Urbanization and the ban on DDT, not climate change, have caused mosquito populations to explode in parts of the U.S. a recent study shows.
Mosquito populations have exploded in parts of the United States, but not because of global warming, according to a recent study published in Nature Communications.
The research indicates urbanization and the ban on the insecticide DDT are likely responsible for the surge in mosquito populations.
According to the researchers, some types of mosquitoes, including those that commonly spread diseases, have adapted to human-created habitat; urbanization has created fertile ground for mosquito populations to expand. This doesn’t augur well for city dwellers, who are already feeling the brunt of mosquito-borne tropical diseases such as chikungunya, dengue fever, West Nile virus, and Zika virus.
Tracking mosquito populations in California, New Jersey, and New York, the researchers found mosquito populations have increased as much as 1000 percent over the past five decades.
The study was a collaborative effort between public health authorities in New York City and Salt Lake City, Utah and researchers at Rutgers University, the University of California–Davis, and the University of California–Santa Cruz.
Climate Change Not Primary Cause
A variety of factors impact the environment, and climate change is not the driving force behind most environmental problems, says Merrill Matthews, a resident scholar at the Institute for Policy Innovation.
“What the Nature Communications study reminds us is several factors can and almost always do play a role in environmental changes, [and] climate change is not the source of most environmental ills,” Matthews said. “In this case, the causes seem to be human progress and [neglect of] the remarkably effective role DDT plays in eliminating mosquito populations.
“As humans change the landscape through urbanization, the mosquito populations also change, favoring those feeding on humans, which also appear to be major disease carriers,” said Matthews. “DDT was used heavily in the 1940s to the 1960s because it was cheap and very effective, and it apparently decimated some U.S. mosquito populations so they are only just now recovering. But even though several countries are using DDT, at least in a restricted way, there remains heavy international pressure for them to not do so.”
All public policies have costs and benefits, and those can change based on location, relative wealth or poverty, and other factors, says Matthews.
“With Scott Pruitt taking over at the [Environmental Protection Agency], it may be a good time to reevaluate the use of DDT and ask whether the benefits of limited DDT use to reduce mosquito populations, either here are abroad, outweigh the costs,” Matthews said.
Kenneth Artz ([email protected]) writes from Dallas, Texas.
Ilia Rochlin et al., “Anthropogenic impacts on mosquito populations in North America over the past century,” Nature Communications, December 6, 2016: https://www.heartland.org/publications-resources/publications/anthropogenic-impacts-on-mosquito-populations-in-north-america-over-the-past-century