Southern Mexico and Central America Regional Precipitation Variability: Community-informed Science

Southern Mexico and Central America (SMCA) is a geographically connected region that shares climate features as well as human livelihoods. The latest compilation of scientific work on the region (IPCC, 2021) is inconclusive regarding heavy precipitation trends during the observational period, both in direction and anthropogenic attribution. In contrast, case studies have reported food security hardship and labor migration due to severe hydroclimate variability and extremes especially in communities that depend on subsistence agriculture. However, communities’ accounts of changing rainfall patterns vary vastly across the SMCA region. This signals that drought and precipitation indexing based on regional averaging may obscure sub-regional differences in the climatological baseline and trending, leading to products or conclusions with little transferability to the fine grid of human experience and that are ultimately of scarce utility to rural agricultural communities. To elucidate SMCA’s precipitation spatio-temporal variability - particularly those most relevant to local communities’ agricultural practices - I am using a combination of climate science methods and social science methods. I have analyzed the sub-regional and sub-seasonal patterns of precipitation, as well as their changes in the observational period, using 70 and 40 years of daily gridded rainfall estimates from two different data set (ERA5 and CHIRPS respectively). Concurrently, I have integrated ethnographic information - collected during an exploratory ethnographic fieldwork during Nov 15 - Nov 30, 2021, in two agricultural-rural communities of eastern El Salvador - to the numerical results examination and interpretation that provides immense insight on precipitation variability and changes that influence the agricultural sowing-harvesting cycle via the traditional, collective, and trans-generational knowledge of climate.

Speaker: Janin Guzman-Morales, UC Santa Barbara