Climate change and human health

Climate change is probably the most complex global challenge to which the environmental sciences have been alerted since their inception. It has, or is likely to have, major impacts on health, via a variety of more or less finely characterized mechanisms : increased frequency of temperatures and extreme climatic events, rising sea levels and acidification, changes in the distribution of infectious disease vectors and biodiversity, and so on. Given that the main greenhouse gas-emitting sectors responsible for climate change (transport, agriculture, energy production) are also linked to major health risk factors (physical activity, diet, exposure to atmospheric pollutants), measures to adapt to and combat climate change could a priori be as much a threat to public health as an opportunity to improve it. More generally, given the commitment of governments to create greenhouse gas-neutral societies within the next thirty years, and the current role of fossil fuels in all sectors of activity, climate change is likely to lead to a profound restructuring of all these sectors in the short term. The challenge for science and society is to accompany this restructuring by ensuring that, in addition to limiting greenhouse gas levels, health improvements and the reduction of inequalities within and between countries are also targeted. This illustrates the ability of environmental health research to identify conditions contributing to the well-being of populations, which is the side that prescribes, complementary to the other side, which proscribes and seeks to limit the effect of the pollutants of greatest concern, presented in the previous lessons.