(CNN)This week, governments have gathered in Katowice, Poland, for COP24 -- the annual UN climate change conference.
It's been dubbed "Paris 2.0" and "the most important COP since the Paris Agreement," and many believe that what happens there over the remaining week is crucial to the fight against climate change.
What is the Paris Agreement?
In 2015, COP21 led to the landmark Paris Agreement, where almost 200 countries committed to keeping global warming well below 2 degrees Celsius above pre-industrial levels and, if possible, below 1.5 degrees.
The Paris Agreement is due to come into effect in 2020, and this year's COP (Conference of Parties) has the crucial task of getting countries to adopt a "Work Program" or "Rulebook" with the details needed to implement the Paris commitments.
2018 is the deadline for the rulebook to be adopted. Any delay could slow down the implementation of the Agreement.
What's at stake?
In October, a report from the UN Intergovernmental Panel on Climate Change (IPCC), said the planet will reach 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels by as early as 2030, precipitating the risk of extreme drought, wildfires, floods and food shortages for hundreds of millions of people.
Dramatic reductions in global carbon emissions would be needed to avoid that.
What will be covered in the Paris Rulebook?
Under the Paris Agreement, each country produces its own climate action pledges, called Nationally Determined Contributions (NDCs). Part of the Rulebook will involve finalizing details of how countries should format and report on their NDCs, so others can monitor their progress.
Michał Kurtyka, President of COP and Secretary of State in the Ministry of Environment, told CNN. "The Paris work program will give us rules for the coming years for global climate policy: what nationally determined contributions mean, how countries contribute, how they're being accounted for, how they are implemented, and what information is shared."
Other key negotiations
Also up for discussion at COP24 is climate financing. In 2009, wealthy countries agreed to provide $100bn a year in climate finance to developing countries by 2020.
"In 2025 the countries will set a new collective finance target," explains Steffen Kallbekken, research director at The Center for International Climate Research, based in Norway. "In Katowice this year they're discussing the process for negotiating and agreeing that target."
Others hope to see countries at COP24 show they will adopt more ambitious climate pledges when NDCs are updated in 2020.
"We need to see in the outcomes here that governments will commit to reviewing their targets," said Lou Leonard, WWF senior vice president for climate change and energy. "Then, they can spend the next year working within their national context to develop their new targets, so in 2020 they can put those new targets on the table."
Potential sticking points
When it comes to rules around the NDCs, one key issue is "differentiation" -- essentially, the idea that developing countries should be subject to less stringent rules around reporting on NDCs than developed nations.
China, representing a group called the Like-Minded Developing Countries, which includes India, Saudi Arabia, Malaysia and Indonesia, among others, is pushing for differentiation, according to Kallbekken, who has been monitoring negotiations from Katowice.
"Essentially, it's a two-tier system at the least ensuring that developing countries don't have to take on obligations that are too demanding for them to meet," he says. "Rich countries insist on one common rulebook, that all rules apply to all, with some concessions."
Leaders and negotiators from almost 200 nations listen to speeches during the opening of the COP24 on December 3.
Another key issue is whether NDCs must include mitigation measures -- that is, actions to reduce carbon emissions -- or if it's enough for them to include actions like adaptation (preparing for the damaging effects of climate change).
Finance is another potential stumbling block.
"The issue is that developing countries want assurances from developed countries on what to expect over a two-year cycle -- what finance is upcoming, and what the priorities are, whether it's mitigation or adaption," says Kallbekken.
Developed countries are reluctant to give this longer-term information, saying they are constrained by their annual budget cycle, according to Kallbekken.
Adaptation will also be on the table.
"There are going to be a lot of discussions about the issue of adaptation," said Kurtyka, ahead of the talks.
"Not every country has the same challenge of reducing emissions -- many countries are trying to adapt to climate change that's already happening, already impacting their society and economies. So we must work out a balanced outcome in Katowice between mitigation, adaption and finance in order to accommodate all these points of view."
What progress has been made?
The first week of COP meetings is traditionally about technical talks. In Katowice, negotiators have been working to produce a streamlined text for the Rulebook, so there are only a few clear options to be negotiated by the politicians who will arrive next week.
"So far, negotiators have resolved minor disagreements and it's clear what the options are, but there's still lots of work to do next week," said Kallbekken.
While some heads of state have been in attendance, those from the biggest countries, and biggest carbon emitters, have yet made an appearance. If they do show up, that could help smooth negotiations, according to Kallbekken.
"The professional negotiators in the first week have limited mandates, they can only yield so much in the negotiations," he said. "The ministers who arrive in the second week have quite a bit more to give, and heads of state have even more flexibility in negotiations.
"If more world leaders were present it probably would have been easier to achieve an ambitious outcome."
Although he is hopeful that the talks will be successful, Kallbekken says he's not ruling out that a rulebook won't be finalized, and that negotiations will have to continue next year.
That would be a grave outcome, according to Kurtyka. At the opening ceremony on Monday, he told attendees, "Without success in Katowice there is no success of Paris."
