Personal net carbon removal

2008-06-10

in Science, The environment

Bridge outline

Those wanting to reduce their contribution to climate change are generally presented with two options: cut back on your own emissions or pay someone else to do so. The first requires sacrifice and/or time and/or capital. You can give up flying, meat, and air conditioning; you can take trains instead of planes; you can invest in solar panels and ground source heat pumps. The second set of options is arguably more practically challenging and morally problematic. It is harder to verify that someone else has actually cut emissions, and done so in response to your payment rather than any other incentive. There are also those who think it unacceptable to buy your way out of taking action yourself.

There is, at least theoretically, a third option. Suppose I buy an area of land in British Columbia. The place is ideal for growing trees and the trees on the lot grow each year, absorbing carbon from the air in order to do so. As a result, my little forest is a net carbon sink. The danger, of course, is that the carbon will be re-released. Someone might cut down my forest. My forest might dry out or burn down (possibly because of climate change). Then, I will have accomplished little of value, given that carbon dioxide has a long atmospheric life. For most intents and purposes, it may as well never have been absorbed.

What I need to do is ensure the carbon doesn’t go anywhere. Here are some options I have come up with:

  1. Cut down trees at the growth rate (if one matures per month, cut one per month). This ensures that the forest will always be absorbing the same amount of carbon per unit time. Then, encase the lumber in something durable and air tight – keeping the carbon inside sequestered indefinitely. Then, either use the wood as building material or simply bury it.
  2. Cut down trees as described above and bury them somewhere they are relatively unlikely to decompose: such as a peat bog or the Arctic tundra.
  3. Cut down trees as described, chop them into chips, burn the chips for energy, capture and sequester the carbon dioxide underground. This approach has some variants: (a) seperate oxygen from air and burn the chips in that to produce gaseous outputs that are mostly CO2 or (b) convert the biomass chips into syngas (hydrogen and carbon monoxide) before combustion.

Of course, there are issues with all of these:

  1. Is it possible to shrink wrap wood in a way that will keep the carbon inside indefinitely? How many carbon emissions would be associated with making the shrink wrapping material?
  2. The Arctic tundra is melting, threatening massive carbon releases. Global temperature rise could do the same to peat bogs.
  3. This may require tens or hundreds of millions of dollars worth of capital and skilled labour, depending on how much all the equipment costs. Nobody could do this alone, though it may be possible to do at a commercial scale, partly in exchange for payments from those having their emissions offset.

None of these are great options, but they do offer at least the logical possibility of actually, literally offsetting one’s carbon emissions. For those with aspirations for world travel, but also serious ethical concerns about climate change, such options may prove the only choice.

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{ 22 comments… read them below or add one }

. June 10, 2008 at 11:32 am

Tough but fair criticism
BBC program on Kyoto offsets

“The idea behind offsets is that you pay someone else to reduce emissions on your behalf when they can make the reductions more cheaply than you can. The leading offset method use to fight climate chaos is the Clean Development Mechanism. This is an extremely controversial topic, with many (including me) contending it does not work. The BBC has an excellent radio broadcast covering both sides of the controversy. The broadcaster concludes that offsets don’t make sense. But he gives leading intelligent pro-CDM experts plenty of time to make their case. It is an example of a program that is, while not the least bit objective, still being fair.”

Sasha June 10, 2008 at 12:21 pm

The June Wired magazine had some of what I found to be the most interesting green movement/global warming coverage I’ve read in quite some time. While I definitely don’t agree with all of it, it’s an interesting read. http://www.wired.com/science/planetearth/magazine/16-06/ff_heresies_intro
If you read the article, be sure to also read Alex Steffen’s counterpoint (which I might actually agree with…).

. June 10, 2008 at 12:41 pm

Tired
Wired magazine bursts a blood vessel doing its contrarian thing

Tristan June 10, 2008 at 12:49 pm

This completely insane.

“Cut down trees at the growth rate (if one matures per month, cut one per month). This ensures that the forest will always be absorbing the same amount of carbon per unit time. Then, encase the lumber in something durable and air tight – keeping the carbon inside sequestered indefinitely. Then, either use the wood as building material or simply bury it.”

First, because it ignores that this is essentially what we already do, the only difference being presumably you wouldn’t burn the slash pile. Secondly, because it falls into the “individuals can make a difference against climate change”, which might be true if you are Pierre fucking Trudeau, but not if your Joe Shmo looking on the internet for offset credits.

Third, because certainty is a poor mistress in this dilemma. We can’t afford to need certainty about what will happen to the trees, in the same way that we couldn’t really afford certainty in knowing whether climate change was human produced. The point is to recognize what change is rationally required, and then do whatever is necessary to produce that change. What if Fascism, or worse, Religious Fanaticism cold stop climate change? What if they could grab hold of state power, world-state power, and make the effective reductions necessary for the endurance of humans on the planet? What if they did it by lying about everything, by curtailing free speech, by murdering some ethnicity?

Milan June 10, 2008 at 12:57 pm

Secondly, because it falls into the “individuals can make a difference against climate change”, which might be true if you are Pierre fucking Trudeau, but not if your Joe Shmo looking on the internet for offset credits.

This is a big part of the point I was making. Leonardo DiCaprio might be able to actually offset his emissions through an operation he finances personally. It is unlikely that you or I could, though it might be possible for us to buy a share in the sequestration done by a biomass facility. Even if doing so cost 50% of one’s income, it could be argued that it is ethically required.

Milan June 10, 2008 at 12:59 pm

First, because it ignores that this is essentially what we already do, the only difference being presumably you wouldn’t burn the slash pile.

The big difference is that we would need to do a lot more to ensure that the carbon doesn’t get re-released. Just building things from the wood does not accomplish this.

A better option than trees – which only just occurred to me – might be to breed Foraminifera and bury their shells to form limestone.

Anon June 10, 2008 at 1:09 pm

While this kind of option isn’t open to most people, it could be within the reach of the rich and famous.

Here’s the question, though: Is it better for Madonna or the Pope or whoever to spend $10,000 a tonne ‘actually’ offsetting CO2 through some kind of tree scheme, or to devote the same amount of money to trying to reduce the emissions of others. Chances are, they could do more good by paying for better insulation in houses, or CF lightbulbs for people in hot climates.

. June 10, 2008 at 4:04 pm

The World Wildlife Federation estimates that an acre of bamboo can store 6.88 metric tons of carbon per year, about 70 percent more than an acre of hardwoods. If that bamboo is turned into flooring or furniture that won’t rot due to the treatments applied, then that carbon can remain fixed for decades.

Tristan June 11, 2008 at 1:52 am

“Even if doing so cost 50% of one’s income, it could be argued that it is ethically required.”

What ethical justification could possible come with acts which, in order to save the world, require universalzation which we know factually will not occur?

Why can anything other than effectivity, pragmatic use, be an ethical standard?

When we look back at this challenge if and when we solve it, the ones we will praise are not those who offset their credits, but rather those who managed to act in creative ways which changed the way we approach the problem as a whole.

I am not a communist, and I don’t advocate violence, but I still think that Lenin and Castro/Che offer us some of the few concrete examples of effective revolutionary change. Maybe climate change advocates need to take Lenin more seriously.

What might count as an example of this? One thing that comes to mind is Google’s prize for the development of cheap solar power. If capitalism is not up for question, then revolutionary change needs to make use of the infinite adaptability of capitalism.

Milan June 11, 2008 at 9:49 am

It could be universalized. It would just require big sacrifices. Again, I feel inclined to use the slavery metaphor. Giving up my slaves might cost me 50% of my income, but ethics might still demand that I – and all other slave owners – do so anyhow.

The basic fallacy of those who argue that we can ethically do nothing is the assumption that we have the right to live as we do. Basically regardless of your moral framework, that doesn’t hold up when our way of life is comprehensibly and immediately harmful to other morally considerable beings.

In any case, this is a long-running argument that we are unlikely to sort out here.

I agree that Google’s prize is a good idea, and it would be a major boon if they succeeded in making solar cheaper than coal per kilowatt hour.

Milan June 11, 2008 at 9:50 am

Is it better for Madonna or the Pope or whoever to spend $10,000 a tonne ‘actually’ offsetting CO2 through some kind of tree scheme, or to devote the same amount of money to trying to reduce the emissions of others.

It is hard not to say the latter, though I definitely see the appeal of being able to actually personally withdraw your annual share of global GHG stocks from the atmosphere.

Tristan June 11, 2008 at 4:08 pm

Ok, let’s take the slavery metaphor seriously. What does it show?

“Giving up my slaves might cost me 50% of my income, but ethics might still demand that I – and all other slave owners – do so anyhow.”

Is it right to give up your slaves? Possibly, that seems right. But is it nearly enough? No. What is ethically demanded would be far more than this – the freeing of all the other slaves. In fact, why are your slaves more important than someone elses? If you could free twice as many slaves by keeping your own, can you do it? What if you could free ten times as many slaves? Why are your slaves more special than anyone elses?

Milan June 11, 2008 at 4:55 pm

Tristan,

First, there is a difference between what is ethically required and what is ethically ideal. It is ethically ideal to devote your entire life to fighting injustice. To do what is ethically required is a lot less demanding.

Secondly, on the matter of quantity, is seems implausible that there would be situations in which keeping your slaves would let you free more of someone else’s. I suppose if your slaves were super productive and their output would let you buy the freedom of others, it might be possible.

All I mean by the slavery example is to say that doing the ethical minimum can require you to abandon much of your way of life. The fact that you were born into a slave dominated economic system does not give you the right to perpetuate it. The same is true for a carbon intensive economic system.

Tristan June 11, 2008 at 5:23 pm

I am confused by this notion of an ethical minimum. How can there be some moral demand which you must meet only to a minimum requirement? It seems to me that if there are moral demands at all, then they must be followed all the way through. That’s what it means for something to be a moral demand – to be some demand which as a rational being you must submit to.

“is seems implausible that there would be situations in which keeping your slaves would let you free more of someone else’s.”

In the case of slaves, possibly – but not in the case of global warming. It is very easy to imagine someone who themselves pollutes a lot, but produces by that huge pollution a huge net reduction in emissions. Al Gore is an example of this – there is no rational requirement for him to buy offset credits, he buys them as a matter of pure pragmatics – without buying them he would appear a hypocrit to people who fail to understand that the real moral standard is pragmatic change.

The moral requirement, both in the slavery case, and in the Co2 case, is simply to do as much good as is possible. And it’s certainly logically possible that one could do more good by increasing one’s carbon footprint. Therefore, reducing one’s carbon footprint cannot be the moral demand, the moral act can be determined only by what is pragmatically effective.

Milan June 11, 2008 at 5:30 pm

I am confused by this notion of an ethical minimum. How can there be some moral demand which you must meet only to a minimum requirement? It seems to me that if there are moral demands at all, then they must be followed all the way through.

For example, you find someone lying unconscious on the side of the highway. The ethical minimum is to call an ambulance. You could do much more, and doing more is probably ethically optimal.

In the case of slaves, possibly – but not in the case of global warming. It is very easy to imagine someone who themselves pollutes a lot, but produces by that huge pollution a huge net reduction in emissions.

I agree, and I agree that buying carbon offsets is often a matter of optics. The point of the post above is to ask whether it could actually be possible for an individual to literally offset their own emissions.

The moral requirement, both in the slavery case, and in the Co2 case, is simply to do as much good as is possible.

Within what bounds? Bounds of personal sacrifice come immediately to mind. Should I refuse an airlift to a hospital if I need it? Then come bounds of harming others. If I could sabotage a major oilfield so nothing would be extracted there again, should I do so?

Tristan June 12, 2008 at 2:11 am

“Within what bounds? Bounds of personal sacrifice come immediately to mind. Should I refuse an airlift to a hospital if I need it? Then come bounds of harming others. If I could sabotage a major oilfield so nothing would be extracted there again, should I do so?”

You continue to think that what would count as a moral structure is something you could adhere to all the time, something that would approve of all your actions. When, in fact, everyone commits undue evils all the time, no matter what external standard you set up. The point is not to reduce the amount the amount of harm one does to zero, neither is it to set up the fixed amount of good which is required.

If your choosing between ethical systems and you find one that looks like it would be comfortable and possible to obey all its commands, keep looking.

. June 16, 2008 at 9:47 am

15 June 2008
Wired Magazine’s Incoherent Truths

Many of our tech-savvy friends — the kind of folks who nurse along the beowulf clusters our climate models run on — are scratching their heads over some cheeky shrieking that recently appeared in a WIRED magazine article on Rethinking What it Means to be Green . Crank up the A/C! Kill the Spotted Owl! Keep the SUV! What’s all that supposed to be about?

. June 16, 2008 at 9:59 am

So, WIRED got the story egregiously wrong, and not just because they did the arithmetic wrong. In their rush to be cute, they didn’t even make a half-baked attempt to do the arithmetic…

The conclusion is that it makes a lot of sense to build houses in places where the environment requires neither much heating nor much cooling. This is in fact why Los Angeles scores pretty well in carbon footprint per capita, despite all the driving (as noted recently in The Economist.). Another conclusion to be drawn from the carbon footprint of New England heating is that there are probably a lot of leaky homes up there heated by inefficient oil-fired furnaces. Fixing that situation represents a huge untapped virtual energy source…

And by the way, the decrease in efficiency of heat pumps as the temperature differential increases has another implication that WIRED missed: not only does global warming increase the basic demand for air conditioning, with all the attendant pressures on electricity demand, but it exacerbates the situation by decreasing the efficiency of the entire installed base of air conditioners…

Worse, they ignore the abundant literature indicating that old growth forests can be a net sink of carbon even in equilibrium, whereas the soil disturbance of clear cutting and industrial forestry can lead to large soil carbon releases. A classic article in the genre is “Effects on carbon storage of conversion of old-growth forests to young forests” (Harmon et al. Science 1990) . They state “Simulations of carbon storage suggest that conversion of old-growth forests to young fast-growing forests will not decrease atmospheric carbon dioxide (CO2) in general, as has been suggested recently.”. For more recent work, take a look at what Leighty et al. (ECOSYSTEMS Volume: 9 Issue: 7 Pages: 1051-1065. 2006 ) have to say about the Tongass…

They say that if you want to be green, you ought to buy a used Civic or something like that, not a Prius. That’s because the used car already has the manufacturing carbon emissions “written down” (or, I guess at least the carbon guilt accrues to the original owner, not that the atmospheric radiative forcing is going to care much about that). However, this advice, sensible-sounding though it is — ignores the fact that to make that used car available to you, the original owner almost certainly had to buy something else, and probably that was a new car, or at least a newer one. So, for the scheme to work, you’d have to buy your used Civic from somebody who was giving up driving altogether…

The real implication is that manufacturing costs count, so most people should buy a small, efficient hybrid and keep it until it runs into the ground. The implication is also that durability of cars counts for nearly as much as gas mileage, since an efficient car that needs to be replaced every five years isn’t really all that efficient.

Milan June 19, 2008 at 11:40 pm

If your choosing between ethical systems and you find one that looks like it would be comfortable and possible to obey all its commands, keep looking.

Perfection is impossible, but striving is important. Considering options like the ones above is part of a basic duty of investigation. When one is causing harm that may be avoidable, there is a strong moral imperative to investigate how it might be mitigated.

The comment on how one can do the most good is in that vein.

. June 11, 2009 at 5:09 pm

“In a future world where carbon pollution is priced appropriately to prevent catastrophic climate change, we will be interested in any power scheme that can at low cost put extra carbon down a hole in the ground. Such carbon-neutralization schemes might permit us to continue flying at 2004 levels (while oil lasts). In 2004, average UK emissions of CO2 from flying were about 0.5 t CO2 per year per person. Accounting for the full greenhouse impact of flying, perhaps the effective emissions were about 1 t CO2e per year per person. Now, in all five of these plans I assumed that one eighth of the UK was devoted to the production of energy crops which were then used for heating or for combined heat and power. If instead we directed all these crops to power stations with carbon capture and storage – the “clean-coal” plants that featured in three of the plans – then the amount of extra CO2 captured would be about 1 t of CO2 per year per person. If the municipal and agricultural waste incinerators were located at clean-coal plants too so that they could share the same chimney, perhaps the total captured could be increased to 2 t CO2 per year per person. This arrangement would have additional costs: the biomass and waste might have to be transported further; the carbon-capture process would require a significant fraction of the energy from the crops; and the lost building-heating would have to be replaced by more air-source heat pumps. But, if carbon-neutrality is our aim, it would be worth planning ahead by seeking to locate new clean-coal plants with waste incinerators in regions close to potential biomass plantations.”

. June 11, 2009 at 6:21 pm

Before we go into details of how to capture carbon from thin air, let’s discuss the unavoidable energy cost of carbon capture. Whatever technologies we use, they have to respect the laws of physics, and unfortunately grabbing CO2 from thin air and concentrating it requires energy. The laws of physics say that the energy required must be at least 0.2 kWh per kg of CO2 (table 31.5). Given that real processes are typically 35% efficient at best, I’d be amazed if the energy cost of carbon capture is ever reduced below 0.55 kWh per kg.

Now, let’s assume that we wish to neutralize a typical European’s CO2 output of 11 tons per year, which is 30 kg per day per person. The energy required, assuming a cost of 0.55 kWh per kg of CO2, is 16.5 kWh per day per person. This is exactly the same as British electricity consumption. So powering the giant vacuum cleaner may require us to double our electricity production – or at least, to somehow obtain extra power equal to our current electricity production.

. June 11, 2009 at 6:29 pm

The best plants in Europe capture carbon at a rate of roughly 10 tons of dry wood per hectare per year – equivalent to about 15 tons of CO2 per hectare per year – so to fix a European’s output of 11 tons of CO2 per year we need 7500 square metres of forest per person. This required area of 7500 square metres per person is twice the area of Britain per person. And then you’d have to find somewhere to permanently store 7.5 tons of wood per person per year! At a density of 500 kg per m3, each person’s wood would occupy 15 m^3 per year. A lifetime’s wood – which, remember, must be safely stored away and never burned – would occupy 1000 m^3. That’s five times the entire volume of a typical house. If anyone proposes using trees to undo climate change, they need to realise that country-sized facilities are required. I don’t see how it could ever work.

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