That is, how can we prove that an offset project would have taken place without the carbon market?

I'll stand aside and let one of the offset salesmen or unambiguous supporters tell you how they do it.

The 5% Project

What I'm saying is that I don't think the additionality thing is really provable.  You can't know everyone's microeconomic picture and the opportunity costs they face.  Thus, you can't know whether the carbon sequestration would have occurred under "business as usual."

If you can't know that, you can't use the additionality argument against offsets now can you?

Thus, you can't know whether the carbon sequestration would have occurred under "business as usual."

If you can't know that, you can't use the additionality argument against offsets now can you?

I'm not saying I don't agree with the principle.  I'm saying it's pretty much impossible to say what would be "business as usual."

As for your "weakest argument" thing.  That's nice.  But why don't you explain for the rest of your readers why you think so?

I posted a link to an article that I thought was interesting, in large part because it followed a series of rather intense discussions about offsets here at Gristmill, and somewhat because of the source (a survivor of the Biosphere II project).
I didn't add to it because I didn't have anything to add; I made my ambivalence about voluntary offsets clear during those discussions.  So I don't wish to be drawn into a debate about offsets with you; I don't have any more insight into them than before.

Tell you what, why don't we just agree that I'm wrong and should be sharply smacked around for my heinous misstatements and atrocious misunderstandings, and then you can write a comment that makes whatever point it is you're trying to make about offsets, pro, con, or undecided.  But if your only point is that I could know more about offsets, consider it conceded.

The 5% Project

I think the article is interesting too, and when I got to the part about additionality, I really thought about it for a moment.  I decided that yeah, the principle makes sense, but I couldn't come up with a way to prove that the offset would have occurred under "business as usual".  So that got me to thinking that there are no pragmatic teeth to this argument, no matter how sound the principle is.

If you want to avoid discourse, that's fine. You don't have to respond, you know.  But next time you decide to, don't call my arguments weak and then avoid explaining why.

A project's additionality is the carbon reduction it represents over and above what would have occurred under a business as usual scenario. That's what you buy when you buy an offset: additional CO2 reductions that wouldn't otherwise have happened. To take an uncontroversial example: without offset money, a sewage treatment plant would have simply released its methane into the air; with offset money, it can afford to build a methane capture facility that burns the methane to make electricity. All that methane capture is additional, i.e., it would have otherwise gone into the atmosphere.

So additionality is absolutely central to offsets. If it cannot be established reliably and with some precision, then there can be no (non-fraudulent) offset market, no CDM, etc.

Some people -- say, Gar -- think that measuring additionality is intrinsically impossible, and thus that offsets cannot ever be what they say they are (i.e., precise measurements of avoided emissions).

Other people -- say, offset providers -- think that measuring additionality is difficult, but possible. A number of different ways of measuring are floating around, with different standards. It's a subject of much ferment and controversy. Sooner or later, one supposes there will be federal regulatory guidelines on the subject.

NativeEnergy has a decent guide to additionality here.

grist.org

What I want is a case (aside from using already protected forest/land) where we can prove that an offset does not meet this requirement.  Who decides what the "business as usual" standard is, and how do they do it?

I think I agree with Gar to some extent then.  It seems to me that additionality is impossible to measure.  I don't think this is a fatal flaw at all, since these offsets exist in the voluntary market.  

I'm willing to concede it's a more complex issue when we talk about using offsets under a regulatory scheme.  

But... I think there are possibilities here still.  What it boils down to is that the additionality argument is basically pointing out the uncertainty associated with emissions reductions benefits.  

I think the major uncertainty is that we have no way of knowing what "business as usual" really would mean.  We can introduce some mechanisms to reduce this uncertainty.  The idea of trading ratios comes into play here.  If we are talking about offsets under a regulatory scheme, then maybe there should be a trading ratio that establishes that a certain number of offset credits (for example, 5) is equal to one carbon credit.  This 5:1 ratio doesn't change the fact that we can't measure additionality, but it might increase the chances that we do offset the emissions.

I would be interested in hearing how offset provider claim to measure additionality.

Usually phrased as the question "is the project reducing emissions in a way that is business as usual, or is it beyond business as usual," the concept of additionality reflects people's gut feeling that if a project was or is reducing emissions regardless of the prospect of offset revenues, we shouldn't be giving it offset revenues.  Instead, we should give offsets revenues only to those projects that really need them.

I'm not so sure about the "gut feeling" about giving money only to offset projects "that really need them"

In markets you don't necessarily pay money to people that "really need" revenue.  You pay money to people that offer products or services that you want.  

You're making Gar's case for him. If you believe that additionality is, in principle, impossible to measure, then you believe that offsets are a fraud. An offset just is a CO2 reduction over and above what would have happened if you hadn't paid for the offset. Offsets purport to be -- are sold as -- a precise amount of CO2. If you're just approximating, or you don't really know if the CO2 reductions would have happened either way, then you can't sell it as a precise, measurable amount.

You could still offer it as a kind of charity -- "give us money and we'll reduce some amount of CO2 that probably wouldn't have been reduced otherwise" -- but you can't offer it as "X dollars for X tons of CO2."

In short, if you think measuring additionality is impossible, you think offsets are impossible.

grist.org

Maybe I can help. You're actually mixing together two slightly different concepts, and perhaps teasing them apart will simplify the discussion. (Alternatively, maybe it will make it twice as confusing.)

The first concept is that of additionality. This is essentially the notion of whether the project would have happened in the absence of offsets. Additionality is important, because otherwise the offset is essentially worthless. Without additionality, you're paying for something that would have happened anyway.

The way that additionality is typically determined is by applying a series of tests (called, oddly enough, "additionality tests") to a project. The tests differ depending on project type, but the simplest to understand is the financial additionality test. That is, if an offsetting project isn't financially viable in the absence of offsets, then it is most likely additional. Financial additionality can be easy to establish (e.g., landfill methane digesters) or relatively harder to establish (wind farms that get tax breaks and also sell electricity). Needless to say, there is a lot of complexity around this topic, but that's the basic idea.

The second concept is that of an emissions baseline. Even once you establish additionality, you also have to establish what level of emissions would have occurred in the absence of the project. Even if you don't care about additionality (which you should), you still need to know what the baseline is, because this determines the number of offsets generated by the project.

Like additionality, the means of measuring the baseline is project dependent. Usually it's pretty easy. If you cap a landfill, all the methane is captured and can be directly measured by sensors before being destroyed. Sometimes establishing a baseline is hard. One of the big raps on tree-planting projects is that it's very difficult to determine how much CO2 trees actually absorb, particularly given all sorts of complicated secondary effects.

Not sure if this helps, but that's the basic idea.

www.terrapass.com/blog

So maybe that's one of the big differences here.  I guess if I was only concerned about reducing carbon emissions, then I would be much more wary of offsets.  But, even through the carbon uncertainty, I see so many potential benefits, such as investments in alternative energies, habitat restoration and creation, and the potential for money to flow from developed countries to developing countries.  I see offsets as the way to break open a larger market for ecological goods and services.

Maybe Adam is right, that the additionality of some projects can be measured (or at least reasonably estimated).  Also, thanks for splitting the additionality and baseline concepts for me, that clears some things up conceptually.

I guess I also am more sympathetic to the arguments against tree offsets now (although like I mentioned above, I think there is room for these in a larger market for environmental goods & services).  

What do you think, Adam.  Is it a matter of technological ability to measure additionality and baselines, or are there some projects for which these will always be elusive?

Glad I could clear up some of the confusion. Here are some further thoughts.

First, a nitpick. Carbon offsets are definitely not a fraud. Fraud implies a deliberate deception, such as fake carbon offsets that don't come from real projects. You can definitely raise legitimate questions about the effectiveness of some offsets, but this is a quality concern, not a matter of fraudulence. I hope this doesn't seem too touchy, but it seems worthwhile to note that the intentions of carbon offsetters are good.

OK, on to more substantive stuff. First baselines, because that's an easier question. Yes, I think it's basically a technical matter to establish a baseline, and it will become increasingly easy to do so for a wide variety of projects. Truthfully, it's already pretty easy for many established project types, and the interesting thing will be establishing techniques for trickier project types such as building efficiency or avoided deforestation. These types of things are the subject of active academic study.

Additionality is a more complicated topic. You don't really "measure" additionality, per se. Rather, you make an additionality determination for each project. So on a per project basis, additionality is a binary property. But on a market-level basis, additionality is a statistical property. That is, you recognize that given a set of additionality criteria, some percentage of non-additional projects will sneak through, and some percentage of additional projects will be mistakenly rejected. You can adjust these levels by tightening or weakening your additionality criteria.

Why would you ever want anything other than the tightest possible additionality criteria? Because you'll end up weeding out a lot of good projects with the bad. Incidentally, this is a property of many types of decision-making processes in which it's difficult to make determinations with complete precision. Medical diagnosis is probably the best known example.

So getting back to your original question -- do I think additionality can be determined with some accuracy? Yes, and the level of accuracy is a matter of choice. Basically, it's a policy question that balances two separate goals: offset integrity and the total volume of reductions. Right now, my sense is that the balance needs to tip further towards offset integrity.

And to your follow-up question on liability -- TerraPass is independently audited to ensure that our offsets are real, not double-counted, etc. But there is no legal liability around additionality, and I don't expect there will ever be, for the reason cited above -- some non-additional projects will always sneak through. Instead, what you'll see is the emergence of industry-wide standards that provide assurance regarding overall market integrity.

www.terrapass.com/blog

Don't get me wrong when I almost conceded that offsets are a "fraud."  I never meant to imply that the motives weren't good.  (You'll also see that I'm a big fan of offsets for many other reasons besides the carbon reductions.)

You've pretty much cleared this thing up for me.  More or less, I'm in the same position I was before I started these comments.  I'm a supporter of the voluntary carbon market, but I do acknowledge that it will take some time and effort to tweak it in order to get the biggest possible benefit.