Global warming to boost Arctic mosquitoes

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Global warming likely to boost Arctic mosquito populations.

Impacts likely to ripple through Arctic ecosystem

Staff Report

LINZ — Global warming is likely to lead to bigger and badder Arctic mosquito swarms, according to a new Dartmouth College study. Already, warming temperatures are causing Arctic mosquitoes to grow faster and hatch earlier, significantly boosting their population and threatening caribou.

The study predicts the mosquitoes’ probability of surviving and emerging as adults will increase by more than 50 percent if Arctic temperatures rise 2 degrees Celsius. Changes in the timing and intensity of mosquito emergence will have a ripple effect on other parts of Arctic ecosystems, including Arctic and migratory birds.

“Increased mosquito abundance, in addition to northward range expansions of additional pest species, will have negative consequences for the health and reproduction of caribou,” said lead author Lauren Culler, a postdoctoral researcher at Dartmouth’s Dickey Center’s Institute of Arctic Studies.

Average temperatures in the Arctic have increased at twice the global rate in the past 100 years, and the low biodiversity of Arctic ecosystems provided a simple predator-prey interaction for this study. Arctic mosquitoes develop in shallow temporary ponds of springtime snowmelt on the tundra, where their top predators are diving beetles.

The researchers studied the response of mosquitoes to warming in filed and lab studies in western Greenland, then built a computer model to project how those changes will play out over their life cycle, from birth to adult feeding stage, under a range of temperatures in future climate change scenarios for the Arctic.

The results show that warmer spring temperatures caused the mosquitoes to emerge two weeks early and shortened their development time through the larval and pupal stages by about 10 percent for every 1 degree Celsius increase in temperature.

Warming increased the number of mosquitoes being eaten by diving beetles, their main predators. But the vulnerable, juvenile mosquitoes also grew faster; reducing their exposure to predators and increasing their chance of surviving to adulthood. With 2 degrees of warming, the mosquitoes’ probability of survival will increase by 53 percent.

Arctic mosquitoes’ reproductive success depends on the females finding a blood meal, which is expected to increase because warming more closely synchronizes their life cycle with caribou calving. The calving season benefits mosquitoes by giving them a larger, less mobile herd to feed on, including vulnerable calves.

The researchers say the climate-population model they developed for Arctic mosquitoes and their predators can be generalized to any ecosystem where survival depends on sensitivities to changing temperatures.

The study appears in the journal Proceedings of the Royal Society B: Biological Sciences.

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One thought on “Global warming to boost Arctic mosquitoes

  1. Exxon’s Own Research Confirmed

    Fossil Fuels’ Role in Global Warming Decades Ago

    Top executives were warned of possible catastrophe from greenhouse effect, then led efforts to block solutions.

    By Neela Banerjee, Lisa Song and David Hasemyer

    Sep 16, 2015

    Exxon Experiment

    Exxon’s Richard Werthamer (right) and Edward Garvey (left) are aboard the company’s Esso Atlantic tanker working on a project to measure the carbon dioxide levels in the ocean and atmosphere. The project ran from 1979 to 1982. (Credit: Richard Werthamer)

    At a meeting in Exxon Corporation’s headquarters, a senior company scientist named James F. Black addressed an audience of powerful oilmen. Speaking without a text as he flipped through detailed slides, Black delivered a sobering message: carbon dioxide from the world’s use of fossil fuels would warm the planet and could eventually endanger humanity.

    “In the first place, there is general scientific agreement that the most likely manner in which mankind is influencing the global climate is through carbon dioxide release from the burning of fossil fuels,” Black told Exxon’s Management Committee, according to a written version he recorded later.

    It was July 1977 when Exxon’s leaders received this blunt assessment, well before most of the world had heard of the looming climate crisis.

    A year later, Black, a top technical expert in Exxon’s Research & Engineering division, took an updated version of his presentation to a broader audience. He warned Exxon scientists and managers that independent researchers estimated a doubling of the carbon dioxide (CO2) concentration in the atmosphere would increase average global temperatures by 2 to 3 degrees Celsius (4 to 5 degrees Fahrenheit), and as much as 10 degrees Celsius (18 degrees Fahrenheit) at the poles. Rainfall might get heavier in some regions, and other places might turn to desert.

    “Some countries would benefit but others would have their agricultural output reduced or destroyed,” Black said, in the written summary of his 1978 talk.

    His presentations reflected uncertainty running through scientific circles about the details of climate change, such as the role the oceans played in absorbing emissions. Still, Black estimated quick action was needed. “Present thinking,” he wrote in the 1978 summary, “holds that man has a time window of five to ten years before the need for hard decisions regarding changes in energy strategies might become critical.”

    Exxon responded swiftly. Within months the company launched its own extraordinary research into carbon dioxide from fossil fuels and its impact on the earth. Exxon’s ambitious program included both empirical CO2 sampling and rigorous climate modeling. It assembled a brain trust that would spend more than a decade deepening the company’s understanding of an environmental problem that posed an existential threat to the oil business.

    Then, toward the end of the 1980s, Exxon curtailed its carbon dioxide research. In the decades that followed, Exxon worked instead at the forefront of climate denial. It put its muscle behind efforts to manufacture doubt about the reality of global warming its own scientists had once confirmed. It lobbied to block federal and international action to control greenhouse gas emissions. It helped to erect a vast edifice of misinformation that stands to this day.

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