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HCD? Part II [Jun. 25th, 2006|03:03 pm]
Beemer
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Okay! So as promised, the discussion of how to address the question of global warming / human climate disruption, given that it is steeped in uncertainty.

The problem in a nutshell, is that we have discovered this new thing, and it might be a problem. We have to decide what, if anything, we want to do about it (partly because it's the kind of problem that's more difficult or even impossible to address later on, and partly because, as the Rush lyric goes, "if you choose not to decide, you still have made a choice". If we decide not to try and fix it, we should at least be doing that consciously, rather than by default.)

This is a hard problem, because we have to make it without a lot of information that we'd like. What I'm going to try and do here is to present a line of logic that, I think, suggests a sensible course of action given those contraints, and then hypothesize talk out my ass a bit about how I think it all relates to the public "debate" going on. This kind of logic is a sort of super-simplified version of a technique I learned called "decision analysis".

Let's start with what we know for sure:

Unarguably, the greenhouse effect exists, and CO2 is a greenhouse gas. Everyone agrees on these things, they're pretty basic physics.

Also, CO2 concentrations have increased by about 30% since the mid-19th century, and are continuing to increase. We know this with certainty because we can measure it directly.

Now the stuff people argue about:

We don't know precisely how much atmospheric CO2 contributes to the greenhouse effect. It's a non-zero amount, but people disagree on just how much that is. Still, it's pretty clear that it's not negligible.

We also don't know for sure whether the CO2 increases are directly due to human activity. It's the most obvious and straightforward explanation, but as some folks mentioned in the previous post, there are a whole bunch of carbon sources and sinks, the dynamics of which are poorly understood, and the overall atmospheric carbon flux is large compared to human emissions.

But consider this: since the beginning of the Industrial Revolution, we've been burning fossil fuels as an energy source. You can estimate how much, and it's an awful lot: the IPCC figures it's 290 gigatons of carbon. That's more than a quarter of a trillion tons. (We've also burned a lot of limestone to make cement, which puts off CO2 as well.) Of course, the natural fluxes are even bigger.

Now, does it seem likely that generating a lot of CO2 would increase the concentration of it in the atmosphere? Sure. How about the odds that it would have no effect, because there are other systems that compensate for it? Sure, that seems plausible, too. How about it generating a net decrease? Well, while it might be possible, we don't have any mechanisms that we expect to have that effect, and it would mean that there's both a negative feedback system over-compensating for human emissions and an unrelated system that's increasing CO2 faster than this hypothetical system is decreasing it. So that seems pretty unlikely.

So, despite all this uncertainty, we can conclude that the effect of human activity on atmospheric CO2 is that it's not unlikely that it's increasing it, and at best is having no effect. (And increasing CO2 will increase the greenhouse effect.)

Okay. Now, what about climate change? We know that climate is plenty variable on its own, and that some climate change is occurring independently of any effects of human activity. So whatever effects human activity have on climate are going to be added on top of that natural variability.

Are things getting hotter? Yes. Although this is a debated point, if you look at polar regions and alpine glaciers, I think it's pretty clear that a lot of things are melting that haven't melted in a very long time. I have a colleague who spends a lot of time with native Alaskans, and she says it's abundantly clear to them what's going on.

Fine. Does it matter? Again, this is a subject that's fraught with unknowns, but it's likely to be undesirable. There are some recent studies that project long-term losses will offset any short-term gains due to climate shift. Heating also gives you sea-level rise, which is bad. Any kind of major environmental change is disruptive simply because our infrastructure is adapted to things as they are, and changing it will take a lot of effort. And finally, climate change exacerbates ecological degradation, because it adds stress to already taxed systems.

What about the costs of doing something about it? There are a lot of arguments that various measures like the Kyoto Protocol would ruin the economy. I call bullshit. Economics is vastly more uncertain than climate science -- economists didn't even believe in positive feedback until the '80s. I'm not arguing in favor of the Kyoto Protocol, I'm just saying that "it'll be bad for the economy" is an indefensible argument against it. Major changes in how business is done can cripple an economy, but they can also lead to innovation, growth, and prosperity. There's no clear reason to believe that implementing greenhouse-gas (GHG) emissions policies would be either good or bad for the economy, so in this analysis we should consider it neutral.

Okay, so let's add it all up.

We know that CO2 causes greenhouse effects, CO2 is increasing, and warming is almost certainly occurring right now. Human activity is probably contributing to CO2 increase, and at best is having no effect. Warming will, in all likelihood, be inconvenient and undesirable, and whatever effects human activity has will be added on top of the already occurring natural climate variability, accelerating it. If we do something to mitigate GHG emissions, it will decrease the human contribution to these effects. We have no idea whether the long-term economic impacts of such mitigation would be positive, negative, or neutral, so we should call it a wash.

So in the best-case scenario, our activity isn't affecting the climate anyway, and mitigating emissions will have no effect. In the worst case, our activity is having a big effect on climate, and mitigating emissions will significantly decrease the resulting negative impact. The truth is probably somewhere in the middle. We can expect some up-front costs (any policy has costs), but the net secondary impacts for all policies (including "do nothing") are highly uncertain.

Therefore: we ought to do something, because even though we've got all this uncertainty in the various elements of the equation, it still ends up on the positive side.

Now, once we get into the details of what, in particular, we should be doing, we can try to attach numeric probabilities to these various quantities and compare policy A versus policy B versus the opportunity cost of doing either instead of policy C. And it's possible that in that debate, we might decide that the benefits we get from any climate change mitigation policy pale in comparison to other options like solving world hunger or what have you, but the important thing is that a necessary prerequisite for any policy discussion is agreeing that climate change mitigation is a problem that needs to be considered.

And I think that's where the public discussion is currently getting stuck. Public opinion is coming to the conclusion that it's an issue that needs to be addressed, but it's been slowed by interests who have fought against recognition of the problem at all. And we can't really have productive discussions until we reach that starting ground of agreeing to evaluate it on an equal level with all our other problems...

EDIT: I forgot about a couple other lines of evidence that strongly support the idea that increased CO2 is due to burning fossil fuels: (1) there's a geographic correlation (northern hemisphere vs southern hemisphere, taking into account atmospheric mixing times) between CO2 levels and industrialization, and (2) the isotope ratio of atmospheric carbon is consistent with the extra CO2 coming from fossil fuels. So actually, when you take that along with the correlation in timing and amount of CO2 increase, what I said above is wrong -- we ARE fairly sure where the extra CO2 is coming from, and it's from human activity.
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Comments:
From: thetarnishedowl
2006-06-25 09:39 pm (UTC)
I agree, and well stated. Unfortunately, such reasoned arguments don't make for good sound bites on the evening news, nor do they appeal to those on both sides with political agendas.

My thoughts land here: we need to do our scientific best to figure out, if possible, what percentage of the warming is caused by humans. It's not sufficient to simply accept, even in the absence of hard evidence, that the whole of global warming is caused by humans. Why? Because if the natural climate change aspect far outweighs the human aspect, than human efforts to mitigate the human portion of the change will have little overall effect. And in this case, instead of putting all our energy into buying Priuses and shutting down factories, we would need to be taking different action, like moving people away from the coastal areas that will flood, no matter what we do.
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[User Picture]From: dr_tectonic
2006-06-25 10:01 pm (UTC)
Oh, people are on it, trust me. I have lots of colleagues who are working hard to figure out more about how climate works and reduce the uncertainty in all those terms... =)

I also think the right answers won't be just doing less of what we currently do, but things that fix several problems at once, like changing how we grow food so that it uses less fertilizer, travels a shorter distance before consumption, and fits better into our urban and natural landscapes.
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[User Picture]From: zalena
2006-06-26 12:08 am (UTC)

Joke heard on the radio

Conservatives continue to claim it's not the global warming, it's the global humidity.
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[User Picture]From: dpolicar
2006-06-26 12:51 am (UTC)
So, OK.

IF we agree that problem X exists and is major
THEN we ought to agree to fix problem X

IF we agree that activity Y might plausibly be making X worse and might possibly be orthogonal to X but _certainly_ isn't making X better
THEN when looking for solutions to X we should consider schemes for reducing Y... though not restrict ourselves to such schemes, and not accept any such scheme as a valid solution without careful analysis.

100% agreed with all of that.

So folks who kneejerk-reject programs for reducing Y are behaving badly... and folks who kneejerk-support for reducing Y are, too. A sensible person evaluates the likely costs and benefits.

Well, of course.

So, OK I've got a billion dollars lying around.

Should I spend it on lower-gas-emission cars, or on preventing fighter planes from constant aerial missions, or on establishing coastal evacuation plans, or on establishing a system of dikes and pumps around our low-lying coastal regions, or on buying up rainforest so it doesn't get burned down?

If I believe that anthrogenic CO2 emissions are the _only_ cause of climate change... well, I don't know.

If I believe they are _completely irrelevant_ to climate change... well, I still don't know.

Clearly there's more to be said here.
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[User Picture]From: dr_tectonic
2006-06-26 03:01 am (UTC)
Yup, pretty much.
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[User Picture]From: melted_snowball
2006-06-26 02:53 pm (UTC)
Shouldn't you try all of them, and then study what their effects were ex post facto?
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[User Picture]From: dpolicar
2006-06-26 04:03 pm (UTC)
Sure... if my billion dollars spread across all possible solutions will provide a plausible test of those solutions, or if there's another N billion where that came from, or there's another N people in the same boat (so we can each pick one solution and then compare results later).

Still, and obviously, the more principled the basis on which I select my candidates, the more efficient that process becomes.

If I have good reason to believe the process is reversible, dikes and evacuations may not be good things to spend money on. If I have good reason to believe it's irreversible, they may be the _best_ things to spend money on.

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[User Picture]From: dr_tectonic
2006-06-26 03:27 am (UTC)
To be more specific:

We have been measuring CO2 concentrations directly since 1958 at Mauna Loa: http://cdiac.ornl.gov/trends/co2/sio-mlo.htm

We can also directly measure CO2 concentrations at various times further in the past using ice-core data. As snow gets compacted into layers of ice in Antarctica, bubbles of air get trapped and preserved, unchanged, until they are dug up. With a little work, you can figure out the age of the bubbles and measure the gases within: http://cdiac.ornl.gov/trends/co2/lawdome.html

I'll see what I can track down in the way of graphs showing how CO2 levels track with industrial activity.
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[User Picture]From: dr_tectonic
2006-06-26 03:45 am (UTC)
Here's a graph of atmospheric CO2 for the last 1100 years:

http://www.gcrio.org/ipcc/qa/05.html#fig1

The page also discusses the other two other lines of evidence suggesting that CO2 increases are due to human activity that I had forgotten to mention: (1) there's a geographic correlation with industralization (between northern and southern hemisphere) and (2) the isotopic ratios of CO2 have changed in a way consistent with the source of extra CO2 being fossil fuels.
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[User Picture]From: melted_snowball
2006-06-26 02:52 pm (UTC)
Two comments:

1) I'm not convinced by the claim that we don't know enough about the economic effects of restricting greenhouse gases, so we should assume that they're neutral. We do have some evidence from other treaties that restricted the use of chemicals for environmental reasons; if I don't misremember, the CFC treaty makes buying a fridge a few tens of dollars more expensive, for example.

And I don't agree that the argument that technological advancement will increase economic success in parallel with restricting it (or, rather, I don't agree that that alone is a valid yardstick). This will turn into an economic opportunity for wealthy countries: if resource extraction is made more expensive, however, that may reduce the economic success of poorer countries.

[Heck, even a nationalistic f'rinstance: one cannot refine the oil sands in alberta without steaming them. Now, I'm not jumping up and down saying, "hooray!" about the oil sands, but that does feel pretty damn economically subject to serious problems under climate change treaties.]

2) More broadly, one consequence of climate change treaties is that they restrict the opportunity of developing countries to use the cheap route to development. This, to me, is troubling, because global capitalism will make it be the case that poor countries will essentially have to mortgage their people to the developed world in order to develop, to a greater extent than they already are. I'm concerned.

Oh, and how about if I complain about my least favourite argument in this particular genre, even if you didn't make it... :-)

3) I am very skeptical of the argument that "we are at a tipping point in the next ten years" for climate change. This seems hopelessly pat to me. I know how catastrophe theory works, and I have seen some of the fish population examples that show it actually happens in the real world and not just in simulations. But it's still an event of low probability that in a particular 10-year period, the catastrophe point will happen. This, of course, is not helped when it's being spouted by people in the sillier parts of the environmental movement.
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[User Picture]From: dr_tectonic
2006-06-26 03:37 pm (UTC)
1) Sure, it makes sense that there will probably be some cost to each policy, but my point is mostly that the economics is so much more uncertain than the rest of the problem that you can't put too much weight on it. It's perfectly sensible to look at the costs for individual policies, but I have yet to see an estimate of the general cost of dealing with the problem that didn't stink deeply of voodoo handwaving. So you can't say "cost" outweighs everything else and throw out the whole issue. (There's probably a better way to express that in the context of my argument, but I don't know what it is.)

2) That strikes me not as a problem inherent to the issue, but simply a problem with the policies that have been proposed so far -- none of which I'm arguing in favor of.

3) Yeah, I agree. It might be a tipping point problem, but we have no strong theoretical reasons to think so, and even if it was, it's really hard to tell when you're getting close. More likely, it's just an exponential/logistic growth problem, which is scary enough...
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[User Picture]From: dpolicar
2006-06-26 04:11 pm (UTC)
That strikes me not as a problem inherent to the issue, but simply a problem with the policies that have been proposed so far -- none of which I'm arguing in favor of.

So... hrm. Let me ask the question this way, Dr.T.:
Supposing the likely scenarios being proposed in your posts all prove completely and without exception true, and everyone is convinced of them. That is, suppose the uncertainty problems and the propaganda problems all go away.
What would we then do that would improve the situation in any way?
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[User Picture]From: dr_tectonic
2006-06-27 12:04 am (UTC)
So are you asking "what are some of the mitigation policies"? I don't know very much about specific proposals or treaties, but here are some basic ideas, without regard for feasibility or effectiveness.

* Everybody just agrees to cut emissions down to target levels and does it however they want. This can be done with varying levels of fairness between groups of signatories.

* Increase efficiency/emissions requirements for cars, airplanes, computers, whatever.

* Stop changes in land-use that affect CO2 emissions negatively.

* Dump lots of money into carbon sequestration research.

* Impose taxes on carbon/GHG emissions.

* Impose caps on emissions and license emitters.

* Abandon modern civilization and return to hunting and gathering (only without the use of fire).

* et cetera
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[User Picture]From: boat_of_car
2006-06-27 06:17 pm (UTC)

Ah HA !!

"Abandon modern civilization and return to hunting and gathering (only without the use of fire). "

Now I see your *real* agenda. I knew all along you must be a closeted NRA/survivalist.
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[User Picture]From: drdeleto
2006-06-27 06:50 pm (UTC)

Re: Ah HA !!

And a carbon segregationist!
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[User Picture]From: dr_tectonic
2006-06-27 07:06 pm (UTC)

Re: Ah HA !!

Hey, it would be an incredibly effective policy.
It's just that the other costs would be a bit high...
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From: thetarnishedowl
2006-07-03 03:32 am (UTC)
Your thoughts on this article in the Wall Street Journal?
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[User Picture]From: dr_tectonic
2006-07-03 04:44 pm (UTC)
Gimme a few days to ask around and see if this guy is who I think he is. I think this is a serious case of professional sour grapes...
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From: thetarnishedowl
2006-07-03 05:03 pm (UTC)
I'll look forward to your response. That's a big frustration for me - not knowing whether the scientific information I'm reading is "clean", that is not politicized.
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