On Sunday, I posted a short iPhone video of an osprey nest next to an 800 kw wind turbine at River John, Nova Scotia, to make the tongue-in-cheek point that someone forgot to tell the osprey about the perils of infrasound and shadow flicker. The point was tongue-in-cheek in the sense that I have no way of knowing whether young birds successfully fledged from the nest, but serious in the sense that I think health arguments against wind turbines are largely spurious.
Bruce Wark, former reporter, CBC radio producer, and King’s journalism professor, thinks I overlooked the most obvious threat wind farms pose for Osprey and other birds:
Here’s an excerpt from a scientific abstract based on a study by K. Shawn Smallwood in the peer-reviewed publication Wildlife Society Bulletin: “I estimated 888,000 bat and 573,000 bird fatalities/year (including 83,000 raptor fatalities) at 51,630 megawatt (MW) of installed wind-energy capacity in the United States in 2012. As wind energy continues to expand, there is urgent need to improve fatality monitoring methods, especially in the implementation of detection trials, which should be more realistically incorporated into routine monitoring.”
These numbers sound shocking. Indeed, I think they are presented in a contextless way* that insures they will shock. But they are actually surprisingly low, especially for birds. He estimates 573,000 bird fatalities for year based on an installed capacity of 51,630 megawatt (MW) If we assume 1 MW/turbine, the average turbine kills about 10 birds a year.
Whenever you hear numbers like this, it’s always useful to ask, “compared to what?”
Compared to what energy sources? The large array of windows on the south side of my passive solar house kills more than 10 birds a year. More to the point, the coal-fired power plants in Nova Scotia that could be displaced by wind power destroy bird habitat, cause deleterious climate change, and release pollutants that must impact mortality among birds with their supercharged respiratory systems. Gas does the same, only less so (or possibly less so, depending on methane leakage during production and transmission). Hydro dams destroy wildlife (including bird) habitat.
Compared to what other causes of human-assisted bird mortality? In a paper published in the journal Nature,** Peter Marra of the Smithsonian Conservation Biology Institute in Washington, D.C., estimates that domestic and feral cats kill between 1.4 billion and 3.7 billion birds per year, along with 6.9 billion to 20.7 billion wild mammals per year in the US alone.
Taking the median of Marra’s ranges, we can say that US cats, feral and domestic, kill about 2.4 billion birds and 12.4 billion birds per year. Marra estimates the US cat population at 114 million, so each cat kills an average 21 birds per year—making a cat twice as lethal as a wind turbine (without even counting the 101 mammals an average
bird cat kills per year).
Wark was kind enough to respond to these points:
In my Coast cover piece on wind, I stayed away from birds and bats because, as you point out, the relative numbers are low especially compared to cats. I concede that point. However, the reason I responded to you is that you were trying to use the osprey nest video to make a questionable point, i.e. that noise and flicker must not be as big a problem as wind turbine opponents claim because an osprey had built its nest near one of them. A more telling point from the opponents’ perspective is that the osprey risks flying into the turning blades as it navigates around the turbines near the nest.
I think where you and I would agree is that we consume too much electricity and that there is no environmentally costless way of producing large amounts of it. People pin their hopes on wind and hydro because they’re supposedly “clean and green” and so, the reasoning goes, if we could only kick our dirty coal habit and use wind and water instead, we’d be able to “save” the planet without having to cut our consumption too much. It’s the same reasoning environmentalists use when they contribute to various “save the planet funds” to offset their addiction to air travel. As I see it, the problems involved in cutting consumption are compounded by the fact that our economy depends on it so we’re caught on a treadmill where household spending fuels growth, jobs and all the other hallmarks of “prosperity.”
I do agree with Wark that there is no costless way of producing large amounts of energy, but the environmental cost of producing it with coal dwarfs the cost of doing so with wind, hydro, solar, nuclear, and probably outstrips that of doing it with gas. If it is true that we face planetary disaster owing to human induced climate change, then it is irresponsible to dwell of what are really NIMBY objections in disguise.
* This comment applies only to the abstract of Smallwood’s paper. Unfortunately, the Wildlife Society Bulletin follows the increasingly common and lamentable practice of putting the full text of its studies behind a paywall. It’s possible that, in the full text, Smallwood contextualizes the numbers that seem so sensational in the abstract.
** The full text of Marra’s paper is likewise behind a paywall.