The study brings together data on climate and population trends and quantifies the future global health impacts of climate change. It looks at both direct impacts of extreme weather like heat, floods and storms, and adverse indirect effects of food insecurity, poor air quality or even displacement. For instance, three times more people will be exposed to drought by the end of the century and four times more to extreme rainfall. In many areas, this implies no less than reversing development gains. Urgent action on mitigating climate change and preparing for its health-related challenges is needed: actual carbon emission rates have been even higher than in the worst-case scenario of the previous Lancet study (2009) on health and climate.

Major health co-benefits of climate action should encourage policy-makers to act more decisively. Fortunately, there is increasing momentum. For example, the intergovernmental Climate and Clean Air Coalition to Reduce Short Lived Climate Pollutants (CCAC), initiated in 2012, emphasises that mitigating methane, black carbon, and HFCs can help avoid two million premature deaths every year. In fact, air pollution was proclaimed one of “the leading avoidable causes of disease and death globally” by the World Health Assembly in a resolution of 26 May 2015, as every year 8 million deaths can be attributed to polluted air exposure indoor and outdoor.

This video explains the report's findings.