Vulnerability to the Effects of Climate Change: Future Aridness and Present Governance in the Coastal Municipalities of Mexico

Abstract

We estimated vulnerability to climate change in the coastal municipalities of Mexico through an interdisciplinary approach using an index model with three components: (1) Exposure to dryness and climate change (Lang’s dryness index), (2) socioeconomic sensitivity, and (3) adaptation capacity. Data input were national census data and general circulation model outputs (2045–2069 scenario). Scenarios were compared to reference climatology through Lang’s aridity index, which was found to be practical as an aridity indicator and foresee its future change in value. This methodological approach allowed to set priorities by identifying groups of more threatened and less prepared municipalities in the territories, which show more differences between the present climatological parameter values and the values predicted assuming future climatic scenarios, have less climate change related institutional instruments, present social weaknesses (poverty and inequality), or show environmental degradation. Our results showed the presence of arid zones in 43% of Mexico’s 266 coastal municipalities, comprising more than half of the total coastal population. Comparing present and future scenarios allows differentiating regions already arid that will remain in this situation (Northern Pacific) from regions that are currently humid but will shift to an arid (Caribbean Sea) or desert category (Northern Gulf of Mexico). Both used models predicted a future shift of all categories towards dryness and a worrisome number that will turn to desert and arid categories. We found regional heterogeneity and a complex contribution of each subindex to the total coastal vulnerability index. We concluded that our results can be used as an input to guide the current coastal policies to promote a development model that decreases the vulnerability of coastal municipalities and advance towards a model that includes the complexities of the Mexican coastal dryland socio-ecological systems, its challenges, and its opportunities.