With climate change, existing health risks may worsen. For example, heat waves and floods may become more frequent and intense. Climate change can also bring unfamiliar health risks to new areas (such as when Lyme disease-carrying ticks expand their territory). Periodic health risks, like allergy seasons, may shift in timing or have a longer window.
Climate Change and Human Health
Knowing your health risks gives you the power to manage them.
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Climate influences temperatures, cloudiness, humidity, wind, and how much and how hard it rains. These factors all play a role in making the air we breathe indoors and outdoors better or worse. Rising temperatures, altered rain patterns, and more carbon dioxide in the atmosphere will lead to higher pollen counts, longer pollen seasons, and associated increases in asthma episodes and other allergic illnesses.
Older adults are particularly at risk from extreme heat events, especially if they take certain medications that make it harder to maintain a healthy body temperature. In general, health risks from climate change will not be evenly spread among people. Some groups will experience worse health challenges than others. Other people who are more vulnerable to climate change include pregnant women, children, and people who work outdoors. People with mental illness, disabilities, or chronic medical conditions also face higher risks. High-risk communities include low-income groups, people of color, and immigrant groups.
Even small differences in seasonal average temperatures can result in increased illnesses and deaths. Extremely hot days can compromise your body’s ability to regulate your temperature. This can lead to dehydration, heat cramps, heatstroke, and other conditions. Extreme heat can particularly harm people who already suffer from chronic illnesses like heart, kidney, and lung disorders.
The correct answer is based on data from the National Weather Service. Extreme heat was the leading cause of weather-related deaths (more than 1,200) in the United States between 2004 and 2013. Hurricanes caused more than 1,000 deaths while floods caused less than 800. Not only do extreme weather events injure and kill people, they can also disrupt important infrastructure (such as utilities, roads, bridges, and power supplies). This reduces people’s access to medical care and safe food and water.
Changing conditions could make disease-carrying pests (such as ticks, mosquitoes, and fleas) more common. Climate change could also allow these pests to move into new regions or survive for a longer part of the year. People who spend the most time outdoors (such as outdoor workers and children) carry the most risk of contact with disease-carrying pests.
West Nile virus is the most common mosquito-carried illness in the United States. Traditionally, the peak time for outbreaks is June through September. Birds are the natural hosts for West Nile virus, but mosquitoes can also pass the illness to humans after biting an infected bird. Climate influences the number and distribution of both birds and mosquitoes capable of transmitting West Nile virus in different regions.
Weather-related disasters such as hurricanes are becoming more common. After disasters, people can experience serious emotional consequences. For example, people may develop PTSD, depression, anxiety, or grief. Children especially may have distress after traumatic events. Other high-risk groups include the elderly, first responders, farmers, residents in coastal areas, and people with pre-existing mental illness.
Climate change can increase water-related illnesses in different ways. As mentioned in the question, heavy downpours can pollute some drinking water sources (such as lakes and rivers) with unhealthy bacteria and chemicals. Swimming in polluted water also carries health risks. Pollution combined with higher water temperatures can help blooms of harmful algae grow in drinking water sources or recreational waters.
More carbon dioxide is in the air. Plants like wheat, rice, barley, and potatoes react by building more carbohydrates into their tissues. They also draw less water into their roots. So less essential minerals make it into our food. This results in less nutritional value (lower amounts of protein, calcium, copper, iron, magnesium, and zinc) in our food.