Beyond Kyoto

John Browne

From Foreign Affairs, July/August 2004

Summary:  Global warming is real and needs to be addressed now. Rather than bash or mourn the defunct Kyoto Protocol, we should start taking the small steps to reduce carbon dioxide emissions today that can make a big difference down the road. The private sector already understands this, and its efforts will be crucial in improving fossil fuel efficiency and developing alternative sources of energy. To harness business potential, however, governments in the developed world must create incentives, improve scientific research, and forge international partnerships.

Lord Browne of Madingley is Group Chief Executive of BP plc.

The most recent IPCC assessment, published in 2001, concludes that if no precautionary action is taken, carbon dioxide concentrations will rise by 2050 to between 450 and 550 ppm and will continue to increase throughout the twenty-first century. The IPCC estimates that temperatures will rise by between 0.5 degrees Celsius and 2.5 degrees Celsius by 2050, with an increase of 1.4 degrees to 5.8 degrees possible by 2100.

One of the most likely effects of global warming is a rise in sea level, as glaciers melt and warmer water expands in the oceans. The best projections suggest seas of between 5 centimeters and 32 centimeters higher by 2050; the outer limit projected for 2100 approaches one meter. These numbers seem small, but coastlines are shallow slopes, not firm walls, so a rise in water levels of just tens of centimeters would erase kilometers of wetlands and beaches.

Industrialized countries will probably be able to handle rising water levels, at least in the next few decades. London and cities in the Netherlands, for example, already have defenses to hold back surging seas. And farmers in wealthy countries can respond to changes in climate by adjusting irrigation and varying the crops they plant, in many cases with government financial support. But the developing world, home to four-fifths of humanity, is likely to fare considerably worse on both fronts. Hundreds of thousands of people have already been displaced by periodic flooding in Bangladesh, and subsistence farmers -- who are far less adaptive than their richer counterparts -- are already struggling at the climatic margin.

The most dramatic scenarios, although unlikely, would have grave consequences for humanity and ecosystems. Rapid changes in climate could upset the circulation of the North Atlantic, for example -- which, ironically, would cause much colder regional temperatures in northern Europe by weakening the heat-rich Gulf Stream. The Amazon rain forest could deplete dramatically due to drying in the atmosphere, in turn releasing huge volumes of carbon that is stored in trees. And an accelerated rise in sea level from melting ice in Antarctica could occur. These uncertain consequences do not lead to crisp timetables for policy. But they mean that precaution and improvements in measurement and learning will be crucial.

A sober strategy would ensure that any increase in the world's temperature is limited to between 2 or 3 degrees Celsius above the current level in the long run. Focused on that goal, a growing number of governments and experts have concluded that policy should aim to stabilize concentrations of carbon dioxide in the atmosphere in the range from 500 to 550 ppm over the next century, which is less than twice the pre-industrial level.

On the basis of known technology, the cost of meeting this goal would be high. But the track record of technological progress in other fields indicates an enormous potential for costs to fall as new ideas are developed and applied. In the energy industry, for example, the costs of deep-water oil and gas development have fallen by a factor of three over the last 15 years, dramatically extending the frontier of commercial activity. There is no reason to think that research and development in the area of benign energy systems would be less successful. Predicting where that success might come will not be easy -- but that means progress must be made on multiple fronts.

Many people believe that the 500-550 ppm goal would help avoid the worst calamities. But we must recognize this assessment for what it is: a judgment informed by current knowledge, rather than a confirmed conclusion to the story. Taking that judgment as the starting point, the two figures on the following page reveal the magnitude of the task ahead. Figure 1 shows an anticipated projection for emissions from industrialized and developing countries -- a "business as usual" pathway that reflects the normal improvements in efficiency, the shift away from carbon-heavy fuels such as coal to carbon-light natural gas, and the expected increase in use of zero-carbon energy sources such as nuclear and wind power. Figure 2 shows the total world emissions from that business-as-usual pathway along with a "path to future stability" -- an optimistic but realistic projection of what it will take to stabilize the atmosphere at 500-550 ppm by around 2100. The large gray shaded area is the difference: the wedge of emissions that must be avoided.

Almost every sensible analysis of the effort needed to stabilize carbon dioxide concentration arrives at a hump-shaped trajectory like the path to future stability in Figure 2. In other words, the long-term target of 500-550 ppm is reachable even if levels of emissions continue to rise in the short term -- as long as emissions start declining thereafter. (Emissions must be progressively curtailed beyond a certain point because previously emitted carbon dioxide lingers in the atmosphere for hundreds of years.) The implication of Figure 2 is that we still have time to take measured steps. But if we are to avoid having to make dramatic and economically destructive decisions in the future, we must act soon.

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