As long as I can remember, I’ve been nervous about wind power. Not for the usual reasons that you hear – objections based on the physical effect on the landscape, or noise pollution, or the effect on migratory birds, all of which seem minor in terms of the potential benefits of this technology, and the disastrous effects of carbon based technologies. In fact I actually quite like wind turbines as structures. No, my fear is based on two factors:
- The potential of actual damage to the global environment in terms of climate change.
- The lack of deep critical thinking, or research, about this technology.
Don’t mess with Circulation
So what are these risks? In short they are the potential to effect the circulatory system of the planets natural ecosystems. Taking energy out of these circulatory systems is a high risk strategy, which should only be undertook based on a deep understanding of the subtle and unpredictable effects that messing with the planets circulatory systems can have on ecosystems and the global climate.
To take an analogy, it is as if we were to try and tamper with the way blood or oxygen circulates around the body, and claim this to be nothing more than a “harmless” medical intervention. Wind carries not just the rains, but also has profound effects on pollination and a wide range of ecosystems. You don’t need to be a farmer to realize that which plants grow and which animal systems thrive can in large part be determined by the nature of the prevailing winds in the environment. The question is whether the large scale removal of energy from our circulatory systems, could significantly alter regional or global climate.
What’s the evidence?
So how does this proposed impact work? Well in one sense it’s straight forward; weather systems are driven by energy imbalances, and the aim of wind farms is to take energy out of the atmosphere, and they do this by reducing wind speed. The issue is that we simply have no idea what effect this will have, and what little research has been done on the subject, indicates that large wind farms can at the very least, significantly affect local weather.
Recent research has indicated that the turbulences created by a large windmill array, can decrease wind speeds by as much as 6.7 miles per hour, increase evaporation and raise local temperatures (by about 2 degrees Celsius for several miles downwind from the farm). In another study, offshore wind farms have been shown to affect ocean currents, causing an upwelling of water currents and a consequent alteration to the pattern of temperature flows.
What about large scale effects?
Slowing wind speeds by 5 or 6 miles per hour – while it sounds negligible, could have significant impacts on the large-scale atmospheric flow and yield consequences we do not yet understand. The models quoted, indicate that local effects, could rippled out like waves that appeared to trigger substantial changes in the development and track of storms over the North Atlantic. Ensemble forecasting has shown that even apparently innocuous changes in the low-level wind field can result in large uncertainties in the timing, strength and motion of major storms over a period of just a few days.
The Big Freeze
Of particular interest in this area of research, are the fascinating events that took place in the Northern hemisphere as little as 12,000 years ago, know as the Younger Dryas. Against the tide of a consistent period of global warming (that continues to this day), there was an unexplained and extremely rapid re-emergence of the ice age with temperatures dropping 15ºC in Greenland and 5ºC in the UK with glaciers returning to the highlands in Britain. The Big Freeze lasted around 1,300 years, and was followed an even more rapid 10ºC warming that took place in a truly remarkably short period of time (as little as a decade).
Now one of the main contenders for an explanation for this extremely unstable period of our recent climatic history, has been the postulated disruption of the North Atlantic thermohaline circulation. In other words it is a well respected scientific hypothesis that relatively small changes in global circulation patterns can cause rapid and profoundly dramatic effects on our global climate.
The science here is highly debated. There are for instance, other equally good theories as to why the climate changed so rapidly during the Younger Dryas:
While much of the catastrophic thinking around some of these theories remains speculative, what everyone agrees with is that disruptions to the core planetary circulatory systems can have every bit as dramatic effect of global temperature as other drivers (such as CO2 levels):
- El Nino
- Permian-Triassic extinction event due to a shift in ocean currents?
- Nasa on the Great Ocean Conveyor Belt
- Abrupt Climate Change
Probably the main reason that we should be concerned however is simply the casual lack of concern that we have with regard to this technology. We seem to have the naive idea that simply because the wind, is “natural”, harvesting it must be harmless, while nuclear energy is man-made and high risk. As a consequence we do not demand the same levels of research, and caution when calling for the wide scale deployment of wind farms or similar technology, and as ever it is this mind set that is the true danger.
We should respect the power, unpredictability, and value of our climate and weather systems, and know the extreme limits of our current understanding. Respecting the environment is not compatible with allowing ourselves to abuse it in the name of blind faith – we should listen more carefully to the wind.