American satellites were seeing the ozone hole - but the computer was failing to record it. This and other findings led to the international Montreal Protocol which everyone hopes will save us from super-serious ozone depletion. So far we have been lucky - but nobody knows for sure what will happen in the future.

Global Warming

In 1968, we thought we knew the basics of global warming. It has been known since the last century that we would warm the planet by adding carbon dioxide to the atmosphere. But in 1968, there were some factors tha t were not thoroughly understood. One was the possibility that we were putting so many other things into the atmosphere - aerosols and so forth - that there might be a cooling effect to counterbalance the warming. It is now known that this cooling effect is unlikely to be very great. More importantly, we now know that carbon dioxide is responsible for only about half of the global warming to come. Methane, nitrous oxide and CFCs are also important greenhouse gases.

There are still many uncertainties, however. Has warming actually been observed? (Most climatologists think yes, probably of the order of 0.5°C in the last century.) How much warming are we already committed to? And what will be the regional climatic effects? Most climatologists believe we shall experience very dramatic climatic change in the next half century or so, including a global average temperature rise of 2-5°C. And that would be catastrophic for biodiversity, to say nothing of severely disruptive for agriculture and human societies in a variety of ways.

The Genetic Library

There are good ethical and aesthetic reasons for maintaining biodiversity. There are also good economic reasons for doing so. Biodiversity generates a lot of direct economic benefits through people's interest in birds, tropical fishes, gardens and nature films. In fact, the very basis of our civilisation - our crops, domestic animals and many of our medicines and industrial products - have been derived from the planet's vast genetic library. Innumerable potential new

foods, drugs and useful products may yet be discovered - if we do not bum down the library first.

Ecosystem Services

Important as these reasons are, let us focus on the loss of what can be called 'ecosystem services'. The main argument that can be given to an economist or a politician about the value of biodiversity is that those other organisms are working parts of our life-support systems, and if we destroy them, we are basically destroying ourselves. If a politician says we have got to give the economy preference over ecology, he must be either an idiot or totally uninformed. Because you cannot have an economic system at all without the support of the ecosystems of the planet. It is like saying you are going to give eating preference over breathing. Try it some time, it does not last long!

What kind of things do the planet 's ecosystems do for us on a scale that we do not know how to do ourselves, that we cannot replicate even if we did know how they work? First, they maintain the gaseous quality of the atmosphere. The destruction of the tropical forests is one of the main contributors to the increasing carbon dioxide content of the atmosphere; and the methane content too; and to some extent, perhaps, the nitrous oxide content. So one of the ecosystem services which buffers the atmosphere from that kind of change is already starting to get into trouble. The ecosystems of the planet (of which the plants, animals and micro-organisms are working parts) run the hydrological cycle which gives us fresh water. They generate and maintain soils and recycle nutrients. The living organisms in soils are very often critical even in seeing to it that the nutrients in the soils can actually get into the plants. Soils are not just crushed rock, but very complex ecosystems in their own right, and one of the truly endangered resources on planet Earth.

Capital Expenditure

One of the interesting things about humanity today is that we cannot come close to maintaining 5.4 billion people on income alone. We have to do it by spending our capital. What is capital in this case? It is not so much the fossil fuels, which we shall have to stop using soon anyway because of the carbon dioxide that we shall be adding to

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the atmosphere. The really crucial capital is first of all the soil. The world is losing about 24 billion tonnes of top-soil annually, through erosion in excess o f r egenera t ion . That is about the equivalent each year of all the top-soil that once overlaid the wheat-lands of Australia. It is not a trivial amount. Soils are one of our main forms of capi tal , and the func t iona l parts of soils - involved in their generation, maintenance and fertility - are intimately tied in with the activities of other organisms. This is something which some people cannot come to grips with. It was Ronald Reagan who said, when he was Governor of California, "Who needs a redwood tree? We can replace them with plastic ones".

Another part of our essential capital is fossil groundwater, which is being pumped out much faster in many regions than it can be recharged. And, of course, biodiversity is also part of our planetary capital.

Other organisms of the planet help to dispose of our wastes , and in doing so recyc le the nu t r ien ts which are absolu te ly cr i t ical to agr icu l tu re and forestry. If natural sys tems stopped recycling the nutrients w e would all be dead within a few years. Wild organisms also pollinate a lot of our crops, and natural systems control for us, gratis, the vast majority (probably over 97 percent) of the pests that would attack those crops, as well as the majority of vectors that would bring disease to us.

Concern for Life

Concern for dwindling biodiversity is, therefore, not just a matter of concern for the charismatic mega -ve r t eb r a t e s , the condors and pandas, elephants and rhinos. It is actually a concern for the life-support systems of the planet. In this sense, the mission of WWF is the most important mission that we have on the planet. If WWF, and other similar concerned organisations and people, are not successful, then without any question at all, our civilisation is going to collapse. If we lose the planet's biodiversity, that is it! It is a resource that is simply not replaceable on a time-scale of interest to our civilisation.

One can get a good idea of the scale of the problem by considering the current world food situation. Every year, the farmers of the world have to feed something like 95 million more people. They have to do this with 24 billion tonnes less top-soil, with trillions of gallons less g r o u n d w a t e r and with con t inua l ly fa l ter ing

support from the natural ecosystems which play crit ical roles in mainta ining our agricultural systems.

What can we do? What, for instance, can WWF do about all this? I do not think that WWF should start handing out contraceptives or trying to impose carbon taxes, impor tan t as these measures might be. What WWF can do is to constantly remind people of the overall picture. When providing a helicopter to transport game wardens, for example, it is important to spell out to the country concerned that unless- i t does something about its population growth, all the helicopters and game wardens in the world will not save the elephant or the tiger or the spotted owl, or whatever,

Humanity is already appropriating, in one form or another, 40 percent of all the ' food energy' (net primary production) available to all the animals on land. If the human population doubles, it is not difficult to see what effect this would have on other organisms. While recycling materials is very important, we will still lose the game if more and more people continue to use more and more of everything.

A crucial problem is the concentration of biodiversity in poor tropical countries. These count r ies have very l eg i t ima te aims for development which must be taken into account if conservation initiatives are to have any hope of success. Ways have to be found to allow those countries reasonable deve lopment while still conserving biodiversity. That means putting effort into population control, and also into international aid and trade, and into finding ways to combine conservation with some degree of sustainable exploitation. Therefore, we have got to become concerned with development if we are concerned about saving biodiversity. And it is going to have to be a cooperative effort.

How can we possibly do this? To start with, since so much of the environmental impact of people is caused by, or associated with, our use of ene rgy (espec ia l ly fossil fuels) , the rich countries should become a lot more energy- eff icient . The energy use by people in rich countries averages about 7.5 kW per person. The United Kingdom runs at about 8 kW, with the United States at around 11 kW. Poor countries use about 1 kW per person. By using known technologies, the rich countries could reduce their consumption over the next century to about 3 kW per person, with most of the reduction being in the early years. If everybody could converge on

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3 kW, the r ich mov ing down and the poor developing up (but with efficiency), and if we could manage to hold the population peak to no more than 10 billion people, the total impact of humanity on the planet, when the population was at its maximum size, would be slightly more than twice what it is today.

Reason to Hope

Although we are weakening the p lanet ' s life-support systems, even at today's impact level, there is reason to hope that if we are clever in our use of technology we can be supported, at least temporarily, at the higher level with a lot less damage than we cause today. At the very least, there is the hope that if we start doing things fight, and soon, we might move to a situation in which both civilisation and biodiversity could surv ive the current outbreak in the human population. And that this would be followed, not by a crash (as usually happens in nature), but by a gradual planned reduction in the population to an easily sustainable level. Maybe within a century everybody on Earth could enjoy what

would pass for a decent life in the rich countries today.

I predict that it will not be easy to achieve all this, but there are indications that human societies can change very rapidly when the time is ripe. For example, demographers in the United States stated in the 1960s that even with government support, it would be well into the twenty-first century before the reproductive rate of American women dropped to replacement level or below. Nevertheless, it happened in the short space of about two years in the early 1970s. Even more dramatically, if it had been predicted three years ago that the Soviet Union would be coming apart and the Warsaw Pact d ismant led , that the Germanies would be reunited and the Berlin Wall sold off for souvenirs , you would not have believed it. It turns out, for reasons we do not understand, that when the time is ripe human societies can change very d r ama t i ca l l y - and change in directions which I think most of us would consider to be the fight directions. So the problem that now faces all of us is: how do we ripen the time?

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