Climate Change Is Creating a Global Pest Problem That Will Spread Disease and Threaten Food Production

Climate change is accelerating the damages caused by pests, which could result in the wider spread of diseases and increased crop destruction.

Vector-borne infectious diseases, including malaria, dengue virus, Zika virus and Lyme disease, affect nearly half of the world’s population and can create international public health emergencies. Global warming increases the lifespan of pests, allowing them to thrive in regions that were previously uninhabitable.

In 2015 and 2016, the outbreak of Zika virus, which is spread mainly by mosquitoes, was widely linked to global warming by the scientific community, following a spell of unusually high temperatures.

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A mosquito (Aedes aegypti) feeding. The Aedes genus is responsible for spreading numerous serious diseases, including dengue fever, yellow fever, the Zika virus and chikungunya. (image: Muhammad Mahdi Karim/Wikipedia)

"A number of factors ... had to line up for the Zika virus—a disease that’s been associated with birth defects—to spread so far and wide so quickly, but chief among them is heavy rain and heat," writes Brian Kahn of Climate Central.

"Climate change could play a future role in this virus’—as well as other mosquito-borne illnesses—spread as it creates conditions more favorable to the mosquitoes that transmit it."

No natural enemies

"Invasive species have always been a problem, but they will likely spread further as the global temperature increases, causing the establishment of new, exotic species with no natural enemies," said Judy Black, Vice President of Technical Services for Rentokil Steritech, a global pest control firm.

With the global temperature expected to increase by around 2°C in the next few decades, pests will migrate to cooler climate environments. This could result in insects becoming an exponential threat, as they become more resistant to insecticides and experience additional generations.

"Higher temperatures can result in faster population growth, and the quicker breakdown of conventional insecticide through volatilization," Black warns.

To protect public health, local communities must track the movements and populations of invasive species and explore all options for controlling their populations.

Threat to food security

"Scientists have found that as climates "migrate," insects and fungi are moving toward the poles too," Emily Logan of Care2 writes on EarthHour.org.

"Researchers from Exeter and Oxford calculated that pests move an average of nearly two miles each year. Already, the amount of crops lost to pests could feed nearly 650 million people—currently about nine percent of the world’s population. As they spread, this number will only increase."

The coffee berry borer (Hypothenemus hampei) is a prime example of the effect of climate change on pests that threaten crops. Native to Africa, this small insect is now present in virtually every coffee-growing region in the world, including Hawaii. It is estimated that the borer causes around $500 million in damages to coffee growers each year.

According to a 2010 study led by environmental scientist Dr. Juliana Jaramillo and published in the Journal of Economic Entomology, the borer becomes 8.5% more infectious for every 1.8°F increase in temperature.

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Adult coffee borer beetles on a damaged coffee bean. The beetle is among the most harmful pests to coffee crops across the world. (image: L. Shyamal/Wikipedia)

"Global food security is one of the major challenges we are going to face over the next few decades," said Dr. Dan Bebber, the lead author of the Exeter study. "We really don't want to be losing any more of our crops than is absolutely necessary to pests and pathogens."

Check out the infographic below for more about how climate change is creating a global pest problem.

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Infographic courtesy Rentokil Steritech.