TIME climate change

What to Know About the Paris Climate Change Conference

Over 40,000 people are meeting in Paris for a historic conference on climate change

More than 100 heads of government and 40,000 other attendees are meeting on Nov. 30 for the launch of the two-week United Nations conference on climate change. Negotiators expect the gathering, formally known as the 21st Conference of Parties (COP 21) to the United Nations Framework Convention on Climate Change (UNFCCC), to yield the most significant international agreement yet to reduce global greenhouse gas emissions, and slow the effect of climate change. But the negotiations are likely to be contentious as developed nations wrestle with developing ones in the effort to divide the global bill over global warming. Here’s what you need to know:

This isn’t the first time that there’s been a lot of hype surrounding international climate negotiations. Why are people so optimistic this time around?

Leaders of past climate summits tried to build top-down climate agreements in which countries would agree to broad guidelines to reduce their greenhouse gas emissions. Treaties borne out of that approach—like the 1997 Kyoto Protocol, which required developed countries to commit to binding greenhouse gas reduction targets—gave governments little flexibility in addressing climate change. Some countries, like the United States, opted not to participate in the agreement. Others, like Canada, ratified it, but ultimately ignored its provisions. Climate advocates set a 2009 conference in Denmark as an opportunity to achieve a comprehensive agreement that would actually lead to a reduction in emissions. But the conference was poorly organized and China and other countries refused to cooperate. In the end, the negotiations fell apart and the resulting Copenhagen Accord fell flat.

The Paris conference will instead focus on reaching a bottom-up agreement. Governments around the world have already created their own plans—called Intended Nationally Determined Contributions (INDC)—laying out how they plan to cut greenhouse gas emissions based on what they believe is politically and economically feasible for their own country. The Paris agreement would lay out a legal framework to verify that countries follow through on commitments to reduce emissions and provide for climate financing for poor countries, among other things.

A bottom-up approach may sound less ambitious than rigid international standards required of everyone. But climate negotiators hope the flexibility allowed each country by having them make their own commitments will help avoid another Kyoto, where countries simply ignored their commitments because they found them unattainable.

Paris comes at a time when scientists are telling us that the evidence for damaging climate change is greater than ever. Average temperatures reached a record high in 2014, and the U.N. confirmed Wednesday that 2015 would likely be the hottest on record. In the face of those realities, countries like the U.S., China and Canada have shown newfound interest in addressing climate change. Even oil producing countries like Saudi Arabia, which could face unlivable temperatures in the coming century, have submitted plans to address global warming

“There is a tremendous drumbeat that we can get the kind of ambitious agreement in Paris,” said Alden Meyer, director of strategy and policy at the Union of Concerned Scientists, after China announced a cap-and-trade program earlier this year. “But the job’s not done yet.”

Read More: Most Non-Climate Scientists Agree on Global Warming Too

What are some of the key issues being negotiated?

Most negotiators see finance as a key sticking point that could hold up a strong agreement. Developed countries agreed in 2009 to finance projects to address climate change in developing countries to the tune of $100 billion a year, beginning in 2020. But while money is flowing into the coffers of a Green Climate Fund founded for that purpose, it’s far from enough to support the $100 billion a year commitment, and many critics are skeptical that rich nations will ever meet that goal. Meanwhile, many developing countries have said they won’t be able to follow through on the most aggressive parts of their own climate plans without receiving their share of the money.

How to address the process of adapting to the effects of climate change will also be a key point of contention. Many of the world’s most vulnerable developing countries, including low-lying island countries that could be wiped off the map by sea-level rise, want to know that the international community will support efforts to protect their land from the sea-level rise that will happen even if the world does manage to slow the pace of global warming. “The discussion tends to be hijacked by mitigation concerns,” said Shyla Raghav, climate policy director at Conservation International. “Adaption is increasingly becoming a concern and a necessity, not only in the future but today.”

What makes for a successful conference?

A previous international agreement in 2010 formalized 2°C (3.6 F) as the target maximum global temperature rise by 2100, a level that most scientists believe would help prevent the most catastrophic effects of global warming. (Temperatures already have risen about 1°C above preindustrial levels, according to the British Met Office). Global temperature rise over preindustrial levels is expected to top 5°C (9 F) by the end of the century unless steps are taken to cut greenhouse gas emissions. But commitments that countries including the U.S. have submitted so far fall far short of the 2°C threshold, according to research, and many experts have called for the Paris agreement to include provisions by which countries review and strengthen their commitments every five years. Still, many of the world’s most vulnerable nations say that even if the world can meet 2°C goal, it won’t be enough and have called for a more aggressive target.

More broadly, many policy experts believe that the most significant impact of a strong climate agreement at Paris would be the signal it would send that the world needs to truly move away from fossil fuels.

Read More: Authorities Cancel Massive Paris Climate Rallies After Attacks

What’s the U.S. role in Paris?

President Barack Obama has sought to position the U.S. as a global leader on climate, hoping to reverse years of inaction and outright opposition by Washington at past UN climate conferences. Domestically, Obama has instituted a slew of policies to push a decline in greenhouse gas emissions. Chief among them is the Clean Power Plan, which calls for a 32% reduction in carbon emissions from power plants from 2005 levels by 2030. On the international front, Obama has signed up the U.S. for a number of bilateral climate agreements, including joint commitments with China.

Obama hopes that these moves—a sharp turnaround from the delaying tactics of the Bush Administration—will give the rest of the world confidence that the U.S. is taking climate seriously. Most other countries—especially big developing nations like China—would be reluctant to make deep cuts without the U.S., the world’s second largest emitter, at the table. “There’s a good understanding internationally of the path that the U.S. is now taking, that the actions are credible,” said Jennifer Morgan, global director of the climate program at World Resources Institute.

And while Obama’s actions give the U.S. an escalated role in the upcoming climate negotiations, the President will almost certainly play less of a personal role than he has in the past. Deputy National Security Advisor Ben Rhodes described Obama’s role as an opportunity to build “momentum toward the successful outcome” while having other senior officials “finalize the various details.” That’s a sharp contrast from a climate conference in Copenhagen six years ago where Obama showed up at the last minute in hopes of negotiating the finishing touches on a significant climate agreement. That effort was widely seen as a failure. Obama himself admitted after the conference that the agreement was “not enough.”

What about China?

China—the world’s largest emitter—actively sought to undermine negotiations in past climate conferences, but under the leadership of President Xi Jinping the country appears to have turned over a new leaf. The country has launched a national cap-and-trade program, gotten serious about tracking and reporting carbon emissions and, most importantly, committed to peaking carbon emissions by 2030. The ramped up committed is good news for a strong outcome in Paris. No climate deal would be meaningful without China’s full participation. The country generates more than a quarter of the world’s carbon dioxide emissions, and many countries would be reluctant to commit to cutting their own emissions with the world’s largest emitter on the sidelines.

Will the deal be “binding”?

Much of the weight of agreement will depend on whether its legal form will make its provisions “binding.” Most supporters of strong climate action see a binding agreement as necessary to ensure that countries follow through on their commitments. The issue erupted this month when U.S. Secretary of State John Kerry ruled out framing the agreement as a “international treaty.” Such an agreement would almost certainly fail to win approval in a Republican Senate and leave the U.S. out of the agreement. Instead, the U.S. seems to be advocating a binding agreement without labeling it a formal treaty. It remains unclear whether such an approach will be sufficient to placate the European Union and others. “If the deal is not legally binding, there is no accord, because that would mean it’s not possible to verify or control commitments that are made,” French President Francois Hollande said earlier this month.

What concrete changes will be prompted by a climate agreement?

Climate negotiations can sound like a lot of abstract numbers with little reality behind them. But a strong agreement will lead to a slew of positive developments when negotiators return to their countries. China has committed to a cap-and-trade program and said it will peak its emissions by 2030. India will increase its forest cover. The U.S. will phase out coal power plants. A climate deal will provide the framework to lock some of those commitments into place and push new efforts. “Done right, this will set in train a set of policies and actions that would take us across a number of these positive tipping points in a way we design our cities, in the way we consume, in the way we deliver electricity, in the way we work and how we go to work,” said Andrew Steer, president and CEO of the World Resources Institute, on a conference call for journalists.

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