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

Additionally, a positive relationship of precipitation with planted cropland area was observed (p<0.05, cor = 0.19). This indicates that lower rainfall is associated with a smaller total planted area, which in turn affects income (p<0.05, cor = 0.18). On average, from 1980 to 2017, income decreased by 230,951 million pesos during dry years (i.e. those with precipitation 1sd below the average), while the total agricultural area decreased by 350,717 hectares, equiva- lent to approximately 3% of the total area. 3.1.3 Long-term seasonal trends. We study long-term changes in agrarian occupation in Mexico from 2005 to 2017 by dividing the time series into four-month periods (quarters) (Fig 7). In this way, each quarterly transition coincides with the beginning or end of the two main rainy seasons in the country. The transitions from Q4 to Q1 (fourth quarter to first quar- ter) not only reflects the shift from one year to the next but also marks the transition from the wet to the dry season (Fig 7A). During this transition, there is a decrease in people who start working in the agriculture (inputs) and an increase in the people who leave this sector (out- puts). Nevertheless, most people employed in agriculture remained in the same activity. Inter- estingly, we found a positive correlation (r = 0.69, p<0.05) between rainfall and changes in activities within the agricultural sector (e.g. people shifting from rainfed agriculture to live- stock raising). In other words, with an increase in rainfall the possibilities of changing eco-

nomic activity in agriculture increased; for example, transitioning from cultivating crops to raising cattle, for a larger profit. The transitions from Q1 to Q2 (first quarter to second quarter) (Fig 7B) marks the full extent of the dry season and the onset of the rainy season. Here inputs to the agrarian sector increase while outputs decrease, marked by the need for more people employed in agriculture as rainfall starts (e.g. to plow the fields). Interestingly, during this transition, precipitation vari- ability seems to have little impact on demographic flows and occupation decisions; thus, the seasonal flux of people entering the activity seems to be unrelated to the amount of precipitation. Fig 6. Livestock occupation immediate season. Correlation between mean annual precipitation and livestock raising occupation. The figure illustrates the immediate impact of drought on livestock herds, the lower the rainfall, the higher the number of workers who quit the livestock activity in any particular year. The Pearson correlation coefficient and significance test are presented in the top left part of the figure. (Source of data: calculations by the authors using EDER 2017 [50]). https://doi.org/10.1371/journal.pone.0313891.g006 PLOS ONE Agrarian abandonment and extreme events PLOS ONE | https://doi.org/10.1371/journal.pone.0313891 February 10, 2025 11 / 22