ANDREW C. REVKIN
Global warming has become perhaps the most complicated issue facing world leaders. On the
one hand, warnings from the scientific community are becoming louder, as an increasing body of
science points to rising dangers from the ongoing buildup of human-related greenhouse gases —
produced mainly by the burning of fossil fuels and forests. On the other, the technological,
economic and political issues that have to be resolved before a concerted worldwide effort to
reduce emissions can begin have gotten no simpler, particularly in the face of a global economic
After years of preparation for climate talks taking place in Copenhagen through Dec. 18, 2009,
President Obama and other leaders announced on Nov. 15 what had already become evident —
that no formal treaty could be produced anytime soon. Instead, the leaders pledged to reach a
placeholder accord that would call for reductions in emissions and increased aid to help
developing nations adapt to a changing climate and get access to non-polluting energy options.
This would in theory give the nations more time to work out the all-important details.
Negotiators would then seek a binding global agreement in 2010, complete with firm emission
targets, enforcement mechanisms and specific dollar amounts to aid poorer nations.
At the heart of the debate is a momentous tussle between rich and poor countries over who steps
up first and who pays most for changed energy menus.
Within the United States, Congress is similarly fighting over legislation on climate change. The
House in the summer of 2009 passed a bill outlining a cap-and-trade system that could, over the
next few decades, lead to an early end to conventional use of coal and oil, fuels that have
underpinned prosperity and growth for more than a century. But between stiff opposition from
energy interests and the overwhelming distractions of health care reform and the economy, the
legislation has stalled in the Senate.
In international discussions over climate, Mr. Obama has urged other countries not to be
discouraged by the stasis on Capitol Hill, pointing to big investments in energy efficiency, solar
and wind power and his move to restrict greenhouse gases using environmental regulations.
In the meantime, recent fluctuations in temperature, seized on by opponents of emissions
restrictions, have intensified the public debate over how urgently to respond. The long-term
warming trend over the last century has been well-established, and scientists immersed in
studying the climate are projecting substantial disruption in water supplies, agriculture,
ecosystems and coastal communities. Passionate activists at both ends of the discourse are
pushing ever harder for or against rapid action, while polls show the public locked durably in