The scientific expedition to collect glacial ice from Earth’s highest tropical mountain had, so far, gone smoothly. The weather had been perfect. The machines had worked without failure. No one had gotten sick, and though avalanches had forced the team to find a new route up the mountain, they had done so relatively quickly.

It was late July 2019, and the trip, to the mountain Huascarán in the Cordilleras Blanca region of rural Peru, was shaping up to be one of the most successful this team had ever attempted.

They had drilled 471 meters of glacial ice cores under clear skies. The cores, long columns of ice that had been frozen since the last Ice Age, were clear and clean, and waiting to be carried off the mountain to a freezer truck, to Lima, to an airplane that would fly them back to the United States and to their eventual home at The Ohio State University. There, they would stay, carefully cataloged in a polar-temperature freezer, until their contents could be analyzed, offering up new clues and histories of the Earth’s climate.

It all changed on one afternoon.

An angry mob from the village of Musho, a small community at the western base of Huascarán, stood at the researchers’ hut, shouting in a mix of Spanish and their indigenous language.

One of the scientists, a postdoctoral researcher at The Ohio State University Byrd Polar and Climate Research Center who was born in Mexico, listened carefully, then translated for the group.

“They think we are here to mine the mountain for gold,” the scientist, Roxana Sierra-Hernandez, told her colleagues. “They think the government has sold the mountain to the Americans.”

Lonnie Thompson, a distinguished university professor at Ohio State who has led some 80 scientific expeditions in search of glacial ice, rubbed his forehead.

It was not the first time that he would need to negotiate with a local community in order to do his research.

But he had spent the last year working with the Peruvian government in the hopes of avoiding this type of complication. The ice cores his team had drilled would be, he believed, some of the most complete records of Earth’s air quality and climate going back some 20,000 years.

The urgent need for the work was obvious: From the peak of Huascarán, 22,000 feet above sea level, his team had seen hazy smoke that seemed to be coming from the direction of the Amazon.

He knew the cores would give scientists greater insights into Earth’s warming atmosphere. But first, he had to get them off the mountain.

Thompson also knew that something larger was at play, something that spoke to the relationship the people in this rural community had with the federal government, about the history of this mountain and what it had been used for and who had been given access to its resources. And though it might not have had anything to do with his team or their work, it didn’t matter: In order to get the ice safely off the mountain – itself a challenge – he needed to make sure these villagers understood the researchers’ purpose.

“They were upset for a number of reasons,” Thompson said in an interview after the team returned to Columbus. “And in the beginning, there really was no discussion. They just wanted us off the mountain, and they wanted us off immediately.”

Thompson understood why they were upset. Huascarán, the highest peak in Peru and the highest mountain in the tropics, is also part of the Huascarán Peruvian national park. It is home to the spectacled bear and the Andean condor, two species whose populations are declining. The Peruvian government had banned mining on the mountain, but illegal mining continued despite the ban, contaminating local water supplies and endangering the ecosystem. And, Thompson said, the local communities used to climb the mountain to collect ice – something the Peruvian government had also made illegal. Yet a team of foreign scientists had been granted permission to not only take ice off the mountain, but out of Peru.

To make matters worse, the president of Peru had traveled to Huascarán to see the scientists before their journey – and had not stopped in Musho to meet with the villagers.

“It was a difficult thing, but so much of this was not about the science or about our research team,” said Paolo Gabrielli, a research scientist at the Byrd Polar and Climate Research Center who was part of this team.

The team included Wilmer Sánchez Rodriguez, a Peruvian scientist who is indigenous. They hired local mountaineers to help them climb Huascarán and navigate its avalanches and crevasses. Part of the expedition’s budget included money to buy a few chest freezers and a generator to keep the ice cores frozen at a hostel run by a group of Catholic priests partway up the mountain, and the team had agreed to leave that equipment behind for the priests to use. In choosing the scientists who would be a part of this fieldwork, Thompson had assessed not only physical fitness and the ability to deal with difficult weather conditions and lower oxygen levels at high altitude, but also communication skills. Sierra-Hernandez, he said, was a natural fit: In addition to being a strong scientist, she spoke fluent Spanish.

The villagers, at first, gave the researchers 12 hours to leave – an impossible deadline, if the team had any hope of bringing the ice cores and their equipment off the mountain, too.

In 2010, on an expedition to a glacier in Papua (New Guinea), Thompson and his team were confronted by four different tribes. The tribes, in the past, had fought one another. But all worshipped the mountain, and they came together to defend it against what they thought was an attack by the researchers.

“The thing to know is that, in many rural areas, be it Bolivia, Peru or Papua, glaciers are gods,” Thompson says. “They are holy places. And as scientists, we need to operate with respect for those cultures.”

In Papua, the tribes believed that Thompson and his team were, by removing ice from the mountaintop glacier, removing their god’s brain. They had seen the ice cap growing smaller and smaller, and were fearful about what it meant for their god.

“I have always believed that the best way to navigate conflict is to have face-to-face conversations,” Thompson said. “I do not in any way want to disrespect these people – their beliefs and ways of life are valid. We are simply trying to maintain a record of these ice cores, something that will be preserved after the glaciers melt. Because the glaciers will melt. In two to three years, that glacier in New Guinea will be gone.”

In New Guinea, the tribes ultimately voted to allow Thompson and his team to take the ice cores back to Columbus.

“They came to believe what we told them – that, while there was no stopping the ice from melting, that we would keep these parts of the ice safe,” Thompson said.

In Huascarán, the scientists tried talking with the villagers as he had talked with the tribes in New Guinea. They eventually relented – somewhat – and told the team to be off the mountain in two days.

It still wasn’t enough time, but the scientists wanted to be respectful. So, they left the ice cores and their drilling equipment on the mountain, and they headed down to a nearby city, in the hopes of working out a compromise.

“We didn’t feel that we were in danger, but we were aware that tensions were high,” Gabrielli said. “And we wanted the expedition to be successful, not just in getting the cores off the mountain, but in the way we interacted with the Musho people.”

The mayor of Musho reached out to Thompson, and the two agreed to meet at a café in a city about an hour away from the mountain. Thompson explained that, by leaving the equipment on the mountain, they were in effect polluting it. And, he said, the goal of the expedition was to collect ice cores so that humankind might have a greater understanding of how climate change is affecting the Huascarán glacier. Leaving them behind would do nothing to educate people, in Peru and around the world, about the mountain.

The mayor agreed, and asked Thompson and the rest of the scientists to come to a public meeting in the village so that the people could ask their own questions.

At first, Thompson was hesitant – the villagers had been so angry, and he didn’t want to put his team in danger. The Peruvian government had assigned Thompson and his team a military adviser, who told them he could not recommend they to go to the village because of the danger.

“So we talked about it,” Thompson said. “And all nine of us agreed that we should go.”

It took some convincing, but the military adviser agreed. And on a Sunday morning in August, the team of scientists – a multinational group composed of people from the U.S., Mexico, Italy, Peru, France and Russia – headed to Musho to try and salvage the work.

In video from that meeting, held in Musho’s public square, it is clear that the community members are angry. Many stand with crossed arms, some speak in raised voices. One villager holds up a dead fish, accusing the researchers of poisoning the water. Thompson, through Sierra-Hernandez, who translated, explains the scientists’ mission, then listens as the villagers call out their concerns. Ultimately, the villagers agreed that the scientists could take the cores and their equipment. But, the villagers said, they wanted the team gone in five days.

It would have to work. The Peruvian government supplied a helicopter, which carried most of the ice cores and equipment to the base of Huascarán, where freezer trucks were waiting. The cores arrived safely in Columbus on Aug. 24, and are now stored in the Byrd Polar and Climate Research Center’s frozen vault. Parts of the cores will be preserved indefinitely, for future generations of scientists to analyze. And parts will be studied in the coming months and years, with the hope of understanding more about our planet.

For Thompson and the rest of the team, it was a reminder that fieldwork is often about more than just science.

“If you’re working in a remote area, and an area where indigenous people have lived for thousands of years, you are the outsider,” he said. “And you don’t judge what they believe or don’t believe. Your job is to try the best you can to get them to understand what you’re doing and why you’re doing it – if at all possible, to get them to help you. But you have to be willing to go and stand in front of them and tell them where you’re coming from. And you have to understand how important that little piece of land is to them and their family.”