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

4. Discussion 4.1 Long term agrarian occupation variability Human societies are complex systems characterized by multiple patterns, structures, and prop- erties that determine their demographic processes [63]. Therefore, deterministic narratives that suggest climate inevitably causes migration, violence, or ill health should be avoided [64]. Thus, climate should be conceived as one of several factors influencing decision-making in the face of potential challenges facing humans [65], and not as a delimiting factor. In that sense, the control of climate over agriculture is evident, but how this influences people’s decisions it’s mediated by a plethora of other factors. In the particular case of our study, climate seems to influence agrarian occupation, particularly during extreme dry years. In the long term we found a steady decline of people engaged in agriculture in Mexico from 1980 to 2017, consistent across all datasets. This was also reported by Herna´ndez Pe´rez [66], who estimated a loss of more than one million rural jobs (1,178,067) between 1995 and 2020. Similarly, Weisbrot et al. [67] reported a decrease of 1.9 million jobs, but the loss was in family labor employed in the family farm sector. Cypher and Crossa [68] argue that this phenomenon is an indication of the country’s agrarian policies, since Mexican manufacturing employment increased, but never counteracted the vertiginous reduction of labor and disarticulation of the peasant economy. Weisbrot et al. [67] further explain that this phenomenon develops because

family farms in Mexico cannot compete with subsidized U.S. production. So, workers are dis- placed to other occupations, such as industry or seasonal jobs, including growing vegetables or fruits for export. Therefore, it is undeniable that there is research focused on explaining the decrease in Mexican agrarian occupation as a socioeconomic and political consequence. How- ever, not much is known about the influence of climate, specifically the high variability in pre- cipitation, on the decision making of farmers and livestock farmers. We found that the average age at which individuals abandon agrarian occupations has con- sistently increased over time, indicating a gradual exit from agricultural work. Initially, youn- ger people tend to leave first, followed by older individuals as we get closer to the present day. A study by the Food and Agriculture Organization of the United Nations (FAO) and the Secre- tariat of Agriculture and Rural Development (SADER) [69] revealed that by 2014, nearly 60% of the agricultural workforce in the country was over 50 years old. This is significant because older farmers may leave due to health issues or the presence of a successor, whereas younger farmers often exit for professional, lifestyle, and financial reasons [70]. Therefore, it would be incorrect to conclude that the abandonment of agrarian occupations is primarily driven by demographic age factors; instead, this aspect is secondary to other individual and household characteristics [71]. In addition, we identified the climate influence on the agrarian occupation in Mexico on

two-time scales: first, across years, and secondly, throughout the year. These results align with Zhao et al. [72], who demonstrated that there are inter-annual variations in agricultural market yields as a consequence of the incidence of climate. However, this phenomenon is further mag- nified by endogenous market fluctuations generated by producers’ imperfect expectations about weather conditions. 4.1.1 Interannual variability. In terms of interannual variability, our results suggest that rainfall influences the percentage of people engaged in rainfed agriculture and livestock in every year and the subsequent year. Similar relationships have been observed by other researchers. For example, Macfarlan et al. [73] found that livestock farmers in Baja California Sur adjust herd composition and usage during drought years, becoming more risk averse. The authors suggest that future expectations are important in the preference structure. Thus, indi- viduals who expected to lose a substantial fraction of their herds during a drought were more PLOS ONE Agrarian abandonment and extreme events PLOS ONE | https://doi.org/10.1371/journal.pone.0313891 February 10, 2025 13 / 22