Melding heart and head

Robert May calls for agriculture that goes with the grain of
nature to help preserve biodiversity in an
increasingly crowded world

Today we are living at a very special time in the history of the Earth. It is a time which might come in the history of any inhabited planet, when the activities of one particular species – in this case, ourselves – come to rival the scale and scope of the natural processes which built, and which maintain, the planet’s biosphere.

It is easy to be sceptical of such dramatic claims, which are often voiced around millennia or other years with many zeros in them. But there are objective facts which demonstrate just how special our own time is. For one thing, humans today take for their own use somewhere between a quarter and a half of all plant material that grows on earth each year. For another – from the tropical rainforests, across the grain fields of America, Europe and Asia, to the Arctic tundra – fully half of all the atoms of nitrogen and of phosphorous annually fixed in new plants come from human intervention in the form of fertilizers rather than natural cycles. Turning to the sea, we take 10 per cent of all its production each year, and larger amounts (around 30 per cent) in rich areas of nutrient upwelling.

On the whole, however, human life has improved during the 20th century. As one example, average life expectancy at birth, around the globe, in the 1950s was 46 years. Today it is 64 years. The 1950s figure may seem surprising to those who live in the developed world, but it comes into clearer perspective when it is recognized that, over the same roughly 50-year period, the average difference in longevity between the developed and the developing world shrank from 26 years to 12.

Partly as a result of such global changes in average health – and particularly in infant survival rates – human numbers have shown unprecedented growth over the latter half of the past century. The world population of 6 billion represents a fourfold increase over the century, and a 60 per cent increase over just the past 35 years. During this same 35 years, global food production has doubled. So there is 25 per cent more food per person today than there was three and a half decades ago. Today’s lamentable problems of malnourishment and even famine in many parts of the world are problems of distribution – problems as old as agriculture itself, and not easily cured – rather than of food production as such.

Unforeseen costs
The Green Revolution that has doubled food supplies has, however, had unforeseen environmental costs. The doubling was achieved with an increase of only 10 or 20 per cent of arable land. But herbicides, pesticides, fertilizers and other inputs, all subsidized by fossil fuel energy subsidies, have much more than doubled. In particular, nitrogen from fertilizers has increased roughly seven times and is having adverse impacts on many rivers and water tables.

More generally, the Green Revolution has taken us a long way toward realizing the age-old aim of agriculture, which is efficiently to grow crops which only humans eat, not losing productivity to weeds (plants in the wrong place) or to insects, pathogens or other pests. Such increases in efficiency, and accompanying intensification, may be good news for farmers, and consequently for consumers (British people today spend, on average, 16 per cent of disposable income on feeding themselves, and in this sense food has never been so plentiful or cheap).

But all this represents bad news for the diverse populations of invertebrates, birds, and other creatures that share the countryside with us. The State of the UK’s Birds 1999, recently published by the Royal Society for the Protection of Birds (RSPB) and the British Trust for Ornithology (BTO), for example, documents declines in populations of 41 species of woodland birds (on average down 20 per cent from the mid-1970s) and of 20 species of farmland birds (down 40 per cent over the same period).

More broadly, the outcome of intensification of agriculture, around the world, is an ever more Silent Spring. Documented extinctions of bird and mammal species over the past century or so are at a rate roughly 1,000 times faster than the rates seen, on average, over the half-billion-year sweep of the fossil record. The various causes are habitat destruction, unsustainably excessive harvesting and other exploitation, adverse impacts by introduced alien species, and – more often – combinations of all three.
The challenge of the century is to emphasize valid emotional and ethical arguments for conserving biological diversity

Projections of future extinction rates are more difficult to make. Four different lines of argument, ranging from one which applies generally to all plants and animals, through to others which generalize from particular families of birds, reptiles and mammals, all suggest a roughly tenfold increase in extinction rates over the coming few centuries. These are sober, analytic estimates, free of the rhetorical exaggerations which sometimes afflict the subject. These estimates make it clear that we are currently on the breaking tip of a sixth great wave of extinction in the history of life on Earth, fully comparable with the Big Five in the fossil record, such as the one that extinguished the dinosaurs.

Relative value
So what will tomorrow’s world be like? The extent to which biodiversity will actually diminish depends on the actions we take now. Estimates by Andrew Balmford and colleagues at Cambridge University suggest that worldwide we currently spend about $6 billion annually on nature reserves and other protected areas, which cover something like 6 per cent of the planet’s land area. Increasing this to 10 per cent of the land, properly protected and managed, and with appropriate and sustainable compensation for local people, would cost around $30 billion each year. More important, but much more costly, Balmford and others estimate that current agriculture could be made more environmentally friendly, without significant loss of productivity, for an additional annual cost of around $300 billion. These are huge numbers, but they only represent about 1 per cent of global GDP, as it is conventionally calculated. These usual economists’calculations of GDP, however, take no account of the many services delivered to us by natural ecosystems, although the actual value of such ecosystem services has recently been estimated to be of similar magnitude to conventional GDP. Looking at it this way, I think an investment of 1 per cent of GDP to preserve such services is good value.

Diminishing gains
Toward the end of this century, estimates which I rate as rather optimistic suggest that – barring catastrophes – our descendants will live in a world of 10 billion people. How will they be fed? The Green Revolution, underpinned as it is by massive and unsustainable inputs of fossil fuel energy, already shows signs of diminishing gains. Just as we could not feed today’s global population with yesterday’s agriculture, I do not believe we can feed tomorrow’s population with today’s.

I share the belief of Gordon Conway, President of the Rockefeller Foundation (expressed in the last Our Planet) that we need his Doubly Green Revolution, where further gains in productivity are achieved in a sustainable and environmentally friendly way. Here I believe, looking beyond current debates, that new techniques of genetic manipulation (GM) offer us possibilities that can be used wisely or unwisely. GM methods are essentially just tools for achieving in a more precise, focused and rapid way the kinds of modification of crops that plant breeding has always given us (and in increasingly artificial ways over the past few decades). But we will get what we aim at. If we seek only further intensification of agriculture – a further ratcheting up in the spirit of the Green Revolution – then we may feed tomorrow’s world, but it will be biologically impoverished, and I doubt its sustainability. If, on the other hand, we use our increasing understanding of the molecular machinery of life, along with other cultural changes, to produce an agriculture that works with the grain of nature – rather than using fossil fuel subsidies to wrench nature to our crops – then I hope we can achieve Conway’s Doubly Green Revolution.

Harnessing impulse
Part of the motive for all this must be a more sustainable way of doing things. But a related part of the motive must come from our natural impulses of concern, and even affection, for the other creatures we share the world with. Too often, however, such concern expresses itself through a disproportionate focus on large mammals and colourful birds: ‘charismatic megafauna’. Although understandable and effective in engaging a wider public, particularly in the developed world, these targets are not necessarily those that would be chosen in an analytic quest to preserve the maximum amount of the planet’s evolutionary history, as written in the genetic richness and variability within today’s living species. Although our emotions may relate most easily to the big mammals and the interesting birds, the smaller invertebrates and the diverse plant kingdom are more important for the functioning of many ecosystems, and they also carry more of the record of how life evolved on our planet. The justification that by saving charismatic megafauna we necessarily save large areas of habitat, and thence a host of less emotionally resonant invertebrates and plants, does not always survive close examination: such studies as do exist suggest that ‘hot spots’ for birds are often weakly correlated with ‘hot spots’ for particular plant and insect groups.

To summarize, I believe the challenge of the century is to emphasize valid emotional and ethical arguments for conserving biological diversity, but also to combine them with analytic approaches that ask questions – often cold and difficult ones – about which actions will, in the long run, be most effective in sustaining as much as possible of the biological riches and the unaccounted ecosystem services we have inherited. This melding of heart and head will, I think, pose tough challenges and choices. It is not an easy recipe for a new beginning to a new millennium

Sir Robert May is Chief Scientific Advisor to the United Kingdom Government, and head of its Office of Science and Technology.

PHOTOGRAPH: Thomas Raupach/Still Pictures

This issue:
Contents | Editorial K. Toepfer | Time to act | A climate of change | Melding heart and head | Looking through green glasses | Multi-local business | World Environment Day 2000 |
At a glance | Competition | The greening of Goliath | Unfair trade | No sleeping after Seattle | Disproportionate effects | Liberal rations | New millennium, new regulation | Secretary-General’s Report | Pachamama: Our Earth, Our Future


Complementary articles in other issues:
Issue on Biodiversity 2000, including:
Gordon Conway: Genetically engineered crops: who benefits?
Issue on Food 1996, including:
Oscar B. Zamora: The real roots of security
Hans Jonsson: Greening the fields
Don de Silva: Chemical-free farming   (Chemicals) 1997