California's mosquito population is on the rise, and scientists say that humans are to blame. A study published yesterday in Nature Communications reports that the number of the winged creatures has increased tenfold in the state over the past 50 years. And while some may assume that climate change has been the driving factor in this growth, other human behavior is believed to actually be the main cause.
"Although there were significant increases in temperature over this period," the study explains, "multiple regression analyses suggested that long-term trends in mosquito communities were driven primarily by variation in DDT use and persistence and long-term increases in urbanization, with some of the year-to-year variation driven in part by precipitation, which showed little long-term trend."
As the state continues to industrialize and urbanize, and as use of the pesticide DDT has decreased over the years, it seems mosquitoes have reaped the benefits.
“The major drivers in trends in mosquito populations were in fact changes in uses of chemicals, especially DDT, which was used, you know, in a widespread way for both agricultural and mosquito control, and land use," study author Marm Kilpatrick told CBS 5. "So, basically the urbanization of these landscapes.”
That is to say, as humans continue to reshape the state to fit our desires, we are creating the conditions for a mosquito population explosion. To make matters worse, the channel reports that species capable of carrying the West Nile virus and Zika do well in California's human-made environment. And scientists expect it to only get worse.
"Urbanization, driven by human population growth and movement, has been a major driver of environmental change during the last century and is projected to increase substantially in the future across the globe," the study authors write. "Our results suggest that urbanization is likely to drive additional changes in mosquito communities, including the expansion of habitat for urban mosquitoes."
So, sadly, and in short order, mosquitos may not just be a summertime-in-a-drought phenomenon in SF anymore.