Global health. The current scenario and future perspectives

104 constitute or are part of biodiversity (Sarukhán et al., 2009). We are not only ending the lives of several species, but we are also making many areas of our planet uninhabitable. Pesticides are used to protect crops from pests, agrochemicals are used to replenish lost nutrients due to intensive soil use, but this reduces the diversity of species necessary for biological and productive balances. The use of fertilizers by the agricultural industry has increased to the point that in 2007, developing countries used 160 million tons compared to 40 million tons in developed countries (Marquet et al., 2018). Lakes, rivers and coastal areas reported on between 2008 and 2010 shows high levels of fecal coliforms (serious concentration that exceeds thresholds) in practically the entire coastal area of Latin America and the Caribbean (UNEP 2016, cited by Ramsar 2018). The introduction of livestock and forest plantations and the replacement of native forests have had devastating effects on global biodiversity, particularly in Latin America (Vinicius et al., 2018; González- Andújar et al., 2018), as well as on water availability, according to studies carried out in Chile (Lara et al., 2009; Little et al., 2010; Alvarez-Garreton et al., 2019; Marquet et al., 2018). Consequently, the ecological integrity of rivers and wetlands is being altered, and everything that happens in their surroundings affects them. Alterations in these systems have synergistic causes and patterns, and global scientific research has shown the risks to our subsistence (Ramsar 2018). Aquatic ecosystems tolerate some stress conditions with certain thresholds of tolerance, but when exceeded, they cease to be resilient and change their configuration in terms of structure and function, and can become a social and health problem. Appealing to the theoretical framework of social metabolism (Fischer- Kowalski 1998; Toledo 2013), it can be argued that as society increases its needs, it relies on these systems to meet them, without considering their complexity. The social and global metabolic process is similar to processes at cellular and organism level. However, it seems that society as a whole produces, discards and consumes beyond the limits it can bear and far beyond the limits that the biosphere can sustain. Thus, the social metabolism, with its various levels, leaves its mark by taking what it requires (a first level of “appropriation”; Toledo et al., 2013, p. 47) and discarding what it does not need (from industrial to organic waste). In this process, we accumulate material goods such as houses, industries and roads, or expand agricultural land, but our development capacity is reduced. This leads to an environmental and social crisis, and, as Toledo (2013) states, we have a problem created by society “with new dynamics and unpredictable synergies” (Toledo 2013, p. 41) and “planetary boundaries” (Rockström et al., 2009; Steffen et al., 2015) that leave many people out of