The talks are taking place under the United Nations Framework Convention on Climate Change (UNFCCC), a treaty adopted in 1992 in Rio de Janeiro. This year is the 21st meeting of signatories to that treaty, commonly referred to as the Conference of Parties, or COP.
The meeting is the largest single gathering of heads of state in history, according to United Nations officials. French authorities accredited about 3,000 journalists to cover the talks — and an additional 3,000 were turned away for lack of available press space.
The schism between developing and developed countries is key to explaining the failure of past climate change agreements.
Under earlier climate change treaties, including the 1997 Kyoto Protocol, only rich countries were required to reduce emissions. That treaty therefore lacked the participation of China, India and other major developing economies. The U.S., the world’s biggest emitter at the time, never ratified it. As support for the Kyoto Protocol dwindled, a number of other countries, including Canada, eventually pulled out.
But since then, the global development landscape has changed. Many less developed countries are relying extensively on coal and oil to fuel development and pull their populations out of poverty — climbing the same ladder used by the world’s now wealthy countries decades before.
China now surpasses the U.S. as the world’s leading greenhouse gas polluter. Other developing countries — including India, Indonesia, Brazil and Mexico — are among the top 10.
This year’s talks are aimed at developing a treaty that will be applicable to all countries, blending a mixture of top-down emissions targets negotiated in Paris with bottom-up voluntary commitments, giving flexibility to the type of participation by developing states.
More than 180 countries, accounting for about 94 percent of global emissions, have submitted pledges to curb greenhouse gas emissions. The commitments “represent a clear and determined down payment on a new era of climate ambition from the global community of nations,” said Christiana Figueres, the executive secretary of the UNFCCC, in a statement in October.
Climate scientists say global warming must not exceed 2 degrees Celsius, or 3.6 degrees Fahrenheit, to avoid catastrophic alterations to the world’s climate, including rising sea levels, increased drought and storms and shortages of food and water.
Yet the breakneck pace of global development has the world set to go far past this tipping point. Earth has already warmed about 1.7 degrees Fahrenheit since records were first kept in 1880. And if economic activity continues under current trends, without a global commitment to reducing emissions — called the business-as-usual scenario — worldwide average temperatures are estimated to increase 8.1 degrees Fahrenheit by 2100.
With the voluntary pledges, the increase could be reduced to approximately 2.7 degrees Celsius, or 4.8 degrees Fahrenheit — still above the threshold to avoid disaster — calling into question the effectiveness of the approach.
Perhaps more contentious are disagreements over how to finance a scheme to fund programs that help poor countries adapt to climate change effects and adopt cleaner technologies and to compensate them for damage caused by previous emissions.
Some of the cash would be a contribution by rich countries to a climate package that would eventually total $100 billion a year by 2020. It is considered a condition for many poorer countries to sign on to any global climate change plan.
But developed countries are reluctant to commit any new financial commitments without the participation of middle-income countries like China, Singapore and Brazil.
“Everybody knows there needs to be money on the table to seal a deal here in Paris. There needs to be a new commitment on finance, but as yet, no one knows how much or who is going to pay,” said Tim Gore, the head of policy, advocacy and research at Oxfam.
With worldwide support for a global climate change agreement slipping, selling any agreement and finance package to domestic constituencies would be no easy task.
The biggest polluters — China, the United States and European Union members — would have to commit to cutting their emissions at rates that could be economically disruptive and politically unfeasible.
According to a recent poll by research group GlobeScan, only four of 20 countries surveyed showed majority support for setting concrete targets at this year’s conference. Fewer than half of the people surveyed thought climate change was a “very serious” issue, down from 63 percent in 2009.
On Monday the White House is set to release the final rules for its Clean Power Plan, which Obama in a video on Saturday called “the biggest, most important step we’ve ever taken to combat climate change.” The new rules regulate emissions from coal-fired power plants, the largest source of greenhouse gases in the United States, and would reduce U.S. emissions by 32 percent from 2005 levels by 2030, according to White House figures.
“As the leader of the world's largest economy and the second-largest emitter … the United States of America not only recognizes our role in creating this problem — we embrace our responsibility to do something about it,” he said at the summit on Monday.
But more than half of U.S. states are suing the administration over the plan. Congressional Republicans have vowed to block any contribution to the U.N. climate fund and are planning a series of votes against Obama’s domestic climate change agenda during the Paris conference.
Despite the difficult task ahead, activists and delegates say the Paris talks are the last chance for the world to reach an agreement on climate reductions.
“Everybody realizes this is the last meeting, so there’s no point in asserting strong positions,” said a delegate from a small island state, who spoke on condition of anonymity because negotiations are underway. “It’s time to show some flexibility and find middle ground where you can.”