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

component of the country’s economy, history, and politics; however, its importance is declin- ing [27, 28]. Some researchers attribute this decline to the country’s development process, where a constant reduction has been observed [29]. This is partially the result of a large portion of the agricultural labor force shifting to the manufacturing or service sectors [27, 30]. How- ever, determining the causes of changes in agricultural employment is difficult, as the chal- lenges faced by farmers and livestock farmers are not solely due to socio-political and economic factors that limit their market inclusion [31, 32]. The shift in occupation is also likely influenced by climate. For example, it has been observed that during the period between 1980 and 2007there was a reduction in local employment by up to 1.4% linked to high heat inci- dence [33]. However, there is no long-term, nationwide longitudinal research that has studied the impact of climate variability on agrarian occupation. The objective of this project is to analyze how climate variability correlates with occupa- tional changes in the Mexican agricultural sector over the last four decades (1980–2017). We studied this over an extended period and at the national scale, comparing occupational changes (per year and per quarter) with annual precipitation. We were particularly interested in identifying how drought altered occupations in key vulnerable groups, such as farmers and livestock farmers, considering the total population surveyed. 2. Methodology 2.1 Study area

2.1.1 Biophysical characteristics. Mexico, situated in the southwest of the North Ameri- can continent [34], is a mountainous country spanning just under two million square kilome- ters [35]. Approximately two-thirds of its land area experiences arid or semi-arid climates, while the remaining third is characterized by humid climates [36]. Climate variability is strongly influenced by factors associated with the topography of the terrain and sea surface temperature [37]. For example, precipitation depends, among other factors, on phenomena such as El Niño and the hurricane season in the North Atlantic and Pacific [38]. Researchers have determined that Mexico’s geophysical features contribute to its highly complex and het- erogeneous landscapes [39]. These features facilitate the convergence of two biogeographic zones, the Nearctic and the Neotropical, fostering the development of species with temperate and tropical affinities [40]. Consequently, the soils exhibit high fertility levels, supporting vari- ous economic activities such as agriculture [41]. 2.1.2 Socioeconomic characteristics. To comprehend Mexico’s vulnerability to climate change, it is essential not only to analyze its geographical location but also to examine the high levels of poverty and the skewed income distribution within the country [35]. Poverty is not merely the absence of income; it represents the inability of individuals to fully participate in society and the deprivation of the freedom to satisfy hunger, receive education, and maintain

good health [42, 43]. Income distribution, on the other hand, involves providing equal oppor- tunities for individuals to attain desired capabilities [44]. In Mexico, between 2008 and 2018, the percentage of the population living in poverty at the national level decreased from 44.4% to 41.9% [45]. In other words, in 2018, approximately 42 out of every 100 people experienced at least one social deprivation and had insufficient monthly income to acquire necessary food, goods, and services. By 2022, this figure had reduced to 36 out of every 100 individuals [46]. Moreover, it has been reported that since 2014, two-thirds of the wealth has been concentrated in the hands of the top 10% of the country’s richest, with the top 1% of the very wealthy hold- ing more than a third [44]. It is worth noting that the impact of poverty and income distribu- tion is not uniform; there is a higher likelihood of accessing resources if one comes from the PLOS ONE Agrarian abandonment and extreme events PLOS ONE | https://doi.org/10.1371/journal.pone.0313891 February 10, 2025 3 / 22