Here's a study that evaluated exactly what you're looking for, if I understand correctly: http://www.mdpi.com/1996-1073/2/4/816/htm

In summary, if the entire Earth was powered by wind, it would result in a net loss in the lowest 1 km of the atmosphere of ~0.007%.

Looks like some far more competent folks have pretty thoroughly looked into it. I'll sleep better knowing I'm not the wind's sole protector

I know it's bad form to just offer an unexplained video link, but your phrase "the wind's sole protector" reminded me of this delightfully understated French commercial that illustrates why the wind has so few people looking out for it: https://www.youtube.com/watch?v=2mTLO2F_ERY

Although that would be a cool job description.

I'd really hope wind has a bus factor of more than one though.

If we increase our energy consumption 100-fold this estimation of net loss in wind would approach 1% which sounds bad. I guess we might need wind protector after all.

That's a pretty big "if".

Is it? Given current energy consumption growth it's just 100-150 years away

Edit: From covering the entire surface of the earth, which is the bigger if. (Should have read the context)

Aren't trees and tall buildings in cities doing a million times more then if the whole world was powered by the wind?

Very likely, yes. Until wind farms dwarf the scale of our cities and forests, I doubt there's any reason to worry.

Besides, don't we usually consider trees to be good things? They block a lot more wind than any wind turbine.

I think once we solved the storage of energy from solar panels the wind won't really be needed. I still would love to see tidal generators that work but I guess it is to much upkeep.

Don't forget that CO2 is heavier than O2, [1]. So if we don't keep that wind going, all the CO2 will sink to the bottom of the atmosphere, pushing the O2 up. I'm not sure if that is a linear process (x percent less wind meaning x percent less oxygen).

[1] https://www.quora.com/Which-is-heavier-oxygen-or-carbon-diox...

You mean CO2 would concentrate at tree level to be more easily absorbed and converted back into oxygen, rather than in the upper atmosphere where it heats the earth? I'm not sure I see the downside.

Even in "still" air, the individual molecules have random velocities due to temperature - on the order of 100 m/s. Combined with the fact that there are more mixed configurations than unmixed configurations (entropy of mixing), this randomness effectively stirs the atmosphere without the need for the bulk motion of the wind.

Don't worry about pushing up O2 all them airliners will suck it up.

The amount of deforestation that we've engaged in, reducing "surface roughness" on a large quantity of the Earth's surface, that's a lot of wind energy we've stopped from being extracted.

We can draw an enormous amount before we'd even get close to break-even on our influence on the wind.

The amount of forest biomass on Earth is going up rather than down. https://theconversation.com/despite-decades-of-deforestation...

Quick "I have no idea how plants work" question, would a more carbon rich atmosphere promote faster growth?

That depends on the plant. Some plants are CO2 limited, and would grow better. Thus out competing other plants that are limited by something else. This is not necessarily good though, such plants tend to be ones we already consider weeds with little useful value.

Of course in the dry deserts everything is water limited. There are also temperature and altitude (air pressure) limits that affect various other regions/climates.

In specific controlled environments, yes. In the real world not so much. https://www.skepticalscience.com/Increasing-Carbon-Dioxide-i...

> In specific controlled environments

I think you mean, with sufficient soil nutrients, yes. That's not a controlled environment, that's a environmental requirement.

That's an interesting point. I wonder what exactly happens to wind (kinetic) energy when it is absorbed by trees moved by the wind. Does it turn into anything useful, like heat available to the tree for easier transportation of fluids, i.e. have some trees adapted to benefit from wind (other than by transporting seeds/pollen over longer distances)?

Without wind, trees don't grow strong enough to support themselves. The wind toughens them up. (This was a problem in the Biosphere project studying how to build a closed environment for use on other planets.)

Even if we covered the earth in windmills, we'd still only affect the lowest 100-200m of the atmosphere. And windmills can only extract 50% of the winds energy. I'm thinking a forest full of trees might even reduce the windspeed more than a field of mills.

I'm pretty sure that 50% number is for single mill. For a farm there should be no such limit.

Placing a windmill behind another one would be stupid. So, when you have a farm, you still capture a maximum of 50% of the energy that flows through the farm - only, you cover a bigger area and thus you get <= 50% of a bigger mass of moving air.

In (current) practice, yes, but not necessarily.

If windmills are dirt cheap, energy and land scarce/expensive, or transport losses large, a windmill in the wind shade of another windmill could still make economic sense, just as it can make economic sense to install solar cells on roofs in places far from the equator that often have cloud cover.

I don't know how practical they are but I've seen that inflatable flying windmill wind turbine thing that is meant to be 500-1000ft or higher? So doesn't that make the 100-200m a bit low on what altitude we can extract from?

The inflatable flying windmill thing isn't particularly efficient, the future high-atmosphere wind energy source is much more likely to be kite-based wind:

https://www.youtube.com/watch?v=vMTchVXedkk

And I assume that the two systems (upper and lower atmosphere) aren't so isolated from one another that they don't interact

50% sounds way higher than I'd expect. Windmills don't exactly block the wind. Most of it just blows through it unhindered.

In order for the windmill to turn, some energy must be taken from the wind and turned into that rotation. This hinders the wind.

If you were going to try and go turn that windmill, would you just freely spin it with 0 effort? No you'd have to push, it would hinder you.

I think the parent is saying is that, if you consider the circle traced by the outer tips of the windmill blades, the windmill blades themselves take up a very small fraction of the surface area of that circle. Thus, the windmill is fundamentally only capable of capturing a small fraction of the energy that flows through that circle.

The way I look at it, if you consider the air mass from ground level up to the top of the atmosphere, the bottom will always have a roughly zero speed since it is down in the terrain and the weeds. A carpet of windmills a hundred meters tall could at best move that zero speed edge a little higher. The kilometers of air above will be relatively unaffected.

To illustrate, consider https://embed.windy.com/embed2.html?lat=41.327&lon=-88.033&z... which if I've got that URL right will show you winds at a windmill farm in Illinois USA (nope, it misses slightly for some reason, odd, it is right when I copy it). Look in the lower right of the screen and find the slider with an airplane at the top and a mountain at the bottom. You can use this to change altitudes and explore the wind speed above ground level. Lots more windspeed up there even if the density goes down. Consider the 5500 meters up, about half the air pressure, but twice the wind speed today, so that works out to twice the energy per square foot (on edge).

The effect of wind turbines on birds and other wildlife is probably far more important, and also routinely gets ignored imo.

That's a conservative straw man. Skyscrapers have much more impact and no one notices.

If conservatives care so much about wildlife why do they support things that lead to deforestation and desertification and loss of biodiversity and pollution and...?

To be a conservative is to hold multiple contradictory positions at once, many of which directly harm your own health or well-being

Exactly. All these questionable concerns about the negative impacts of clean energy are straw men conjured up to protect the real devastating energy sources.

Not to mention cats. Some stats here:

http://www.currykerlinger.com/birds.htm

I'm pretty sure some people notice. I'm also reasonably sure that if we produce a substantial amount of our energy needs from wind, turbines will far outnumber any skyscrapers.

"Wind turbines kill between 214,000 and 368,000 birds annually ... compared with the estimated 6.8 million fatalities from collisions with cell and radio towers and the 1.4 billion to 3.7 billion deaths from cats, "

https://www.treehugger.com/renewable-energy/north-america-wi...

The problem is not wind turbines or radio towers. The problem is cats.

That data isn’t true. Multiple studies put that number into the millions.

http://www.nature.com/news/the-trouble-with-turbines-an-ill-...

Well, the data is definitely questionable - but unclear whether the Ornithological Society (or TreeHugger) cites unbiased studies, I'll give you that. Here is a Stanford Study with some sources:

http://large.stanford.edu/courses/2016/ph240/white1/

What I like about it, is that it cites avian mortality in terms of Mortality per MW, (though one might suggest MWh is a better number, but we can extract that by assuming 20% Capacity Factor) which is the more relevant number than total deaths, because are going to see a lot more MW in the future, and presumably deaths will scale linearly.

Total Average US was 4.12 Avian Deaths / MW. With California really leading the pack at a high 18.76 per MW.

Presuming a 20% capacity factor, and assuming the united states uses about 10 million MwH/day, that means the United States will need 10 million * 5 / 24 MW in capacity, or about 2 million MW capacity (Sanity Check - 2 million MW = 2000 GW which is about 400 GW of nuclear power plants @ 100% Capacity factor - about 400 Reactors,- seems within the realm of reason given the US has about 100 Reactors right now), which means that on average, we'll see about 8 million bird deaths in the future because of wind farms.

That compares to (in 2009) - 4 million due to communication towers, 14 million due to fossil fuels, 72 million due to Pesticide, 97 million due to Building Windows, and 110 million due to feral cats.

And bird deaths from cats and skyscrapers will be many orders of magnitude greater. This is well-reasearched, and it's not hard to find the journal articles on this topic. We need not guess.

How is “protecting birds” a conservative straw man? Non-conservatives routinely block all sorts of projects because of endangered fish or frogs. How often do non-conservatives use the Endangered Species Act as a tool to prevent projects with which they ideologically disagree? It’s like they oppose a project and then find whatever legal means they have available to block it. It isn’t like non-conservatives in California have a profound desire to protect the delta smelt; if they did, then why wouldn’t they oppose the Altamont Pass wind farm that kills 114 golden eagles each year? How about the death of highly endangered condors because of of California wind farms? A skyscraper has never killed a condor but a wind farm has.

http://savetheeaglesinternational.org/new/us-windfarms-kill-...

Non-conservatives use the same straw man by somehow suggesting fossil fuels harm wildlife. But their own pet projects seem to escape the same scrutiny with which they apply to fossil fuels. My theory is that by restricting fossil fuels they can redirect the balance of economic power towards a direction that is more in line with their particular ideology. My point is that “environment” itself is being used as a straw man with the ultimate goal of changing wealth distribution.

Oil spills definitely harm wildlife and windmills also definitely harm wildlife.

It’s fair to point out the ecological effects of fields of windmills just as it’s fair to point out the harms of oil spills.

Also, we aren’t talking about skyscrapers— we are talking about energy generation. Whether or not skyscrapers harm wildlife and to what degree isn’t relevant because skyscrapers already exist and people aren’t suggesting we cover the countryside with skyscrapers. If that were the topic under debate, then the effects of skyscrapers on wildlife would be a relevant point.

Various international bird (and bat) societies support wind power as a net positive for their particular species, while contributing expert guidance on siting and design to minimize bird casualties and opposing individual projects that they feel are poorly designed or sited. (Of relevant interest to HN are computer vision projects that track rare birds and stop nearby turbines when they come too close)

So, if conservatives are really opposing wind power on the basis of "saving birds" then they're massively misinformed and ignoring the relevant experts.

Since they don't actually care about the birds, it's obviously a cynical ploy to protect fossil fuels that on balance are a greater threat to the very birds they claim to want to save.

And in doing so they're choosing not only an environmentally destructive option, but one which is more costly to society, just because the special interests who receive the benefits will provide kick backs to politicians that help them.

You couldn't really summarize modern conservative thought better if you tried.

If you want to protect birds, you have to ban people from keeping cats and letting them loose in rural areas. Good luck with that.

When complaining about loose cats, no one ever seems concerned about all the rats that are also killed.

As always, you should compare with other sources of energy. As long as windmills replace CO2 producing energy sources, it's a net gain for wildlife - not the mention the other pollutants you're displacing, which are usually much worse in the short term.

Do you still operate a car?

https://www.codot.gov/programs/environmental/wildlife/data/a...

It kills birds, albeit 10,000x fewer than housecats.

Trump likes to whinge about it.

> If there were no wind tomorrow, we can agree that this would be bad.

I think Houston would disagree.

There's an enormous amount of energy in wind. There's not a chance that we can hope to capture more than the tiniest fraction of it. And if we could, we'd certainly love to drain some energy from tropical storms.

It's good to think about such risks, though. There are people who thought burning carbon couldn't possibly have any meaningful impact, and quite clearly it can.

I've seen a proposal for clean energy, 1 km tall solar towers that create energy out of the difference between warm air close to the ground and cold air high up in the atmosphere, that felt to me like it might have some impact of weather patterns. I doubt it actually does, but it can't hurt to do the math.

I suppose if the energy source with the least possible side effects would be solar panels in the desert. Without them, the sun is just going to heat the sand and the air and make the place even drier. And you need only a tiny bit of the solar energy from the desert to power the entire world. Less than what's regularly lost to desertification, deforestation, or the land we pave with asphalt and concrete. Before we get worried about any potential negative impact there, we should first worry about all the very real negative impact we're having all across the world.

The question has been asked in the past and modelled with some level of detail. For example: Estimating maximum global land surface wind power extractability and associated climatic consequences [0].

At a higher level the question is easy: Sun shines, warms the air more in the tropics, creates a gradient, and wind flows. What if we capture all this energy? But the details of the calculation are subtle. The cited paper says: It could have dire climatic consequences!

But it may be over-estimating how many locations are really suitable for wind turbines. Many things limit the efficiency (i.e. cost effectiveness) of a wind farm (turbulence, minimum average wind speed, maximum speeds, access to the site, distance from cities, etc).

One important point is that most of the energy exchange happens at high altitude (where the turbines can't reach).

[0] https://www.earth-syst-dynam.net/2/1/2011/esd-2-1-2011.pdf

it's good to think through, but first order intuition on this (for me) goes something like:

1. the wind gets it's power (directly and indirectly) from the sun and we"re just too miniscule to affect that in any meaningful way.

2.on top of that, we return most of the acquired energy back to the atmosphere in the form of heat.

3. and we haven't built anything close to large and extensive enough in one place to create even micro-environmental effects.

we're just too miniscule to matter so it's a problem that might affect the planet in 1000 years when there are trillions(?) of people on earth but not worth worrying too much about now. by then, we might have become the brains of a superorganism or something and then it's time to worry =)

Wind also gets some of its energy from Earth rotation.

> we're just too miniscule to affect that in any meaningful way

Though this same argument is dismissed by those who support the idea that we're changing the weather by CO2 emissions.

You kinda took that out of context. "That" is "the amount of energy the sun radiates to the Earth's surface". That amount of energy 100% dwarfs anything the human race could ever hope to use

Well dwarfs what we need before we start colonizing the galaxy.

> Though this same argument is dismissed by those who support the idea that we're changing the weather by CO2 emissions.

Our direct effect is minuscule, it just so happens that our efforts magnify the not so minuscule effect the sun has.

In terms of wind energy, rotating mills are not going to have any measurable impact on wind energy or patterns.

But with CFCs, we clearly aren’t minuscule. We saw a hole in the ozone layer that opened when we used them, and is closing now that we’ve stopped.

For some things, we’re too minuscule, for others we’re not.

Who argues that human greenhouse gas emissions are minuscule?

Climate change will also increase wind levels tremendously (more energy => more wind)

Wind must blow in order to extract energy from it. Therefore, we will never slow down wind to zero with windmills. Also we already have mountains changing weather patterns. Sure, the weather patterns will change at some point as windmills grow to mountain size but in this case we will notice it way before it goes out of hand. In an emergency situation we can bring the windmills down at free fall speed with some thermate and gasoline.

Yeah, it must blow to get there, but it by definition has less "blow" on the other side. I think I'm getting that the scale of this is negligible, but it is certainly less

I understand the amount we might ever extract pales in comparison to the amount that would upset any natural phenomena.

Is it true that we once had the same rationale with coal?

I would say that with coal, we never even considered the impact - carbon dioxide, much less the greenhouse effect, were unknown when we started burning coal in earnest.

With wind power, smart people have at least sat down and done the math.

I've seen studies of this before, and googling "wind energy climate effects" pulls some up. I think the upshot was that there would be some climate effects but it would take a truly massive expansion of wind energy to amount to much, and would still be much less damaging than fossil fuels.

With traditional (coal, gas, nuclear) electrical power generation, one unit of energy is delivered to your wall socket by dumping about two units of heat directly into the environment somewhere else.

The star-studded and scientifically profound movie Southland Tales touches upon this, but with respect to tidal energy. It's quite a fascinating story that you may enjoy, given your questions.

Glad I'm not the only one who's thought about this :)

Based on that line of reasoning you ought to be really nervous about solar panels :)