Global health. The current scenario and future perspectives

100 Climate change, the limits of the biosphere and risk The magnitude of the changes on the planet in the last 100 years has been marked by climate change, with increasing temperatures, and has defined a new era known as the Anthropocene, which corresponds to “the temporal interval in which many geological processes are profoundly altered by human activities” (Moreno et al., 2018, p. 16). There is consensus among scientists that the environmental changes the planet has experienced in the last century are unprecedented. The thresholds to sustain life as we currently know it are out of control (Rockström et al., 2009). In 2018, global alarms were raised, triggered by the communication from the Intergovernmental Panel on Climate Change (IPCC): the temperature of the planet cannot increase by 1.5°C (IPCC, 2018a). The effects of global warming had been reported for decades by the IPCC, with irrefutable evidence such as increased tides, accelerated ice loss in the poles, glacier melting and changes in hydrometeorological events. However, it was not until 2018 that the direct link between biodiversity loss and climate change was strongly emphasized. The gravity of these events is expressed not only by the loss of ecosystems and species but also by the risk to humanity and its inhabited spaces. Land use change is the greatest threat to biodiversity, mostly driven by agriculture. Its expansion affects native terrestrial ecosystems as well as continental and coastal water ecosystems (Foley et al., 2005; Newbold, 2018). There is consensus among scientists that the interaction of direct and indirect “drivers of change” influences nature and our impact on it. The “direct drivers” of change on nature that affect all types of ecosystems include climate change, pollution, deforestation, and invasive exotic species. The indirect drivers correspond to the underlying causes of environmental change, such as public policies with perverse incentives, governance systems or the lack thereof, societal constructed threats, and economic inequalities, among others. All of these drivers can act independently or synergistically (IPBES, 2019). Climate change has been identified as the factor with the greatest impact on biodiversity in the coming decades. Along with increasing temperatures and changes in precipitation, chemical and biological phenomena occur synergistically and create unstable and adverse conditions for species and ecosystems. This leads to changes in migratory patterns and the composition of biological communities (Arneth et al., 2020) as well as the structure and functioning of various terrestrial and aquatic ecosystems (Walther et al., 2002; Brooker et al., 2007, cited by Koleff et al., 2019). Furthermore, climate models have been improved with more and