The forgotten part of climate change: slower winds

Temperature and precipitation get all the glory in the discussions surrounding climate change. Ocean acidification has earned itself a seat at the table as well. But nobody has really paid any attention to wind. Maybe that’s because you can’t actually see wind, or that the changes have been more subtle than the triple-digit (Fahrenheit) heat that’s stretching later and later into the autumn.

Thanks to new research by Brandon Barton, a Univiersity of Wisconsin–Madison postdoctoral researcher in the Department of Zoology, wind may finally get its moment in the climate change spotlight.

Wind is created thanks to differences in temperature. And since the poles are warming faster than the equator, there is a smaller global temperature differential, reducing the speed of wind. In his paper, online this month in the journal Ecology, Barton points out that global wind speeds have decreased by some 5 to 15 percent over the last three decades, and are expected to decrease another 15 perfect in the coming century. You’ve heard of global warming? Get ready for “global stilling.”

But it’s not just the warming climate that’s slowing wind – it’s also human architecture. Physical, manmade structures are blocking the flow of wind, at least on a local scale. So are trees. “In North America, we’ve been replanting trees that were lost in the 1800s, after settlers showed up and just leveled places like New England,” Barton said in a statement. Ecologists have long investigated the affects of wind on seed dispersal and pollination, or on the ways that winds modify ocean currents. But the affects of wind on predator-prey dynamics have been largely ignored. Barton set out to change all that by looking at the way that wind altered the dynamics between ladybugs (in particular, the multicolored Asian lady beetle Harmonia axyridis), and their prey, the soybean aphids Aphis glycines, pests who can ravage soy plants.

The experiment was very simple. Barton planted soybeans in alfalfa fields. Some plots he guarded with wind blocks, and others were left unprotected. He found that ladybugs were two-thirds more abundant in the protected plots than in the parts of the field that were wind-blown. As a result, there were twice as many aphids in in the windy plots.

That’s because the ladybugs are more susceptible to wind-related disturbance than are the smaller aphids, who can anchor themselves onto a plant thanks to their needle-like mouth parts. He verified that by doing a second experiment, in a greenhouse, where he found that aphids were equally abundant on potted soybean plants subjected to wind or kept still.
But once you factor the aphids’ predators into the mix, they do a lot better in windy environments. Ladybugs made meals out of almost twice as many aphids in wind-protected plots. And in the greenhouse, Barton found that ladybugs found and consumed their snacks five times faster on still plants than on windy ones.

Together, this study shows that wind doesn’t directly affect aphid abundance, but does affect predator performance. That’s probably because aphids are really small, and benefit from the tiny layer of still air clinging to a leaf’s surface – a stable microclimate – even in wind. The ladybugs’ larger surface area gives the wind a better chance to blow them away.

“The behavioral experiments suggest that ladybeetles avoid windy plots because the physical disturbance makes it difficult for them to move among plants and locate their prey,” writes Barton, But there are other possible explanations as well. For example, “wind may interfere with visual or olfactory cues that ladybeetles use to find their prey,” he adds.

The study not only sheds important light on how our changing climate will affect ecosystems in ways we haven’t yet even begun to consider; it also reveals a useful method for farmers who wish to control aphids. They might consider erecting wind barriers near their soy fields, or – for a more ecologically friendly approach – planting tall trees at the edges of their fields, which could not only buffer the wind, but provide an additional refuge for other wildlife.

And the silver lining to this aspect of climate change, if there is one, is that in a world with slower winds, ladybugs will be more adept at controlling soybean aphids. Which means that farmers could use ladybugs as a more natural form of pest control to preserve their soybean crops, reducing their reliance on pesticides. – Jason G. Goldman | 24 September 2014

Source: Barton B.T. (2014). Reduced wind strengthens top-down control of an insect herbivore, Ecology, 95 (9) 2375-2381. DOI: http://dx.doi.org/10.1890/13-2171.1

Header image: An asian lady beetle rests on a plant in a soybean field, copyright Brandon Barton, used with permission.

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9 Comments

  • Larry Wilhelmsen September 24, 2014 at 9:04 am

    In July 2000 Dr. Joseph Fletcher gave a lecture on the study of wind over the entire world since 1854 and by proxie before and found that wind velocity varies by 34% on a century basis. This explains much of the temperature variation over time as well as rain distribution. His group predicted the stop in warming and suggests it will last about 80 years. This work puts the IPCC modelers to same.

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  • Winston Bela September 27, 2014 at 6:28 am

    When Climate Change/Global Warming/Whatever causes everything, it causes nothing.
    Just add this one to the list.
    http://www.numberwatch.co.uk/warmlist.htm

    Reply

  • Eric Jennings September 27, 2014 at 4:12 pm

    “The forgotten part of climate change: slower winds”

    And thank goodness! I don’t know about you guys, but it’s been really windy outside recently, so we could certainly use a break. I’m also looking forward to warmer temps in the future, given that roughly 99% of the civilized world freezes its buns off for most of the year. Who wouldn’t want it warmer?

    As for 95% of all species dying off within the next decade, I say to heck with them. As long as cats, dogs, horses, cows and pigs survive, we’ll be able to manage just fine. I mean, when was the last time you saw a tiger or elephant in the wild? Never? That’s living proof you won’t miss them at all.

    And one thing I’m sure we won’t miss are all those crowded, smoggy coastal cities. If the UN report is right and the oceans rise 35′ feet over the next two decades, it’ll be like God’s own hand washing away our sins. And 20 years will be plenty of time to move everybody to the nearest mountains, so I don’t see any major loss of life. Plus, it’ll be fun speculating where the new beachfront properties will be, so we’ll have that to look forward to.

    Yes, as it says down below this comment box, “contribute to environmental optimism”, and that’s certainly what we should all be doing. Let’s all look on the bright side!

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  • downtown dave September 29, 2014 at 6:12 am

    It’s good to take care of the planet we live on. It’s also good to understand the real cause of disasters.
    http://downtownministries.blogspot.com/2012/11/their-protection-is-gone.

    Reply

  • Jay Caplan September 30, 2014 at 6:04 pm

    There was NOT a 5-15% reduction in wind over the last 30 years (someone’s prediction for the next century), but rather 0.3%. Please issue a correction. I value wind predictions for the next century as much as weather forecasts for 3 weeks from now.

    “A study with lead investigator Bichet A. reported 0.3% decrease in mid latitude land area wind velocity over a period of 30 years in northern hemisphere. “

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  • tonyon February 27, 2015 at 4:27 am

    never stop pouring million Tm/year contamination to the foul air, they are almost suffocating in cities…and blame to the Anticyclone

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  • tonyon February 27, 2015 at 5:03 am

    …global warming (“good” no longer spend cold)… pouring pollutants greenhouse effect into the air is melting the Poles. Besides on melting permafrost will free into the Atmosphere million Tm of methane with big greenhouse effect. This large amount of freshwater to the ocean could stop (ThermoHaline Circulation) vertical deep sea currents which depend on starting in Poles from surface ↓↓ downwards on a delicate balance between fresh and salty water and temperatures, and continuing go away slow and cold for the bottom loading nutrients and carrying large heat quantities. Deep sea currents move 90 % of all the oceans water. Heat from the Sun reaches the equator and currents distribute it throughout the Planet, then…goodbye to our warm climate. The horizontal oceanic currents on surface (move 10 % of all the ocean waters) produced by winds, rotating (Gyres) all by the Coriolis effect, and some others in all levels by the rotation of the Earth from West → East, like the Antarctic circumpolar current, will continue…but the vertical currents produced by the sinking of horizontal currents of dense salty water that reaches the Poles where the water is sweeter, less salty, and form cold bottom currents going heat transvasing between different latitudes would stop (why are the Grand Banks fishing in cold latitudes?…because over there is the POLAR ICE, freshwater, different sweet/salty density, salty dense water arriving and sinks in a little salty water environment…nutrients that are removed from the bottom cold water and rise to the surface, phytoplankton that feed on nutrients, zooplankton that feed on phytoplankton, fish that feed on zooplankton)… No polar ice over there will be no vertical currents…could reduce the rise of nutrients to the surface and therefore PHYTOPLANKTON SHORTAGE MAY DECREASING ITS VITAL CONTRIBUTION WITH OXYGEN TO THE ATMOSPHERE (90 %)…fish…winds in some places of more warm latitudes carry out the surface hot water permitting the outcropping ↑↑ to surface of water and plankton (the upwelling) from the bottom cold current coming from the Pole, forming other Banks fishing, and returning on surface again like warm water towards the Poles completing the THC circuit… Without polar ice the sea it could almost stratified into horizontal layers with little energetic movement of water masses in vertical which is what removes fertilizer nutrients from the bottom cold water, and also produces the THC… Besides lowering salinity of the sea, for that great contribution with freshwater to melt the Poles, will increase evaporation (ebullioscopy: the less salt has, more evaporates) producing gigantic storm clouds as have never seen, that together with altering of the ocean currents, could cool areas of the Planet causing a new ice age… Warming…invasion of tropical diseases carried by their transfer agents, already without the “general winter” containing them would fall upon the World like a plague…can produce a cooling, a new ice age, like living at the North Pole…and less oxygen in the Atmosphere… Is not known to be worse… Go choosing.

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  • tonyon March 1, 2015 at 11:41 am

    …the beginning of the End of the World (no polar ice: the countdown has already begun)… the World is silenced by politicians and their armies and their control of the media by the religious. They are leading the Planet to catastrophe worrying only on the economy, “their” economy. Politicians do not want to know anything about climate change, even bothers to talk topic, do not care about anything other than “utilizer” their way through the power to… ((The scientists say:…Examining 20,000 data points, the researchers showed that the Southern Ocean surface has freshened during the last 60 years. They also found that vertical gradients of salinity and density have increased in the Southern Ocean, suggesting that mixing has been reduced. Seven of the models suggest that increased freshwater in the Southern Ocean could stop the convection from occurring altogether by 2030, and most models show strong decreases in convection during the 21st century, reducing the Antarctic Bottom Water´s formation. The absence of polynyas in recent decades could mean that heat is getting trapped in the deeper ocean, possibly contributing to the recent “hiatus” in global atmospheric warming and the increase in Antarctic sea ice extent that have been observed in recent years””))… Scientists checking that there can be NO and CONVECTION in 2030 in the stratified ocean with almost fresh surface water…the beginning of the End of the World…and the experts interested in Laws POLITICIANS not even know what it is and looking elsewhere unsigned serious international protocols that IMMEDIATELY STOP AROUND THE PLANET POURING OF CONTAMINATION. It´s the economy…

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  • Peter June 10, 2015 at 10:58 pm

    Ironically, though seemingly usual for climate change, the story of wind during the reality of climate change is not as simple as less or more… While AVERAGE wind speed is decreasing, the FREQUENCY of strong wind gust events is projected to increase: http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-13-00020.1

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