Climate Change Is Killing Us

Last summer, New Yorkers again found themselves wearing face masks and avoiding public places.

But, unlike four years ago, it wasn’t a virus that brought the city to a standstill. It was the air.

The orange haze that blanketed swaths of the East Coast over a couple of days in early June 2023 had travelled south from Quebec, where a record number of wildfires were burning. These fires and other blazes decimated more than 59,000 square miles of Canadian forests over the summer.

While most of the 2023 blazes in Canada were caused by human actions or lightning, according to Mike Flannigan, research chair of Predictive Services, Emergency Management, and Fire Science at Thompson Rivers University in British Columbia, speaking to USA Today, dryness in northeastern North America may have improved the conditions for the spread of the flames.

The wildfires’ impacts spread far beyond the obvious physical damage, threatening the health of countless people.

“There is no safe level of exposure for some of the pollutants associated with wildfire smoke, and as smoke levels increase, the health impacts also increase,” the Public Health Agency of Canada said in a June 2023 health risk profile as the fires burned. “While the health impacts of wildfire smoke exposure are greatest in those closest to the source of the smoke, wildfire smoke can travel large distances, and many studies have documented the adverse health impacts of wildfire smoke or wildfire [fine particulate matter] in populations at great distance from wildfires.”

As the climate changes, populations will deal with health issues from both heat exposure and its more deadly opposite, excessive cold, which during the 2000-2019 period caused 90% of all temperature-related deaths, according to a 2021 study by Lancet Planetary Health. Disease vectors and pollution add to the climate-induced concerns.

“There are a lot of people that think that climate change will take place in some remote time and place, but the point of fact is it’s here now,” says Howard Frumkin, senior vice president of the Trust for Public Land and former dean at the University of Washington School of Public Health. “We are seeing the effects close to home and in real time.”

With 2023 the hottest year on record by 0.27 degree F (0.15 C), according to the National Oceanic and Atmospheric Administration (NOAA), climate experts only anticipate the problem worsening. The number of climate-related disasters causing billions of dollars in damage skyrocketed from about five per year in 2000 to around 20 annually in 2020, according to a recent report by the nongovernmental National Commission on Climate and Workforce Health.

These events all directly impact our health.

“Climate change is harming human health, and that is unequivocal,” says Mary Hayden, research professor and behavioral scientist at the Lyda Hill Institute for Human Resilience. “And it’s not just our physical health but mental and spiritual, along with our community health and well-being.”

The death toll related to climate change from 2030 to 2050 is projected to be about 250,000 people annually solely from malnutrition, diarrhea, heat stress, and malaria, according to the World Health Organization (WHO). The National Commission report notes that about 62% of people who have health insurance through their employers have at least one chronic condition—for example, asthma or heart disease—that can be worsened by intense heat or poor air quality.

Health costs are expected to grow by billions or even hundreds of billions of dollars in coming years, based on different projections.

“Climate change puts the life and health insurance industry front and center in coping with the resulting health effects,” the Boston Consulting Group said in a January 2024 report, adding: “Health insurers must deal with more claims as well as higher overall costs and costs per claim. In addition, climate change tends to increase both short- and long-term inaccessibility to health care, heightening policymaker and regulator attention to rising health inequity and the industry’s response to it.”

Some insurance companies are already offering solutions for this reality, the report says. Boston Consulting offers an extensive set of additional avenues insurers can pursue to lead on climate change, including new products and services. The long list of separate measures for adapting the healthcare system encompasses adequate public health funding, increased disease surveillance, and providing sufficient cooling spaces during heat waves.

Getting Warmer

As of 2023, Earth’s temperature was on average 1.35 degrees Celsius higher than the pre-industrial average from 1850 to 1900, NOAA says. The nonprofit National Center for Atmospheric Research has estimated that, by the end of this century, global temperatures will rise by 4 degrees Celsius (7.2 degrees Fahrenheit) if greenhouse gas emissions are not drastically reduced.

To put that into perspective, scientists estimated that an event like the June 2021 heat wave in the Pacific Northwest—which would normally occur every 1,000 years or so—could happen every five to 10 years if temperatures reach 2 degrees Celsius higher than pre-industrial levels. During the heat wave, temperatures exceeded 104 degrees Fahrenheit over a three-day period. These record-setting temperatures happened a month before the normally warmest days in this area and caused several hundred deaths.

These northern areas—where people are unaccustomed to managing increasing heat (and are ill-prepared)—are particularly vulnerable to its health consequences. Seattle, for instance, has less air conditioning than most metropolitan areas in the United States, with units in about 50% of homes and apartments.

According to the federal government’s Fifth National Climate Assessment submitted to Congress in November 2023, extreme heat has myriad impacts on human health. Those include adverse effects on pregnancies and mental health, along with more patients being brought to hospitals for conditions involving heart disease, renal failure, respiratory health, and other conditions.

“Heat-related health impacts are greatest among children, adults over age 65, those with disabilities, people with mental health or substance-use disorders; and those who are pregnant, lack access to cooling, or engage in outdoor labor and activities,” the report says.

A 2023 meta-analysis published in the journal Neurology examined research on the association between common neurological conditions and increased temperatures. One report the study authors analyzed found that a mean rise of 1.5 degrees Celsius increased emergency room visits for New England residents with dementia by 12% during the summer.

Rates of new asthma diagnoses in children could increase by 34,500 to 89,600 annually when temperatures rise by 2 degrees Celsius and 4 degrees Celsius, respectively, according to the Environmental Protection Agency (EPA). Hospital visits for children with asthma could increase from 6,240 to 15,800 with equal temperature increases.

Warmer weather and more exposure to particulate matter can increase inflammation levels and increase blood coagulation, exacerbating heart disease, stroke, and related conditions. A 2022 meta-analysis in Nature Reviews Cardiology found that research in the space is somewhat conflicting but that an increase in temperature by 1 degree Celsius increased deaths from stroke by about 1.5% and mortality from cardiovascular disease by about 3.44%. The study looked at 18 papers spanning from 1975 to 2015 that were based in Europe, Asia, North America, and South America.

Older people tend to have limited mobility so may find it harder to leave an area impacted by extreme heat or flooding. They are also more likely to have one or more chronic conditions that make them susceptible to the negative impacts of air pollution.

Simply going inside to escape the heat is not necessarily an answer or even possible for some. People who work outdoors and homeless people, among other populations, all have high exposure to heat.

Because urban areas have replaced grass and trees with buildings and pavement (which absorb and hold heat), many major cities are impacted by the “heat island effect.” If you layer increasing heat duration and frequency and longer heat wave seasons on top of heat islands, the already-stressed cities become even more vulnerable to rising temperatures. Today, urban areas in North America have a mean of 19 days a year in which the temperature spikes higher than 95 degrees Fahrenheit. If temperatures rise by 1.5 degrees Celsius, that could increase to 28 days; if temperatures rise by 3 degrees Celsius, that number would be 48 days, according to a 2023 report by the World Resources Institute.

“Historically, people living in red-lined communities, which are often BIPOC [black, indigenous, and other people of color] and low-income often live in areas that tend to be hotter,” Lyda Hill Institute’s Hayden says. “And economics plays a big factor. People may not be able to afford air conditioning or, if they have it, the electricity to run it or fix it if it breaks.”

Older people may live in old houses that aren’t weatherized as efficiently as new ones. And people who are socially isolated (often older people or ones who are disabled) may not have someone to check on them during extreme weather. Or they may not have the transportation or resources to get to a cooling center, Hayden says.

Airborne Threats

The smoke that drifted south from the Canadian wildfires last summer led the EPA to declare the air in many places hazardous. Not only do trees burn during a wildfire, but the blazes roll over homes and cars, burning metal and synthetic materials and releasing carcinogenic compounds into the air.

Scientists suggest the problem and its health repercussions will only worsen in the coming years. Rising temperatures, coupled with drier forest conditions caused by climate change, only increase the amount of arid fuel (trees, brush, and grasses) primed to burn. Human-induced climate change has been responsible for much of the decreased moisture in forest vegetation in the western United States in the past few decades and has also doubled the areas that burned from 1984 to 2015, according to NOAA. The federal agency also noted that, should temperatures rise by, on average, 1 degree Celsius annually, western states would see a median increase in area burned by up to 600% in some places. The Southeast could also see a 30% increase in burn area by 2060.

Breathing in wildfire smoke causes lung problems and aggravates asthma. But it is also dangerous for people with underlying heart conditions like angina (chest pain). High air pollution can also increase the number of ER and hospital visits due to asthma-related illnesses and increase the risk of premature death. During the October 2007 wildfires in Southern California, there were three more visits than normal to the ER for shortness of breath each day and about two more diagnoses of asthma in the ER every day when compared to pre-fire levels.

“Wildfire smoke is really bad,” says Kim Knowlton, assistant clinical professor at Columbia University’s Mailman School of Public Health. “And it is increasingly coming indoors. With air conditioners, you can recirculate indoor air, but during wildfires, those don’t even work enough to keep the indoor air clean.”

Allergies have also worsened in recent years. Various factors contribute to allergies, but climate-related contributors include increasing temperatures and air pollutants spurring plants to produce more pollen (studies have shown that pollen created near roads with high traffic is more allergenic than pollen created in lower-traffic areas). Hotter weather has also made allergy season arrive earlier and last longer.

“It’s soon going to be tree pollen season, and with higher temperatures and higher carbon dioxide levels, there is a lot more pollen made over a longer period of time,” Knowlton says. “And there is some evidence that pollen grains may be causing a worse reaction.”

Extreme Weather Events

Hurricane formation requires a weather disturbance near an ocean coupled with warm water, humidity, and winds. Experts say climate change may not necessarily be causing more hurricanes but it can contribute to stronger ones (studies have shown a 25% increase in Category 4 and 5 storms per 1 degree Celsius of temperature increases) that produce much larger amounts of damaging rain, intensify more quickly, and move more slowly across inhabited areas.

A hurricane or other severe weather event causes immediate injuries and deaths from exposure to the elements. People drown, are injured by wind and falling trees and structures, and are electrocuted. Hurricane Katrina, which devastated New Orleans and other areas of the southeastern United States in August 2005, has been connected to between 1,300 and 1,850 direct and indirect deaths. Recovery from disasters on this scale can also be dangerous—a 2021 article in the International Journal of Environmental Research and Public Health cited frequent injuries from mishaps including chainsaw use, falls, lacerations, and car accidents.

Such a major climate event can also exacerbate long-term conditions, causing indirect and excess deaths. People with chronic health conditions often suffer from the disruption in medical care that comes when hospitals and other health providers are shuttered. More than 1,200 excess deaths were reported in the two months after Hurricane Maria hit the Caribbean in 2017, from conditions including heart disease, Alzheimer’s disease, and diabetes. The deaths were determined to be directly related to the event.

Air quality is greatly impacted by extreme weather events like floods and hurricanes. When a hurricane hits an area, water causes mold in buildings, and damaged structures can release contaminants into the air. After Katrina, for instance, there were reports of illnesses like sinusitis, lung irritation, and “Katrina cough,” according to an International Journal of Environmental Research and Public Health article. Cleaning up after a hurricane can also expose people in the area to airborne contaminants including carbon monoxide and gasoline. These things also exacerbate conditions like cardiovascular disease, asthma, and allergies.

One underreported impact of extreme weather events is the mental health toll it takes on residents of the communities.

“There is displacement, loss of community, and it can just be really scary going through one of these events,” Hayden says. “It causes an incredible leap in people’s anxiety levels.”

Months after Hurricane Sandy in 2012 there was an increase in visits to healthcare providers and to emergency rooms for mental health-related issues in eight counties touched by the storm in New York state. Reports of depression, post-traumatic stress disorder, and anxiety increased in many areas after hurricanes including Sandy, Mitch, Katrina, and Rita. These effects can linger for years, particularly among people who experienced the loss of a loved one, saw or experienced violence during the event, could not get needed healthcare, or had major material losses. The journal article also noted that children 5 and younger who experience at least one major natural disaster have an increased risk of mental health disorder into adulthood.

“There are young adults choosing not to have children because of climate change,” Knowlton says. “There are mental health harms to people who may just be disturbed by the state of environmental disruption. We have to face that and figure out how to increase our resilience.”

Diseases on the Move

Climate change is not only dislocating humans from their natural environment; it is doing the same with disease-carrying pests.

Mosquitoes, in particular, are moving from their normal environments into others because of milder temperatures and increased rainfall. With this, diseases they spread are moving to these new locales as well.

Hayden, who studies mosquito-borne diseases, says the movement of the dengue virus is a telling indicator of this phenomenon. The condition is typically found in the Middle East, Africa, the Pacific Islands, and Asia. It’s not typically found in the United States but has begun popping up in hot, humid areas. Along with a small number of people infected in California last year, there was an outbreak of 88 locally acquired cases in Key West, Florida, in 2009 and 2010.

“We have two kinds of threats from mosquitoes,” Hayden says. “One is with those with West Nile spreading, and the other is mosquitoes bringing new, typically tropical, pathogens into the U.S.”

 Malaria, another mosquito-borne disease, is also spreading in many countries. According to the Third National Climate Assessment issued in 2014, the disease’s transmission season in North America has lengthened by one week. This is likely due to an increase in heat, rainfall, and humidity in some areas that increase the number of mosquitoes that carry the disease. (Malaria is transmitted year-round in tropical climates and seasonally in other areas. The temperature must be higher than 68 degrees Fahrenheit for the protozoa that causes the disease to grow.) Warmer climates could increase transmission of the disease in new areas and worsen it where it already exists, according to the United Nations.

Ticks are another pest expanding their footprint, along with the diseases they carry. According to the Centers for Disease Control and Prevention, about 63,000 cases of Lyme disease were reported to the CDC in 2022, though 2000-2018 CDC insurance data on treatment for prevention and diagnosed infection suggest 476,000 people in the United States are seen each year for Lyme symptoms. Hayden says that tick-borne Alpha-gal syndrome, a condition that causes an allergic reaction to many meat and dairy products, is also increasing in prevalence in the United States.

Heat impacts air quality in other ways as well. Cryptococcus gattii, a fungus normally found in warm climates, has recently migrated to the northern United States. When inhaled, the spores can cause a lung infection similar to pneumonia and cryptococcal meningitis (a brain infection). The fungus, found in British Columbia in 2000, spread down into Washington state by 2006.

“We’ve had just a few cases but it’s a reminder we aren’t immune from ecosystem changes that lead to the spread of microorganisms which can be pathogenic for humans,” Frumkin says.

Adapting the Healthcare System

NOAA provides estimates of the cost of extreme weather events, but it doesn’t tease out the healthcare expenses that result.

Estimates of the actual costs vary widely, depending on how the data are tallied. For instance, the WHO projects costs of direct damage to health will be between $2 billion and $4 billion annually by 2030. The nongovernmental Natural Resources Defense Council logged in a much higher prediction—$860 billion a year for the United States alone. That tally included premature deaths, prescriptions and medical visits related to climate change, lost wages, reduced worker productivity, and other downstream health costs.

In 2019, Knowlton and colleagues released a report analyzing the mortality and morbidity costs of several events that hit the United States in 2012. They tallied health costs of wildfires in Colorado and Washington; air pollution in Nevada; extreme heat in Wisconsin; Lyme disease outbreaks in Michigan; West Nile outbreaks in Texas; extreme weather in Ohio; Hurricane Sandy in New York and New Jersey; oak pollen in North Carolina; and algal blooms in Florida. From these events they found 917 deaths, more than 20,000 hospitalizations, and nearly 18,000 visits to the emergency room. The costs totaled about $10 billion.

“For society at large, we need to get our arms around the cost of this,” Knowlton says. “When people are affected by extreme weather events, it leads to premature mortality, increased healthcare and ER visits, lost workdays, and decreased worker productivity. We are causing this, and we need to uncause it.”

Whether or not we are able to curb rising temperatures, climate change will still impact the country to varying degrees in the coming decades. Prevention of negative impacts is important, but there also has to be a focus on resilience.

“A climate-resilient health system can ‘anticipate, respond to, cope with, recover from, and adapt to’ climate change to improve the health of communities,” the Fifth National Assessment says. “Focusing on equity, proactively addressing mental health needs, and linking to community health resources such as community health workers and long-term support and services can create a climate-resilient health system.”

Among the assessment’s recommendations: establishing surveillance systems for infectious diseases that could get a climate boost, along with other health threats such as heat stroke and impacts on mental or behavioral health; ensuring widespread access to cooling locations during a heat wave and enhancing heat warning measures; better management of combustible material in areas prone to wildfires; and community-focused adaptation and resilience methods.

Each community will have different solutions for localized climate impacts. For instance, Frumkin says, our hospitals should be improved so they are the last buildings standing in a community. Generators should be in the attic, not the basement, so the facilities can maintain operations during floods. Hospital staff should be trained in trauma and ways to manage patients’ mental health needs during and after traumatic events.

Public health should be well funded to support disease surveillance in communities. A simple way to combat some vector-borne diseases is to have mosquito control offices in areas where West Nile and other conditions are present.

Where heat is a problem, public cooling spaces should be ample. People should be educated to check in on loved ones, neighbors, and friends who may be dealing with social isolation during weather events. New York City has created a Be a Buddy program to distribute information to people vulnerable to heat waves and has increased the number of cooling stations in the city. Heat warning systems, and those for extreme weather events, need to be augmented so people can be forewarned and prepared.

After analyzing its exposure to climate change, Chicago has taken steps to make flat roofs meet Environmental Protection Agency Cool Roof standards. The city also has a process to expedite the permit processes for green building projects.

 Health and life insurers in the United States haven’t really begun grappling with the issue yet, but the industry has a “chance to lead,” the Boston Consulting Group says. “Where there is risk there is also often opportunity.”

The consulting firm recommends four approaches for insurance leadership on climate change.

• Develop greater insight on how climate change affects business, including by working with climate-focused research organizations and joining policymaking talks on the intersection of climate and health.
• Establish educational campaigns, apps that provide time-sensitive alerts and data, and other programs to enhance prevention and response for climate-related health threats.
• Prepare products and customer-focused procedures for climate threats, such as broader coverage for diseases with expanding geographic ranges and generally augmenting equitable access to healthcare.
• Create a range of new offerings, encompassing everything from wellness programs for endangered populations to investing in companies that manufacture heat-resistant clothes for outdoor workers to providing services for drug delivery and in-home care.

As noted in the report, insurers in other countries are already taking steps in this direction.

Two major insurers in Japan have created heatstroke plans that allow people to opt in on a day-to-day basis for US$0.73 based on that day’s weather forecast. The health plan covers medical costs for conditions related to heat exposure. In Australia, some health insurers offer premium waivers to customers for a couple of months after natural disasters like wildfires or floods.

“We need collaboration and cooperation over scale,” Hayden says. “It will take government resources, but we also need to design solutions at the community level to address inequities. One size does not fit all.”