A recent article in the New York Times (NYT), “Cases of Mosquito-Borne Chikungunya Virus Are Surging Globally: What to Know,” claims climate change is causing the spread of mosquito-borne diseases by expanding mosquitoes’ ranges. This is a scientifically unsubstantiated claim. [emphasis, links added]
The truth, grounded in actual data and entomological science, is that the spread of mosquitoes—and the viruses they sometimes carry—is closely tied to human activity, urbanization, and global transportation than to incremental changes in temperature and climate.
“A mosquito-borne virus that can leave infected people debilitated for years is spreading to more regions of the world, as climate change creates new habitats for the insects that carry it,” writes the NYT. “Climate change is driving the spread of chikungunya-carrying mosquitoes.”
“A warmer, wetter world provides more suitable habitat,” continues the NYT. “And extreme weather events can cause more breeding in floods—or displace people, who cluster in areas with poor water and sanitation supply,” the NYT says.
It sounds dramatic, but the evidence undercuts this simplistic narrative. Let’s look at the facts.
First, let’s dispense with the notion that mosquitoes are creatures of the tropics alone, kept in check only by the beneficent hand of a stable cool climate.
Global average temperatures are not a limiting factor for mosquitoes, and the recent modest change in the global average temperatures hasn’t opened up new areas for colonization that weren’t amenable to mosquito habitation previously.
There are more than 3,500 species of mosquitoes, many of which are perfectly at home in cold climates. In fact, mosquitoes exist as far north as the Arctic Circle. As documented by the Alaska Department of Fish and Game, there are over 35 species of mosquitoes in Alaska alone, some of which are legendary for their size and abundance.
The notorious Aedes communis mosquito is found well into northern Canada and Alaska, where summer temperatures remain cool. If climate were the limiting factor, Alaska would be a mosquito-free paradise.
Instead, anyone who has camped there in June knows better.
Malaria-carrying mosquitoes were endemic to North America and Europe, spreading the disease, until modern interventions, primarily the use of DDT, ended the domestic spread of the disease.
The vast body of scientific literature detailed in Chapter Four of Climate Change Reconsidered II: Fossil Fuels, including studies from Africa, England and Wales, to North and South America, to Thailand and beyond, finds no link between human climate change and the spread of malaria, Dengue fever, West Nile virus, and other vector-borne diseases.
Even the Aedes albopictus (“Asian tiger mosquito”) and Aedes aegypti—the supposed climate-driven villains in the NYT story—long ago adapted to temperate zones.
If warming were truly the driving factor, we would not see mosquitoes comfortably inhabiting places with chilly summers and freezing winters.
The Aedes albopictus is found in parts of Europe, including southern Germany, Switzerland, and even Paris. Meanwhile, Aedes vexans, another common vector, is found from the subtropics to Scandinavia.
If warming were truly the driving factor, we would not see mosquitoes comfortably inhabiting places with chilly summers and freezing winters.
Instead, mosquitoes survive cold months as eggs or larvae in frozen water, hatching out when temperatures rise above 50°F (10°C)—that huge seasonal temperature swing is far greater than any climate-induced temperature change.
The real reasons for the spread of mosquitoes and mosquito-borne diseases are urbanization, infrastructure, transportation, pest-control measures (or lack thereof), and globalization.
Epidemiological and vector studies repeatedly show that mosquito range and the spread of mosquito-borne disease are closely tied to human movement and the expansion of urban areas.
Mosquitoes, especially Aedes aegypti, thrive in cities where standing water collects in artificial containers—discarded tires, flowerpots, gutters, and neglected infrastructure, such as seen below.
The urban mosquito is a product of globalization and poor city planning, not climate change.
In fact, Aedes albopictus—found across much of Europe and the U.S.—made its way from Asia in shipments of used tires and ornamental plants.
The Centers for Disease Control and Prevention (CDC) notes that the spread of this species to new regions “was primarily through the international trade in used tires” by way of human commerce.
Even the World Health Organization (WHO) recognizes that increased travel and trade are responsible for the global spread of chikungunya and other arboviruses.
As Climate Realism highlights in multiple articles, “the principal drivers of expanding mosquito range are not temperature or rainfall, but rather the global shipping industry, the proliferation of artificial water containers in urban environments, and ineffective public health measures.”
Furthermore, Climate at a Glance points out that “the resurgence of mosquito-borne diseases in recent decades has much more to do with reduced mosquito control efforts, population growth, and increased urbanization than with any small change in climate.”
The NYT, as with many other mainstream media outlets, defaults to climate change as the cause of any global health phenomenon because it advances their preconceived belief that such phenomena stem from human greenhouse-gas emissions and cause “dangerous” climate change.
Rather than dig into the messy details of urban water management, the tire trade, the eradication of the powerful but safe insecticide DDT, and failing mosquito control programs, the NYT simply hoists the “warming climate” flag and moves on.
The NYT ignores the real culprits responsible for the expansion and, in some cases, resurgence of mosquito-borne diseases in Northern latitudes, the well-documented roles of: global transportation; international trade, especially in used tires; the discontinuation of effective chemical eradication efforts; and urbanization.
The facts are out there, free for the taking, if one cares to look.
The NYT could have talked to any number of entomologists, epidemiologists, or even—heaven forbid—read the CDC or WHO reports, and they would have discovered that “climate change” is, at best, a minor player in this story.
History and science show mosquitoes and the diseases they spread will always find a way—regardless of the global thermometer reading. History also shows that direct eradication and prevention efforts can be effective in suppressing mosquitoes and the diseases they can spread.
By contrast, attempting to halt the spread of mosquito-borne diseases indirectly by suppressing fossil fuel use to cut carbon dioxide emissions in the vain hope that this will control future temperatures will do nothing to save lives today or in the future. If the NYT had made this point, it would have done a true public service to its readers.
Read more at Climate Realism
