Article updated at 6:15 p.m. EDT.
BONN, Germany -- Almost everything about a new U.N. climate change accord expected to be adopted in Paris six months from now is still unresolved.
That's not a huge surprise, given that the challenge ahead of delegates from 194 countries is to design a deal that holds all of their governments accountable for fighting climate change.
Furthermore, officials say, the past two weeks of discussions that ended here yesterday were never supposed to delve into the thorniest political issues. As delegates headed for the doors of a shiny new convention center now housing their midyear discussions, many said they felt satisfied that their opinions on various issues had been heard. Trust was restored to a contentious process, they said, and a negotiating text crammed with redundant views was streamlined and made ready for decisionmaking.
"This process has been known to run off the rails," said Elliot Diringer, executive vice president of the Center for Climate and Energy Solutions.
"It hasn't happened here," he said. "It's staying on track, and that's not always a given. That's a good indication at this stage."
Now, negotiators best known for battling over the placement of semicolons say they are finally ready to get down to business. But the slow pace of talks so far virtually ensures that the toughest items will be left for the final days of Paris. Here are five big ones to watch for:
The challenge of designing a fair deal for countries of different levels of wealth, development, past and future greenhouse gas emissions, and ability to withstand the impacts of rising temperatures is at the heart of every other fight in this debate.
The 1997 Kyoto Protocol created an architecture that lumped countries into one of two categories, or "annexes": industrialized and developing. Under it, the rich took legal responsibilities for cutting carbon, while the poor cut emissions voluntarily. The Paris deal is aimed at recognizing that the 20-year-old economic data that cast countries like China, Singapore and Qatar as developing nations no longer holds true in 2015. The problem is, no one has yet come up with a new system for carving up responsibility.
Several negotiators are now saying that the Paris agreement might deal with the issue by ignoring it. The annexes will likely live on, because getting rid of them or even updating them to create new categories would spark a fight no one seems to want. But the categories, many said, will lose their power to strictly define who does what.
"I think what we're all talking about is a way to make sure those annexes do not remain the sole determinant of who has obligations under the agreement," New Zealand's lead negotiator, Ambassador Jo Tyndall, said in Washington, D.C., recently.
As countries put forward emissions targets reflecting their own national capabilities, she said, the Paris deal will start to naturally reflect countries' differences in wealth and capabilities "without making the annexes the driving force of who has to do what in the agreement."
Chinese negotiator Gao Feng agreed.
"The annexes will remain," Gao said, and pointed to the climate agreement between the United States and China that put an emphasis on countries' national capabilities guiding their actions.
"It's a very useful kind of reference, if you like, and we can also continue to use this sentence of course in Paris," he said.
Who has it? Who gets it? Where does it come from? And when will it materialize?
Cash is key to this climate deal, which will ask many countries too poor to act on their own to eschew the coal and oil that helped industrialize the United States and Europe and turn to still-expensive renewables. At the same time, vulnerable countries like Bangladesh and Vanuatu need assistance to protect their lands from rising sea levels, droughts and storms not of their making as well as grapple with the suffering they already face from extreme weather events.
A central issue in Paris will be the $100 billion that wealthy countries vowed to mobilize annually by 2020 from public and private sources. Even though Group of Seven leaders this week reaffirmed their commitment to delivering on the promise, they divulged no details about from where and how it will be delivered.
The G-7 did launch a major new insurance scheme to protect vulnerable countries. But activists say they remain suspicious that the insurance program -- which now has only funding from Germany -- will be the rich polluters' only offer for protecting those who can't adapt to climate change.
The anti-poverty group Oxfam estimates that there is an annual funding gap of $80 billion, with just a fraction of aid right now going to help poor countries adapt. Poor countries say nailing down assurances about when they will see the promised money will be key. Meanwhile, a related fight is playing out over whether countries -- rich ones, in particular -- should be held legally accountable to provide the dollars.
"Developed countries are playing their cards pretty close to the chest," said Jaco du Toit, a climate change officer with WWF South Africa.
"Getting into an agreement in Paris without clarity on finance would be very difficult, if not impossible," du Toit warned.
3. Pre-2020 action
The carbon cuts in the Paris deal won't go into effect until 2020, and that's too late for vulnerable countries. Without more work now, they say, there will be no chance of keeping global average temperatures from zooming past 2 degrees Celsius over preindustrial levels.
They are pushing a measure in the negotiations that would call on countries to both beef up their existing pledges and bolster work happening in other areas, like the ratcheting down of non-CO2 greenhouse gases like soot and methane.
Diplomats said there actually was progress in this area made in Bonn, with all the large blocs of countries submitting proposals for how to close the so-called emissions gap. All of them said a decision on the issue should be part of the Paris deal.
4. Cycles of commitments
This is one of those typically jargony U.N. phrases that masks something incredibly important: Is the Paris deal perpetual?
The Paris agreement will include promises from countries to cut emissions after 2020. Some go out to 2025, like the United States, which is pledging to slash emissions 26 to 28 percent 2005 levels by that year. Others go out to 2030, like China, which says it will peak emissions by that time.
Some, like the United States, want to see countries' targets reviewed and scaled up every five years. That means come the end of this decade, those that made a 2025 pledge would make a new and improved one taking it out to 2030.
Others, like the European Union, which set a 2030 target and could have a difficult time internally coming up with new goals every five years, are against synchronizing commitments. But an equally big problem is China, which activists and diplomats say so far has been trying to block the entire discussion.
"They're not happy about a review," said WWF's du Toit of China. "They don't like a situation where others are going to investigate their pledge."
5. Will it be the Paris Treaty? Protocol? Charter?
It turns out, there's not much in a name, at least legally. So says Arizona State University professor Dan Bodansky, who convened a group of negotiators with C2ES last week to discuss what the legal nature of the Paris deal might look like.
Bodansky points out that the title is "legally irrelevant" and has nothing to do with how binding the measures inside it will be.
"From a legal perspective, you can call it an agreement, a treaty, a protocol, the 16th chapter. It doesn't matter," agreed Switzerland Ambassador Franz Perrez. "From a legal perspective, we can be relaxed about that."
That's about all diplomats can be relaxed about, though. The legal nature of the Paris deal is all-consuming for the United States, whose leaders have flatly told their European counterparts that it cannot enter into an internationally legally binding treaty -- the reason being, of course, that the GOP-led Congress will undoubtedly shoot it down, creating the second situation in the past two decades in which a liberal American president signs a climate deal but the Senate refuses ratification.
Europeans and others say they are acutely aware of the bind President Obama is in when it comes to a climate deal.
"I think we all recognize that's part of the challenge, and I think we are all desperate between now and Paris to resolve it," said Jake Werksman, an adviser to the European Commission's climate team. But he and others argued that a deal must be legally binding to have any teeth.
"For us, it represents the highest form of political will," he said. "A legally binding agreement is a guarantee that a country's commitment will survive changes in administration. ... It doesn't mean they can't withdraw, but it does bind the country as a whole."
Countries are trying to find a "hybrid" solution, but for the United States, the real question will be whether it will be bound under the Vienna Convention on Treaties to reach its carbon-cutting goals. To be sure, others like Diringer noted, the United States is in the spotlight, but countries like China and India are also not keen on being bound under U.N. laws, either.
For now, at least, Europe, small island nations and other vulnerable nations are holding firm for a full-blown treaty.
If there is a compromise to be found, former U.N. climate chief Michael Zammit Cutajar said, "I don't see it yet."