The world is gearing up for COP27, the United Nations climate summit that starts Sunday. 

Held in Sharm el-Sheik, Egypt, the summit is expected to draw world leaders including President Biden, new British Prime Minister Rishi Sunak and new Italian Prime Minister Giorgia Meloni, along with representatives of scores of other countries.

Experts say it comes at a critical time in the fight against climate change.

Here are four key issues to watch at COP27: 

Will the global energy crisis eclipse other problems?

A combination of Russia’s invasion of Ukraine, inflation and general pandemic recovery have sent global energy markets into a tailspin, potentially overshadowing efforts to reduce reliance on fossil fuels. 

Europe and the U.S. have sought to reduce their reliance on Russian fuels in the wake of the invasion. But Russia was a major supplier of Europe’s natural gas, meaning some countries have had to take drastic measures in order to ensure that their constituents can keep the lights on. 

Germany, for example, over the summer reactivated previously out-of-commission coal plants. 

Other nations, such as the U.S., have sought to ramp up their natural gas exports to help European allies, even if that means more planet-warming fossil fuels. The U.S. has also called on oil producers to drill more in the wake of high gasoline prices. 

On the other hand, countries that have struggled to replace Russian fuel have also looked to clean energy. Earlier this year, the European Union said it would try to cut its reliance on Russian gas by two-third and that it would pursue more rooftop solar, energy-efficient heat pumps and faster approvals for renewable energy projects. 

A recent report from the International Energy Agency found that the Ukrainian invasion caused some structural changes that may accelerate the transition to carbon-free energy sources. 

Nathan Hultman, who formerly worked on international climate issues for the Biden administration, also pointed to the potential for green energy technologies to help with energy security challenges.

“Thinking about that is possible because it’s not only utilizing the conventional, old technologies that were built previously and maybe could be relied on as a little bit of a temporary bridge, but also the fact that we have good, new clean technologies that we can begin to deploy,” said Hultman, who now directs the University of Maryland’s Center for Global Sustainability, specifically discussing Europe. 

Asked about places such as the U.S., where Biden recently called on corporations to pump more oil, a major contributor to climate change, Hultman said the country needs to be able to “walk and chew gum at the same time” — that is, have both short-term solutions to problems and also medium- and long-term climate policies. 

Will wealthy countries agree to pay climate reparations?

Wealthy nations are major donors to developing nations, including in areas such as resilience to climate change. But many developing nations argue that richer ones have already used more than their fair share of fossil fuels in order to reach where they are today. 

And, they say, rich countries have caused significant harm to developing countries through their use of the planet-warming fuels. They want compensation for the “loss and damage” that they have suffered. 

Madeleine Diouf Sarr, chair of the U.N.’s Least Developed Countries group, told The Associated Press that it would like to see “an agreement to establish a dedicated financial facility” that pays countries that are already experiencing the worst climate impacts. 

In years past, many rich nations have resisted that idea. 

However, U.S. special climate envoy John Kerry recently told reporters that Washington supports a loss and damage dialogue, though he rejected the term “reparations.”

“We have always said that it is imperative for the developed world to help the developing world to deal with the impacts of climate,” Kerry said.

“We’re very supportive of addressing loss and damage in the context of the … COPs,” he added, referring to the global climate conferences.

But while the issue may be discussed, some are skeptical that a specific financing mechanism will get set up. 

“My view is the landing zone will be around agreeing an agenda item, but I don’t think that the conditions are there yet to actually agree to have a new finance facility,” Kaveh Guilanpour, vice president for international strategies at the Center for Climate and Energy Solutions, recently told reporters. “Important questions haven’t been answered, such as ‘What value add would such a facility have over existing facilities?’”

Will China cooperate despite tensions with the U.S.? 

At last year’s global climate summit, the U.S. and China — the world’s largest emitters of greenhouse gases — agreed to cooperate on climate change issues. 

But since then, relations between the two have soured. After Speaker Nancy Pelosi (D-Calif.) became the highest-ranking U.S. official in decades to visit Taiwan, China said that it would halt its climate cooperation with the U.S.

It’s not clear what this means for Beijing’s climate commitments. Previously, China had said it would peak its climate-warming emissions by 2030 and achieve net-zero emissions by 2060.

But some say it needs to be even more ambitious, as other world powers are aiming to decrease their emissions between now and 2030. 

Kerry said during a Council on Foreign Relations (CFR) event that he and his Chinese counterpart have “sent each other a few messages about trying to figure out how we might be able to resume,” but that they currently are not resuming talks. 

He added that China should work to put forward strong climate action because it’s not just an issue between it and the U.S. — planetary warming is expected to have disastrous impacts across the world. 

“The key is that this is not a bilateral issue and that we need to get back to the table because the world depends on it,” he said. 

How will climate promises be implemented?

After several nations upped their climate change ambitions at last year’s COP26 in Scotland, this year may focus more on making those promises into reality.

Studies and other analyses have shown that while many countries and companies have made promises to cut their emissions, few have the actual policies in place to achieve them. 

“This year has to be implementation-plus. The test this year is: Will countries put commitment into action?” Kerry asked at the CFR event. 

Hultman said that while countries have made various commitments, the conference provides a chance for each of them to assess and talk about how those promises will be met. 

“There is a very good and important question … of — it’s one thing to just make a goal. It’s another thing to deliver on the goal. … Both of these then become fair game to talk about at these international meetings,” he said. 

He said that in addition to implementation of individual country goals, the world may also want to get a better idea of collective goals — such as the global methane pledge, which seeks to cut worldwide emissions of the planet-warming gas by 30 percent. 

Countries supporting that goal, he added, have to “put some actual policies or strategies in place that countries or subnational entities … will be doing to actually understand better, improve inventories, reduce emissions and what-have-you to enable that 30 percent collective goal to be reached.”

Corporations, too, may take the opportunity to outline how they will meet their ambitions. 

“I do think that we are going to see more information on what exactly companies are doing to hit those goals, what their timelines are for those goals, and I would expect … that we would see certain things disappear from how those goals are stated and reiterated,” said Ken Markowitz, who advises companies on climate and environmental issues with the law firm Akin Gump Strauss Hauer & Feld. 

Many activists have so far been critical of corporate climate pledges, accusing companies of “greenwashing” to make their records appear cleaner than they actually are.