For those hoping Mexico will fully embrace climate protection, natural-resource conservation and clean energy policies, Claudia Sheinbaum Pardo, the mayor of Mexico City, might represent a ray of hope.

Even before serving as Mexico City’s top environmental official for six years and as its mayor since 2018, Sheinbaum possessed relevant expertise. An environmental engineer, she received a doctorate from the Lawrence Berkeley National Laboratory in California, where she researched Mexican energy use, and has served on the United Nations Intergovernmental Panel on Climate Change.

As Mexico City’s first female mayor, she is implementing a 2018-2024 agenda that includes rainwater harvesting, green-space expansion, watershed conservation, extensive planting initiatives, air-quality improvement, waste reduction, transit innovation, and construction of a 20-megawatt, 25-hectare (62-acre) municipal solar farm. She has even been mentioned among potential candidates to succeed Mexican President Andrés Manuel López Obrador, who is limited by the constitution to a single, six-year term that in his case ends in December 2024.

Yet to say there are obstacles standing in the way of Sheinbaum’s green-centric vision for her city and country would be to understate the case. Among the biggest hurdles are national policies being pushed by her Morena political party with the full support of populist President López Obrador, the party’s standard-bearer. Since taking office, López Obrador has undercut previous federal incentives for renewable power, and has instead implemented changes favoring Mexico’s inefficient and pollution-prone oil and gas industry. The approach has allowed López Obrador to score domestic political points by invoking economic nationalism but has put Mexico at risk of missing its greenhouse gas emissions-reduction targets and has caused concern in foreign capitals.

While Mexico City under Sheinbaum is heading in one environmental-policy direction, the federal government in a number of key ways is pulling in another. Pablo Lazo of the World Resources Institute (WRI), a leading international environmental think tank, says a prime example is that the federal government “discredits all technical and scientific evidence as a basis for making changes to environmental policy, particularly with reference to anything related to the climate emergency.” Adds Lazo, WRI’s Mexico-based director of urban development and accessibility: “That is not the case with the Mexico City government, so there is a total disconnect there.”

Lazo also points out that while the federal government “is betting on non-renewable energy,” Mexico City is “interested in transitioning” to renewable power sources. And a third contrast he cites concerns Mexico’s ongoing water-supply shortages, a problem only expected to grow worse as a result of climate change. “The federal government has been very slow to react to the national [water] crisis, particularly in urban areas, and to design legislation, legal frameworks, and strategies that secure water supplies, which is not seen as a priority,” Lazo says. By contrast, he adds, “Mexico City has prioritized this issue on the strategic environmental agenda.”

Sheinbaum and her team downplay any suggestion that the national policies of López Obrador, who was mayor of Mexico City when she was the city’s top environmental official, undercut those of the municipal government. Instead, they cite their progress in implementing the mayor’s 2018-2024 environmental and climate agenda for the federal capital, home to 9.2 million people. The plan aims to benefit a further five to six million commuters to the federal district from other areas of greater Mexico City—the world’s sixth-largest metropolitan area, with a total of 21.8 million people.

The scale of the environmental problems addressed by that plan has been another core challenge facing Sheinbaum and her team. Even if the López Obrador administration were fully invested in clean-energy development, climate protection, and natural-resource conservation, addressing Mexico City’s unguided development, sparse green space, tenuous water supply, and epic traffic would still be daunting.

Sheinbaum has set bold targets and claims progress on many. Regarding green spaces, her 2018-2024 plan calls for planting 40 million plants and trees, restoring 1,000 hectares (2,470 acres) of public spaces, cleaning up 85 kilometers (53 miles) of waterways, and cutting solid waste by 50%. City officials say the greening initiative is not only on track to meet its tree-planting targets, but also its goals for installing pollinator plants in parks and balcony pots across the city to boost the natural urban ecosystem. The project takes a broad geographical approach to improve equity and ensure ecosystem connectivity.

“We need nature to spread across the city, so green corridors connect the periphery to the city center, because humans need the services nature provides,” says Marina Robles García, an oceanographer now serving as Mexico City’s environment minister, the same post Sheinbaum held when López Obrador was mayor. “We have to move beyond seeing nature as a pretty backdrop. It is absolutely essential to our survival.”

Robles says varied re-vegetation, rather than simply planting trees, and the creation of green corridors has helped expand the number of bird species sighted in the city by 42 since 2018. Among the recent arrivals are the mottled owl (Strix virgata) and the dusky hummingbird (Phaeoptila sordida). Some long-absent mammals have reappeared, too. “Recent sightings of species such as the gray fox (Urocyon cinereoargenteus) tell us that the whole ecosystem has benefited from the re-vegetation program because for these species to survive, you need the lower levels of the food chain to be healthy and robust,” Robles says.

Sheinbaum says her top priority, in terms of both development and the environment, is to shore up Mexico City’s water supply. To that end, she has doubled investment in distribution-system repairs aimed at reducing leaks, which according to experts cause the city to lose 40% of its potable water. Her administration has also installed 52,000 rainwater harvesting systems in neighborhoods not connected to municipal water service. That has allowed a corresponding number of households to be self-sufficient in water for six to eight months of the year, benefitting people—most often women—who otherwise must lug water to their homes in containers.

Experts, however, note that Mexico City’s water sources are dwindling fast. They say the city’s biggest water-import system, which draws from the Cutzamala River, is operating 50% under capacity—an all-time low—with water volumes today 24% below levels of just four years ago. Critics of the city’s water policy assert that too little is being invested in the protection of watershed ecosystems in the region. And far too little wastewater and stormwater receives any treatment at all, let alone enough to permit its reuse for irrigation or other purposes.

“A truly sustainable city must treat all types of wastewater,” says Carlos Samayoa, who oversees sustainable-cities initiatives at the environmental group Greenpeace Mexico. “At present less than 15% of the capital’s wastewater is treated … There are very effective decentralized water-treatment options available that would offer a structural solution to water shortages, which are rapidly growing worse.”

Greening transportation has also loomed large in Sheinbaum’s plans, with officials saying spending on that sector of the city budget is on track to total 57 billion pesos (US$3.1 billion) when her six-year term expires in December 2024. Investments thus far have ranged from the purchase of 2,000 electric buses, which have replaced fossil-fuel-powered models, to the construction of 230 kilometers (143 miles) of bicycle lanes—well more than doubling the 180 kilometers (112 miles) built over the previous 18 years. Andrés Lajous Loaeza, Sheinbaum’s transport secretary, calculates that since the mayor took office, clean-energy investments in transportation have mitigated 152,000 tons of CO2.

These and other steps have contributed to a longer-term trend of improving air quality in Mexico City. The capital’s air-quality index, which reflects levels of sulfur dioxide, carbon monoxide, nitrogen dioxide, ozone and particulates, registered 120 clean days in 2022. And IQAir, a Swiss air-quality technology company that maintains a global air pollution ranking, rated Mexico City ahead of 871 other cities around the world last year. Such results would have been unthinkable three decades ago, when the U.N. described Mexico’s capital as “the most polluted city on the planet.”

The turnaround began in the 1980s, when Mexico City pursued a range of air-quality initiatives, including the relocation of factories, reformulation of vehicle fuels, biannual vehicle-emissions checks, restrictions on car use, expanded public transportation, and incentives for residents to buy newer, lower-emission cars.

Lajous, who holds master’s degrees in planning from the Massachusetts Institute of Technology and sociology from Princeton University, says air-quality progress during Sheinbaum’s tenure has been made not only through electrification of transportation, but also through greater transit connectivity.

This effort, he says, has involved extending the transit system to impoverished outlying areas of the Valley of Mexico where densely packed, unplanned settlements crowd steep terrain accessed by dirt tracks rather than paved roads. There, residents whose commutes to and from the city center used to consume up to three hours each way are now able to reach transit hubs by riding one of two new, publicly operated aerial tramways serving their neighborhoods at heavily subsidized rates.

Third cable line due

Route 1 spans 9.2 kilometers (5.7 miles) and Route 2 extends 10.6 kilometers (6.6 miles), with the latter setting a Guinness World Record as the world’s longest aerial tram. The electric-powered system moves passengers at 21 kilometers per hour (13 miles per hour), with each gondola holding 10 seated passengers. Route 2 carried 14 million riders by July 2022, at the end of its first year, while Route 1 reached its first-year in August 2022 after conveying 22 million passengers, the city says. A third, 5.4-kilometer (3.4-mile) route is due to open in November.

While green advocates acknowledge public-transit advances, some argue that far more substantive action must be taken. Greenpeace’s Samayoa points out that 60% of Mexico City residents rely on the capital’s 30,000 pollution-prone minibuses for transport. The privately owned buses, known as peseros, routinely clog key arteries, contributing to Mexico City’s chronic traffic jams and related air pollution. Samayoa asserts Sheinbaum has been reluctant to challenge entrenched interests and remove these minibuses from the road. “Making structural changes in this sector would imply high political costs and Sheinbaum has not wanted to confront those costs,” he says.

Samayoa served on a multistakeholder committee charged with proposing ways to align Mexico City’s air-quality standards with recommendations of the World Health Organization. He criticizes the city for not adopting the new standards and instead sticking with its longtime air-quality index. That index, he asserts, masks “unacceptable air quality,” minimizing the number of days restrictions must be placed on cars, industry and other polluting activities. Says Samayoa: “If we were told the truth about air quality, contingency measures that affect the economy would have to be taken more days of each year. It is clear the health of the economy is given precedence over the health of the population and the environment.”

María Zorrilla Ramos, a researcher at Ibero-American University (UIA) in Mexico City, agrees that environmental considerations, while acknowledged to a greater degree now, too often take a back seat to economic development priorities. She and other experts assert environmentally destructive urban projects have been allowed to go forward on Sheinbaum’s watch. They cite a six-lane bridge built across the wetlands of Xochimilco, a Unesco World Heritage Site.

Conservationists complain that the bridge, opened to traffic in September 2021, caused habitat damage and fragmentation while encouraging the use of private vehicles rather than public transport. “We can’t afford to lose a single ecosystem, half a wetland, or one hectare of natural territory to urbanization,” Zorrilla says. “We haven’t understood that together we’re all responsible for our environment.”

Balancing act

WRI’s Lazo cuts the mayor some slack, however, arguing that sometimes she has had to perform a balancing act. “Mayor Scheinbaum has tried to position environmental concerns alongside other priorities,” Lazo says. “Xochimilco had a dire congestion situation that caused terrible air pollution. The solution of building a bridge over the wetlands did not set aside environmental concerns; it took them into account. It’s the first example of different ministries, including public works and environment, cooperating to solve a problem by taking different needs into consideration, and there are some environmental benefits, such as reduced air pollution, that must be recognized.”

Sheinbaum acknowledges that much work must be done to build environmental consciousness in the capital. “We need to be more environmentally aware, which means not thinking about ourselves so much,” she said in a recent interview with EcoAméricas. “Consumerism cannot be a central part of our lives anymore. We need to think of the collective.”

It is uncertain what posts Sheinbaum might hold to advance such views after she steps down as mayor in December 2024. While she is seen as a possible successor to López Obrador as president, analysts say that Foreign Affairs Secretary Marcelo Ebrard, a fellow Morena Party member, currently has the inside track for the nation’s top job. If Ebrard is elected, experts say, Sheinbaum might head the Secretariat of Environment and Natural Resources (Semarnat), Mexico’s lead environmental agency, and make a run for president in 2030.