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Climate Change and Health: Managing Health Impacts in a Warming World

Contributor Wynne Armand, MD
11 minute read
Many hands holding up a globe against a background of sea and sky.

The scientific evidence is clear: Earth’s temperature is rising faster than at any point in the last 10,000 years. That increase is leading to dramatic changes for the planet — and for the people who live on it.

“Climate change is already impacting health,” says Wynne Armand, MD, a Mass General Brigham internal medicine doctor and associate director of the Center for the Environment and Health at Massachusetts General Hospital.

Those impacts can feel overwhelming and, sometimes, unavoidable. But by understanding the health risks of climate change, you can take steps to protect yourself and the planet.

What is global warming?

Since the mid-1800s, the average temperature of the planet has climbed sharply and steadily. A wealth of scientific evidence reveals that humans are to blame. The fossil fuels we burn for energy release carbon dioxide into the atmosphere, trapping heat.

That heat is transforming our home planet, spurring heat waves, severe weather, melting glaciers, and a rising sea level. Such changes pose the greatest risks to vulnerable populations, including people who lack stable housing, clean water, or adequate food. But anyone — in any country — can experience the health effects of climate change.

With increased heat and more carbon dioxide in the atmosphere, plants produce more pollen. And allergy season is getting longer, lasting for more weeks or months of the year in many places.

Wynne Armand, MD
Internal Medicine Doctor
Mass General Brigham

How does climate change affect health?

In North America and around the world, climate change poses a risk to human health in a variety of ways:

Heat waves

The most obvious risk of global warming is increased heat. “As temperatures rise, we’re experiencing more heat waves, with higher temperatures, lasting for longer periods of time,” Dr. Armand says. Very hot weather is most dangerous for infants and older adults. It can also be unsafe for people who are pregnant or have a chronic illness, and those who must work outdoors. High temperatures can trigger asthma attacks and breathing problems, heart attacks, and preterm labor. High temperatures, especially with high humidity, can also lead to heatstroke — a condition that occurs when the body can’t cool itself by sweating, causing a dangerous spike in body temperature. Staying safe exercising in the heat is one way to help reduce your risk of heat stroke.

Natural disasters

Researchers predict that climate change will bring more severe weather and weather-related events, such as floods, droughts, wildfires, and larger, more powerful storms. Those events can cause serious injuries and deaths, loss of housing, and lasting trauma in survivors. Flooding can also lead to water contamination, increasing the risk of bacterial infections and harmful algal blooms that can make people sick.

Infectious diseases

As the climate warms, or as they lose their natural habitats, animals are spreading into new areas — including animals like ticks and mosquitoes that can spread diseases. Ticks spread infections such as Lyme disease and Rocky Mountain spotted fever. Mosquitoes pass along infections like Zika virus and West Nile virus. As winters become milder in many areas, critters like ticks and mosquitoes are active longer, extending the season that you can be infected through a bug bite. “We’re already seeing changing patterns in the geography and seasonal timing of these diseases, and that will continue to evolve,” Dr. Armand says.

Asthma and allergies

Changing weather patterns can affect seasonal allergies, too. “With increased heat and more carbon dioxide in the atmosphere, plants produce more pollen,” Dr. Armand says. “And allergy season is getting longer, lasting for more weeks or months of the year in many places.” Pollen and other allergens can be problematic for people with seasonal allergies. They can also trigger dangerous flare-ups in people with asthma and chronic obstructive pulmonary disorder (COPD).

Air pollution

Air pollution and climate change aren’t the same, but they go hand-in-hand. “The fossil fuels that contribute to climate change also cause air pollution,” Dr. Armand explains. Air pollution is linked to many problems, including asthma, lung cancerstrokediabetes, and dementia, as well as preterm birth and developmental problems in children. “And with extreme heat, air pollution gets worse,” she adds.

Food production

Changing weather patterns can bring droughts, heavy rains, and wildfires. That extreme weather can damage crops and livestock. Those changes can lead to rising food prices and food insecurity, especially for vulnerable populations.

Climate change and mental health

The changing climate can also affect your mental health. People who survive natural disasters like hurricanes or tornadoes can develop post-traumatic stress disorder, for instance. But you don’t have to live through a disaster to be affected. People in areas at risk of events like wildfires might experience anxiety and stress related to those threats. What’s more, extreme heat can make mental illness worse, Dr. Armand notes. “Rates of aggression and violence actually go up during heat waves,” she says.

How to deal with the health impacts of climate change

Considering all the ways that climate change is affecting our lives, many people experience distress about the future — often referred to as “climate anxiety.” Indeed, climate change is a daunting and distressing problem. But individuals are not powerless, Dr. Armand says. There are ways to manage the impacts of climate change in your own life — while also helping the planet.

Make a plan

Prepare for what you’ll do in extreme weather events, especially if you live in areas at increased risk of hazards like floods or wildfires. Consider packing a “go bag” of essentials that you can grab if you need to evacuate quickly. If you have family members vulnerable to hot weather, find out where to access community cooling centers ahead of a heat wave.

Talk to your doctor, too, about any medications you or your loved ones take. “Certain medications can make people more vulnerable to heatstroke, so it’s a good idea to discuss your risk,” Dr. Armand says.

Check the air

Weather apps often include info about air quality and pollen counts. Check those stats before you head outside. “You might choose not to go on a hike if air quality is poor, or avoid walking in areas with more traffic congestion and worse air quality,” Dr. Armand says. “If pollen is high, keep windows closed. Take a shower and put on clean clothes when you come inside so you don’t spread pollen around the house.”

Keep bugs at bay

Protect yourself from bug bites when you’re outside. Take steps to reduce your risk of Lyme disease from tick bites, such as using insect repellant, keeping yourself covered, and doing tick checks. If mosquito-borne infections occur in your area, use bug spray and avoid going outside at dusk, when mosquitoes are busiest.

Go electric

Renewable energy sources like solar and wind energy are growing by the year. You can help drive that change by choosing electric whenever possible. If you’re shopping for a new car or clothes dryer, consider electric instead of gas-powered. “If you plan ahead, you can look for rebates and other incentives that make these upgrades a more affordable choice,” Dr. Armand says. Those choices will help support a switch to cleaner, greener energy sources.

They can also improve your health in the short term. “Switching from a gas stove to an electric one, for instance, will reduce indoor air pollution, with benefits for your health,” she adds.

Choose plants

Meat production is a top cause of greenhouse gas emissions. Diets high in meat are also associated with an increased risk of heart disease and some cancers. Choosing more plant-based meals is a win-win. “Try to eat a more plant-forward diet, with less meat,” Dr. Armand says. “You don’t have to become a vegetarian to reap the benefits.”

Move yourself

Regular exercise has so many benefits for your body and your brain. “One way to get more exercise is to walk instead of drive or walk to public transportation instead of taking the car,” Dr. Armand says. “You’ll get the benefits of physical activity and lower your carbon emissions.”

Find your people

Climate anxiety is a growing problem. One way to fight back is by building a community around the cause. “Speak to your neighbors about steps you can take to reduce carbon emissions in your community,” Dr. Armand says. “Building community around that goal can build resilience and help you deal with stress.”

Plus, you never know who you might influence when you start talking about living sustainably, she adds. “The next person you talk to might be a decision maker who plans menus for the entire school district or a city planner who can fight for more bike lanes,” she says.

Climate change isn’t a problem any one person can solve by themselves. But every day, we can make choices that keep us — and our planet — healthy.

Wynne Armand, MD


Internal Medicine Doctor