Guest Commentary by Anita Fernandes
Scientists and researchers from around the globe have warned that climate change is the greatest threat to human health in history.
In fact, the United Nation’s Intergovernmental Panel on Climate Change (IPCC) has concluded that all life on our planet is under existential threat.
From hurricanes and floods to drought and catastrophic wildfires, there’s no denying that climate change is affecting us right now. However, climate change also poses long-term problems particularly to sustainability issues that impact our economy, society and health.
In focus: The Impacts of Climate Change on Human Health in the United States
1. Temperature-related illnesses
Rising temperatures have direct and indirect effects on human health. Higher temperatures lead to an increase in the incidence of heatstroke, hyperthermia and dehydration-related deaths. High temperatures pose a greater risk to those with existing health problems such as cardiovascular, respiratory and kidney conditions.
It is difficult to calculate heat-related morbidity and mortality but researchers predict that future warming will result in an increase of from 2,000-to-10,000 deaths annually in each of 209 US cities.
This may seem like inordinately inflated figures until we consider that the 2003 European heat wave was responsible for approximately 70,000 premature deaths.
Higher temperatures are also linked to the spread of infectious diseases due to the increased populations of vectors such as mosquitoes and ticks.
Since the 1990s, the number of cases of Lyme disease (spread through deer ticks) has more than doubled in the US and affects approximately 300,000 Americans annually.
2. Extreme weather events
Weather extremes such as heat waves, droughts, tornadoes and hurricanes pose a significant threat to human health. Extreme heat was a rare occurrence in the USA just 50 years ago but now, extreme summer heat occurs about 7 per cent of the time.
We have also seen increases in concurrent droughts as well as heavy downpours and as the climate continues to warm, the number of fatalities will rise dramatically in the US.
Extreme weather events also have a significant impact on the country’s economy. For instance, hurricanes Harvey, Irma and Maria in 2017 cost over US$300 billion in damages.
Hospitals that are affected by hurricanes are forced to grapple with recovery costs in the following year — which is likely to have a negative impact on their operating performance.
Extreme weather events also cause damage to roads and bridges which disrupts access to hospitals and health care services.
3. Air pollution
Climate change impacts air quality and conversely, air quality impacts climate change. Hotter summers pose a serious health risk as the increased temperature results in stationary domes of hot air that trap air pollutants in the lower atmosphere.
These “stagnation events” have become more prevalent especially in cities as data shows that 83% of US cities have experienced an increase in stagnant days.
This also increases the risk of ground-level ozone — which is a dangerous air pollutant that causes chest pain and coughing and can worsen asthma, bronchitis and emphysema.
People with a history of these respiratory problems are at a higher risk of pneumonia and other pneumococcal diseases. Increased CO2 coupled with higher temperatures increases the growth rate of plants such as ragweed that are linked to allergies and asthma episodes.
Pneumonia information (“What you need to know”) is at: https://www.everydayhealth.com/pneumonia/guide/
4. Food and water shortages
Increased water temperatures brought on by climate change affects the habitat range for fresh water and can increase marine algae that produce toxins. Furthermore, flooding compromises human waste water treatment and can compromise drinking water leading to water shortages.
Reduced rainfall leads to diminished flow in rivers and streams which subsequently results in an increased concentration of harmful pollutants in these waters.
Similarly, climate changes in the American Southwest has resulted in less precipitation which has resulted in more severe and longer periods of drought. Crops fail to mature due to the lack of precipitation, which can lead to food shortages and food insecurity.
5. Mental health effects
Studies show that visits to the emergency department for mental illness and attempted suicides increase with higher temperatures. Furthermore, extreme heat poses greater risks to the physical and mental health of people with mental illnesses.
Disasters such as flooding and prolonged droughts can result in severe and even chronic mental health disorders including anxiety, depression and post-traumatic stress disorders. Increases in extreme heat also increase the risk of death for people with mental illnesses.

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Guest author Anita Fernandes has been writing extensively on health and wellness for over a decade. She has expertise in nutrition, fitness, public health, and weight loss and has contributed content to a variety of leading digital health publishers.
Anita has a unique perspective on healthy living and lifestyle, as she has battled and overcome eating disorders and obesity. She shares her experiences in an effort to help others overcome the physical and mental health problems that can sometimes seem insurmountable.