The impact of climate variability on agricultural employment in Mexico from 1980–2017

3. Results 3.1 Long term precipitation and agrarian occupation variability Precipitation in Mexico during the study period displays high interannual variability (Fig 2). The mean annual precipitation during this period was 750 mm, with a standard deviation of 63 mm. In this context, years with less than 687 mm of rainfall can be considered dry (one standard deviation below the average), while years with precipitation greater than 813 mm can be considered a wet year (one standard deviation above). When agrarian occupation was analyzed in the long term (1980–2017), we found a continu- ous decrease in the number of people engaged in such activities (Fig 3). The total number of people employed in an agrarian occupation according to EDER decreased from 37% in 1980 to 11% in 2017. During the same period, rainfed agriculture dropped from 32% to 10%, while livestock farming fell from 5% to 1% respectively. Interestingly, within the population employed in agrarian occupations, 90% are enrolled in agriculture and the remaining 10% in livestock raising across the whole period. This decline is also evident in ENE and ENOE, with the proportion of agrarian occupations decreasing from 19% in 1998 to 16% in 2004, and fur- ther to 13% in 2017. Despite the sharp decline, there is some small interannual variability in the change of occu- pation. For example, the variation for the entire agrarian occupation sector ranges from -2.2% (in 1980) to +0.1% (in 2008). For agriculture specifically, the variation ranges from -2.1% (in

1980 and 1982) to +0.1 (in 2016); while for livestock, in ranges from -0.6% (in 1983) to 0 in dif- ferent years. Thus, the sharpest decline is observed in the first decades of the study period, while some stability seems to have appeared in the last two decades. We also observed that the average age of departure from agrarian occupations shows a consistent increment. For exam- ple, between 1980 and 1990, it ranged between 15 and 19 years, whereas from 2000 to 2017, it Fig 2. Mean annual precipitation from 1980 to 2017. Years with precipitation above one standard deviation are represented in blue, while years with precipitation below one standard deviation are shown in orange. The wettest year of the entire period is 2013, with 908 mm, and the driest year is 1987, with 636 mm. The dashed line in the center represents the average annual precipitation, and the two dashed lines indicate plus and minus one standard deviation. (Source of data: Calculations by the authors using CRU 4.06 precipitation [50]). https://doi.org/10.1371/journal.pone.0313891.g002 PLOS ONE Agrarian abandonment and extreme events PLOS ONE | https://doi.org/10.1371/journal.pone.0313891 February 10, 2025 8 / 22