The disappearing deal: American obstacles in Copenhagen

This December representatives from around the world will meet in Copenhagen under U.N. auspices to hammer out a new agreement for reducing greenhouse-gas emissions and taking other measures to tackle climate change. The deal is expected to include a commitment by developed countries to pay for measures in developing states to adapt to the impact of climate change and to cut emissions, as well as providing them with easy access to clean technologies.

If there is a deal, that is. In recent months, the prospects that states will actually agree to anything in Copenhagen are starting to look worse and worse. Although the Obama administration initially raised hopes by reengaging in the negotiation process, the U.S. Congress has since emerged as a potential spoiler. While the European Union has resolved to reduce emissions 20 percent (from 1990 levels) by 2020, and Japan's newly elected government has set an even higher target of 25 percent, the Waxman-Markey bill that passed by the U.S. House of Representatives in June fell well short of this goal. And the Kerry-Boxer bill recently introduced in the U.S. Senate seems unlikely to be passed any time soon.

The world can't wait, however; fast action to reduce emissions is critical. Unfortunately, no such action seems to be forthcoming. At its last annual summit in July, for example, the G8 set a target for limiting any increase in the average global temperature to 2 degrees Celsius above preindustrial levels. It advocated reducing emissions from developed countries by 80 percent by 2050. But the Intergovernmental Panel on Climate Change (IPCC), which I lead, has found that in order to limit temperature increases to 2 degrees, global emissions must peak no later than 2015. Thus, to meet their own goal, the G8 leaders should have committed to lowering emissions by 2020.

All this matters because the effects of climate change are very real. They are also diverse, and will likely hit hardest in the most vulnerable and poorest regions of the world. These areas can expect an increase in the frequency, intensity, and duration of floods, droughts, heat waves, and extreme precipitation. Sea levels, which have already increased in recent decades, are likely to rise even faster, threatening small island states and low-lying coastal areas. Agricultural yields will decline, with some countries in Africa losing up to half of their farm output by 2020. Food security will get worse, and malnutrition and hunger will grow.

Failure to reduce greenhouse-gas emissions could even threaten peace and security. That possibility was implicitly recognized by the Nobel committee in 2007 when it awarded the peace prize to the IPCC and former U.S. vice president Al Gore. Were any part of the Greenland or West Antarctic ice sheets to collapse, for example, sea levels could rise by several meters, resulting in massive destruction of life and property and creating hundreds of millions of refugees.

The reduction of greenhouse-gas emissions, meanwhile, would have numerous benefits beyond avoiding global chaos. It would help lower air pollution, thus reducing health problems. It would increase energy security in countries dependent on foreign oil while creating new jobs in alternative-energy industries. And it would help stabilize agricultural production, all at surprisingly low cost. It's therefore almost impossible to explain why, when world leaders all claim to support action to reduce emissions, an agreement remains elusive. All countries, rich and poor, seem to be shirking their "common but differentiated responsibility" (in the words of the Kyoto Protocol) to strike a strong agreement in Copenhagen.

Whatever the real explanation, the key to changing things lies in making the public aware of the alarming scientific realities of climate change, for that's the only way to create the sort of pressure that can compel leaders in democratic societies to act. Whether such a swing in public opinion can be managed in time for Copenhagen remains to be seen. What is clear is that if a strong agreement is not reached this year, the world will have lost a key opportunity to protect future generations and to ensure the well-being of all species on the planet before it's too late.