The Health Risks of Climate Change

Researchers can now document how climate change makes people sick.

Posted Apr 15, 2019

bruno ismael alves/Adobe Stock
Source: bruno ismael alves/Adobe Stock

Climate change is a well-documented phenomenon.  2018 was the 42nd consecutive year that the global temperature was above average, according to the National Oceanic and Atmospheric Administration.

Rising temperatures have clear effects on the oceans, plants and animals across the globe. Now researchers are beginning to document the effect of climate change on human health. A review article published earlier this year in the New England Journal of Medicine takes a careful look at how climate change is affecting our health and healthcare systems.

The review relies on a statistical method called detection and attribution. Detection is a process that shows a statistically meaningful change occurred, and attribution involves using statistics to determine the likelihood of specific circumstances causing the change.

So, how does climate change impact human health?

One main way is through major weather events that exacerbate existing health conditions or endanger people physically.

For example, an analysis by the American Meteorologic Society found warmer global temperatures lead to extreme vapor-pressure deficits, which in turn increases the likelihood of wildfires. They were able to demonstrate that destructive wildfires in 2016, 2017 and 2018 were, in part, a result of climate change. These fires burned millions of hectares of land in the western U.S. and Canada, leading to civilian and firefighter deaths and affecting the respiratory health of millions of people.

Another example is the increasingly common heat waves across the globe, which lead to thousands of deaths each year among older adults.

Climate change also promotes vector-borne diseases, or diseases transmitted to humans through the bites of insects such as mosquitoes, ticks and flies. These include the Zika virus, dengue fever, malaria and Lyme disease. Vector-borne diseases are able to spread more easily because warmer temperatures lengthen the season insects are active and increase the geographic range of insects that carry them.

In addition, there is some evidence that climate change erodes mental health because exposure to extreme weather events such as hurricanes and floods increases the risk of anxiety and depression.

Besides affecting human health directly, evidence is building that rising carbon dioxide concentrations harm the nutritional quality of some crops, including rice and wheat. And warmer temperatures lead to lower crop yields in some regions and for some farmers, making it more difficult for the farmer to make ends meet and produce enough food to feed people in those regions.

The take-home message? The authors of the review article put it best: “Climate change is causing injuries, illnesses, and deaths, with the risks projected to increase substantially with additional climate change, threatening the health of many millions of people if there are not rapid increases in investments in adaptation and mitigation.”

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