Health Risks of Climate Change

Changes in temperature and precipitation are expected to increase ground-level ozone particulate matter (mainly from wildfire smoke) and pollen and mold growth. Higher concentrations of ozone and particulate matter in the air may irritate your respiratory and cardiovascular systems. Pollen and mold can cause allergic reactions and respiratory irritation. 

Wildfire Smoke

Hotter and drier conditions are increasing the length of wildfire season across the U.S. Though wildfires are rare in Vermont, residual smoke from fires in Canada can significantly worsen air quality in the Northeast. People with heart or lung disease, older adults and children are especially at risk. The Environmental Protection Agency's Air Quality Index (AQI) can help you understand how to address your health risk at each air quality level.

Learn more about the air quality, wildfire smoke and your health

Pollen and Mold

Pollen and mold are common allergens that can affect your health. Due to our local climate, pollen and mold are common in Vermont. Pollen grains are dispersed from flowering plants, trees, grass and weeds. Mold is a fungus that grows in moist environments. The amount of allergens in the air depends on the season and geographic location.  

A longer growing season, more rainfall, and more carbon dioxide (CO2) in the air are expected to increase:

• The amount of pollen in the air
• The length of the pollen season (and will change when seasonal peaks occur)
• How much pollen you are exposed to and the risk of experiencing allergy symptoms
• The risk of mold growth in buildings and indoor environments 

Explore up-to-date Vermont pollen trends
Learn more about mold in Vermont

Warming temperatures due to climate change are making it less likely for ponds and lakes to be covered by ice. Even when there is cover, the ice is often thin and unstable. For 100 years (1851-1950), Lake Champlain completely froze over every year except for four. Since 2008, Lake Champlain has only completely frozen over three times.

A fall through ice can result in severe, or fatal, hypothermia or drowning. In fact, several Vermonters have died in recent years after falling through the ice while fishing, walking, snowmobiling or driving a vehicle over a lake or pond. Even if you have driven and walked over a frozen water body for many years, be sure to take caution and watch for thin ice.

Learn more about ice safety from the Department of Fish & Wildlife
Find more winter weather safety tips

Cyanobacteria, known as blue-green algae, are naturally found in bodies of fresh water such as Lake Champlain and other Vermont waters. Cyanobacteria can multiply quickly to form surface scums and dense populations known as blooms, especially during late summer and early fall. Some blooms produced by bacteria can create toxins that may cause health problems for people, animals and the local environment.  

Climate change is causing more favorable conditions for cyanobacteria blooms to grow through:

• Increased precipitation that sends nutrient runoff into waterbodies and helps to feed cyanobacteria growth.
• Warmer water temperatures that allow cyanobacteria to grow more rapidly.
• Water stratification in which warm surface waters float on top of colder water layers. Stratification may cause sediments at the bottom of a waterbody to release, which helps keep cyanobacteria afloat in the warm and sunny surface layer. 

Coming into contact with cyanobacteria can make you and your pets sick. 

Learn more about cyanobacteria and your health

Drought is a prolonged dry period caused by less-than-normal rainfall or snowfall for an extended period. Drought can lead to water shortages, meaning there is less water available for drinking, food production and swimming. It can also lead to other impacts such as poor water quality and more wildfires. Drought can have severe effects on the environment, our communities and our health.  

As our climate continues to change, droughts will happen more often. Warmer air temperatures, warmer winters and more intense rain events will increase the severity of droughts, how often they happen, and how long they last.  

Monitor current and forecasted drought conditions in Vermont
See the current fire danger forecast for Vermont
Learn more about drought and your well

Extreme weather events threaten human health and well-being. They can also disrupt the physical and social infrastructure that people and communities rely on to stay safe and healthy before, during and after a weather-related disaster.  

In Vermont, extreme weather events can take the form of extreme rainfall or snowmelt, snow or ice storms, or severe thunder or wind storms. These events can result in flooding, damage to infrastructure and buildings, water and crop contamination, power outages and other hazards.

Although anyone can experience health impacts from extreme weather events, some groups may be at greater risk, including children, pregnant people, older adults, people with outdoor jobs, and people with disabilities or preexisting conditions. Immediate risks during extreme weather include direct injuries and mortality. Possible ongoing risks after a disaster include: 

• Disruptions to medical care – for example, medical facility evacuations and closures, medical personnel unable to get to work, increased call times for ambulances and disruption of home-based care
• Not being able to power medical equipment, keep medications cold and manage hot and cold temperatures when the power is out
• Carbon monoxide poisoning from improper use of generators
• Spoiled food and water contamination
• Mold growth in buildings following storms and flooding
• Hazardous conditions when cleaning up after a disaster
• Mental health impacts such as post-traumatic stress disorder 

Find out how to stay safe before, during and after a flood
Find mental health resources in response to flooding in Vermont

Climate change is expected to increase periods of drought and heavy rain events, which can result in increased contamination of drinking water, recreational water and food sources. Harmful contaminants include human and animal waste, industrial chemicals, oils and other fuels, pesticides and fertilizers. Higher temperatures may also cause an increase in pathogens growing in food and water.

Though the affected food and water may smell, look and taste normal, they can cause a range of health impacts.  

Diseases that spread through contaminated food and water can cause vomiting, diarrhea, stomach cramps and fever. Children under five years old, adults age 65 and older, pregnant people and people with weakened immune systems are more likely to have experience serious illness from contaminated food or water.  

Exposure to water contaminated by chemicals can result in skin and throat irritation, vomiting, diarrhea, fever and other symptoms. Long-term or high-dose exposure can cause organ damage, reproductive issues, developmental problems and even cancer. 

Learn more about foodborne & waterborne illnesses

Average temperatures are rising and periods of extreme heat, or heat waves, are becoming more common due to climate change. Heat waves are increasing in length, frequency and intensity in Vermont. 

Heat can cause serious illness, including heat exhaustion and heat stroke. Your body temperature may be difficult to regulate on dangerously hot days and can get dangerously high. Hot days are especially dangerous for older people and people without access to a place to cool off. The Cooling Site Map shows public places to cool off during hot weather in Vermont.

Learn more about hot weather safety

Climate change has widespread impacts on buildings and infrastructure, businesses, the quality of the environment, recreational opportunities and physical health. These impacts affect individual and community quality of life - resulting in stress, anxiety, depression and other mental, emotional and social impacts. Common mental health impacts of climate change in Vermont are:

• Fear and uncertainty about the future
• Distress caused by environmental changes
• Disruptions to businesses and hobbies
• Trauma from flooding and other disasters
• Impacts associated with physical health problems

It's important to develop a support network by talking about these impacts with family, friends and peers. Climate change stress is common and building community creates resilience. Learn how to take action to mitigate the impacts of climate change and take care of your mental health.

Find resources in response to flooding in Vermont

Mosquitoes are present during warmer months in Vermont and can sometimes transmit serious diseases. West Nile Virus (WNV) and Eastern Equine Encephalitis (EEE) have been detected in Vermont. While infection and illness from these viruses are rare, Vermonters should still take precautions to avoid mosquito bites.  

Climate change is creating favorable conditions for mosquitoes in Vermont since:

• Warmer temperatures can lengthen the season mosquitoes are present in Vermont and accelerate their life cycle.
• Heavy rain events may increase places with standing water where mosquitoes breed.
• Changing conditions can alter bird migration patterns, facilitating the spread of disease by increasing contact between mosquitoes and hosts. 

The risk of WNV and EEE infection is expected to increase. Climate change is also increasing the geographic range of mosquito species and diseases such as Zika, Dengue and Chikungunya, which may introduce new risks to Vermont. 

Learn more about mosquito-borne diseases in Vermont

The spread of tickborne diseases to humans, including Lyme disease, is increasing in Vermont and many other northern states. If you spend time outdoors or in wooded areas, you may be at risk of contracting a tick bite illness.

Longer warm seasons and warmer winters increase the amount of time that ticks are active each year. The geographic range of ticks is expanding further north and into higher-elevation areas because of changing climate conditions. More rainfall and humidity increase tick survival and activity, while drought or dry conditions have the opposite effect. 

Learn about the health risks of tick bites and how to prevent them