Serious question: what is threshold at which the number of these turbines sufficiently disturbs normal wind to induce climate change?
The answer is that it would take a lot and is dwarfed by GHG climate change.
I said nothing about wind vs petro/coal. But we're at a point where we've decided that we've taken petro too far, and it changed the climate, so we need to replace it with something else. We're rolling out something new, but I'm not seeing a lot of activity on addressing the potential for the new thing to change the climate.
"Although large-scale effects are observed, wind power has a negligible effect on global-mean surface temperature."
Hmm. Is that the de facto measure of bad climate change?
But, seriously again, isn't that a weird thing to examine in this study? The researchers hypothesize that wind turbines might increase the surface temperature, and they found that they do not. Great.
I don't know why anyone would look to examine that, since they produce negligible GHG.
If I were examining it, I would look at stuff like how much wind energy getting removed changes things that are contingent on wind.
The wind patterns are already substantially affected by the collapsing of the polar vortex as the reflective ice cover in the Arctic decreases, reducing the (previously consistent) cycling of air around the globe. This is one of the major contributors to more severe weather.
All this to say: it's an interesting question, but I think it's already too late to wonder about any effect on "normal" wind. "Normal" wind is a thing of the past.
All of those things may be true, but I disagree that it's not worth figuring out. I mean, if we're greenwashing everything--I just bought carbon-neutral coffee tf is that--we might as well do the math here.
This is just like how we raced to ping whales to death. Like, let's game out one move ahead.
This one for example mentions in the abstract that by using an amount of turbines collectively making up 300 GW of capacity, it could severely reduce wind speeds of a hurricane: https://www.nature.com/articles/nclimate2120
300 GW is 2/3 of the power consumption of the entire US and you would need all of those in a small-ish area just to dampen, not fully absorb, a catastrophic storm's energy. Even after those wind speed reductions, there is very strong wind.
If you scatter those turbines in a larger area, you can imagine that the effect will be much more diluted. There is so much energy in the atmosphere that we won't put much of a dent in it with our current energy consumption.
Some of the air movement due to high and low pressure and humidity and turbulence becomes infrared radiation (heat) due to mechanical friction and presumably also due to turbulence and convection causing friction in the air.
Now, try to imagine a wind farm tall enough and dense enough to meaningfully impede the flow of air driven by rotation and pressure/temperature differences on the surface of the planet you are looking at.
Next, take a guess as to whether such wind turbines are likely to be built under any circumstances.
So the "tallest and most dense wind farms are long past being completely invisible" means that they are so large as to be visible even from space?
> imagine a wind farm tall enough and dense enough to meaningfully impede the flow of air
Right. This is begging the question.
> whether such wind turbines are likely to be built
Exactly what I'm asking.
As you ascend, the tallest wind farms cease to become visible at about 30-40 miles of altitude. At that point you still have more 200 miles to ascend before reaching the low end of low earth orbit. So by the time you reach LEO, you are long past the point where wind farms became invisible.
> This is begging the question.
I am proposing you attempt to visualize the scale of things involved in your question, and that such a visualization ought to make the answer very clear. If the question were "at what point does my box fan collection affect the climate in my zip code" I would answer in a similar way.
The research posted in this thread concludes that there is a non-negligible effect on climate. It certainly sounds like you have arrived the opposite conclusion, but as you've left it as exercise to me, I can't be sure.
The reason that CO2 has such an oversized impact is that it accumulates in the atmosphere. Wind turbines offset CO2 emissions, and potentially help absorb a little bit of energy. They seem far more likely to reduce or slow the CO2 caused climate change than to cause any direct effects.
There is a paper showing very local surface temperatures going up slightly in the immediate downwind area of some turbines. This doesn’t affect global temperatures, nor air temperatures, but there may be some minor measureable effects very close to turbines.
I asked because it occurred to me that it could. Then, someone pointed me to the paper (linked in this thread) and the researchers say so: "Large-scale use of wind power can alter local and global climate by extracting kinetic energy and altering turbulent transport in the atmospheric boundary layer" and "very large amounts of wind power can produce nonnegligible climatic change"
Whether or not that change is a problem is the next step of the process.
CO2 doesn't have anything to do with this situation, because wind turbines don't produce much CO2.
We probably have several orders of magnitude more turbulence in the air due to cities and airplanes and other man made structures than turbines.
CO2 absolutely has everything to do with this, because you asked about climate change. CO2 is one of the things use of turbines is intended to reduce. You can’t ask a question about climate change and proceed to ignore CO2. CO2 emissions are reduced when coal plants are replaced with turbines. If you want to have any idea of the affect of turbines on climate change, you must account for the relative changes in CO2, and it’s likely to be larger than whatever effects turbulence cause.
If you are interested in what turbulence can do to the climate, then it’s also important to ask the question what has already happened due to deforestation. Does the introduction of turbines have any chance of compensating for the number of trees we’re removed from exposure to surface winds?
What am I supposed to say?
> CO2 absolutely has everything to do with this
In fact, it's not. The climate is not comprised entirely of CO2. You're so wrapped up in the unrelated issue of CO2 that you're not addressing the actual question. My question is "can wind turbines provoke climate change?" It's not "how is wind better than coal?" Why not ask "how do wind turbines reduce atmospheric H2O?"
It's ridiculous. This is a reasonable thing to consider. If there is no material effect, or if there is a mitigation, then we're golden. But I'm hearing "you're so dumb for even thinking that, and have you even seen them from space, and what about coal?" Well fuck me for asking then.
> Does the introduction of turbines have any chance of compensating for the number of trees we’re removed from exposure to surface winds?
Let's ask that question. I don't know why we should conflate those two things, but yeah, what has deforestation done to the climate?
It’s not possible to answer your question about turbines and climate without talking about CO2, so if you refuse to discuss CO2, then... CO2 is the known cause of current climate change. I didn’t ask if wind is better than coal (answer:yes). The pre-supposed answer to your question by many people is that use of turbines will cause positive changes to the climate due to their ability to reduce CO2. Will that be offset by warming caused by turbulence? Personally I doubt it, but maybe.
Deforestation is, as I understand it, contributing to warming, among other environmental negatives. It also removes turbulence causing obstacles from the boundary layer of air at the same time that turbines are adding some. Why wouldn’t you worry about tree turbulence, if you’re going to worry about wind turbine turbulence?