It was not with starry-eyed optimism, but with fierce determination that global climate negotiators launched their treaty talks in Lima on Monday. Nobody is suggesting that it will be easy to draft a comprehensive pact to be signed in Paris next year.
Rather, the leaders of the talks are simply asserting that failure is not an option, as they confront the reality that significant global warming is already locked in and this year's record-breaking temperatures are bound to be exceeded again and again.
"El mundo nos espera," said Peru's Manuel Pulgar Vidal, the presiding officer at the talks. "El mundo no espera que fallemos." The world awaits us. The world does not expect us to fail.
Here are just a few of the difficult pieces of the complex puzzle negotiators need to solve if they are to avoid failure.
Talk of limiting warming of the planet to 2 degrees Celsius is giving way to talk of reducing greenhouse gases emissions to zero this century. It's the same goal, just put more bluntly: total decarbonization of the world's energy economy within a generation.
All eyes are on this revolutionary prize.
Unless the world attains zero emissions, it will miss the 2-degree goal. On the present course, the planet is likely to warm considerably more than that.
So it's not that negotiators are giving up on the temperature target. But it is seen as too abstract, requiring complex math to translate into concrete policies. Depending on how sensitive the climate system is to carbon dioxide pollution, the 2-degree goal probably requires keeping CO2 concentrations in the atmosphere below 450 parts per million. That means staying within a fixed "carbon budget"—one that the world will bust in just a few decades unless emissions are reined in severely. The Intergovernmental Panel on Climate Change, the UN's science authority, has confirmed that humankind must keep its cumulative emissions below 1,000 gigatons to stay within 2 degrees. Countries have already spent more than half of that.
All those numbers are hard to fathom. So climate hawks have started to use a much starker and comprehensible number: zero.
Some time in the second half of this century, net emissions of greenhouse gases are going to have to hit zero. Otherwise, there is no way to keep warming from spiraling out of control. The only question is how quickly it's possible to act.
As Christiana Figueres, the executive secretary of the UN's climate apparatus, put it in her opening remarks on Monday, the task at hand is "ultimately fulfilling a long-term vision of climate neutrality," or the end of further manmade climate change.
Every country, the World Resources Institute said in a report issued as the talks began, "should assimilate this long-term goal as part of its national commitment. Industrialized countries should phase out greenhouse gases first, with staggered phase-outs for developing countries."
Country Pledges Key
Those nation-by-nation commitments, to be spelled out in detail in the next few months, are the key to the Lima talks.
The idea is to let every nation (or bloc, in the case of the European Union) decide for itself how much of a commitment it is willing to make to reduce greenhouse gases.
Much of the positive momentum as the talks began came from the high-profile decisions by Europe, the United States and China to commit to significant reductions in the decades ahead. Together, these three players make up about half of current annual greenhouse gas emissions.
These national contributions are supposed to be presented in full detail by March. A big task in Lima is to put together ground rules for making them easy to calibrate, to compare to each other and to verify—in a word, to make the promises credible.
It won't be easy. Every country may use its own metrics for calculating carbon emissions, energy efficiency, renewable energy use, credits for reforestation, and the like. Some European nations have laws in place to bind them to the EU's targets. But the U.S. goals depend on the Obama administration's executive end-run around Congress, or on new regulations under the Clean Air Act that have not yet been tested in the courts. And China's aspirations have not even been written yet into its next Five-Year Plan, let alone cast in stone. The rest of the world, too, will have its promises submitted to acid tests in the coming year.
As Elina Bardram, a climate official at the European Union, put it at a news conference in Peru: "We don't want to get to Paris and recognize that the targets collectively do not add up to what is needed in light of the science."
But the key problem plaguing these climate talks, like all the talks that came before, is that controlling emissions has never before been a collective endeavor.
Under the old Kyoto Protocol, only developed countries faced limits on emissions. Now everybody is being asked to join in. But many poor countries that are being hit hard by global warming did very little to contribute to 20th-century emissions and today's warming. How to crack the conundrum of fairness?
The answer is to elevate adaptation and financial aid to the same status as cutting emissions. As Figueres urged: to "consolidate progress on adaptation to achieve political parity with mitigation, given the urgency of both," and to "enhance the delivery of finance, in particular to the most vulnerable."
So poorer nations are demanding that each rich country contributes not just its own emissions reductions, but also financial assistance to help developing nations adapt to unavoidable climate change. And they want both commitments—to mitigation and finance—to be equally binding.
This could guarantee rich nations' assistance to poorer ones in reforestation and other emissions offsets, along with bolstering their defenses against global warming. It might even mean compensation for the global warming damages they've already suffered, although rich nations are loath to accept that idea, broached last year in the Warsaw climate talks.
But in Lima, the poor nations are well placed to play the adaptation and finance cards. If they are not satisfied, the march toward Paris could easily peter out.
Naming and Shaming
Not all of these issues are likely to be untangled this month. The question of how to make the treaty legally binding, Bardram of the EU said, is "such a crunch-time issue that it is difficult to see it being resolved here in Lima."
But as more and more countries make commitments in the months ahead, negotiators expect that a process of "naming and shaming" the laggards will ensue, perhaps putting pressure on all to raise their ambitions.
The blame game has already begun. On Monday, Climate Action Network International, a consortium of green groups, called out Australia, Belgium, Ireland and Austria for being the only developed countries that have not made pledges to the Green Climate Fund, a mechanism to finance climate action in poorer nations. And a new paper by the Harvard Project on Climate Negotiations, taking various countries' economic circumstances into consideration while assessing the fairness of their climate commitments, cited Moldova, Singapore and Turkey as three countries that are falling short. Nations as different as Indonesia and Norway are shouldering more than their fair share of the burden, it found; and the United States and China, in their recent pledges, are very close to the mark when it comes to fairness.
The point of putting pressure on stragglers is to raise ambition all around.
One way the Lima negotiators will try to do this is to devise a system of reviewing and revising the commitments made by each country, perhaps every five years or so.
As Figueres put it, "We must stimulate ever-increasing action on the part of all stakeholders to scale up the scope and accelerate the solutions that move us all forward, faster."
Not just faster—sooner, too. If a Paris treaty is delivered in 2015, it would not enter into force until 2020, and its first deadlines might not come until 2025 or even 2030. That's too late, if the world is indeed to zero out its carbon emissions by mid- to-late century.
So the talks in Lima will also try to stimulate rapid action in the years from 2015 to 2020. Any reduction in emissions that can be achieved that early will buy precious time for the struggle that lies ahead.
Anyone who expects a neat picture to emerge in the next two weeks will be disappointed. The negotiators are not painting a still life, but a moving train.
"It's not going to be perfect," Todd Stern, the top U.S. negotiator, told reporters in Washington. "But it's a strong start that would get better and better."