Heat wave risks to health clearly increase with increased warming, but adaptation can make a difference, IPCC Says
The Intergovernmental Panel on Climate Change (IPCC) this week released a Special Report on 1.5°C, outlining the impacts of global warming of 1.5°C and 2°C above pre-industrial temperatures. The report concludes that climate change is already affecting human health, including by increasing the number of deaths caused by heatwaves. It also concluded that each additional unit of warming will further increase these risks if no actions are taken to reduce greenhouse gas emissions and to implement programmes to protect population health.
Requested at the United Nations climate summit in Paris in 2015 by the 21st Conference of Parties (COP21), the Special Report on 1.5°C was tasked with informing global leaders of the impacts of global warming at levels of 1.5°C and 2°C. A synthesis of the health implications outlined in the special report was prepared by lead authors in collaboration with the World Health Organization.
The assessment evaluated projections of heat-related mortality in a changing climate published over about the last decade. Key findings of the assessment included that climate change has already contributed to increased heat-related mortality; that climate change is affecting the frequency, intensity, and duration of heatwaves; and that exposure to high ambient temperatures is projected to increase with further warming.
The extent to which mortality could increase with rising temperatures will vary by region, presumably because of acclimatisation, population vulnerability, the built environment, access to air conditioning, and other factors. Populations at higher risk include older adults, children, women, those with chronic diseases, and people taking certain medications.
Dr. Kristie Ebi, an author of the report, and member of the Global Heat Health Information ad-hoc Steering Committee says that, ‘This report underlines some important messages. The first is that the greater the warming, the greater the risks to overall health. The second, is that there are many co-benefits to health from actions to mitigate climate change, such as improvements in health outcomes associated with air quality via reductions in black carbon emissions. Large public health investments are needed because no matter the extent of mitigation, there will be residual risks that health systems will need to manage.”
"Adaptation has reduced the impact of heatwaves on human health"
Evidence assessed in the report suggests that adaptation can reduce the impacts of heatwaves on human health. Therefore, projections of mortality at higher temperatures that assumed additional adaptation to heatwaves found a reduction in the magnitude of health risks.
The report suggests that heat action plans that provide early alerts and advisories combined with emergency public health measures can drastically reduce heat-related morbidity and mortality. These findings underscore the need to invest in adaptation and preparedness, and to rapidly scale up efforts to manage the complex human health risks associated with exposure to extreme heat.