Mexico water supply buckles on worsening drought, crops at risk

A long-term drought that has hit two-thirds of Mexico is likely to worsen in coming weeks with forecasts of high temperatures and warnings of crop damage and water supply shortages on the horizon, including in the populous capital of Mexico City.

Experts are sounding the alarm that parched crops could under-produce after temperatures hit 40 degrees Celsius (104F) on June 30 in some parts of northern Mexico, including key farming areas.

“In some states, irrigation is practically disappearing due to lack of precipitation,” said Rafael Sanchez Bravo, a water expert at Chapingo Autonomous University, noting low reservoirs and reduced water transfers to farms.

Mexico’s drought parallels that of the western United States and Canada, where crop yields are threatened and water rationing has been imposed amid extreme heat, a consequence of worldwide climate change.

Nearly 500 people died in western Canada in the past week as record-breaking temperatures produced life-threatening conditions for the elderly and vulnerable groups. In the US, the heat buckled highways, hobbled public transit and triggered rolling electricity outages.

While rains were 3 percent below average across Mexico as a whole last year, the strain on water reserves was exacerbated by increased domestic demand during the COVID-19 pandemic, a US government report showed last month.

Hopes to replenish Mexico’s parched reservoirs now hinge on the traditional rainy season, known formally as the North American Monsoon, which is currently under way.

“The next three months will be really crucial in how this drought turns out,” said Andreas Prein, an atmospheric scientist for the National Center for Atmospheric Research in Boulder, Colorado.

Much of Mexico gets between 50 percent and 80 percent of its annual rainfall between July and September.

Water shortages are common in parts of Mexico, but have worsened amid heat extremes blamed on climate change, according to scientists and data from Mexico’s federal water commission CONAGUA.

About 70 percent of Mexico is affected by drought, up from about half in December. About a fifth of the country is experiencing extreme drought compared with less than 5 percent each year since 2012.

Experts fear the drought will reach the 22 million inhabitants of Mexico City’s metro area, which is quenched by a network of reservoirs. Some districts have no piped drinking water at the best of times.

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“I have no doubt that in 2022 there will be a crisis,” said Sanchez, who anticipates possible social unrest. “The reservoirs are completely depleted.”

Sanchez is encouraging local authorities to invest in collecting rainfall for domestic use.

Villa Victoria, an important source for Mexico City, was among 77 of 210 principal reservoirs below 25 percent capacity at the end of June, according to CONAGUA data. Cracked lake beds can be seen in others around the city.

Images by a European Commission satellite show a visible depletion at Villa Victoria on June 15 of this year, compared with June 30 last year when it was already half empty.

This time last year, there were 56 reservoirs below 25 percent capacity. Two years ago, there were just 40.

The drought has prompted the government to seed clouds with silver iodide in the next three months in a trio of northern farming states – Sinaloa, Sonora and Chihuahua – in a bid to induce rain with the help of specially-equipped air force planes, according to an agriculture ministry statement.

But this year’s corn production target of 28 million tonnes is still at risk.

“The scenario is pessimistic and we can’t deny we’re worried,” said a senior agriculture ministry official, speaking on condition of anonymity.

It can be difficult for scientists to attribute any single event to climate change, but more extreme droughts point to warming global temperatures that researchers say are due to greenhouse gas emissions, said Prein.

The heat saps moisture from soil.

“That’s a big deal. If you are already in a very dry region like the western part of Mexico and you increase the temperature, you lose a lot of water just by evaporation,” added Prein.