Over the past 30 years, numerous scientific reports have highlighted the health impacts of climate change, starting with the first Intergovernmental Panel on Climate Change Report in 1990. The report included a short summary on heat stress, vector and water borne diseases and air pollution health effects like asthma and heart attacks.
Yet health impacts are not fully accounted for in cost of carbon estimates – presenting a missed opportunity. Public health researchers and economists should continue to work together to more fully capture the health value of policies that cut climate pollution.
Climate and health
The most recent National Climate Assessment, published in 2018, provides an extensive review of climate change effects on human health in U.S. regions. Public health impacts include:
- changes in mortality and hospitalizations due to extreme weather events including heat waves, floods, and droughts.
- changes in vector-, food-, and waterborne infectious diseases.
- changes in chemical exposures via air, food and water.
- stresses to mental health.
The World Health Organization (WHO) quantifies global health impacts of climate change, utilizing the burden of disease methodology to estimate mortality and disability-adjusted life years. Based on heat-related mortality, diarrheal disease, malnutrition and malaria, the most recent WHO assessment projected 250,000 additional deaths per year in 2030 – despite only quantifying a subset of health impacts from climate change.
The Lancet has also commissioned several series of articles and reports detailing the human health implications of climate change. After the Paris Agreement, the outlet initiated the Lancet Countdown, tracking the status of health effects from climate change through reporting on numerous indicators across impacts, exposures and vulnerabilities, as well as adaptation and mitigation actions. For example, the most recent Lancet report estimated a 53.7% increase in heat-related mortality over the last 20 years and an estimated 15% increase in climate suitability for transmission of dengue.
Health benefits largely absent
Benefit-cost analysis – typically managed by economists – is a cornerstone of U.S. regulatory analysis. The U.S. Government is required to use a monetized estimate of the net impacts of global climate change, referred to as the social cost of carbon (SCC), in regulatory rulemakings of greenhouse gas emissions. The current models used to estimate the SCC incorporate impacts to agriculture productivity, energy use, property damage and, within the health sector, an estimation of changes in cold and heat-related mortality.
Yet, while the research community continues to provide more detailed characterizations of climate change’s health effects, health researchers have been less involved in applying these findings to estimate the SCC. As a result, health is still not fully represented in the SCC.
Quantification of health benefits, like lives saved and hospitalizations avoided, can provide critical justification for and evidence of success of environmental policies. For example, the regulatory impact analysis of the Clean Power Plan included an estimation of health and other benefits from reduced greenhouse gas emissions using the SCC estimate, as well as expected health co-benefits via reduced air pollution.
Improving health benefits estimates
A 2017 National Academies of Science Engineering and Medicine report recommended two critical research needs for advancing the science behind the SCC estimate:
- Updating health damage modules to incorporate recent health literature.
- Improving delineation of the different effects of climate change across regions of the world – e.g., trying to determine the different health impacts expected in different areas.
Since the release of this report, several groups have been working to address these recommendations. For example, the Climate Impact Lab has developed an improved temperature-related mortality estimate that incorporates adaptation and delineates distributional effects across areas of the globe.
A recent analysis utilized WHO, Climate Impact Lab, and Lancet Countdown temperature-mortality functions to produce estimated mortality costs associated with climate change – suggesting a seven-fold increase in estimated monetary damages from previous estimates. In other words, adding in more specific health damage estimates increased the estimated cost of carbon pollution by seven times—from $37 to $258 per metric ton of carbon dioxide emitted.
Although climate change is a global phenomenon, the impacts are unequal and disproportionately burden underserved, low-income and marginalized communities. For example, the U.S. Environmental Protection Agency found that socially vulnerable populations are likely to experience the most severe harms from climate change. Evaluating distributional health effects of climate change at a finer geographical scale could help policymakers address inequities.
It’s critical for policymakers to have accurate information to weigh the benefits and costs of cutting carbon. With health researchers involved, benefit-cost analyses can more accurately capture the threat that climate change poses to people’s health – and the benefits that come with acting on climate.