Hidden carbon fluxes from groundwater use in Mexico using satellite storage change and bicarbonate degassing

Groundwater depletion undermines water security and contributes to atmospheric carbon dioxide emissions through dissolved carbon release and energy use for groundwater pumping. Mexico, one of Latin America’s largest agricultural groundwater users, provides an important case within the water–energy–climate nexus. Here we show national groundwater-related carbon dioxide emissions by combining satellite-derived groundwater storage changes, groundwater bicarbonate concentrations, and pumping energy for 2012, 2017, and 2021. Groundwater depletion is most pronounced in Chihuahua, Sonora, Zacatecas, Guanajuato, and San Luis Potosí, where intensive groundwater extraction coincides with elevated bicarbonate concentrations, resulting in the highest emissions. Cluster analysis separates these northern and central states from lower-emission southern and Gulf states. In contrast, Veracruz, Campeche, Tabasco, Chiapas, and Yucatán exhibit lower emissions despite relatively high bicarbonate concentrations because groundwater depletion is less pronounced. These findings show that groundwater depletion and mineralization act together to amplify emissions and highlight the need for low-carbon pumping and improved water management. Groundwater depletion raises carbon dioxide emissions via bicarbonate release and pumping, highest in northern and central Mexico with rising levels by 2021; according to combined satellite groundwater storage anomalies, bicarbonate concentrations, and pumping energy analysis for 2012, 2017, and 2021.