Presidents and prime ministers have left town. Now the hard work starts, with diplomats hunkering down in a cavernous tent complex at the U.N. climate talks here for the next week and a half, trying to hammer out deals to cut planet-warming emissions.

More nations than ever are pledging to reduce emissions, move away from coal, eliminate deforestation and deliver money to help poor countries adapt. Environmental groups and poor nations are not as optimistic. They have seen promises come and go before.

Here are five take-aways from the early, frenetic days of the climate conference:

Holding a global conference in a pandemic is hard.

More than 39,000 people are registered for the summit. One problem: Capacity in the main venue is limited to 10,000 people because of COVID restrictions.

That has led to bottlenecks, long security lines and frustration, especially among civil society groups that were already angry that the U.N. had capped their presence inside the negotiating halls.

Everyone entering the venue, known as the “blue zone,” is asked to take a daily rapid coronavirus test. But for all the talk of strict controls, participants simply self-report their results. It is basically an honor system.

The United States ‘showed up.’

For nearly four years, the United States worked to undermine the progress of climate talks. Former President Donald Trump withdrew the United States from the Paris climate agreement and vowed to burn more, not less, gas, oil and coal.

President Joe Biden arrived in Glasgow and flipped the script. He promised to show the world that the United States is “leading by the power of our example.”

Asked about the leaders of other countries, particularly those of China and Russia, who did not attend, Biden said, “We showed up.”

But some pivotal leaders didn’t.

The absences of Presidents Xi Jinping of China, Vladimir Putin of Russia and Jair Bolsonaro of Brazil were notable.

Prime Minister Scott Morrison of Australia did show up — but with an emissions target that experts said falls far short of what is needed. Brazil pledged to end deforestation by 2028. Activists are skeptical that Bolsonaro will follow through.

Both Russia and China have targets that, experts say, are not enough to keep the planet on a relatively safe trajectory. Leaving Glasgow, Biden scolded Xi and Putin for not attending. Officials in Beijing hit back, noting Biden was unable to persuade his own party to vote for climate legislation necessary to meet the United States’ aggressive targets.

Sparring will not solve the climate crisis. And it remains unclear whether the two biggest emitters, China and the United States, can move past tensions over trade and human rights to work together.

Money was pledged, but will it flow?

Banks and other lenders said they had $130 trillion to finance projects that aim to get companies and countries to net-zero emissions. The number, more than five times the size of the U.S. economy, grabbed headlines.

Environmentalists quickly threw cold water on it, arguing that scant details were provided and that banks still invest hundreds of billions of dollars in fossil fuels each year.

The next target: Ending coal

Poland, Vietnam, Egypt, Chile and Morocco are among 18 countries that will pledge Thursday to phase out coal-fired generation and stop building new plants. The British hosts of the U.N. conference want to leave their mark by ensuring the end of coal “is in sight.”

Yet the issue is deeply contentious. At the start of the summit, the prime minister of Fiji, Frank Bainimarama, told Morrison of Australia that “coal has no place in this century.” Morrison has clearly said he will not discuss fossil fuel mandates or bans.

Expect more pushback in the coming days from Australia, as well as China, India and Russia, to any language formalizing a phaseout of coal in any final decision from the summit.