There’s a struggle for law and order in many of the world’s tropical forests, and nature is losing.

Last week, I wrote about the major progress Colombia made in 2023, slashing deforestation rates by 49 percent in a single year. But this week, we learned the trend reversed significantly in the first quarter of this year. Preliminary figures show tree loss was up 40 percent since the start of the year, Colombia’s Minister of Environment, Susana Muhamad, told reporters on Monday.

Why have things changed so quickly? Mostly because a single armed group controls much of Colombia’s rainforests.

Muhamad explained that conflicts with Estado Mayor Central, a group that is thought to run a sprawling cocaine operation among other illegal activities, were partly behind the striking numbers. “In this case, nature is being placed in the middle of the conflict,” she said. According to experts, E.M.C. had largely banned deforestation and in recent months it seems to have allowed it again.

A 2023 United Nations report referred to this entanglement between drug trafficking and environmental crime as “narco-deforestation.” Perhaps nowhere is that phenomenon more clear than in Colombia, a country that’s both a stage for the decades-old global war on drugs and one of the most biodiverse corners of the planet, where the Andes Mountains meet the vast Amazon rainforest.

But what’s happening in Colombia underscores a growing challenge for many developing countries. Vast pristine forests are both essential to curb climate change and biodiversity loss, and they’re also prized by groups who want to hide illegal activities beneath thick tree canopies.

Today I want to explain why experts on the ground say that there’s no way to protect crucial forests like the Amazon without dealing with the growing power of armed groups.

The Colombian case

Armed groups in Colombia have long prohibited logging in the forest. The main reason, experts say, was to protect the illegal drug operations that the Revolutionary Armed Forces of Colombia, or FARC, ran in the forest.

FARC’s role protecting the forest became clear after 2016, when it signed a peace deal with the Colombian government, which disarmed the group and turned it into a political party called Comunes. When FARC disbanded, a local power vacuum caused deforestation rates to skyrocket as cattle ranchers, illegal miners and dissident groups cut down forests.

But as the dust settled, the Estado Mayor Central, a dissident group controlled by Ivan Mordisco, a former FARC commander, consolidated power in much of the Colombian rainforest. The old FARC tactics of restricting logging seemed to return and deforestation rates started to fall again. Until recently.

Muhamad noted that El Niño may have also made the Amazon more vulnerable to forest fires this year. I called Rodrigo Botero, the director of an environmental nonprofit in Colombia called the Foundation for Conservation and Sustainable Development, to understand what else changed. He told me they can see new roads being opened and ranches expanding in the region. Government agents can’t stop it because the group, which is estimated to have over 3,000 troops, controls access to much of the forest.

It’s not totally clear why the E.M.C. seems to have begun allowing logging again. Botero said he feared the E.M.C. could be trying to use deforestation rates as leverage to get more favorable treatment from the government.

First, they showed the government the benefits they could deliver by forbidding deforestation, he explained. And then, Botero added, it was like they told the government, “if you can’t count on us, look at what we can do.”

It’s a global problem, too

There is no evidence that the E.M.C. were successful in what seems to be an attempt to use the Amazon as a political tool. The government says it’s actively trying to arrest Mordisco.

Politics aside, what the Colombian case made clear to me is that controlling armed groups is now a fundamental part of conservation policy.

Bram Ebus, a consultant at the International Crisis Group and an investigative reporter, has spent years documenting how both drug traffickers and rebel groups like the E.M.C. are expanding their reach in the rainforests of South America in a project called Amazon Underworld.

He told me the illegal trade managed by these powerful criminal groups is no longer restricted to drugs or minerals, though they are still major sources of income. There is growing concern that criminal networks are also tapping into a vast menu of businesses to launder their illegal gains, such as illegal logging, wildlife trafficking, ranching and land grabbing.

Researchers, journalists and government officials have long documented how mining funded conflict in Africa, Asia and Latin America. Nature was collateral damage. Illegal mining operations connected to conflict have been very harmful to biodiversity in the Congo River Basin’s rainforest, for example.

Colombia continues to negotiate for peace, and its Ministry of Environment and Sustainable Development didn’t comment on whether the Amazon was being used as a political tool, but added that violations will be investigated and that it will continue working to curb deforestation. (The E.M.C. could not be reached for comment.) But, in many cases, it’s becoming hard to tell politically motived groups from purely criminal gangs. That’s bad news for nature and whoever dares defend it.

Many countries simply don’t have the resources to protect forests, let alone take on armed groups. Right now, one of the developing countries with the biggest budget for forest protection, Brazil, has so few officers that each worker patrols on average an area the size of Denmark, according to an association of environmental protection officers. They are now striking to protest poor working conditions.

Meanwhile, criminal and rebel groups have continued to expand their reach.

“You see that all these groups who are participating in the conflict have one key objective, which is to expand, to get more troops, to get more money, to get more territorial control,” Ebus told me. “The environment right now is a hostage of war.”

Getting rid of ‘forever chemicals’

What happened: For the first time, the federal government is requiring municipal water systems to remove six synthetic chemicals linked to cancer and other health problems that are present in the tap water of hundreds of millions of Americans, my colleague Lisa Friedman reported.

The Environmental Protection Agency will start requiring that water providers reduce perfluoroalkyl and polyfluoroalkyl substances, known collectively as PFAS, to near-zero levels. The compounds, found in everything from dental floss to firefighting foams to children’s toys, are called “forever chemicals” because they never fully degrade and can accumulate in the body and the environment. The new effort will cost at least $1.5 billion per year.

Where PFAS are found: The chemicals are so ubiquitous that they can be found in the blood of almost every person in the United States. A recent study that tested 45,000 water samples around the world found that about 31 percent of samples that weren’t near any obvious source of contamination had PFAS levels considered harmful to human health, as my colleague Delger Erdenesanaa wrote this week.

Exposure to PFAS has been associated with metabolic disorders, decreased fertility in women, developmental delays in children and increased risk of some prostate, kidney and testicular cancers, according to the E.P.A. (Lisa wrote a helpful explainer on what else we need to know about PFAS.)

The new regulation is “life changing,” Michael S. Regan, the E.P.A. administrator, told Lisa. “We are one huge step closer to finally shutting off the tap on forever chemicals once and for all.”

So what can you do to avoid PFAS? The E.P.A. maintains a list of cleaning products that are safe from these chemicals. And the Environmental Working Group, a nonprofit, has been tracking companies that say they are stripping them from their products. — Manuela Andreoni