Rio+20 Portal

This Perspective was written by Stephen A. Marglin of Harvard University. It draws from the consensus statement of a 2010 workshop, “The challenge of sustainability: towards Rio+20”, organized by the United Nations Division for Sustainable Development, which was endorsed by the following attendees (in alphabetical order): Frank Ackerman, Lois Barber, Peter Brown, Robert Costanza, Paul Ekins, Marina Fischer-Kowalski, Maja Göpel, Tim Jackson, Ashok Khosla, Nebosja Nakicenovic, Paul Raskin, William Rees, Wolfgang Sachs, Juliet Schor, Gus Speth, Peter Victor, and Ernst von Weiszäcker, many of whom contributed to the text.

THERE IS CONSIDERABLE UNCERTAINTY ABOUT HOW TIGHTLY ECOLOGY CONSTRAINS PLANETARY GROWTH.

Given this uncertainty, prudence dictates a conservative approach that takes limits to growth seriously. In an ecologically constrained world, both the global North and the global South need to consider new obligations and limits. A basic commitment to social justice requires that the claims of the poor, chiefly residing in the South, take precedence over the claims of the rich, chiefly residing in the North. The North may have to accept an actual reduction in conventional measures of standard of living to create ecological space for Southern growth. At any rate, the scope for further growth to contribute to well-being in affluent regions is quite limited, so the costs to the North of reducing growth may be modest—especially if a new economy is organized to provide the economic basis of a good life based on precepts other than more, more, and still more.

While recognizing a priority for the poor imposes obligations on the North, this recognition cannot be a license for the South to replicate the wasteful disregard for ecosystem boundaries that has characterized growth in the North. Nor ought the South to countenance the wanton disregard for the claims of the disadvantaged that has allowed large islands of Northern poverty to continue to exist in oceans of Northern wealth.

1. The intertwined problems of development, equity, and ecology require a new economy. In 1992, officials from 172 nations met at the Earth Summit in Rio de Janeiro and made a set of commitments to address global equity and development within the ecological limits of the planet. In 2012, “Rio + 20” will re-assemble these nations. Its agenda must begin from a recognition that none of the commitments has been fulfilled. Indeed, since 1992 this nexus of problems has worsened.

2. We are living in a danger zone. Since the dawn of industrialization, economic growth has been associated with ever greater use of non-renewable materials and energy, as well as the degradation of renewable resources beyond their regenerative capacities. This has eroded the ecosystems upon which the economy depends and will ultimately lead to destructive transformation or even collapse.A century ago, the day of reckoning appeared so far away that we could ignore the ecological constraints on growth. We seemed to be living in an empty world, operating comfortably within the safe zone of the ecosphere. No longer. In 2009, a distinguished group of scientists confirmed the cumulative message of environmental science: humanity is already operating beyond the safe spacedefined by these boundaries.1 A case in point is the inability of the atmosphere to neutralize the detritus of economic activity, particularly, CO2 and other greenhouse gases—“global climate change,” for short.

By historical standards, the path from an empty to a full world has been remarkably swift; most of the expansion took place in the last century. If the world economy continues to grow at the rate of the last 30 years, output would expand 16-fold by century’s end. To maintain the same rate of per capita growth as was achieved over the last 30 years would be less demanding since world population is expected to stabilize over the next 50 years, but this more modest trajectory would still imply a 6-fold expansion over the rest of this century. Using current technologies, either of these scenarios would require the equivalent of the atmospheres of several additional Earths to absorb the pollutants generated by growth.

3. We must recognize that a dramatically different way of how we live, work, and understand the world—as distinct from an energy techno-fix—may be required. A necessary condition for avoiding potentially catastrophic consequences of climate change is to “decarbonize” the economy, that is, to reduce energy use, neutralize car- bon emissions from fossil fuels, and shift to renewable sources of clean energy. Technological optimists believe that decarbonization will allow us to transcend limits to growth. If GDP growth could be decoupled from increased energy use and energy use decoupled from CO2 emissions, we could hope to achieve safe emissions targets even with 20th century rates of economic growth. However, up to now the results of decoupling have been meager at best. Carbon dioxide emissions from fossil fuel consumption increased by 40 percent over the last two decades. Whatever the theoretical possibilities, the practical reality today is that decarbonization on the requisite scale would require global rates of improvement in energy systems several times faster than any historical experience.