NEW YORK CITY—More than 100 countries have signed on to the Copenhagen Accord—the nonbinding agreement to combat climate change hastily agreed to this past December at a summit of world leaders. As signatories, the countries agree to cut greenhouse gas emissions to keep global average temperatures from warming more than 2 degrees Celsius. The countries that have signed up to date represent more than 80 percent of the global emissions of such heat-trapping gases.

"Climate change is one of the most important challenges humanity faces today," said Mexico President Felipe Calderón Hinojosa via videoconference from Mexico City at the State of the Planet gathering at Columbia University hosted by its Earth Institute on March 25. "This is urgent, we need to act now as countries and as governments."

As part of signing on, countries also listed their national goals for emission reductions. Mexico, for its part, pledged to cut 50 million metric tons of greenhouse gas emissions annually by 2012. The U.S. pledged to reduce emissions by 4 percent below 1990 levels, pending legislation, whereas China promised cuts of 40 to 45 percent of the total CO2 per unit of economic production, so-called carbon intensity. And it will fall to Calderón and his colleagues in the Mexican government as hosts of the next climate change negotiation meetings in Cancún this November to continue progress toward an international, binding agreement. After all, without a legally binding treaty there will be no accountability on greenhouse gas emissions, warned United Nations Secretary General Ban Ki-moon at the conference.

"The U.N. is important because it's the only place where we can get a truly comprehensive agreement," Nitin Desai, a former U.N. undersecretary general, told attendees via videoconference from New Delhi. However, "the U.N. is important, but not the only game in town."

Government action is key
Citing the various national action plans announced since Copenhagen, and in some cases listed therein, Desai argued that "what really matters is the degree of legal force behind national action," such as India's commitment to at least a 25 percent reduction in its carbon intensity.

That means U.S. governmental action will be vitally important; details of legislation to reduce greenhouse gas emissions are currently being worked on in the Senate while the House of Representatives has passed a bill that would match the Obama administration's pledge under the Copenhagen Accord. "It's up to the U.S. now to cut our carbon emissions if the rest of the world can reasonably be expected to do anything," said climate modeler Mark Cane of Columbia University's Earth Institute.

At the same time, the U.S. is pushing for international monitoring and verification of emission reductions in emerging countries, such as China. But political scientist Zha Daojiong of Peking University noted via videoconference from Beijing that "in the West, if something is not put into law then that won't work. In China when the government comes out and says, 'We have a target,' we are going to do this, because the culture and [political] institutions are different. They are going to do it—look at the past 30 years."

The key to doing it, according to Calderón, is "to find out a new model of development that will allow us to grow in harmony with the environment, which will imply a new Industrial Revolution based on low carbon growth."

In essence, the challenge is "how to link fighting poverty, which is a main concern of developing countries, with fighting climate change," he added. Mexico has begun to address that by providing direct cash payments to impoverished residents to purchase energy-efficient goods or preserve local forests.

"The day that a tree standing is worth more than a tree cut down" is the day economics align with sustainability, Achim Steiner, executive director of the U.N. Environmental Programme, said via videoconference from Nairobi, Kenya. "The myth of the 20th century made the services the environment provides invisible."

In fact, countries ranging from the U.S. to China treat the continent of Africa as "a large mine. You extract what you need for the world economy," Steiner charged. Some environmental economists have estimated that the entire continent has lost as much as 50 percent of its profusion of flora and fauna in just the last decade as a result of such exploitation. "We have to become more efficient in the way we use resources. The only other option is to run out of them," he added.

The role of economic development
A big part of any linkage between fighting climate change and poverty alleviation will be building a more comprehensive energy infrastructure. "When hundreds of millions [of Indians] don't have access to electricity, it's unrealistic to expect India to cut growth," noted Jyoti Parikh, executive director of Integrated Research and Action for Development, a think tank, via videoconference from New Delhi. "People got a free ride because of delay [in combating climate change], and those who delayed did not have anything to pay later in any way.... Whatever has happened has affected our [global] carbon budget."

But economic growth can be paired with climate change solutions. For example, the Indian government has instituted a goal of 20,000 megawatts of new solar power installations by 2022. "With the solar energy program, the strongest pressure is not from green groups," Desai noted. "The corporate sector in India is showing huge interest in getting into this area."

At the same time, locally appropriate technologies must play a role, such as using cattle to drive a generator or using livestock waste to produce biogas, Devin Narang, chairman of the Freeplay Group, a maker of consumer electronics for the poor, argued via videoconference from New Delhi.

Using clean technologies to promote economic growth is already a reality. China has surpassed the U.S. and other nations in total clean energy investment—securing $34.6 billion in investments and finance for wind, solar and hydropower, among other renewable energy technologies in 2009 alone, according to a new report from The Pew Charitable Trusts.

The key will be further speed and scale in efforts to reduce greenhouse gas emissions from energy, agriculture, buildings and other sectors. "All the science shows that technology is not a silver bullet. We'll have to see lifestyle changes, as well," said Johan Rockström, executive director of the Stockholm Environment Institute. "This is the most decisive decade, when we have to start bending the curve on greenhouse gas emissions and biodiversity. What if we push this too far?"

After all, scientists generally agree that to hold average temperature rise to 2 degrees C, atmospheric concentrations of greenhouse gases must be stabilized at 450 parts per million—and they are already nearing 390 ppm. Holding to the 450-ppm level is "ludicrous, unless we were to gear up like we were fighting World War II again," argued geochemist Wallace Broecker of Columbia's Lamont–Doherty Earth Observatory, and one of the first scientists to identify modern global warming in the 1970s. "We could do it but the chances of the world taking it that seriously are very small."