Climate change is physical. We know that it physically affects the planet--increasing the sea levels, severity of storms, frequency of extreme weather events, and so on. Less talked about is the ways in which climate change physically harms the human body, increasing the frequency of tick-borne, mosquito-borne, and zoonotic diseases and viruses.
Increase in tick-borne illnesses like Lyme disease
Climate change is creating favorable conditions for the tick population to grow in size and expand to more regions. Ticks die out in cold weather, and so cold winters are an important means of controlling their population. Increase in warming, even by a few degrees, means milder winters, which means more favorable conditions for ticks to live. As places experience milder winters, more ticks can survive into the spring, which means a larger population. In addition, climate change impacts our planet’s water cycle, increasing cloud cover and rainfall, which also helps ticks live. With more ticks in existence, there are more chances for humans to be infected with the diseases that ticks carry. We’re already seeing this: Lyme disease doubled from 1991 to 2013.
Increase in mosquito-borne illnesses like malaria
Climate change will also increase the frequency of mosquito-borne illnesses such as malaria “in areas the disease has been controlled, as well as in new areas which have been traditionally non-malarious” according to Professor S.D. Fernando, writing for the UN. The professor continues, “An increase in temperature, rainfall, and humidity may cause a proliferation of the malaria-carrying mosquitoes at higher altitudes, resulting in an increase in malaria transmission in areas in which it was not reported earlier. At lower altitudes where malaria is already a problem, warmer temperatures will alter the growth cycle of the parasite in the mosquito enabling it to develop faster, increasing transmission and thus having implications on the burden of disease.”
Increase in zoonotic viruses like Ebola
As humans encroach on wild animals’ space through deforestation and other economic development projects, there is an opportunity for diseases that those wild animals carry to jump from animals to humans due to increased interaction and exposure. New viruses can be especially dangerous for humans, since we haven’t developed any defenses for them over the centuries. According to a 2017 study looking at 27 Ebola outbreaks and 280 comparable control sites, the “outbreaks located along the limits of the rainforest biome were significantly associated with forest losses within the previous 2 years.” Protecting our forests from human intrusion is thus crucial for preventing the spread of deadly diseases.
Bottom line: Climate change is increasing the spread of life-threatening diseases, and potentially future pandemics, perhaps ones that are more deadly and contagious than COVID-19. Climate change is often discussed as a matter of planetary health, but we need to also emphasize and educate the public about the impact of climate change on human health.