Lester Brown

The pace of change in our world is speeding up, accelerating to the point where it threatens to overwhelm the management capacity of political leaders. This acceleration of history comes not only from advancing technology, but also from unprecedented world population growth, even faster economic growth, and the increasingly frequent collisions between expanding human demands and the limits of the earth's natural systems.

History is not about the status quo; it is about change. Throughout most of the time since civilisation began, the agents of change worked slowly. Until recently, in historical terms, the growth of population was so slow as to be imperceptible during an individual's lifetime. Economic expansion was similarly sluggish. But since mid-century, the pace of change has been breathtaking.

Today, it is difficult to grasp the sheer magnitude of human population growth. Those of us born before 1950 have seen more population growth during our lifetimes than occurred during the preceding four million years since our early ancestors first stood upright.

The world economy is growing even faster. It has expanded from $4 trillion in output in 1950 to more than $20 trillion in 1995. In just the ten years from 1985 to 1995 it grew by $4 trillion - more than from the beginning of civilisation until 1950. Countries industrialising now are doing so much faster than in the past, simply because they can draw on the experiences and technology of those who went first. Economic growth in East Asia, for instance, has averaged some 8 percent annually in recent years. And from 1991 to 1995, the Chinese economy expanded by a staggering 57 percent, raising the income per person of 1.2 billion people by more than half.

Yet the benefits of this rapid global growth have not been evenly distributed. Living conditions for roughly a fifth of humanity have remained at subsistence level, essentially unchanged. As a result, the ratio between income in the richest one fifth of countries and the poorest one fifth has widened from 30 to 1 in 1960 to 61 to 1 in 1991, creating tensions between those on the upper rungs of the global economic ladder and those stuck on the bottom steps.

As population has doubled since mid-century and the global economy has nearly quintupled in size, the demand for natural resources has grown at a phenomenal rate. Since 1950, the need for grain has nearly tripled. Consumption of seafood has increased more than four times. Water use has tripled. Demand for the principal rangeland products, beef and mutton, has also tripled since 1950. Firewood demand has tripled, lumber has more than doubled, and paper has gone up sixfold. The burning of fossil fuels has increased nearly fourfold, and carbon emissions have risen accordingly.

These spiralling human demands for resources are beginning to outgrow the capacity of the earth's natural systems. As this happens, the global economy is damaging the foundation on which it rests. Evidence of the damage to the earth's ecological infrastructure takes the form of collapsing fisheries, falling waer tables, shrinking forests, eroding soils, dying lakes, crop-withering heat waves, and disappearing species.

Even as the effects of unprecedented population growth are threatening to overwhelm some governments, the collisions between the expanding demands of the global economy and the earth's natural limits are creating additional burdens. Collisions with the sustainable yield limits of fisheries, aquifers, forests, rangelands, and other natural systems are occurring with increasing frequency. As a result, national political leaders and UN agencies are spending more and more time dealing with these collisions and their consequences - fishery conflicts, water scarcity, food shortages, increasingly destructive storms, and swelling flows of environmental refugees.

As hunters and gatherers, our effect on the earth was limited indeed. Neither our hunting skills nor our gathering capacity threatened many other species, much less whole ecosystems. Only recently has the scale of human activities reached a point where it affects the habitability of the planet.

When a sustainable yield threshold is crossed, it signals a fundamental change in the relationship between the consumer and that which is being consumed. To use an analogy from economics, the distinction is between consuming interest and spending the capital stock itself. If an organisation such as a university is living off an endowment, it can operate indefinitely as long as its needs do not exceed the income from the endowment. But if at some point it begins drawing down the principal, it will soon find itself in trouble, forced to cut back operations. If it cannot lower its annual demands to the sustainable yield of the endowment, eventually it will face bankruptcy.

The demands of our generation now exceed the income, the sustainable yield, of the earth's ecological endowment. Since mid-century the sustainable yield thresholds of natural systems have been crossed in country after country. It is difficult, if not impossible, to find a developing country that is not losing tree cover. Every major food-producing country is suffering heavy topsoil losses from erosion by wind and water.

The list continues.

'State of the World 1996' published by the Worldwatch Institute.