The expected impacts of sea level on the Mexican Atlantic coast

The Mexican Atlantic coast is vulnerable to sea level rise due to its low, sandy shorelines with extensive adjacent wetlands. The increasing trends at the regional level are similar to global trends (~3 ± 0.04 mm/year): between 1.8 mm/year in Alvarado, Veracruz, to 3.6 mm/year in Isla Mujeres, Quintana Roo. A synthetic model was applied to Mexican Atlantic coast under two sea level rise scenarios for the year 2100. Our objectives were: 1) to identify potentially floodable zones in the face of a sea level rise of one and two meters on the Mexican Atlantic coast with a synthetic model using SRTM and LiDAR topographic data; 2) to determine vegetation and land use affected in the potentially floodable zones; and 3) quantify the vulnerable human population. With topographic data we identified low areas (one and two meters) to assess potentially floodable zones; these were intersected with data layers of vegetation, land use, and human population. Deltaic zones, coastal lagoons and low-lying areas of the Yucatan Peninsula were regions with the largest potentially floodable surface. In the one-meter sea rise scenario, 581,674 ha were identified as potentially floodable, and 896,151 in the two-meter scenario. The most vulnerable vegetation and land use types were wetlands, such as cattail marshes (tulares; ~29 %) and mangroves (~27 %), as well as cultivated grasslands (~6 %). The indirectly affected coastal population could be approximately 5.5 million in these scenarios (~33 %), and the directly affected population could range between 124,000 and 440,000 (~0.72 and 2.55 %, respectively). These results indicate that there will be strong effects in economic, social, and environmental impacts on the Atlantic coast of Mexico in the event of a one- and two-meters sea level rise. This type of work will enable proposal conservation and adaptation strategies for human populations and coastal cities.