An economy for the Earth.

In 1543, Polish astronomer Nicolaus Copernicus published "On the Revolutions of the Celestial Spheres," in which he challenged the view that the sun revolves around the Earth, arguing instead that the Earth revolves around the sun. With his new model of the solar system, he began a wide-ranging debate among scientists, theologians, and others. His alternative to the earlier Ptolemaic model, which had the Earth at the center of the universe, led to a revolution in thinking, to a new worldview.

Today we need a similar shift in our worldview in how we think about the relationship between the Earth and the economy. The issue now is not which celestial sphere revolves around the other but whether the environment is part of the economy or the economy is part of the environment. Economists see the environment as a subset of the economy. Ecologists, on the other hand, see the economy as a subset of the environment.

Like Ptolemy's view of the solar system, the economists' view is confusing efforts to understand our modern world. This has resulted in an economy that is out of sync with the ecosystem on which it depends.

Economic theory and economic indicators don't explain how the economy is disrupting and destroying the Earth's natural systems. Economic theory doesn't explain why Arctic Sea ice is melting, why grasslands are turning into desert in northwestern China, why coral reefs are dying in the South Pacific, or why the Newfoundland cod fishery collapsed. Nor does it explain why we are in the early stages of the greatest extinction of plants and animals since the dinosaurs disappeared 65 million years ago. Yet economics is essential to measuring the cost to society of these excesses.

Evidence that the economy is in conflict with the Earth's natural systems can be seen in the daily news reports of shrinking forests, eroding soils, deteriorating rangelands, expanding deserts, rising carbon dioxide levels, falling water tables, rising temperatures, more destructive storms, melting glaciers, rising sea level, dying coral reefs, collapsing fisheries, and disappearing species. These trends, which mark an increasingly stressed relationship between the economy and the ecosystem, are taking a growing economic toll. At some point this could overwhelm the worldwide forces of progress, leading to economic decline. The challenge for our generation is to reverse these trends before environmental deterioration leads to long-term economic decline--as it did for so many earlier civilizations.

These increasingly visible trends indicate that, if the operation of the subsystem--the economy--is not compatible with the behavior of the larger system--the ecosystem--both will eventually suffer. The larger the economy becomes relative to the ecosystem, and the more it presses against the Earth's natural limits, the more destructive this incompatibility will be.

An environmentally sustainable economy--an eco-economy --requires that the principles of ecology establish the frame work for the formulation of economic policy and that economists and ecologists work together to fashion the new economy. Ecologists understand that all economic activity, indeed all life, depends on the Earth's ecosystem--the complex of individual species living together, interacting with each other and their physical habitat. These millions of species exist in an intricate balance, woven together by food chains, nutrient cycles, the hydrological cycle, and the climate system. Economists know how to translate goals into policy. Ecologists and economists working together can design and build an eco-economy that can sustain progress.

Just as recognition that the Earth is not the center of the solar system set the stage for advances in astronomy, physics, and related sciences, so will recognition that the economy isn't the center of our world create the conditions to sustain economic progress and improve the human condition.

Converting the world economy into an eco-economy, however, is a monumental undertaking, as the current gap between economists and ecologists in their perception of the world could not be wider. There is no precedent for transforming an economy shaped largely by market forces into one shaped by the principles of ecology.

The scale of projected economic growth outlines the dimensions of the challenge. The growth in world output of goods and services from $6 trillion in 1950 to $43 trillion in 2000 has caused environmental devastation on a scale that we could not easily have imagined a half-century ago. If the world economy continues to expand at 3 percent annually, the output of goods and services will increase fourfold over the next half-century, reaching $172 trillion.

Building an eco-economy in the time available requires rapid systemic change. We won't succeed with a project here and a project there. We are winning occasional battles, but we are losing the war because we don't have a strategy for the systemic economic change that will put the world on a development path that is environmentally sustainable.

Although the concept of environmentally sustainable development evolved a quarter-century ago, not one country has a strategy to build an eco-economy--to restore balances, to stabilize population and water tables, and to conserve forests, soils, and diversity of plant and animal life. We can find individual countries that are succeeding with one or more elements of restructuring but not one that is progressing satisfactorily on all fronts.

Nevertheless, glimpses of the eco-economy are clearly visible in some countries. For example, thirty-one nations in Europe, as well as Japan, have stabilized their population size, satisfying one of the most basic conditions of an eco-economy. Europe has stabilized its population within its food-producing capacity, leaving it with an exportable surplus of grain to help meet the deficits in developing countries. Furthermore, China--the world's most populous country--now has lower fertility than the United States and is moving toward population stability.

Currently Denmark is the eco-economy leader. It has stabilized its population, banned the construction of coal-fired power plants, banned the use of nonrefillable beverage containers, and is now getting 15 percent of its electricity from wind. In addition, it has restructured its urban transport network; now 32 percent of all trips in Copenhagen are on bicycle. Denmark is still not close to balancing carbon emissions and fixation, but it is moving in that direction.

Other countries have also achieved specific goals. A reforestation program in South Korea, begun more than a generation ago, has blanketed that country's hills and mountains with trees. Costa Rica has a plan to shift entirely to renewable energy by 2025. Iceland plans to be the world's first hydrogen-powered economy.

According to Seth Dunn in the November/December 2000 issue of World Watch magazine, a consortium of corporations led by Shell Hydrogen and DaimlerChrysler reached an agreement in 1999 with the government of Iceland to establish this new economy. Shell is interested because it wants to begin developing its hydrogen production and distribution capacity, and DaimlerChrysler expects to have the first fuel cell-powered automobile on the market. Shell plans to open its first chain of hydrogen stations in Iceland.

So we can see pieces of the eco-economy emerging, but systemic change requires a fundamental shift in market signals --signals that respect the principles of ecological sustainability. Unless we are prepared to shift taxes from income to environmentally destructive activities--such as carbon emissions and the wasteful use of water--we won't succeed in building an eco-economy.

It is a huge undertaking to restore the balances of nature. For energy, this will depend on shifting from a carbon-based economy to a hydrogen-based one. Even the most progressive oil companies, such as British Petroleum and Royal Dutch Shell, which are all talking extensively about building a solar/hydrogen energy economy, are still investing overwhelmingly in oil, with funds going into climate-benign sources accounting for a minute share of their investment.

Reducing soil erosion to the level of new soil formation will require changes in farming practices. In some situations, it will mean shifting from intense tillage to minimum tillage or no tillage. Agroforestry will loom large in an eco-economy.

Restoring forests that recycle rainfall inland and control flooding is itself a huge undertaking. It means reversing decades of tree cutting and land clearing with forest restoration--an activity that will require millions of people planting billions of trees.

Building an eco-economy will affect every facet of our lives. It will alter how we light our homes, what we eat, where we live, how we use our leisure time, and how many children we have. It will give us a world in which we are a part of nature instead of estranged from it.

In May 2001, the Bush White House released with great fanfare a twenty-year plan for the United States' energy economy. It disappointed many people because it largely overlooked the enormous potential for raising energy efficiency. It also overlooked the huge potential of wind power, which is likely to add more to U.S. generating capacity over the next twenty years than coal does. The plan was indicative of the problems some governments are having in fashioning an energy economy that is compatible with the Earth's ecosystem.

Prepared under the direction of Vice-President Dick Cheney, the administration's plan centers on expanding production of fossil fuels--something more appropriate for the early twentieth century than the early twenty-first. It emphasizes the role of coal, but its architects were apparently unaware that world coal use peaked in 1996 and has declined some 7 percent since then as other countries have turned away from this fuel. Even China, which rivals the United States as a coal-burning country, has reduced its coal use by an estimated 14 percent since 1996.

Bush's energy plan notes that the 2 percent of U.S. electricity generation that today comes from renewable sources, excluding hydropower, would increase to 2.8 percent in 2020. But months before the Bush plan was released, the American Wind Energy Association was projecting a staggering 60 percent growth in U.S. wind-generating capacity in 2001. Worldwide, use of wind power alone has multiplied nearly fourfold over the last five years--a growth rate matched only by the computer industry.

The solar cell is a relatively new source of alternative energy and, after wind power, is already the second fastest growing source. In 1952, three scientists at Bell Labs in Princeton, New Jersey, discovered that sunlight striking a silicon-based material produces electricity. The discovery of this photovoltaic, or solar cell, opened up a vast new potential for power generation. Initially very costly, solar cells were used mostly for high-value purposes such as providing the electricity to operate satellites. As the solar cell became economical, it opened the potential for providing electricity to remote sites not yet linked to an electrical grid. It is already more economical in remote areas to install solar cells than to build a power plant and connect villages by grid. By the end of 2000, about a million homes worldwide were getting their electricity from solar cell installations. An estimated 700,000 of these were in villages in developing countries.

Today, as the cost of solar cells continues to decline, this technology is becoming competitive with large, centralized power sources. For many of the two billion people in the world who don't have access to conventional electricity sources, small solar cell arrays provide an affordable shortcut. In the developing world, in some communities not serviced by a centralized power system, local entrepreneurs are investing in solar cell generating facilities and selling the energy to village families.

Perhaps the most exciting technological advance has been the development of a photovoltaic roofing material in Japan. A joint effort involving the construction industry, the solar cell manufacturing industry, and the Japanese government plans to have 4,600 megawatts of electrical generating capacity in place by 2010--enough to satisfy all of the electricity needs of a country like Estonia. With photovoltaic roofing material, the roof of a building becomes the power plant. In some countries, including Germany and Japan, buildings now have a two-way meter--selling electricity to the local utility when they have an excess and buying it when they don't have enough.

In contrast to these other sources of renewable energy, geothermal energy comes from within the Earth itself. Produced radioactively and by the pressures of gravity, it is a vast resource, most of which is deep within the planet. Geothermal energy can be economically tapped when it is relatively close to the surface, as evidenced by hot springs, geysers, and volcanic activity. It is used directly both to supply heat and generate electricity.

Geothermal energy is much more abundant in some parts of the world than in others. The richest region is the vast Pacific Rim: along the western coastal regions of Latin America, Central America, and North America; and widely distributed in eastern Russia, Japan, the Korean Peninsula, China, and island nations like the Philippines, Indonesia, New Guinea, Australia, and New Zealand.

This energy source is essentially inexhaustible. Hot baths, for example, have been used for millennia. It is possible to extract heat faster than it is generated at any local site, but this is a matter of adjusting the extraction of heat to the amount generated. In contrast to oil fields, which are eventually depleted, properly managed geothermal fields keep producing indefinitely. In a time of mounting concern about climate change, many governments are beginning to exploit the geothermal potential--as in Iceland, where it heats some 85 percent of buildings; as in Japan, for hot baths when springs bring geothermal energy to the surface; as in the United States for generating electricity. In fact, the U.S. Department of Energy announced in 2000 that it was launching a program to develop the rich geothermal energy resources in the western United States. The goal is to have 10 percent of the electricity in the West coming from geothermal energy by 2020.

Although the Bush energy plan doesn't reflect it, the world energy economy is on the verge of a major transformation. Historically, the twentieth century was the century of fossil fuels: first coal, then oil, and finally natural gas were the workhorses of the world economy. But with the advent of the twenty-first century, the sun is setting on the fossil fuel era. The last several decades have shown a steady shift from the most polluting and climate-disrupting fuels toward clean, climate-benign energy sources.

Even the oil companies are now beginning to recognize that the time has come for an energy transition. After years of denying any link between fossil fuel burning and climate change, John Browne, the chief executive officer of BP, announced his new position in a historic speech at Stanford University in May 1997:

   My colleagues and I now take the threat of global warming seriously. The
   time to consider the policy dimensions of climate change is not when the
   link between greenhouse gases and climate change is conclusively proven but
   when the possibility cannot be discounted and is taken seriously by the
   society of which we are a part. We in BP have reached that point.

At an energy conference in Houston, Texas, in February 1999, Michael Bowlin, CEO of ARCO, said that the beginning of the end of the age of oil was in sight. He went on to discuss the need to shift from a carbon-based to a hydrogen-based energy economy.

The signs of restructuring the global energy economy are unmistakable. Events are moving far faster than would have been expected even a few years ago, driven in part by the mounting evidence that the Earth is indeed warming up and that the burning of fossil fuels is responsible. But can we do what needs to be done fast enough?

We know that social change often takes time. In Eastern Europe, it was fully four decades from the imposition of communism until its demise. Thirty-four years passed between the first U.S. Surgeon General's report on smoking and health and the landmark agreement between the tobacco industry and state governments. Thirty-eight years have passed since biologist. Rachel Carson published Silent Spring, the wakeup call that gave rise to the modern environmental movement.

Sometimes things move much faster, especially when the magnitude of the threat is understood and the nature of the response is obvious, such as the U.S. response to the attack on Pearl Harbor. Within one year, the U.S. economy had largely been reconstructed. In less than four years, the war was over.

Accelerating the transition to a sustainable future means overcoming the inertia of both individuals and institutions. In some ways, inertia is our worst enemy. As individuals we often resist change. When we are gathered into large organizations, we resist it even more.

At the institutional level, we are looking for massive changes in industry, especially in energy. We are looking for changes in the material economy, shifting from a throwaway mentality to a closed loop/recycle mindset. If future food needs are to be satisfied adequately, we need a worldwide effort to reforest the land, conserve soil, and raise water productivity. Stabilizing population growth means quite literally a revolution in human reproductive behavior--one that recognizes a sustainable future is possible only if we average two children per couple. This isn't a debatable point. It is a mathematical reality.

The big remaining challenge is on the educational front: how can we help literally billions of people in the world understand not only the need for change but how that change can bring a life far better than they have today?

In this connection, I am frequently asked if it is too late. My response is: "Too late for what?" Is it too late to save the Aral Sea? Yes, the Aral Sea is dead; its fish have died, and its fisheries have collapsed. Is it too late to save the glaciers in Glacier National Park in the United States? Most likely. They are already half gone, and it would be virtually impossible now to reverse the rise in temperature in time to save them. Is it too late to avoid a rise in temperature from the buildup of greenhouse gases? Yes. A greenhouse gas-induced rise in temperature is apparently already underway. But is it too late to avoid runaway climate change? Perhaps not, if we quickly restructure the energy economy.

For many specifics, the answer is, yes, it is too late. But there is a broader, more fundamental question: is it too late to reverse the trends that will eventually lead to economic decline? Here I think the answer is no--not if we act quickly.

Perhaps the biggest challenge we face is shifting from a carbon-based to a hydrogen-based energy economy--basically moving from fossil fuels to renewable sources of energy, such as solar, wind, and geothermal. How fast can we make this change? Can it be done before we trigger irreversible damage, such as a disastrous rise in sea level? As I indicated, we know from the United States' response to the attack on Pearl Harbor that economic restructuring can occur at an incredible pace if a society is convinced of the need for it.

We study the archaeological sites of civilizations that moved onto economic paths that were environmentally destructive and could not make the needed course corrections in time. We face the same risk.

There is no middle path. Do we join together to build an economy that is sustainable, or do we stay with our environmentally unsustainable economy until it declines? It isn't a goal that can be compromised. One way or another, the choice will be made by our generation. But what we choose will affect life on Earth for all generations to come.

Lester R. Brown is president and founder of the Earth Policy Institute; the founder and former president of the Worldwatch Institute; a MacArthur Fellow; and the recipient of twenty-two honorary degrees and many awards, including the 1987 UN Environment Prize, the 1989 World Wide Fund for Nature Gold Medal, the 1991 Humanist of the Year Award, and the 1994 Blue Planet Prize for his "exceptional contributions to solving global environmental problems. "He has authored or coauthored forty-seven books, nineteen monographs, and countless articles. This article is adapted from Eco-Economy: Building an Economy for the Earth, which is available online at www.earth-policy.org.