A green light for ecology

Nothing is more important than studying the environment. This planet is threatened with overpopulation by humans, and their growing indulgence in conspicuous consumption, the seven deadly sins, and private cars. Although for 20 years they listened with apparent sympathy to the environmentalist message, and now take newspaper, drinks cans and old vests for recycling, they no longer seem interested in the wider implications. Warnings of imminent catastrophes which never arrived may have something to do with this lack of concern: swarms of mosquitoes have not invaded the UK; new plagues are not wiping out the world; trees have not all died from acid rain; and the Second Flood is not lapping at our doors.

Endless green alerts have achieved little but a lowering of public esteem for this branch of science - if science it is. It is this threat, of not being taken seriously by the rest of the scientific community, which appears to be the strongest motivation behind Scientific Uncertainty and Environmental Problem Solving. This is a compilation of 14 chapters, and while some are heavy going, most are well worth reading. Its authors want to secure scientific respectability for their discipline, but are faced with the seemingly impossible task of coping with too many imponderables, variables and confounding factors, so that it becomes difficult even to set up reliable models. The conclusion is that environmentalists must not be paralysed into inaction by uncertainty, but come to terms with it, and work within its limitations.

About half the chapters address the philosophical implications of uncertainty and risk, while the other half concentrate on analysing specific problems. The chapter which best introduces the book is by Carl Jordan and Christopher Miller of Georgia University. They examine the problem from many angles, asking what constitutes a "fact" in the ecological sense, looking at the role of statistics and logistics, and assessing the predictions and the constraints on these. They then apply these approaches to four cases: the disappearing Florida Everglades, oil spills, national parks and biological diversity.

Jordan and Miller also scan the spectrum of hard-to-soft sciences, which they see as Newtonian physics, chemistry, biology, ecology, economics, anthropology, and sociology. Positioning within the spectrum depends on the quality of underlying theory, the extent to which it is accepted as true, and its susceptibility to mathematical expression. Environment comes nicely in the middle, but its adherents have to decide which way to face, or they may end up with a split personality.

Those who want to be accepted by the hard sciences struggle to achieve the respect accorded their biological colleagues. Others reject the reductionist rigours of the scientific discipline, and look the other way. They see a world ruled by chaos theory and academic controversy; theories that can be overlapping but inconsistent, and where uncertainty is assumed. And on the far shore of this type of environmentalism are the academic prima donnas and television personalities, journalists and eco-activists, green politicians and global warming doomsters.

This book will never be their bible. Its authors are struggling to save the souls of their fellows by converting them to the gospel of the harder sciences. Jordan and Miller end their chapter with a timely warning which deserves quoting in full: "Scientists, by continuing a charade that if they were only given more money and more facilities they can solve the environmental crises, will only contribute to a greater discreditation of science. The longer they hold on to this myth, the greater will be the crash when the public finally realises the limitations of science. It would be better for scientists to publicise the limitations of science. While such candour might result in decreased funding, in the long term it will be beneficial because it will enable scientists to retain some measure of credibility, and not be entirely destroyed when the truth is finally understood by all."

Most of the authors in Scientific Uncertainty and Environmental Problem Solving have heeded these sentiments and you will search in vain for the alarmist issues of global warming, ozone holes, desertification, genetic engineering and gender-bending. However, the emotive question of radioactive waste disposal is covered by the book's editor, John Lemons of the University of New England, in a chapter that is long on science but short on ecopolitics. He deals mainly with the high-level waste repository at Yucca Mountain in the US and shows there is a way of dealing sensibly with such highly charged issues.

Richard Carpenter writes about managed ecosystems, and looks closely at the sustainability of high crop yields, since nothing less will cope with the demands of the next millennium. Scientific uncertainty bedevils those who seek to research this vital area. Not only is there a lack of data, which hampers those who try to set up models, but it confounds those who want to extrapolate on the basis of such models. Carpenter looks closely at agriculture, forestry, grazing lands, and fisheries, and concludes that all will be severely stressed, even under supposedly sustainable regimes. The stresses will come from the increasing demands for more goods and services from more people.

Theory is all very well, and the more scientific it is, the better it should be, but it is specific examples which test its value. Judith Weis looks at four pollution case studies: the dumping of sewage in the sea off New York; acid precipitation; tributyltin antifouling paints; and estuary eutrophication. She concludes that better monitoring is needed to identify early indicators of stress. If this had happened, then the adverse effects of disposing of New York's sewage might have been avoided. While sewage can be a fertiliser for the marine environment as well as for that on land, it proved not to be so off the New Jersey coast where it produced a "dead sea", killing many organisms and creating disease among the species which managed to survive.

When the dump sites were moved from 12 miles to 106 miles offshore, the problem should have been solved, and scientifically it was, but coastal pollution convinced the public and Congress to prohibit sludge dumping totally. In the face of such highly charged public emotion, scientific counter-arguments went by the board. In fact pollution was coming from entirely different sources. The objects washed up were medical waste and various unmentionables. The upshot is that sewage sludge has to be disposed of on land, which is more expensive and may also become unacceptable. Weis concludes that ocean dumping may yet live again.

Some of the chapters in Scientific Uncertainty and Environmental Problem Solving concentrate solely on the theory of uncertainty and risk assessment, and are really meant for the dedicated connoisseur. The first chapter in the book looks at the methodological rules for four classes of scientific uncertainty, but I found this rather hard going, and the same was true for the chapter dealing with ecotoxicology.

It is somewhat disconcerting to find that all but one of the contributors to this book are American. The exception is Mahmoud El-Sayed of the University of Alexandria, who deals with the implications of climate change for the Nile Delta.

The current version of global warming predicts the Second Flood will happen in the next century, as melting ice at the poles inundates coastal regions, where most of the world's population lives. The delta would be particularly at risk on its northern coastal region where much of the land is less than two metres above sea level. This is where six million people live. Its chief city, Alexandria, already has a population of 3.5 million which will rise to five million by the year 2005. Will it fall to zero by the year 2100? Or will it become an unplanned Venice - along with 100 other cities around the world?

What should the Egyptians do if they accept this theory and do not want their second largest city to disappear under the waters of the Mediterranean? El-Sayed realises that existing data are woefully inadequate and the computer models built on them are resting on sand, yet clearly something should be done in the way of preparation. But what? I believe that El-Sayed is right in remaining cool-headed in the face of ever-changing forecasts, and to ask for improved data collection and better monitoring before taking action. Meanwhile those under threat should work out a set of priorities for action at local and regional levels.

Because humans are land-based creatures, we feel threatened by the sea and its awesome power, and maybe this is why we tend to focus our attention instead on those parts of the environment above it, which we can monitor more easily.

But most worrying is what is happening under the waves. It is from this source that we extract 100 million tonnes of fish every year as nutritious protein, yet we remain so ignorant about the biomass of the oceans. We may think that fishing fleets are creaming off a surplus, living off the interest, so to speak, but we may in fact be using up the capital. If so, we may be doing to the world's oceans what we have already done to the massive fishing grounds off northeastern America: spent the lot. Forty years ago the Grand Banks were teeming. Today they are empty, and overfishing is to blame.

Charles Cole's chapter on the uncertainty of marine fisheries management shows just how difficult it is to bring this under control. In his words, our lack of understanding of marine biology "nearly beggars the imagination" and yet we continue to plunder. Uncertainty here stems mainly from the expense of gathering the data. If ever an area of research deserves to be better funded it is this, and the marine environment should be placed top of the global agenda.

At this stage in the development of their subject, environmentalists are doing very nicely, but quo vadis? time has come. Scientific Uncertainty and Environmental Problem Solving is evidence of a will to tread the stony path to the scientific summit. A similarly daunting walk faced physicists 300 years ago (in understanding the forces of nature), chemists 200 years ago (in understanding matter), and biologists 100 years ago (in understanding the living cell). The progress that these sciences made was truly phenomenal. Perhaps techniques as yet unimagined will come to the aid of environmentalists. Let us pray.

John Emsley is the science writer in residence at Imperial College, London.