What is it with some media outlets and their tendency to gloss over the difference between ‘weather‘ and ‘climate‘? Let me give you the basics. Here’s the Wikipedia* explanation of the term ‘weather‘:

…the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy.

And here’s the one for ‘climate‘:

…the statistics of temperature, humidity, atmospheric pressure, wind, precipitation, atmospheric particle count and other meteorological elemental measurements in a given region over long periods. Climate can be contrasted to weather, which is the present condition of these elements and their variations over shorter periods. 

[*Those with a morbid mistrust of Wikipedia can consult the corresponding Oxford English Dictionary definitions here and here. (Hint: weather = ‘…at a particular place and time‘; climate = ‘…over a long period‘. You know. The same as in Wikipedia.)]

Weather is that short-term burst of meteorological whatchamacallit that just happens to be occurring right now, perhaps as the result of — hey, I don’t know — a “ridge of low pressure” or something. Like, today it happens to be rainy and cold. That’s weather.

Climate, on the other hand, is the default setting for everything meteorological. It’s the stuff that is most typical of a particular place, the more-or-less average conditions you’d expect across many many years. For example, where I am, you usually wouldn’t expect it to be rainy and cold at this time of year. That’s the climate. But this year it is. That’s the weather.

So you see, weather and climate are not the same. One’s a fleeting instant, the other’s a lasting reality. One’s a flash in the pan, the other’s a lifetime’s condition. One’s a cheap and grubby one-night-stand, the other’s a passionate and fulfilling long-term relationship. You get the picture.

So now take yesterday’s newly published research findings concerning the impact of wind farms on local land surface temperature. According to some media outlets, this was evidence of the terrible effect of wind farms on climate.

The Daily Telegraph warned us starkly that “Wind farms can cause climate change“. The people at Forbes Magazine were happy to dispense with any element of doubt, replacing it with an exclamation mark: “Wind Farms Cause Global Warming!“ they told us, sagely noting that “this is not some joke nor some strange denialist ‘science’“. Meanwhile, the Daily Mail were in the mood for some Caps Lock. “Wind farms make climate change WORSE,” they declared (but only on their website).

I mean, what are the pro-wind eco-loons thinking? They must really hate the environment.

The study being described was published in the latest issue of the science journal Nature Climate Change. A New York-based research team reported patterns of increased temperature readings clustered around some wind farms in Texas. The statistical clustering was so close as to strongly suggest a causal link between the location of the wind farms and the relative increase in land surface temperature nearby. And the extent of this impact? Well, the data showed that areas near wind farms became 0.72 degrees warmer across the decade from 2003 to 2011 than did similar areas without wind farms.

But there were a few caveats. First of all, the finding here is not exactly new. The same group of researchers have themselves reported similar results on a number of previous occasions. What makes this new study scientifically interesting is its methodology. It is the first such study to test the (known) effect of wind farms on local temperatures by analysing satellite images on a pixel-by-pixel basis.

However, the bigger point here is that the temperature shift caused by wind farms relates to the very reasonable fact that wind turbines alter the flow of wind in their immediate surroundings. In short, wind turbine rotors cause air turbulence, and moving air around changes its temperature. And incidentally, sometimes the effect of wind turbines is to lower nearby air temperatures rather than increase them.

But why is all this really weather rather than climate? Because if you take the turbines away, you immediately undo the temperature changes. The temperature changes here do not amount to “climate change” in the normal sense, they are entirely contingent on the presence of wind turbines and entirely localized to their immediate surroundings.

Saying that turbines “make climate change worse” is a bit like saying toasters contribute to global warming. Or candles. Or even gentle farts. Because each of these things cause short-term localized changes in air temperature too, and you can record the differences for a research study if you get the right instrumentation close enough to measure them. (Good luck with that, by the way.)

The point is that the change in air temperature around wind farms represents a localized weather effect that has nothing to do with global climate change.

The only reason to link the two in newspaper headlines would be to cause a fuss.

Or turbulence, if you prefer.

Brian Hughes

Brian Hughes is an academic psychologist and university professor in Galway, Ireland, specialising in stress, health, and the application of psychology to social issues. He writes widely on the psychology of empiricism and of empirically disputable claims, especially as they pertain to science, health, medicine, and politics.