Burning embers: synthesis of the health risks of climate change

Abstract

Since 2001, a synthesizing element in Intergovernmental Panel on Climate Change assessment reports has been a summary of how risks in a particular system could change with additional warming above pre-industrial levels, generally accompanied by a figure called the burning embers. We present a first effort to develop burning embers for climate change risks for heat-related morbidity and mortality, ozone-related mortality, malaria, diseases carried by Aedes sp., Lyme disease, and West Nile fever. We used an evidence-based approach to construct the embers based on a comprehensive global literature review. Projected risks for these health outcomes under 1.5 °C, 2 °C, and >2 °C of warming were used to estimate at what temperatures risk levels increased from undetectable to medium, high, and very high, from the pre-industrial baseline, under three adaptation scenarios. Recent climate change has likely increased risks from undetectable to moderate for heat-related morbidity and mortality, ozone-related mortality, dengue, and Lyme disease. Recent climate change also was assessed as likely beginning to affect the burden of West Nile fever. A detectable impact of climate change on malaria is not yet apparent but is expected to occur with additional warming. The risk for each climate-sensitive health outcome is projected to increase as global mean surface temperature increases above pre-industrial levels, with the extent and pace of adaptation expected to affect the timing and magnitude of risks. The embers may be an effective tool for informing efforts to build climate-resilient health systems including through vulnerability, capacity, and adaptation assessments and the development of national adaptation plans. The embers also can be used to raise awareness of future threats from climate change and advocate for mitigation actions to reduce the overall magnitude of health risks later this century and to expand current adaptation efforts to protect populations now.

Managing climate change risks is imperative for human health

“…e-mail: krisebi@uw.edu countries or regions and marginalized and/or under-resourced communities are particularly at risk. A 2021 analysis used an evidence-based approach to estimate the impact of climatechange-induced temperature increases on the risks of heat-related morbidity and mortality, ozone-related mortality, malaria, Lyme disease, West Nile fever and diseases carried by various species of Aedes mosquito, such as dengue fever and Zika virus 7 . The assessment determined the temperatures at which risks increase from undetectable to medium, high and very high levels compared to the pre-industrial baseline, under three scenarios of future development.…”

“…Adapted from REF. 7 , CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). www.nature.com/nrneph…”

Climate action for health and hope

“…15 16 Morbidity and mortality from heat, ground level ozone, and undernutrition are predicted to be much greater at 2°C of warming than at 1.5°C. 15 The higher threshold will also mean 61 million more people exposed to severe drought, 1.8 billion more people experiencing severe heatwaves at least once every five years, and twice the habitat loss for insects, plants, and vertebrates. 17 This is why health professionals must view advocacy for climate mitigation, both inside and outside the healthcare sector, 18 in the same way as cardiac catheterisation for STEMI.…”

“…20 Interventions and adaptations can reduce health harms when they are interdisciplinary, proactive, and prioritise iterative decision making in the face of uncertainty. 15 The climate crisis is a health crisis and, just like a STEMI, has a narrow window for intervention. The health community has a responsibility to respond to this dire diagnosis, and it is time for clinicians to do what they do best: generate evidence based hope through timely action on climate change.…”

Environmental health research needed to inform strategies, policies, and measures to manage the risks of anthropogenic climate change

“…Focusing on mitigation to keep warming to 1.5–2.0 °C ignores the inherent inertia in the climate system that will continue to drive anthropogenic climate change for several decades [ 3 ] and what that increased warming could mean for the magnitude and burden of climate-sensitive health outcomes. A synthesis of projections for six climate-sensitive health outcomes concluded risks will continue to increase as the global mean surface temperature increases, with the pace of adaptation altering the extent of risk [ 4 ]. In other words, adaptation and mitigation are equally important.…”