Climate change is causing a global health crisis that could approach the death toll of some of history’s deadliest pests. Unlike the 1918 flu epidemic or the COVID-19 pandemic, which were caused by the widespread outbreak of one type of bacteria or virus, diseases fueled by climate change are a Hydra-major challenge that is eroding human health on several separate fronts . Efforts are underway to quantify this risk, and a growing body of research suggests that climate-related health threats, such as cardiovascular, diarrheal and vector-borne diseases, already killed millions of people — a score that will steepen as the warming accelerates.
A recent one report of the World Economic Forum, a non-governmental organization that promotes public-private partnership on global issues, and Oliver Wyman, a consulting firm, project that rising temperatures will “place great pressure on global healthcare systems” in the coming years. Climate change will cause 14.5 million additional deaths by 2050, the report says, and spur $12.5 trillion in economic losses. Health care systems—hospitals, emergency rooms, doctors and nurses—will also have to provide $1.1 trillion worth of extra treatment by mid-century because of climate change.
These challenges will be felt most acutely in the Global South, where healthcare resources are already limited and governments lack the capacity to respond to cascading climate impacts such as worsening floods, heat waves and storms. According to the report, Central Africa and Southern Asia are two regions particularly vulnerable to the overlap of increasing climate health threats and limited resources.
“Climate change is changing the landscape of morbidity and mortality,” the report says. “The most vulnerable populations, including women, youth, the elderly, lower-income groups and hard-to-reach communities, will be most affected by climate-related consequences.”
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In total, the report identified six weather events that are likely to cause negative health outcomes: floods, droughts, wildfires, sea level rise, tropical storms and heat waves. The authors examined the direct and indirect effects of each of these events.
The burden of indirect impacts far exceeded the direct consequences. For example, flooding can cause landslides that injure and kill people during or immediately after a flood occurs. But the long-term consequences of flooding kill more people. Flooding eats away at coastlines, damages infrastructure and kills crops, which in turn contributes to the expansion of mosquito habitat, increases moisture and humidity in the air and fuels food insecurity. Infectious diseases, respiratory diseases, malnutrition and mental health issues follow. The report predicts that the biggest health consequences of extreme rainfall and flooding in Central Africa and Southeast Asia, two of the regions most affected by climate-driven flooding, will be malaria and post-traumatic stress disorder, respectively. The economic impact of these diseases and other flood-related health issues will exceed $1.6 trillion.
The report found that floods, which pose the greatest risk for climate-related deaths, will kill an estimated 8.5 million additional people worldwide by mid-century due to climate change. Droughts associated with extreme heat, the second largest driver of climate deaths, will lead to more than 3 million extra deaths. The report estimates that 500 million additional people could be exposed to vector-borne diseases such as malaria, dengue fever and Zika virus by 2050, many of them in regions that do not commonly experience those diseases today, such as Europe and the United States. The authors made these projections using a middle-of-the-road climate scenario, in which governments continue to make slow progress toward meeting international climate goals. If fossil fuel use continues unabated or increases further through 2050, the health consequences of climate change will be much more severe, and millions more will die.
Daniel R. Brooks, a professor of evolutionary biology at the University of Toronto and author of a book on climate change and emerging diseases, told Grist that it is encouraging that business-oriented institutions like the World Economic Forum are beginning to count the direct and long-term health effects of climate change. But he noted that more work needs to be done to capture the full extent of the climate change-related public health burden. “These staggering numbers are actually conservative,” said Brooks, who was not involved in the research.
Big epidemiological blind spots covering much of Africa, Southeast Asia and other parts of the world that have historically lacked the resources to collect and publish health and climate data. This means that studies that use existing data to make their projections, as this report did, necessarily miss a large part of the picture. “It is essential to recognize that the true toll of storms may be underestimated due to the lack of comprehensive data capturing indirect effects,” the report acknowledged in a section devoted to the health effects of tropical storms. “This is especially true for low-income and other vulnerable populations.”
Developed countries are already armed with much of the information and many of the tools needed to prevent the mass casualties the report projects. The authors outlined a multifaceted approach that these countries could take. The first step is obvious and essential: Reduce greenhouse gas emissions as quickly as possible. Every tenth of a degree of warming avoided equates to hundreds of thousands of lives saved around the world. “The holy grail will lie in prevention,” said Rolf Fricker, a partner at Oliver Wyman and a co-author of the report. “That’s the most important thing.”
Governments must also treat climate change like a public health crisis, and commit resources to establishing climate and health offices that will guide policy and redirect resources to where they are needed. The United States is an example of a country that started such a process in 2021 through a Office of Climate Change and Health Equity, which is awaiting congressional funding to begin assessing and responding to the risks climate change poses to Americans’ health. The US is something of an outlier in this respect. For example, Fricker, who lives in Germany, said his government has not even begun to quantify the health risks of climate change, despite facing extensive flooding issues and worsening heat waves in recent years. These climate impacts put hospitals, clinics and other parts of Germany’s healthcare system at risk.
In developing countries, where the resources to establish and finance such operations do not exist, wealthier governments, foundations and private companies must step in to fill the void, Fricker said. The Bill and Melinda Gates Foundation has tens of millions of dollars dedicated to this effortand other foundations do similar work, but the scale of investments must increase exponentially. A small fraction of the already limited international climate adaptation funding pledged by rich nations to the Global South is being devoted to health projects. More funding will put countries at risk to make their hospitals and clinics more resilient to climate change, develop medicines and vaccines that can protect people from the projected increase in vector-borne and diarrheal diseases, collect data on how climate change affects the public. , and educate communities about the dangers at hand and what lies ahead.
Last week, Barbados, Fiji, Kenya, the United Kingdom and a handful of other countries proposed a draft decision on climate change and health calling on members of the United Nations to invest in some of the solutions proposed in the World Economic Forum report. The draft, which could be adopted in the spring at the 77th World Health Assembly – the decision-making body of the World Health Organization – proposes that nations conduct periodic climate and health assessments, conduct disease surveillance monitoring and cooperate with other governments on the issue of climate change and human health . The draft, if adopted, would be a historic and important step to protect people from the impacts predicted in the report. Brooks, the professor at the University of Toronto, is hopeful that 2024 will deliver significant progress on the climate health crisis. “Not only do we have a number of challenges that are being addressed individually by very smart people,” he said, “but all of those challenges are related to and influence each other.”
