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Planting trees to counter carbon emissions won't work
05-27-2017, 12:09 AM
http://www.cbc.ca/news/technology/trees ... -1.4132679
tl;dr: If we want to plant trees to counter our carbon emissions, then we have to stop planting food crops and cut down half of the world's existing forests to make enough room for all the carbon-credit trees. Then we have to figure out what to do with all the wood we grow (wood isn't edible even though it would need to replace all of our food crops) without generating any more carbon emissions, because all those trees need to come down to make room for more trees in a decade or two.
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Kind of old news to me. The amount of carbon stored in the terrestrial biosphere is laughably small. I mean, it's huge, but it's the smallest of the large scale sinks, and dwarfed by geological processes. I don't remember the numbers, but it's something like 1-2% of the problem. So every time I hear "plant a tree", I've just assumed it was someone trying to feel good about themselves while entire forests are literally dying from invasive insect diseases and new weather patterns disguised as drought. And the carbon only leaves the system if the wood is buried somewhere to become the next era's fossil fuel.
Carbon credits are basically gamification of preventing pollution, that represents reality in the same way that Catan represents a market economy. I like games, and it's better than nothing, but anything that approaches an actual solution to climate change is nothing short of transforming the entire energy economy. Thankfully you have people like Elon Musk who get that, which is why his "car company" is really trying to be a vertically-integrated energy company.
Also not mentioned in the article: forests are dark, which means they have low albedo. They trap incoming light, and thus energy, from the sun, warming up the atmosphere. I'm sure the researchers accounted for this because it's really well known, but it's just one more negative feedback for the pile.
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The only sensible way planting trees lowers carbon emissions is with the understanding that in say, 50 to 100 years you cut down those trees, turn them into high char charcoal and chuck them into a pit.
Because, you know, that's effectively how nature sequestered all that carbon away in fossil fuels.
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Skip the "turn them into high char charcoal" part - that process would produce greenhouse gasses, which is what the whole "plant a tree to offset carbon" idea is supposed to reduce.
So it'll take a few more millennia to turn the wood into coal or oil...
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I think the idea of making it charcoal is to prevent decay from releasing it ahead of schedule as well.
So.
Recursively impractical?
I guess you could just stack logs in old coal mines in the meantime...
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Carbon sequestration in biomass is roughly as practical as exercising to lose weight - it'll help a very little bit, but the only real solution is to stop adding so much (carbon or calories) in the first place.
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Charcoal is more volume efficient because that's nearly pure carbon, and high char charcoal has a substrate-to-charcoal efficiency of 90 to 95%. Most of the lost weight is oxygen and hydrogen.
The important thing is that it's a net improvement. If you can make that tree grow, harvest and store it in a hole for even half the carbon emission handling the tree takes you basically take out 1 tree worth of carbon for every 2 trees you plant for off setting carbon emissions.
You also don't need a coal mine to stuff those logs. Any hole will do, so long as you plug the hole after you're done. I mean, take an empty open pit mine, point a conveyor belt into the damn thing and just keep the to be sequestered carbon coming.
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In the meantime, as someone who lives in a city where certain stretches of freeway happen to line up perfectly to LASERBEAM YOUR FREAKIN' EYES at sunrise or sunset... May I suggest shading expressways (and parking lots, too) with solar panels?
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Quote:May I suggest shading expressways (and parking lots, too) with solar panels?
As someone who has shared this experience, I most heartily approve of this idea. Also, doing this to parking lots would make walking across them much pleasanter in the summer. Depending on how they're angled, they might make plowing easier in winter too.
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Quote:Inquisitive Raven wrote:
Quote:May I suggest shading expressways (and parking lots, too) with solar panels?
As someone who has shared this experience, I most heartily approve of this idea. Also, doing this to parking lots would make walking across them much pleasanter in the summer. Depending on how they're angled, they might make plowing easier in winter too.
I quite thoroughly agree.
I've also seen proposals for roadbed piezoelectric generators, that make electricity from the weight of the vehicles moving over them. It would be a much more serious rebuild, but it would add to the balance.
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Not really ECS. The amount of copper you'd need to make it work just for 1 continent would break the world economy, and that's if that much copper exists in exploitable deposits on Earth.
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Yeah, photovoltaics are the way to go. Especially if you combine modern, advanced solar cells with the new advances they've had in hydrolysis - you can now run your own little hydrogen plant in your own home, running off nominal electricity and using ordinary tap water (though it'd probably be a good idea to run it through a reverse osmosis filter first to cut down on the minerals).
A company called HyperSolar is working on that right now, and they're very close to achieving their goal of commercially viable solar powered hydrogen production.
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Not the point actually. It's more that creating enough copper cable for the entire road network would break the copper market entirely. And frankly, all photovoltaics do is cut down on the energy needed from any other sources; simple fact is that even with 100% efficiency in renewable energy generation and distribution the entire Earth can't generate enough solar power or any other combination of renewable energy based energy sources to match the energy demand of the Earth.
You need fossil fuels, nuclear fission, or nuclear fusion to make up the difference, or accept a smaller per person energy budget.
And even if you've done that, fossil fuels are still in general to superior to certain purposes. There's simply nothing else that has such a high energy density in so easily handled and relatively safe form.
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Hazard Wrote:Not the point actually. It's more that creating enough copper cable for the entire road network would break the copper market entirely. It would be foolish to install roadbed piezoelectric generators in the entire road network, just as it would be foolish to install waterwheels on rooftop downspouts. Install them only where the electricity generated pays for the hardware, maintenance, and installation and end-of-life recovery costs.
Which leads to the next question: where in the road network is it economically feasible to install such systems? (How much do they cost, how efficient are they, how many vehicles need to drive over them to generate enough power to pay for the hardware?) I would expect that we shouldn't bother with residential side-streets that see maybe two or three vehicles per hour and we should try it on always-extremely-busy roads (e.g. the Brooklyn Bridge or the 401 through Toronto), but where's the cutoff between feasible and not-feasible?
Hazard Wrote:And frankly, all photovoltaics do is cut down on the energy needed from any other sources; simple fact is that even with 100% efficiency in renewable energy generation and distribution the entire Earth can't generate enough solar power or any other combination of renewable energy based energy sources to match the energy demand of the Earth. There's nothing wrong with reducing the reliance on non-renewables, even if they can't be eliminated altogether. Also, the efficiency of photovoltaics has increased remarkably recently (a full order of magnitude over the last decade, IIRC), so the newer hardware will reduce the reliance on non-renewables even more than it would have in the mid-2000s.
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Like the man says, every little bit helps. Dismissing small solutions because they're not big solutions is like not saving $1 because it's not $100.
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Oh, certainly, if it's possible to lessen the carbon emission through fossil fuel derived energy by even 10% it'd probably be a worthwhile interim investment at minimum. I'm just saying that renewables alone cannot be enough, simply because we can't derive enough energy from them.
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The journey of a thousand carbon-reductions begins with a single step.
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I know that people have debunked space-based solar power, but I still think it could be done. It'd probably require a good lifetime's worth of R&D, plus a robust space program... but I think it can be done.
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The biggest issue with space-based solar power is how do you get the power down to the ground. Microwave transmissions are the standard proposal... and people whine about them heating up the atmosphere, frying birds, potentially frying towns and cities...
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Meh. This is why we need orbital tethers. :p
(Like I said - a VERY robust space program.)
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Black Aeronaut Wrote:Meh. This is why we need orbital tethers. :p
(Like I said - a VERY robust space program.) And some breakthroughs in materials science, to create something that's robust enough to remain in one piece when it's that long.
Also, there aren't a lot of places on the Equator to put tethers (anywhere else would require constant thrust applied to the anchors at the space end; the idea is to bring the power down here, not use it in orbit). Brazil, Peru, Columbia, Ecuador, Indonesia, Somalia, Kenya, Uganda, Democratic Republic of the Congo, Republic of the Congo, Gabon, and Sao Tome are the only nations with equatorial land, and most of that is near sea level (which means dealing with weather effects... but, once we have that miracle substance that will remain in one piece in that long a structure, weather effects aren't likely to matter much).
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From what I understand, we're close. Almost ungodly so. Like, another ten years or so of R&D close. In the grand scheme of things, that's not very long at all.
Also, superconducting power lines are a thing. It's just not a widespread thing because power companies don't want to make that kind of investment in the infrastructure - no matter that SCPL's will improve grid efficiency by leaps and bounds, make it easier to place power plants, and help make blackouts a thing of the past.
With superconducting power lines you can get the energy from the receiving plant at the end of the orbital tether down to the distribution station at the base, and send it wherever it needs to go, with virtually no energy loss along the way.
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Last I checked superconductors were actually major power hogs due to the cooling requirements. There is also that, if environmental temperatures become high enough that your superconductors no longer conduct that well while you are tossing hundreds to thousands of amperes of current through them the likely result is 'burning powerline' or 'exploded powerline.' Depending.
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Black Aeronaut Wrote:From what I understand, we're close. Almost ungodly so. Like, another ten years or so of R&D close. ... We've been ten years away from suitable materials for at least the last twenty years.
Call me when there's a laboratory prototype.
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Quote:Hazard wrote:
Last I checked superconductors were actually major power hogs due to the cooling requirements. There is also that, if environmental temperatures become high enough that your superconductors no longer conduct that well while you are tossing hundreds to thousands of amperes of current through them the likely result is 'burning powerline' or 'exploded powerline.' Depending.
Actually, no. Industrial cryogenics has been a thing in use for a while now. Here's some reading material: http://www.eetimes.com/author.asp?doc_id=1320733Quote:robkelk wrote:
Quote:Black Aeronaut wrote:
From what I understand, we're close. Almost ungodly so. Like, another ten years or so of R&D close. ...
We've been ten years away from suitable materials for at least the last twenty years.
Call me when there's a laboratory prototype.
So all the breakthroughs we've been having with carbon nanotubes mean nothing to you?
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