A woman dressed as a dugong, a rare marine mammal, beseeched passers-by to end the burning of fossil fuels. Protesters wiped away tears as they recited the names of Palestinians killed by Israel’s bombardment of Gaza.

And an exiled Emirati dissident joined a panel discussion about human rights via a shaky video connection, speaking out in support of political prisoners held less than 100 miles from the sprawling conference site.

Tens of thousands of people from around the world have descended on the Persian Gulf city-state of Dubai for the annual United Nations summit on climate change, bringing the rare spectacle of political mobilization to the United Arab Emirates, the authoritarian host.

Holding the talks, known as COP28, in a major oil-producing country whose budget is built on revenue from the fossil fuels that scientists say cause the bulk of global warming — spurred controversy in itself. But climate and human rights activists said that COP28 was also testing the limits of a state that effectively outlaws most forms of political action, including protests, typically an essential part of the summit.

To host the event, which began late last month, the Emirates, one of the wealthiest and most powerful countries in the Middle East, complied with U.N. rules that facilitate preapproved protests within part of the venue. That area, known as the “blue zone,” is walled-off and not subject to local laws.

Emirati officials also pledged to make COP28 one of the “most inclusive” editions of the climate meetings by expanding the participation of youths, women and Indigenous people.

Some participants said they were happy that people from parts of the “global South,” who might have struggled to obtain visas to attend a summit in Europe, could travel more easily to the Emirates. Indigenous people from Africa and the Americas have also been a visible presence, wearing face paint and feathered headdresses as they stroll through the site.

But climate activists said that even within the blue zone, this had been one of the most difficult years to stage protests. They also pointed out that protests were nearly impossible outside the zone, and that native Emiratis or foreign residents of Dubai could probably not join without risking repercussions.

In the Emirates, protests are effectively illegal, political parties and labor unions are prohibited, and news coverage is highly restricted.

“The fact that these very limited, contained actions are happening in the blue zone is dangerous, because it creates the impression that this is a rights-tolerating COP when it actually is not,” said Joey Shea, who researches the Emirates for Human Rights Watch.

For attendees familiar with the local political climate, COP28 has created the uncanny impression of a spaceship landing in the desert — temporarily disgorging riotous passengers before it prepares to suck them back up and depart — said James Lynch, a British human rights researcher.

Mr. Lynch was one of several people who was surprised to be able to attend COP28 after being barred from entering Dubai years ago. Using special visas for the summit, Human Rights Watch researchers have arrived in Dubai for the first time since 2013, as has a New York University professor barred from the Emirates in 2015 after researching the exploitation of migrant workers.

“It’s way more important that there are Emiratis who can speak freely here than me,” said Mr. Lynch, co-director of a group called FairSquare that investigates human rights abuses. “That’s the tragedy.”

Political freedoms have been limited in the Emirates since the nation’s founding in the 1970s. But the government cracked down broadly on dissent after the Arab Spring, when pro-democracy uprisings spread across the Middle East.

In 2011, more than 100 Emiratis submitted a petition calling for an elected Parliament with legislative powers. Soon after, the government carried out a number of arrests. Then, in 2013, the authorities held a mass trial for 94 people, accusing them of conspiring to overthrow the state. The crackdown reverberated through Emirati society, pushing even mildly dissenting opinions underground.

For some Emiratis, the part of COP28 that has felt most surreal is watching pro-Palestinian rallies. In a country where many citizens feel deeply for the Palestinian cause, the last march in solidarity was in 2009, and since the Arab Spring, the only public rallies have been nationalistic marches “to renew the pledge of loyalty to the ruler,” said Mira Al Hussein, an Emirati research fellow at the University of Edinburgh.

“It felt really good to have a protest, if one could describe it as such, in solidarity with Palestinians,” Ms. Hussein said. Still, she said, she was saddened that many talented Emiratis “will not get to shine, because activism has a negative connotation in our current political climate.”

Emirati officials sometimes argue that a tight grip is necessary to prevent extremism and maintain peace and safety in a place where foreigners from widely varying backgrounds make up 90 percent of the population. The Emirates provides greater social freedoms than some neighboring states.

Home to many nationalities “representing diverse ethnic and religious backgrounds,” the country is “steadfast in its commitment to and respect for human rights,” the government said in a statement to The Times.

But Mr. Lynch said that over the years the state’s control had grown subtler, with a reliance on sophisticated surveillance technology and digital monitoring.

“The heavy hand of repression here isn’t as obvious to the average person,” Mr. Lynch said.

One of the potentially riskiest events at COP28 was a discussion about human rights held on Wednesday. Hamad Al Shamsi, an exiled Emirati dissident who was sentenced in absentia during the mass trial of 94 people — and later designated a terrorist by the Emirates — joined via video connection to speak about the trial, saying that many of those convicted remain in detention after completing their sentences.

The government declined to comment on “individual cases.”

“It actually saddens me that I am unable to participate in an event that takes place in my own country,” Mr. Al Shamsi said.

On Friday, civil society groups said that U.N. officials were “policing” what they could say about the war in Gaza and where they could hold protests.

“Our experience at this COP, in this blue zone, has been way more difficult and restrictive than any other time,” said Tasneem Essop, executive director of Climate Action Network International, an advocacy organization.

Their complaints came on the eve of a larger day of protest scheduled for Saturday in the blue zone. One of the issues, Ms. Essop and other activists said, is whether they can use the slogan “Cease-fire now” in their chants and banners and whether they can denounce “occupation.”

U.N. rules prohibit singling out individual countries by name or flag, but it was unclear why calling for a cease-fire would violate rules.

The United Nations Framework Convention on Climate Change, which convenes the summit, said there was space for people to “assemble peacefully and make their voices heard on climate-related issues.”

The United Nations received 167 applications for political actions in the blue zone, and 88 of those occurred in the first week, a similar rate to last year’s summit, the organization said. A notable proportion of those were related to the Palestinians this year.

“As part of our commitment to delivering an inclusive COP, COP28 has dedicated spaces and platforms for all voices to be heard,” the Emirati COP28 presidency said in a statement.

But Harjeet Singh, head of global political strategy at Climate Action Network, said that holding the summit in politically restrictive countries for two years in a row — COP27 was in Egypt — has raised questions about the role the United Nations should play as a “custodian of our rights and freedoms.”

The summit should be held in a place “where civil society can freely participate,” he said.

After a rally supporting Palestinians in the blue zone last Sunday, Selma Bichbich, 22, an Algerian climate activist, said that holding COP28 in the Emirates had created a chilling effect for some participants.

Ms. Bichbich said it was essential for her to join the demonstration. Watching the war in Gaza unfold, she said, has filled her with so much anger that she was not sure she was even interested in “leading the future.”

“What do you expect, honestly, just to tolerate everything and address climate?” she asked, openly sobbing. “You think climate will distract us?”

Somini Sengupta contributed reporting.