Five years ago, when ExxonMobil came calling, city officials eagerly signed over a large portion of their water supply so the oil giant could build a $10 billion plant to make plastics out of methane gas.

A year later, they did the same for Steel Dynamics to build a rolled-steel factory.

Never mind that Corpus Christi, a mid-sized city on the semi-arid South Texas coast, had just raced through its 50-year water plan 13 years ahead of schedule. Planners believed they had a solution: large-scale seawater desalination.

According to the plan in 2019, the state’s first plant needed to be running by early 2023 to safely meet industrial water demands that were scheduled to come online. But Corpus Christi never got it done.

That hasn’t stopped the city and its port authority from pursuing broader plans to build out a next-generation industrial sector around Corpus Christi Bay and make this region a rival to Houston, home to the nation’s largest petrochemical complex, 200 miles up the Gulf Coast.

As efforts to cut carbon emissions fall desperately behind the timetables established in decades’ of global climate accords, Corpus Christi is planning a massive expansion of its hydrocarbon sector, aimed at delivering oil and gas from Texas’ shale fields to global markets for decades to come.

All that’s missing is the freshwater. Now the commitments city officials made over the past five years are coming due. Exxon’s plastic plant started operations this year and will eventually consume 25 million gallons of water per day, even as the region’s water plan foresees demand exceeding supplies in this decade.