When Raquel Rubio’s 13-month-old baby developed a 102 fever last week, she rushed to the doctor. Her son, Liam, had been in Rubio’s apartment without air conditioning for several hours; Nuevo León, the Mexican state where she lives, had reached 109 degrees that day. The fever in the region could easily be driving her son’s temperature. 

The doctor confirmed Rubio’s suspicions, sent her back home and instructed her to bathe Liam and keep him hydrated. But Rubio couldn’t go back home; she had been dealing with power shortages for the past two weeks and didn’t want to take her son back into the blistering heat. 

During the heat wave that hit Mexico and Texas in the last two weeks, some states in Mexico saw temperatures exceed 113 degrees, and more than 20 people died from heat stroke. The record-high temperatures have put enormous pressure on the country’s electric system, increasing the electricity demand.

Experts say a lack of investment has left the Mexican electric system unprepared for the challenge. As climate change fosters extreme heat in the country, power shortages could become increasingly common. 

Last Tuesday, the National Energy Control Center declared emergency operational status when Mexico’s electricity reserve reached a historic low. In Mexico, summer is the season with the highest energy demand since people are more likely to use machines like fans or air conditioning, said Rosanety Barrios, an independent energy expert. But this year, even in temperate cities, like Mexico City, where people usually don’t require them, stores ran out of fans, local media reported.

Mexico is one of the countries where the effects of climate change can be seen more obviously, said Andrew Pershing, referring to the Climate Shift Index, a tool that estimates climate change’s influence on local weather. Pershing is the VP for science at Climate Central, the nonprofit that developed the tool. In places closer to the equator, like Mexico, the temperature doesn’t usually vary that much, so it’s easier to identify weather conditions that are “highly unlikely without climate change,” he says. Last week’s temperatures in northeast Mexico and central Texas scored five in the Climate Shift Index, which means researchers calculate they were five or more times likelier because of climate change.

The unprecedented temperatures put the Mexican electric system up against the wall, and more than 10 Mexican states reported power shortages last week. 

For several years, Mexico has neglected investment in its electric system, which gets most of its power from state-owned energy plants, says Barrios. “While the energy demand has steadily increased, energy generation hasn’t increased in the past five years,” said Carlos Flores, an energy expert and head of new markets in America for Lightsource BP. In 2014, the Mexican Congress approved new energy reforms, and private companies supplying clean energy were supposed to replace the state-owned fossil fuel plants, but the current government reversed course. “This government’s bet was that they could cover the country’s energy demand with the state-owned energy plants, and here are the consequences,” Barrios says.

The problem is not only generating enough energy but the fact that the whole system is old and underfunded, Barrios said, adding that the government hasn’t invested in electricity transmission lines in at least a decade. In the past three years, the amount that the Federal Electricity Commission has invested in “physical infrastructure” has been the lowest in at least ten years, says Jesús Carrillo, the sustainable economy director at the Mexican Institute for Competitiveness, a Mexican think tank. 

“When you have a problem the size we have when the demand is increasing, and high temperatures are also causing demand to increase, you are facing more risks,” he says.

While it is hard to know for sure what is causing the power shortages, it is common practice for the National Center for Energy Control to disconnect neighborhoods from the electric network to prevent the system from failing, says Flores. They do this to avoid bigger and harder-to-fix problems, Barrios says. 

Citizens dealing with power outages are scrambling to adjust to the disruption and danger. Luis Alejandro Calderón, an American citizen who lives in Nuevo Laredo, Tamaulipas, and his wife had to sleep on their balcony last Sunday because they didn’t have electricity, and the heat inside was unbearable. The power shortage lasted more than 40 hours, so they stayed in a hotel in another area the next night, and a lot of their food went bad. 

“We have never had to deal with anything like this,” he said. “When there is a power cut, electricity is usually back in 15 minutes.”

Mexico typically surpasses the peak energy demand from the previous year in July, but this year it already happened, leaving many worried that the coming weeks could hold even worse blackouts. “This is a product of the climate emergency, and that is not the government’s responsibility, but it is their responsibility to build an electric system that is prepared for this,” Barrios said. 

Besides being challenging, investing in energy transmission and generation is often not politically beneficial, Carrillo said. “It is not sexy; it is like building a sewer system. Nobody likes to build a sewer system, everybody wants to build highways, statues, parks.”  

Editor’s note: An earlier version of this story used the incorrect surname for Rosanety Barrios. It has been updated.