At the foot of the Andes, a Canadian firm has plans for one of the country's biggest copper mines, but many say the carbon-rich forests and clean rivers are too high a price to pay

As the sun sets over the Colombian Amazon, construction worker Pablo Portillo observes the canopy. Titi monkeys swing in the treetops as the Mocoa River roars nearby. For four years, he and his family have lived quietly in this biodiverse "gateway to the Amazon", where the Andes descend into the rainforest, home to mountain tapirs, spectacled bears and vital rivers.

But Portillo, 46, fears this peaceful landscape is at risk. Canadian company Copper Giant Resources has been exploring nearby mountains with a view to opening one of Colombia's largest copper mines. Beneath Mocoa lie an estimated 2m tonnes of copper, a transition metal vital for clean energy in wind turbines and batteries.

Copper Giant holds four permits for the exploration and possible development of copper and molybdenum, and has expanded its land in Mocoa to more than 136,000 hectares (337,000 acres) by acquiring Grupo Minera Sol in June, a Colombian company that holds 12 mining applications covering 53,474 hectares (132,000 acres).

"We're surrounded by nature and the air you breathe is pure," says Portillo. "What we fear is that all of this would be destroyed, completely finished."

As the world strives toward a carbon-free future, demand for copper has soared. According to the International Energy Agency (IEA) thinktank, copper prices reached a high of $10,800 (£8,000) a tonne last year, while demand is projected to grow by 30% by 2040.

Supplies have not kept pace, with the IEA predicting a 30% shortfall by 2035, and Colombia's leftwing president, Gustavo Petro, has prioritised securing minerals crucial to the energy transition, including copper. But critics say the push to extract copper in Mocoa risks undermining another of Petro's promises: preserving the Amazon.

Mocoa sits along the Cauca metallogenic belt, a stretch of the Andes known to be rich with minerals, and at the edge of the Amazon rainforest. Efforts to develop a mine in the area have long faced resistance from local people, who believe that such a project would cause irreversible damage to the fragile ecosystems and pollute the waters on which they rely.

In March, residents of Pueblo Viejo, near the exploration area, protested over a road to the site. What started as demands for Copper Giant to fix the road turned into a 47-day blockade, demanding that the government stop mining.

Since then, residents have established a "resistance camp" and barred company vehicles during working hours. Signs reading "water is more valuable than copper" and "land, water and life are non-negotiable" are on display. "We're speaking out because we want people to realise we can protect mountains and countryside before it's too late," Portillo says.

In May, CorpoAmazonia, the regional environmental authority, and the environment ministry reached a deal with protesters to review the viability of the mining project. By early June, the authority issued a resolution designating 93,000 hectares (230,000 acres), including land within the mining concessions, as an "area of ecological importance", where mining activities would be restricted. Although the resolution is non-binding, it has increased pressure on the national government.

"What we want to avoid is the displacement and extinction of flora and fauna species and also to avoid the contamination of water sources," says a CorpoAmazonia official, speaking anonymously as they were not authorised to comment publicly.

The official says the report notes the mining concession overlaps with the protective forest reserve of the upper Mocoa River basin, a conservation area that is home to more than 350 species of flora and fauna and serves as a critical water source for local communities. He also warned that the use of explosives and heavy metals in copper extraction endangers the integrity of the protected area and other fragile ecosystems, such as the water-generating páramos (tropical Andean wetland grassland ecosystems), that are located within the mining concessions.

Copper Giant says the project in Colombia is still in the early stages of exploration, a phase that could last another eight to 10 years, and that it is too early to determine the environmental impacts of copper mining in the area. "We don't even have a design for the mine yet," says Thyana Álvarez, Copper Giant country manager.

Álvarez adds that last year, the company requested that Colombia's National Mining Agency excluded the forest reserve areas from its mining concessions. "We are awaiting the new concession contracts with these removals," she says.

Still, the dispute in Mocoa has highlighted tensions within Petro's environmental agenda. In 2023, the president announced a shift away from oil and gas exploration and ordered the exploration of energy transition materials. That same year, his administration classified 17 minerals, copper among them, as "strategic" for their role in the country's energy transition.

"I have asked the energy minister to focus mining exploration on fundamental raw materials so that Colombia can become an enormous generator of clean energy," Petro said in 2023.

But critics have said the rush to extract minerals critical to the energy transition could come at the cost of the Amazon rainforest, considered a vital carbon sink essential for the fight against the climate emergency. About 40% of Colombia's territory is part of the Amazon region.

José Luis López, a researcher at the National University's Observatory of Environmental Conflict in Bogotá, says Colombia's climate crisis strategy would be more effective if it focused on "conserving biodiversity and halting forest degradation" rather than expanding mining.

In May, the environment minister, Lena Estrada, publicly addressed the protests in Mocoa, noting that the ministry is reviewing local calls for stricter protection. "They're asking for environmental zoning of those territories," she said. "We're going to review this possibility. We're going to make the province of Putumayo [where Mocoa is located], like all the other Amazonian provinces, protected areas."

The national mining agency did not respond to a request for comment.

In Pueblo Viejo, Portillo and others remain suspicious and continue to voice their opposition. They hold resistance camp meetings and have launched a campaign to create awareness among the surrounding communities about the impact a mine could have. Portillo says that he will continue until Copper Giant leaves their territory.

"We refuse," he says, "to be sacrificed for the energy transition."

Can Colombia embrace clean energy without damaging the Amazon?