The Colombian government has published a proposed law that will allow it to resume a controversial program of aerial fumigation of coca crops using glyphosate, a weed-killer thought to cause cancer in people exposed to it regularly and in high doses.

“The resumption of the spraying would increase the capacity of the Colombian state to confront drug trafficking in less time and in a more effective way,” said Colombia’s Ministry of Justice in a statement announcing the decree in late December.

The decree, similar in legal status to an executive order in the U.S., calls for a program of new crop-spraying flights, with national police oversight. The plans are in the final stage of their passage to law, and spraying is expected to begin “in the second half of this year,” said Ricardo Vargas, an expert in crop fumigation and coca at National University of Colombia.

The proposals by the Colombian president, Ivan Duque – after a five year hiatus in coca spraying – have been criticized by local government officials, environmentalists, drug policy experts and rural communities living under the proposed toxic flight paths.

The strategy will please U.S. President Donald Trump, who last year admonished his Colombian counterpart for failing to stem record coca crops. In a speech last year, Trump said Duque had “done nothing for us” on cocaine. Trump has also threatened to cut aid and de-certify Colombia, the most U.S.-friendly nation in Latin America, as an ally in the war against drugs if the nation did not do more.

U.S. embassy officials in Bogotá called the move “a critical step." “The US supports the efforts of the Colombian government to achieve our joint objective of halving coca cultivation and cocaine production by the end of 2023,” said an embassy statement. Last week, in what looks like a sweetener for Duque, U.S. officials announced a $5 billion rural aid program for Colombia, via the new U.S. International Development Finance Corporation.

Glyphosate is used as a weedkiller worldwide, albeit at lower concentrations than those generally deployed in Colombia. But U.S. courts have ruled that it has caused cancer in three cases. The German firm Bayer now owns Monsanto, which has sold the chemical in its Roundup line of weedkillers to millions of U.S. householders for decades. Bayer is now liable for hundreds of millions of dollars in damages.

In May 2019, an Oakland, CA, jury ordered agrochemical giant Monsanto to pay more than $2 billion to a husband and wife who contracted non-Hodgkins Lymphoma, a type of cancer, after using Roundup. A jury ruled that Roundup caused Alberta and Alva Pilliod to fall ill. Monsanto appealed, and the couple eventually settled for a joint $86 million in July 2019.

This was the third verdict against the company over the product. Dewayne Johnson, a former school groundskeeper with terminal cancer, won a $289 million victory in state court last year, and Edwin Hardeman, who used Roundup at home, was awarded $80 million.

Colombia already destroys coca crops using manual eradication, in which workers pull the plants up by the roots, and also with small-scale, targeted drone spraying of glyphosate.

But the world’s biggest cocaine producer suspended the aerial spraying of coca fields by U.S. contractors in 2015 after a study by the World Health Organization found that glyphosate is carcinogenic.

During those nearly 25 years, during U.S.-led anti-drug war action Plan Colombia, U.S. pilots and Colombian police sprayed glyphosate on 4,420,000 acres of Colombian territory, said Adam Isacson, of WOLA, the Washington Office on Latin America, a research and advocacy organization. The scale of the proposed new spraying campaign is yet to be decided.

In August 2018, Kevin Whitaker, who was then U.S. ambassador, told the Wall Street Journal that “seven or eight of the crop dusters that had worked the coca fields here remain in Colombia. I told embassy staff and the Colombians the same thing: We need to be ready for a restart.”

Cocaine production has grown despite hopes that the historic peace deal with Farc guerillas in 2016 would curtail it. As part of the peace deal, which put an end to the world’s longest-running civil conflict, the government pledged to help coca farmers move into legal agriculture. But that has not happened in most cases – and so the coca trade has flourished, with cocaine prices dropping, and purity rising to unprecedented levels across the U.S. and EU.

Up to 120 community leaders, some of whom had called for alternative investment in the demilitarized areas including coca alternatives, have been killed in Colombia this year in a wave of extrajudicial killings, according to research this week by human rights group, Frontline Defenders.

Vargas said communities have not had the help they needed to move away from the coca trade and now will take the brunt of the new spraying program. “Many social leaders, some of whom have been for promoting the substitution of coca, have been threatened or killed. The government is failing to offer physical security for them.

“Fumigations disrupt the poor stability of people living in these territories, pollute water, affect people's health, generate forced displacements and with them schools, or sources of income for parents, causing social upheaval. It affects forest and woodland, creating conflict and uncertainty for all communities.”

Colombia is today producing a huge volume of cocaine, with the UN reporting that 1,379 tons were produced in 2017 – up a third on 2016. The UNODC also says the area under coca cultivation in Colombia has tripled over the past five years, reaching 169,000 hectares (417,600 acres) at the end of 2018.

But experts have decried the return to aerial spraying before it has even begun.

“The resumption of aerial spraying is about as effective as shoveling water,” said Sanho Tree, director of the Drug Policy Project at the Institute for Policy Studies, a U.S. think tank. Tree says the cycle of rural poverty and coca-planting is exacerbated by spraying programs, and that investment in roads would be more effective.

“Coca farmers live in remote areas without access to the infrastructure necessary to get hundreds of kilos of food crops to market. A kilo of coca paste is easy to transport and sell,” said Tree. “When the state destroys their livelihood, they are forced into food insecurity and yet they must continue to feed their families. What’s the one crop they know how to grow, for which there are ready and willing buyers, and doesn’t require modern transportation infrastructure? Coca! Lather, rinse, repeat,” he said.

Vargas said spraying crops is 83 times less effective than state aid: “What is observed in Colombia is that in the medium and long-term aerial fumigation does not mean a reduction in supply,” he said. “On the contrary, according to a UNODC evaluation in Colombia, coca re-planting is 0.6 percent when a farmer receives voluntary crop substitution plans, but forced eradication prompts a replanting level of almost 50 percent.”

The new move could force coca farmers to plant in isolated national parks, where spraying of any kind will remain illegal. Coca monoculture and land clearance in these untouched areas causes devastating habitat loss; Colombia is one of the world’s most biologically diverse countries, and is home to 10 percent of the world's species.