Clearly, bats are a valuable resource we cannot afford to lose

Bats' Nemesis—Wind Turbines

By —— Bio and Archives--August 26, 2016

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Bats are known to be some of the world’s saviest aerial acrobats. Using their mysterious sonar system and shape-shifting wings, bats adeptly swerve and swoop and dive in flight to avoid collisions with both stable and moving objects. And yet bats stand no chance against a 200-meter high wind turbine with blades the length of a football field, spinning at speeds up to 275 km per hour. Even if their tiny bodies can avoid a blunt force collision with one of these merciless steel blasts, just the act of drawing near to a wind turbine may nonetheless expose bats to jarring air pressure changes that cause fatal lung damage. This is the main reason why bat carcasses can be found scattered beneath wind turbines at locations across the world, reports Kenneth Richard. (1)


The slaughtering of bats by wind turbines isn’t slowing down; it’s getting worse. The 21st century wind turbine bat-killing rate has already begun to seriously threaten the long-term survival of the world’s 172 endangered bat species. According to scientists publishing in the journal Mammal Review, the spinning blades of wind turbines (along with white nose syndrome) are now the leading causes of multiple mortality events in bats. (2)

The global scale of slaughter of bats promises to get even worse in the coming few decades. In Canada alone, researchers report that an average of 15.5 bats are killed at each individual wind turbine site every year. At 2013 installed wind capacity, 15.5 killings per turbine per year means that 47,400 bats are killed annually in Canada. With the 35% increase in installed wind capacity intended for Canada within the next 15 years, about 166,000 bats are projects to be slaughtered on a yearly bases by about 2030. (3)

The rate is higher in Ontario where wind turbines are killing bats at nearly double the rate set as acceptable by the Ontario government. This rate resulted in an estimated 42, 656 bat fatalities between May 1 and October 31, 2015. (4)

Using the conservative figure of 15.5 bats killed per wind turbine, the 48,500 currently operating US wind turbines are now slaughtering over 750,000 bats per year. This bat killing rate appears to fall in line with other published estimates. For example, Hein and Schirmacher indicate that recent studies suggest US wind turbines were slaughtering between 600,000 and 880,000 pats per year as of 2012. (5)

Worldwide 3 to 5 million bats are killed annually, reaching 10 million soon. There are currently (2015) 314,000 wind turbines spinning around the world and slaughtering bats by the millions. Using the conservative average of 15.5 bats killed year by each wind turbine, it can be estimated that there are now about 4.9 million bats slaughtered every year by the world’s 314,000 wind turbines. Even if the killing rate per individual wind turbine was generously reduced to ten bats per year instead of 15.5, wind turbine bat slaughter rates would still exceed 3 million per year.

Kenneth Richards adds, “A rough estimate of 3 to 5 million bats killed yearly by wind turbines is only the current rate. As of 2015, just 2.5% of electrical energy was supplied by wind worldwide. There are plans to have wind turbines realistically generate 18% to 34% of the world’s electrical energy by 2050. To achieve this massive expansion, installed wind capacity will need to double and triple and quadruple in the coming decades. The number of bats slaughtered by wind turbines could easily grow to a rate of more than 10 million annually within 10 to 15 years. As some point, there may not be enough species of bats left to kill.” (1)

The primary reason why there has been such explosive growth in the use of wind turbines in the 21st century is because wind energy is expected to assume a fundamental role in the transition from fossil fuels to renewable energy in the coming decades. At the Paris Climate Conference in 2015, world governments confirmed plans to rapidly expand their wind energy programs, which will presumably reduce CO2 emissions and, in turn, mitigate the amount of global warming we may have otherwise experienced had we continued using fossil fuels at the current pace. (1)

However, even if all the renewable energy transition planning (wind and solar primarily) were ambitiously implemented as recently professed by world governments, and even if these heavily pro-renewable energy policies remained in place though the year 2100, the total amount of global warming we may ‘save’ the planet from may be less than two-tenths of a degree C (0.17C) overe the next 85 years. (6)

Another serous problems for bats—white nose syndrome. Bat populations across North America have been plunging with the emergence of this fungal disease. Couple this with wind turbines and one can realize the seriousness of the bat problem. (4)

So, how important are bats? They are a precious, but unheralded friend of farmers, providing consistent crop protection. Take away the colonies of pest killers and insect control costs would explode across farmlands. And just how much do bats save agriculture in pesticide use? Globally, the tally may reach a numbing $53 billion per year, according to estimates form the University of Pretoria, US Geological Survey, University of Tennessee and Boston University. A 2006 study proposed that bats save cotton growers $74 per acre in pesticide treatments across eight Texas counties. (7)

Clearly, bats are a valuable resource we cannot afford to lose.


  1. Kenneth Richard, “Wind turbines now kill 3 to 5 million bats a year,” notrickszone.com, August 8, 2016
  2. Thomas J. O’Shea et al., “Multiple mortality events in bats: a global review,” Mammal Review, 46, 175, July 2016
  3. J. Ryan Zimmerling and Charles M. Francis, “Bat mortality due to wind turbines in Canada,” The Journal of Wildlife Management, July 26, 2016
  4. John Miner, “Wind turbines killing tens of thousands of bats, including many on the endangered species list,” The London Free Press, July 20, 2016
  5. Chris D. Hein and Michael R. Schirmacher, “Impact of wind energy on bats: a summary of our current knowledge,” Human-Wildlife Interactions, 10(1):19-27, Spring 2016
  6. Bjorn Lomborg, “Impact of current climate proposals,” Global Policy, 7, 109, February 2016
  7. Chris Bennett, “Bats save billions in pest control,” agweb.com, August 4, 2016


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Jack Dini -- Bio and Archives | Comments

Jack Dini is author of Challenging Environmental Mythology.  He has also written for American Council on Science and Health, Environment & Climate News, and Hawaii Reporter.

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