Two years ago Alfred Brownell was forced to flee Liberia after a successful campaign against a foreign palm oil plantation led to death threats and intimidation. Today, he hopes to return after being named one of this year’s winners of the Goldman environmental prize.

Like several other recipients of the 2019 award, which will be presented at a ceremony on Monday in San Francisco, the Liberian lawyer risked life and liberty to defend people and wildlife in a region of the world that was until recently remote, but is now encroached upon by powerful business interests.

Brownell led a campaign to halt clear-cutting of tropical forests after the Liberian government signed concessions with the palm oil company Golden Veroleum. Under the deal, the company were given a 65-year lease on 220,000 hectares (543,600 acres) in Sinoe County, including land used by forest communities. Golden Veroleum is owned by the US-based Verdant Fund LP, whose sole investor is the Singapore-listed Golden Agri-Resources.

The lawyer and his colleagues collected information from indigenous residents about the destruction of homes, sacred sites, warriors’ graves and the forest. He founded the NGO Green Advocates.

Armed with a file full of malpractice complaints, Brownell persuaded the global certification organisation Roundtable on Sustainable Palm Oil to place a stop work order on the company. This froze forest clearance, protecting 207,800 hectares (94%) of the leased land.

Success made him powerful enemies. Brownell said government officials called him an enemy of the state and accused him of preventing investment in the country. He came under surveillance, his office was burgled, colleagues were assaulted and police raided his home.

One confrontation almost resulted in death. In 2016, his vehicle was stopped by private security guards on the way to visit a palm oil plantation. When they discovered Brownell was inside, the situation became violent.

“They threatened to cut off my head, to eat my heart and drink out of my skull. They began a war dance around the car. They were drinking and said they would cannibalise me,” he told the Guardian. He was saved by the chief of the local village, who took a beating for his intervention.

In October 2016, Brownell and his family sought refuge in the US, where he became a distinguished scholar in residence at Northeastern University. The Goldman prize – which has been awarded to six people each year since 1990, one on each continent – has given him optimism that he may be able to return to his home country. “I hope this award will help change the minds of people in Liberia so we find more allies to speak to the government and the company. We need to find a way to engage with them so I can go home,” he said.

Brownell is not the only winner to suffer harassment for defending the land and environment. This year’s South American recipient, Alberto Curamil, an indigenous Mapuche, was arrested last August, two years after he successfully campaigned against the construction of two hydroelectric projects on the Cautín River in Chile. Still in jail, he will be represented at the ceremony by his daughter, Belen.

Ana Čolović-Lešoska, has been at the forefront of efforts to block hydro-electric dams in North Macedonia. Photograph: Robert Zahariev

In Europe, the prize has been given to Ana Čolović-Lešoska, a biologist who has been at the forefront of efforts to block hydropower dams in North Macedonia that threaten settlements and a national park that is one of the last remaining habitats of the endangered Balkan lynx. “I’ve received death threats and warnings that I will be imprisoned,” said the activist and founder of the NGO Eko-Svest. “Newspaper articles have suggested we are aiding foreign governments just because the rivers we are protecting run to Albania.”

These two cases highlight the growing tensions around hydropower in many parts of the world. This is particularly true in the Balkans, where projects have recently sparked protests in Serbia, North Macedonia and Georgia. Čolović-Lešoska said people have become more aware of the risks than in the past because the negative effects are becoming evident at the sites of older dams.

“Locals and environmental groups realise the impact now … these projects change the local climate. River beds dry up, habitats are lost and humidity and rainfall are affected. This is already evident and yet [the power companies] want to add more.”

The recent history of the Goldman prize is a testimony to the growing dangers of environmental activism. A 2015 winner, Berta Cáceres – a Honduran indigenous rights and anti-dam campaigner, was killed less than a year later. A 2005 recipient, Isidro Baldenegro López, was murdered in Mexico soon after winning. The 2017 recipient Rodrigue Katembo, a park ranger in the Virunga sanctuary for mountain gorillas in the Democratic Republic of the Congo, lost six of his colleagues in a massacre by militia groups.

Linda Garcia organised opposition to a massive proposed oil export terminal in her home town. Photograph: Ashley Kaplan

Other winners this year lobbied on behalf of nature to prevent harmful infrastructure plans and secure protected areas. In the US, Linda Garcia helped to block plans for the country’s biggest oil terminal in Vancouver, Washington, which safeguarded the Columbia River Gorge from potential spills from the facility.

Bayarjargal Agvaantseren persuaded the Mongolian government to cancel mining licences inside a nature reserve.

In Asia, the winner was Bayarjargal Agvaantseren, who persuaded the Mongolian government to cancel 37 mining licenses inside the 728,500-hectare Tost Tosonbumba nature reserve in the southern Gobi desert, which gave breathing space for snow leopards and other vulnerable species. In the island nations category, Jacqueline Evans was selected for her campaign to ban large-scale commercial fishing and seabed mining around the Cook Islands. This led to legislation in 2017 to sustainably manage all 763,000 sq miles of the country’s ocean territory.

Jacqueline Evans campaigned to ban large-scale commercial fishing and seabed mining around the Cook Islands.

Winners hope the awards will draw attention to their causes and prompt people in other countries to reflect on a global economic system predicated on endless growth and exploitation of nature and people.

Brownell called on investors like Blackrock and food multinationals like Nestlé to put money directly into community production rather than outside firms which come in with no knowledge of the local environment and culture. He said individual consumers also had a part to play.

“We all have responsibility,” he said. “When you walk in a grocery store, look at whether the ingredients include palm oil and think about the destruction that brings to other places and people.”