LocationsThe Maya jungle city that already knows how to keep cool
Urban October: Mérida
October 14, 2026
The citizens of Mérida on Mexico's Yucatan peninsular are dealing with the acclerating effects of climate change.
Photo: Shutterstock
Urban October is a month-long campaign focused on sustainable urbanization and resilient cities. As our societies become increasingly urbanized, and the effects of climate change intensify, UNDP works around the world to make cities more livable for all their residents.
I arrived in Mérida at the end of that pandemic year, 2020. I came from months of lockdown and anxiety, and the city welcomed me with exactly what I needed most: life.
Flamboyanes, ceibas, almond trees, courtyards opening up behind façades that look like they belong to another century. Mérida was, quite literally, a breath of fresh air.
My favourite season runs from January to April, when the maculís bloom. They are our cherry blossoms: the trees drop their leaves and covering the streets in pink, and for a few weeks the whole city changes colour. You learn to wait for them. This year it did not happen. They did not bloom when they always do, and when they finally did it was uneven, one tree here, another there, out of step with each other. Mérida never turned pink.
You do not need to be a specialist to read that signal. What those of us who share this place have been feeling in our bodies for years, that the heat keeps rising and arrives a little earlier each time, the trees said first.
That contrast, a green city that is getting hotter, is why I want to write about housing. Because in Mérida "adequate housing" is not defined only by square metres or a property title. It is defined by a more basic question: can you live inside that house at three in the afternoon in May without depending on air conditioning?
A city built on top of another
The Spanish founded Mérida in 1542 and, like so many Mexican cities we know today, it was built on top of a Maya city, T'Hó, whose stones ended up in the cathedral and in the first grand houses of the historic centre. That history is not only in books and museums: you see it when you walk the streets downtown, when you step into one of those old houses. It is in the way people built. The traditional Maya house, this oval floor plan, bajareque walls that breathe, a high-pitched roof of huano palm, is a lesson in physics from long before the word “bioclimatic” existed. Hot air rises and escapes through the roof; the shade of the solar, with its fruit trees and garden, lowers the temperature all around; the orientation catches the breeze. Nobody needed a manual to know this.
The colonial houses of the centre inherited that logic in a different language: masonry walls more than half a metre thick, five-metre ceilings, corridors running from the street to the courtyard so the wind can do its work. When I step into one of those houses in the middle of summer, the temperature drops several degrees without anyone switching anything on.
In Mérida the Maya and colonial houses use self-cooling, energy efficiency technology, which involves less electricity and fewer expenses.
Photo: Shutterstock
And then there is the Mérida growing north and east: subdivisions of flat concrete slabs, low ceilings, small windows, and not a single tree on the pavement. These are houses that heat up like ovens and only work with the air conditioning running for a good part of the day. For a middle-income family, that means the electricity bill competes with the rent. For a low-income family, it means living with the heat. That is where housing stops being adequate, even when it has four walls and a deed. And that is also where the trees disappear, the ones that used to make the city bloom.
What we do at UNDP
I work at the Small Grants Programme of UNDP in Mexico, accompanying community-based organizations across the peninsula and the southeast. My day-to-day is coastal communities restoring mangroves, but SGP has another commitment that connects directly to this story: a just energy transition, led by communities themselves.What interests me most about that strategy is a principle that sounds obvious and is not: before installing a single solar panel, reduce consumption. And to reduce it, recover traditional construction and bioclimatic architecture as tools for thermal regulation.
Put in Mérida’s terms, the Maya house and the colonial house are not nostalgia, they are energy efficiency technology. A home that cools itself needs less electricity, and less electricity means less expense for families and fewer emissions for all of us. That is the first layer. Everything else fits on top of it. Solar refrigeration in the fishing communities along the coast, solar pumping, community electrification where the grid does not reach and a regional innovation network so that a community which has already solved its problem can teach the next one.
That last part is the one that most resembles my own work. In the Network of Mangrove-Restoring Communities we learned that the solution does not travel from office to territory; it travels from one ejido to another, from one cooperative to another. The same is true of energy. Energy justice is not someone showing up to install something, it is the community understanding how it works, managing it, and being able to do it again without us.
What makes Mérida mine
Mérida still feels livable to me whether its walking at night around parks in the traditional neighbourhoods, browsing the markets or the people who greet you. But the city I want is one that does not ask every family to solve the heat on its own. One where new housing is built with the intelligence this land already had 500 years ago, where the tree on the pavement is part of housing policy, and where the energy we do need is generated and governed by the people who use it.
Adequate housing for all in Mérida begins by remembering that the city already knew how to stay cool. And I hope that next January the maculís manage to agree with each other again.
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