When Claudia Sheinbaum donned Mexico’s presidential sash on Oct. 1, she broke more than one barrier. First and foremost, she became the country’s first female chief executive. But she also became Mexico’s first president with deep environmental expertise. Her background includes research of Mexican energy use at Lawrence Berkeley National Laboratory in California, service on the UN Intergovernmental Panel on Climate Change, and a range of green policymaking experience as mayor of Mexico City from 2018 to 2023.

So after Sheinbaum won the presidency in a landslide in June, green advocates were naturally curious whom she would choose to head the Environment and Natural Resources Secretariat (Semarnat), the country’s lead environmental agency. Her pick was Alicia Bárcena, a trained biologist with broad experience stretching from a stint as a Mexican ecology undersecretary four decades ago to the country’s foreign minister in the last year of the previous administration.

In the selection of Bárcena, analysts see a bid by Sheinbaum to advance environmental initiatives broadly in Mexican society in coordination with international climate and biodiversity efforts. “Bárcena is known for working on closing political, social and environmental gaps simultaneously,” says Angélica Vesga, public affairs and communications director in Mexico for the World Resources Institute (WRI), a nonprofit global research and policy thinktank based in Washington, D.C. “[She] has already highlighted the urgency of demonstrating that the environment can contribute to the economy, which aligns with international sustainability policies.”

Bárcena holds a biology degree from the National Autonomous University of Mexico (UNAM) and a master’s in public administration from Harvard University. She became Mexico’s first undersecretary of ecology in 1982. From 2008 to 2022, she served as executive secretary of the Economic Commission for Latin America and the Caribbean (Eclac).

Under Bárcena’s leadership, Eclac, a United Nations body that works with governments in the region to raise living standards, coordinated the negotiations that produced the Escazú Agreement, the first region-wide environmental treaty for Latin America and the Caribbean. The 2018 treaty promotes public access to executive-branch and judicial proceedings involving environmental matters.

Setting priorities

Speaking to her Semarnat team on Oct. 7, Bárcena announced the National Program for Environmental Restoration, an initiative whose priorities range from watershed and coastal-mangrove restoration to greater clean-water access and modern waste-management. The priorities dovetail with the “100 Steps for Transformation” agenda Sheinbaum presented in her Oct. 1 inaugural address.

Arguably the administration’s most complex green goal is to push Mexico toward renewable power. That challenge was largely ignored by previous President Andrés Manuel López Obrador—though he was Sheinbaum’s mentor and a fellow member of the ruling National Regeneration Movement (Morena) party.

“Renewables and energy efficiency will characterize our government,” Sheinbaum said in her inaugural speech. “We will build solar, wind, hydro, geothermal and green-hydrogen plants and promote rooftop solar panels and heaters for households and businesses. This will lower the cost of power and gas, and Mexico will set an example for the community of nations in confronting global climate change.”

Mexico’s renewables sector was just getting off the ground in 2018 when López Obrador, known as AMLO, took office. But his administration stopped the industry in its tracks, prioritizing fossil-fuel dependency in the name of energy sovereignty. Among his highest-profile initiatives was construction in Tabasco state of Mexico’s biggest oil refinery, Dos Bocas.

Sheinbaum aims to boost renewables to 50% of Mexico’s power by 2030 in line with its existing climate-protection targets. Succeeding will be a major challenge, says Eugenio Fernández, an environmental consultant and editor of the publication La Cigarra. That, he argues, is because state oil giant Pemex is struggling to service over US$100 billion in debt, which it can only do by selling fossil fuels. “There is no easy out,” Fernández says. “Realistically, Sheinbaum’s hands are tied to fossils by this debt.”

Eco-humanism

Promising to take an “ecological and environmental humanism” approach, Bárcena says she will ensure that green criteria and values guide design, construction, and use of major infrastructure. This contrasts starkly with the practices of the López Obrador administration, whose infrastructure projects—most notably the Tren Maya passenger-rail line on the Yucatán Peninsula—drew intense fire for their lack of environmental due diligence.

The new administration aims to achieve net-zero deforestation during its six-year term, with Bárcena pledging to join agriculture officials in promoting sustainable practices for the cattle-ranching industry, the main driver of Mexican deforestation. Sheinbaum and Bárcena also are promising to help communities achieve food and energy sovereignty. And they say air quality will be improved, particularly in the federal capital and the cities of Monterrey and Guadalajara, by expanding and modernizing public transit, which produces 40% of Mexico’s transportation emissions.

Bárcena, who vows to promote the use of biological, environmentally friendly insecticides, has joined Sheinbaum in endorsing the previous administration’s phaseout of the controversial herbicide glyphosate. She backs the new president’s opposition to fracking, as well as her decision to halt new open-pit mining concessions and gauge whether active mines are accepted by local populations.

While big business is likely to win its share of green-policy fights, Fernández believes Bárcena’s broad experience and close ties to Sheinbaum will prevent Semarnat from being routinely steamrolled in such disputes, as often appeared to be the case under López Obrador.

Says Fernández: “If an environmental catastrophe one tenth the size of those committed under AMLO were to happen, Bárcena would be forced to resign and the political cost of such a high-profile resignation would be too high for Sheinbaum to allow.”