Global health. The current scenario and future perspectives

122 The United Nations Framework Convention on Climate Change (UNFCCC) in Article 1 of its declaration defines climate change as “a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods” (United Nations, 1992). All these changes in the climate system have a domino effect on other natural systems, including human systems. There is sufficient evidence as to how the effects of climate change negatively impact population health, with the most vulnerable populations generally being the most affected. Climate Change and Human Health: A Close and Dangerous Relationship This section analyzes the main effects of climate change on human health by separating them illustratively into direct and indirect effects (Figure 3). Figure 3. General diagram of the effects of climate change on population health.