Global health. The current scenario and future perspectives

121 Figure 2. Keeling Curve of atmospheric CO 2 concentration measured at the Mauna Loa Observatory as of July 11 th , 2022. Source: Own elaboration. Data source (Tans & Keeling, 2022). As a result of the increase in atmospheric GHG concentration, more heat is trapped in the atmosphere, which leads to an increase in atmospheric temperature and global warming (Figure 1, right diagram). This phenomenon, known as global warming has been defined as “an estimated increase over a 30-year average of the Earth’s surface temperature relative to pre-industrial levels, unless otherwise specified” (IPCC, 2022). According to IPCC data, from 1850-1900 to 2010-2019, the increase in global temperature caused by human activities has been 1.07°C (IPCC, 2022). The increase in temperature in the atmosphere has caused alterations in the climate system, which results in changes in rainfall patterns, melting ice, rising sea levels, droughts and other effects. These changes in the climate system are known as climate change, which has also been defined by the IPCC as “a change in the state of the climate that can be identified by changes in the mean and/or variability of its properties and that persists for an extended period, typically decades or longer” (IPCC, 2022). Furthermore, this alteration can be caused by “natural internal processes or external forcings, such as solar cycle modulations, volcanic eruptions and persistent anthropogenic changes in atmospheric composition or land use” (IPCC, 2022).