The 1.5 Health Report provides a summary of all the implications of global warming on human health and lives, as described in the IPCC Special Report on 1.5°
As scientists and public health professionals, we hereby offer this synthesis of the health content of the IPCC special report on global warming of 1.5C.
Climate change affects health through a range of different pathways: from extreme weather events, to infectious disease, to water and food security. The actions that would be necessary to keep global warming below 1.5C, would themselves have effects on health, for example in reducing the intolerable death rate from air pollution. These diverse connections mean that information on the health implications of restricting global warming are scattered throughout the IPCC report. This synthesis does the valuable service of bringing them together in one place.
The synthesis underlines three important messages. The first is that the greater the warming, the greater the risks to health overall. The IPCC special report makes clear that there are local variations and is frank about the uncertainties in attempting to give precise estimates of the health impacts under each scenario, particularly in specific locations.
However, that is not an excuse for inaction. The report is clear that some of the consequences of global warming, such as the sea level rise that threatens population health, and eventually the existence of small island states and low-lying communities, increase inexorably with temperature. Higher air temperatures eventually pass the thresholds above which it is safe to work or play outside. Increasing energy in the atmosphere, leading to elevated air and water temperatures, increase the potential for extreme weather events and the transmission of certain infectious disease. Uncertainty about the precise magnitude and pattern of these changes should be an argument for caution, not complacency. There is a strong public health case for limiting warming to the greatest extent possible.
The second message is that there can be important health gains from the actions that will be necessary to limit warming. Several important climate pollutants, including black carbon and methane, contribute directly or indirectly to the indoor and outdoor air pollution that causes approximately 7 million deaths a year around the world. Actions that target these pollutants can bring significant near-term health and climate benefits.
Policies that address the upstream drivers of climate pollution, such as cleaner and more sustainable electricity generation systems, and urban design and transport policies that facilitate walking and cycling, promote health in diverse ways while also cutting emissions of carbon dioxide, which is the greatest overall contributor to long-term warming.
The final message is that the speed of reducing emissions will affect the level of adaptation ambition required. The longer it takes to reduce emissions, the greater the adaptation needed to protect population health. No matter the extent of mitigation, there will be residual risks for health that health systems will need to manage.
Not every mitigation actions is beneficial for health, however. Increasing the use of biofuels could for example affect the availability of land for agriculture, thus affecting food security.
This highlights the importance of ensuring health professionals are engaged in decisions regarding specific mitigation actions to ensure that accompanying policies and measures are implemented to protect and promote population health when such actions are necessary.
Ultimately, the report supports a positive vision of a world which safeguards the climate- and is a safer and healthier place to live.
October 8, 2018
Kristie Ebi Lead Author, IPCC-SR1.5, University of Washington
Diarmid Campbell-Lendrum Climate Change and Health Lead, World Health Organization
Arthur Wyns External Reviewer, IPCC-SR1.5, Climate Tracker