How Climate Change Is Making Us Sick

From smog to ticks, the damage we’ve done to the planet is coming back to haunt our health. Here’s how to protect yourself.

health effects of climate change-bugs pests and ticks

Illustration, Justine Wong.

Gina Mawson stood at her living room window in July 2017, watching water bombers fill up to battle the forest fires closing in on her home. She knew she had to get her family out of town—fast. Two giant plumes of smoke had joined in the sky like a grey-scale rainbow over Williams Lake, B.C., and Mawson, who has asthma, was having trouble breathing. She worried about her family, especially her 11-month-old daughter, who also suffers from asthma. “We were surrounded by fire and smoke,” she says. “It was terrifying.”

Four days after the fires broke out, Mawson and her husband shut down their legal practice and packed up their cars. They left Williams Lake shortly before the official evacuation order forced 24,000 people from their homes. As Mawson squeezed family photos and special stuffed animals into her husband’s car with their two daughters and two dogs, her head pounded and her face was turning purple—she couldn’t get enough oxygen from the ash-heavy air.

As they drove away, she was overcome with a mix of emotion: relief that they were getting out alive, fear that their home would be incinerated and frustration that more wasn’t being done to tackle climate change. “I just wanted to be out,” she says. “That’s all I could think about.”

Even if your lungs haven’t been compromised by forest fire smoke, no matter where you live in Canada, climate change is putting your health at risk. Stronger heat waves and increasing air pollution are sending hundreds of people to the hospital every year. At the same time, bugs are moving into newly warm regions, bringing debilitating diseases with them.

A 2017 Health Canada poll found that 79 percent of Canadians accept that climate change is happening; of those, just over half think it’s a health risk now and 40 percent agree it will be in the future. The truth is, climate change is already exacerbating pre-existing conditions and making otherwise healthy people sick.

“Climate change is a public health emergency,” says Courtney Howard, an emergency room doctor in Yellowknife and president of the Canadian Association of Physicians for the Environment. “This is a climate code blue. When a code blue is called in the hospital, we don’t panic. We walk quickly to the bedside of the person who needs help. We push hard, we push fast—and we don’t stop until we have the healthiest outcome possible.”

The Lancet calls climate change “the biggest global health threat of the 21st century” and says tackling it could be our greatest health opportunity. “We need to adapt to the problems; we can no longer avoid them,” says Howard, who authored the Canadian section of The Lancet’s recent report on the health impacts of climate change. Fortunately, there’s plenty we can do to protect ourselves. Here’s how climate change is affecting your health—and what you can do to fight back.

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The air we breathe is more polluted than ever

In Canada, we’re lucky to breathe some of the cleanest air in the world, but according to Health Canada, human-caused air pollution still claims 14,400 lives every year—more than twice as many as diabetes.

While we’ve made gains in regulating and reducing air-borne toxins in Canada—phasing out coal power, for instance—climate change is ushering in longer and more severe episodes of air pollution. The worst offenders are wildfire smoke and periods of high ground-level ozone, a toxic gas that forms when pollutants interact with sunlight and worsens in warmer weather.

Not only are wildfire seasons getting longer, the fires are also burning in more areas. “As the climate changes, we expect wildfires will cause episodes of the worst air quality most people will ever experience,” says Sarah Henderson, a senior scientist at the B.C. Centre for Disease Control.

Exposure to wildfire smoke can cause everything from headaches and coughing to heart attacks and life-threatening asthma. When Henderson and her colleagues compared the 2017 and 2018 wildfire seasons to 2016, they found an 18 percent increase in physician visits for asthma and a 38 percent increase in prescriptions filled for Ventolin inhalers. “It doesn’t take too much smoke for some people to feel the effects,” Henderson says. Symptoms typically resolve once the smoke clears, but the long-term consequences are unknown.

Inhaling ground-level ozone, a significant contributor to smog, also causes breathing problems such as coughing and throat irritation. It can exacerbate lung conditions, leading to hospitalization and even death. Poor air quality in general has been associated with several adverse health effects, including heart disease and cancer. Seniors, children and pregnant women are especially vulnerable, and air pollution has been linked to low birth weight and premature birth.
“When you breathe in air pollution, your body responds to it like it’s a foreign invader,” Henderson explains. Similar to what happens when it’s fighting a virus, your body mounts an immunological response that leads to inflammation. But unlike a virus, air pollution doesn’t die. “There’s always this little bit of inflammation in your body, which can affect all of your organs.”

How to protect yourself: Keep informed of the air quality in your area by checking out government alert systems. You can view the Air Quality Health Index online or download the app, AQHI Canada, and sign up for push notifications. The new WeatherCAN app also includes air-quality alerts, and Environment Canada’s FireWork system forecasts where wildfire smoke is expected to move.

When the air quality is poor, limit your time outdoors and take it easy. When you’re resting, you breathe an average of seven litres of air per minute; when you’re exercising, it can climb to 100 litres. The less air you breathe, the less pollution you breathe. Drinking plenty of water can help your body cope with inflammation.

At home, run a portable high-efficiency particulate air (HEPA) cleaner and put it in your bedroom at night. If you live in a region threatened by forest fires and have a central forced-air system, it may be possible to install a HEPA filter. You can also spend time in public places with good air filtration systems, such as recreation centres, libraries and malls.

Henderson says masks aren’t recommended except for people with outdoor occupations. Many masks aren’t designed to filter out small particles, don’t fit properly and can make it more difficult to breathe. “People might put on a mask and think they’re protected when they’re not,” Henderson says.

health effects of climate change-2

Illustration, Justine Wong.

Heat waves are wreaking havoc

You’ve seen the headlines: In 2009, there were more than 150 deaths from a heat wave in B.C.’s Lower Mainland, and in 2010 about 280 people in Quebec succumbed. Last year, another 90 people died in Quebec as a result of a July heat wave. The annual death toll from extreme heat is only expected to rise.

“Climate change is projected to increase the severity and frequency of extreme heat events,” says Peter Berry, a senior policy analyst and science advisor at Health Canada’s Climate Change and Innovation Bureau. One study, published in the journal PLOS Medicine in 2018, predicted that Canada could see five times as many heat-related deaths between 2031 and 2080 compared to statistics pulled from 1971 to 2015.

While there are different definitions of what constitutes a heat wave—three or more days of temperatures over 32C, for example—studies show death rates increase when the mercury rises above 25C. When your body heats up, your heart rate increases to pump more blood to the skin’s surface to release that heat, and you start to sweat. As your sweat evaporates, you cool down. But if it’s too hot or humid, or if the conditions last too long, your body gets stressed and its cooling system can shut down. You may experience swelling, rashes, cramps, headache and dizziness. Signs of heatstroke, which is a medical emergency and can be fatal, include having a core temperature of more than 40C, confusion and loss of consciousness.

Children and seniors are more at risk. (Kids’ bodies get to a higher temperature before they start to sweat in comparison to adults, while seniors often have decreased sweating ability and are more susceptible to dehydration.)

Heat can exacerbate heart and respiratory conditions and have mental health impacts; for example, studies show suicide increases during hot weather. Women also have some unique vulnerabilities. Research shows that heat waves increase the incidence of intimate partner violence against women and the likelihood that pregnant women will have a stillbirth, a premature baby or an infant with a congenital heart defect.

How to protect yourself: The good news about heat-related illnesses is that they’re preventable. Listen to local forecasts and extreme heat warnings, which may come from your health authority or municipality. Plan outdoor activities for cooler times of day, and wear loose-fitting, light-coloured, breathable clothing and a wide-brimmed hat. Stay hydrated by drinking water before you feel thirsty, and prepare meals that don’t need to be cooked.

You can also heatproof your home by closing curtains or blinds during the day, running an air conditioner and even planting a tree to block the sun and create some shade. If you can’t modify your home, spend time in public places with air conditioning (in extreme heat events, your municipality may open cooling stations). “You only really need three or four hours of cooling to reset your body,” Berry says. “It really helps prevent heat illness.”

Pests are plaguing us

Outdoor enthusiasts need to be on the lookout for more disease-carrying pests. The warming climate allows insects and ticks to put down roots in new regions and speeds up their life cycle, helping them thrive.

“Generally, our winters keep out a lot of bugs,” says Nicholas Ogden, director of Public Health Risk Sciences at the Public Health Agency of Canada. “As it gets warmer, these insects and ticks can move farther north, and we may get more bug-carried diseases coming into Canada from the U.S.”

Blacklegged ticks are already marching into parts of Canada they haven’t been seen in before, bringing Lyme disease with them. Today, ticks can be found in wooded or grassy areas in southern parts of British Columbia, Manitoba, Ontario, Quebec and New Brunswick, and all over Nova Scotia. By 2020, researchers predict 80 percent of people in Central and Eastern Canada will be at risk of exposure to Lyme disease. (The number of new cases of the disease reported in Canada skyrocketed from 144 in 2009 to 2,025 in 2017.)

A tick burrows its head into your skin and feeds for several days, but because its bite is usually painless and it’s as small as a poppy seed, you may not notice that it’s there. And if the tick was infected with Lyme, you could develop flu-like symptoms and a rash at the site of the bite within three to 30 days.

Lyme disease can be treated with antibiotics, but if it’s not caught early you may experience severe headaches, facial paralysis, heart palpitations, confusion and arthritis. It’s also difficult to diagnose, and some people experience symptoms for years. Avril Lavigne, who has publicly shared her experience with Lyme disease, says doctors struggled to diagnose her and she was bedridden for two years with extreme fatigue.

Warming weather is also allowing new mosquito species to migrate north, putting Canadians at risk of West Nile virus and other mosquito-borne diseases. Since 2002, when the first case of West Nile in Canada was confirmed, more than 5,600 cases have been reported, mainly in urban areas of Southern Ontario and Southern Quebec, and rural parts of the Prairies and British Columbia. Most people infected with West Nile have no symptoms or have mild flu-like symptoms, but in about one in 150 cases, the virus can lead to a serious neurological infection, such as encephalitis or meningitis.

With continued warming, Ogden warns, we may see new species of mosquitoes and ticks in Canada, along with the diseases they harbour. For example, over the past three years, authorities have found the Asian tiger mosquito, which carries the Zika virus, in Windsor, Ont. “It used to be that you didn’t need to worry about getting a mosquito bite in Canada, but now we really need to protect ourselves,” Ogden says.

How to protect yourself: When you’re in an area frequented by ticks or mosquitoes, wear clothing that covers your arms and legs, and apply insect repellent containing DEET or icaridin. Light-coloured clothing deters mosquitoes and makes it easier to spot ticks. To keep mosquitoes away from your home, make sure there’s no standing water around and put screens on your windows.

If you’re hiking, stick to the trails and inspect clothing and gear when you’re done. Once home, wash clothing in hot water or put it in the dryer on high for 10 minutes to kill any ticks. Have a shower and thoroughly check yourself, your children and your pets, paying attention to easy to miss places like around the ears and in the armpits. If you find a tick, remove it with tweezers by grasping its head and pulling it straight out. Removing a tick within 24 to 36 hours of a bite usually prevents infection. Save the tick and bring it to your health-care provider or send it to your provincial public health authority for testing.

In the future, we may be able to proactively protect ourselves: A French company is working on a vaccine for Lyme disease, which is being fast-tracked by the U.S. Federal Drug Administration, and research on a West Nile vaccine is underway in Oregon.


Pollen production is on the rise

health effects of climate change-polluted air-girl wears face mask

Illustration, Justine Wong.

Spring signals the end of cold and flu season, but if you’re among the approximately 20 percent of Canadians who suffer from seasonal allergies, the sniffles and congestion can continue for months. If your seasonal allergies seem to be getting worse, it’s not your imagination—it’s climate change.

Warmer weather and higher carbon dioxide levels may help your garden grow, but they spur pollen production, too. Climate change also makes the weather more erratic, which in turn makes the pollen season less predictable. Research has also shown that air pollution can prompt an increase in pollen production and even make pollen more potent.

“What we’ve seen in the past 10 years is a lengthening of the pollen seasons and an increase in the intensity of the pollen in the air,” says Daniel Coates, director of marketing and business development at Aerobiology Research Laboratories, a company that monitors and forecasts pollen and spore levels across Canada. “Now we’re seeing seasons starting anywhere from a week to four weeks earlier and potentially lasting longer.”

Data from Aerobiology shows the extension of pollen seasons between 2006 and 2017: In Vancouver, the birch season was 140 days longer; in Winnipeg, the maple season added 30 days; and, in Saint John, N.B., the grass season grew by 24 days.

The weather can also delay the allergy season or cut it short, but that’s not necessarily a good thing either, as plants can make up for lost time by unloading more pollen, leading to heightened symptoms for allergy sufferers, including asthma attacks.

“As the concentration of pollen gets higher, the types of symptoms people have may change from nasal congestion and watery eyes to asthma-like symptoms—wheezing, coughing and shortness of breath,” says Harold Kim, an allergist in Kitchener, Ont., and president of the Canadian Society of Allergy and Clinical Immunology.

And just like ticks and mosquitoes, different plants are propagating in new regions of the country, exposing people to allergens they haven’t previously experienced. Ragweed, for instance, was typically only seen in the eastern part of Canada but is now showing up in Saskatchewan and Alberta.

How to protect yourself: Find out just what you’re allergic to by getting tested and figuring out when those allergens are in the air. The Aerobiology Allergy Sufferers app provides personalized pollen forecasts up to three days in advance so you can plan when to have a picnic and when to stay inside. Keeping your windows shut and showering after being outside also helps. A HEPA air filter may decrease the allergens in your home, but Kim says there’s no proof your symptoms will improve.

If your allergies are acting up, antihistamines typically start working within hours and prescription nasal sprays within a week or two. Kim advises people to avoid sedating antihistamines (because they interfere with daily life) and over-the-counter nasal decongestants (which can cause a condition known as rebound congestion and make symptoms worse).

If you want a more permanent solution, immunotherapy might be an option. Injections expose you to the allergen in gradually increasing doses to build up a tolerance and are typically given at your doctor’s office once a week for about six months, followed by monthly shots for three to five years. You can also try tablets, which dissolve under your tongue and need to be taken daily, starting 12 weeks prior to the season through to the very end. “The shots and tablets don’t just treat the symptoms—they change your body’s response to the allergens,” Kim says, adding that 70 to 80 percent of people get significantly better with immunotherapy.


After Mawson and her family fled the fires near their home, they drove about 250 kilometres north and checked in with the Canadian Red Cross before staying with friends on their ranch. It wasn’t long though before the smoke followed them there. They had to spend most of their time inside, asthma puffers within reach.

When the evacuation order was finally lifted two and a half weeks later, they headed home. Mawson couldn’t help but cry as she drove by army personnel and signs welcoming back evacuees—she was moved by how everyone had come together to protect her community.

They were home and they were safe, but they weren’t in the clear. The smoke stuck around all summer, so Mawson kept the kids inside with the air filters running: no lake, no park, no trampoline. Last year wasn’t much better—they didn’t have to evacuate, but smoke from nearby fires forced them inside. Mawson now needs to use a puffer every day. She was also diagnosed with high blood pressure, which she attributes to the lack of clean air and the stress it caused, and suffers from mild post-traumatic stress disorder. “The sight of smoke actually causes a physiological reaction in my body of total anxiety,” she says. “When I hear a helicopter going over my house, my first thought is, ‘Where’s the fire?’”

Mawson is doing what she can to protect her family but believes more government action is needed to support individual efforts. Howard agrees. “The most important individual action anybody could take is to vote for politicians who take climate change seriously as a health risk,” says Howard. “If we can’t mitigate it now, we’re heading to a place our children can’t adapt to. Talk to your friends and family. The more we talk about it, the more we’re going to come up with solutions that will help keep everybody safe and healthy. We’re all in this situation, but we’re all in it together.”

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