Stock versus flow variables here. CO2 tends to stay in the air a long time, water vapor does not. Boiling a pot of water does add more water vapor to the air. But for the most part that water came from some ground source which means it will quickly fall out of the air in the not too distant future.

As your science background is much stronger than mine, I’m sure you will recall that water vapor in the air will drop until it hits an equilibrium based on temperature. Long story short, if for some reason we suddenly decided we needed to warm the climate, buring a lot of carbon would work better than trying to boil lots of pots of water. The CO2 stays in the air after you turn the burner off. The (extra) water doesn’t.

One other point on CO2 which points to your question about “where does it go?” is that gases in the atmosphere don’t indiscriminately block reflected (and incoming) radiation but do so in bands. One question asked (and perhaps your papers answer) is that these bands can be saturated, i.e., additional CO2 will not necessarily add to the greenhouse effect if absorption in its band is close to complete. Do the papers touch on that?

Kind of sounds like electron shells in atoms. Once a shell gets all the electrons it ‘wants’, no more will go into the shell but will instead start filling the higher shells. Anyway, no I haven’t read that. Perhaps you could take a moment to read what the IPCC papers have to say about this idea and summarize for us with any criticisms you might have.

There are in fact large tracts of untouched arable land in the north parts of the Northern hemisphere, notably in the Americas and Asia. China, Russia, Canada and the Northern states might benefit from global warming, not pay a cost. Take China for instance, if they stand to benefit from an great increase in arable land from GW … what incentive do they have to cut out CO2 … even if the A is significant.

The world is not suffering from any great shortage of agriculture. The opportunity to grow tomoatos closer to the artic circle does not seem to offset, say, more Katrina type hurricans in areas where we have major fixed capital investments. Like I said, I think the skeptic case is strongest not attacking GW or AGW but attacking cost estimates for various possible levels of warming. I think it is very likely that rapid warming would be very destructive but I’d could see how warming that is very gradual might end up being a net benefit or at least a very low net cost.

The conservative motive, though, would incline us towards starting measures now to address warming. As I’ve said several times now, if additional data proves the concern is overblown then they can be eased, if the opposite then we have a head start.

You point out that the “costs” may be overstated. You suggest just by putting in a few CFLs and taking shorter (or less frequent) showers is all we have to do. I think your methods might assuage your guilt but their CO2 impact will be minimal

Are you paying attention to what I’m saying? The ‘costs’ are overstated for the following reasons:

1. They assume rapid economic growth in developing countries. If this doesn’t happen a lot of the cuts will happen automatically and costlessly since the projected CO2 emmissions will never materialize.

2. They reduce years and decades of costs down to a single present value. A 50 year program to cut CO2 will have a massive present value cost even if its cuts are very modest. But if you go, say, 5 years into the plan and then discover there’s no need to worry about CO2 you can ditch the plan having only incurred a tiny fraction of the costs.

3. They fail to recognize that by internalizing the costs of CO2, the market will find ways to cut CO2. The cost models used by critics assume a simple, brain dead, linear relationship between GDP and CO2. Specifically, they assume that 1 unit of CO2 = 1 unit of GDP therefore a 10% cut in CO2 translates into a 10% cut for GDP. This might make sense of CO2 was a cost that producers and consumers economized on but it isn’t. Therefore a 10% cut in CO2 would *have* to cost less than a 10% cut in GDP. If you want to discuss that point more I can bring in a thought experiment that might make the point more clear.

CO2’s rise in the air has coincided with the industrial revolution.

I recently read that ice cores indicate the current warming trend substantially predates the Industrial revolution, i.e., started in the 16th century. One other point on CO2 which points to your question about “where does it go?” is that gases in the atmosphere don’t indiscriminately block reflected (and incoming) radiation but do so in bands. One question asked (and perhaps your papers answer) is that these bands can be saturated, i.e., additional CO2 will not necessarily add to the greenhouse effect if absorption in its band is close to complete. Do the papers touch on that?

There are in fact large tracts of untouched arable land in the north parts of the Northern hemisphere, notably in the Americas and Asia. China, Russia, Canada and the Northern states might benefit from global warming, not pay a cost. Take China for instance, if they stand to benefit from an great increase in arable land from GW … what incentive do they have to cut out CO2 … even if the A is significant.

You point out that the “costs” may be overstated. You suggest just by putting in a few CFLs and taking shorter (or less frequent) showers is all we have to do. I think your methods might assuage your guilt but their CO2 impact will be minimal. Likewise the “costs” of cutting out CO2 may be overstated (and maybe not) but that cuts both ways, the costs of climate change are likely also overstated.

1. There is no dispute that global warming is happening.

2. There is no dispute that AGW is also happening. CO2 is the second most potent greenhouse gas, that is not a theory but an observable property of the molecule. Water vapor is more potent but as I pointed out water is not produced by human processes and its existence in the atmosphere is the result of natural processes. There are other molecules than CO2 that are better at producing the greenhouse effect. For example, nitrious oxide (N2O) is asorbs 310 times the heat of a CO2 molecule. But its generation is much smaller than CO2 making its relative contribution smaller in proportion (see table 2 in http://www.geocraft.com/WVFossils/greenhouse_data.html this is a skeptical article that makes much of the fact that water vapor accounts for a huge portion of the earth’s greenhouse effect, but the author never addresses the fact that human activity is not increasing water vapor. He even states that human additions to water vapor are negligeable. But the point is to stop the increase in the greenhouse effect, not to eliminate the entire existing greenhouse effect which is part of what makes life on earth viable)

3. A AGW part of GW is not trivial. The ’cause and effect’ argument you’ve presented lacks coherence. CO2′s rise in the air has coincided with the industrial revolution. More importantly, if you’re going to argue that the warming came first and that releases CO2 from the oceans you need to explain where does the CO2 we produce go?

Where the dispute really is if honest skepticism is to be examined is in the extent of warming and its implications. The first question is how much warming will be generated by various levels of CO2 and other gasses. The second question is what are the implications of warming? Does it mean a slightly longer growing season and a bit more flooding in seaside towns or does it mean seawater up to the tenth floor of the Empire State Building?

Here I think the skeptics make their best case. Modest warming may have slightly net benefits and the costs of avoiding warming might be better spent simply compensating its victims directly and finding ways to deal with its consquences (more air conditioning, altered agricultural techniques etc.).

One interesting fact I confirmed from a skeptical FAQ (http://cei.org/pdf/5331.pdf) is that the costs are overstated. Here is how it goes. In order to estimate global warming, you need to estimate CO2. CO2 is tied to economic activity so you need to estimate the economic activity over the next 25, 50, 100 years etc. The IPCC has been criticized for assuming rapid economic growth in developing countries and steady growth in developed ones. In other words, they use a China model where the poor countries of today rapidly converge upon the rich standard of living of developed countries and developed countries continue with steady but modest improvements. The skeptical FAQ wants what I’ll call an ‘Africa model’. There were high hopes for African development in the 1970′s but it turned out there was next to no growth. Less economic growth means less burning of fuels which means less CO2.

Skeptics like the ‘Africa model’ because it downplays warmings potential dangers, the IPCC likes the ‘China model’ because it assumes more CO2 (and….it would be nice not to have to depend on 3/4 of the world staying dirt poor). But this is a double edged sword for both sides.

From the cost estimate, the ‘China model’ is expensive because it requires a lot of cuts to CO2. But if the skeptical criticism is correct, then the true cost is cheap. If the projected growth never happens then there’s nothing to cut. The African or Asian of 2050 won’t be burning 500 gallons of gas in his car per year because he won’t have a car or if he does he won’t be driving it enough to fill it with 500 gallons. No burning gas means no CO2 to cut to begin with.

On the other hand, if the ‘China model’ is correct then the global economy of the future will be fantastically richer than what we have now. The cost of cutting such emmissions might be higher (because there will be more emmissions to begin with) but this needs to be compared to a totally different standard of living. A person living in 1880 might read the ‘requirements’ for an acceptable level of living today (a shower once a day or every other day, wearing a set of clothes at most two times or so before they are washed, most food kept at constant refridgeration, a home kept no colder than 65 even in the coldest winter days or no hotter than 75 on the hottet days) and be dismayed that it could ever be affordable….today this is quite manageable.

Some of the FAQs
http://cei.org/pdf/5331.pdf (skeptical but a bit dated)
http://www.ncdc.noaa.gov
http://www.ucar.edu/news/features/climatechange/faqs.jsp

But that is the independent variable. There is no process either natural or human that is producing or destroying water on the earth’s surface to any significant degree. Water vapor could serve as a feedback loop but not one you’d want to be a climate skeptic. (One you’d want would counter act CO2 warming, unfortunately it appears warming would put more vapor in the air).

Uhm, I’m trying to make the case that we have to understand warming before we can tack the “A” on to AGW. It seems like you agree.

I’m on board except for the ‘before’ part. I believe we are still unclear about how exactly aspirin works. There is not going to be some mystical point in time when we say we understand all there is to know about warming and just because we are ignorant doesn’t magically make the consquences of our actions or inaction today disappear.

Furthermore you seem to indicate that GW/AGW is not very well understood, e.g., the causes of the 300 year warming trend we’re currently seeing are not clear. So … why then spend/bet $10s or $100s of trillions before we really know what’s going on?

So are we also going to put on hold attempts to address diseases of age like heart disease, dementia, arthrities etc. until the causes of old age are understood?

No there are other sources such as water vapor.

Odd you might admit that … as CO2 is one of the weakest sources of warming around.

It could be a complex combination of factors involving multiple sources. The danger is that generating AGW by adding CO2 may or may not disrupt other natural sources of warming.

Uhm, I’m trying to make the case that we have to understand warming before we can tack the “A” on to AGW. It seems like you agree.

Furthermore you seem to indicate that GW/AGW is not very well understood, e.g., the causes of the 300 year warming trend we’re currently seeing are not clear. So … why then spend/bet $10s or $100s of trillions before we really know what’s going on?

It feels like two years now in NJ we had snow storms in December, which is a bit unusual, but the winters themselves turned out to be duds. My brother-in-law plows so every crappy dusting of snow is $800 or more lost income for him…..

Well, in the Midwest last winter was very much not a dud … although March was mild and the summer was one of the coolest on record. Early cold has people thinking here that we’re in for another kicker.

No there are other sources such as water vapor. I suppose you can come up with a more subtle model….say with gradual warming causing more clouds which triggers a sudden collapse in temps. There’s also methane which is produced by animals like cows. I suppose we could have a model where before humans the plants grew up dramatically lowering CO2, driving up O2 and lowering temps until a flash point results in massive forest fires and methane from plant eating herds. I figured the volcano was a good illustration that was a bit more realistic than the 40,000 year impact by a comet of pure frozen CO2.

Some CO2/AGW critics suggest that warming causes the CO2 rise not the reverse (warmer oceans release CO2). Correlation is not causation. You need to identify causes.

Then what do they propose is the cause of the warming? The AGW model has a pretty clear and testable source for the rise in CO2.

And yes, I realize that the volcano was just a stand in for any number of large CO2 sources. It’s just that a large CO2 event should then be located at the start of a warming trend each time. If it isn’t … then that should be a problem for your hypothetical.

The volcano is not a stand in for CO2 sources but warming sources. It could be a complex combination of factors involving multiple sources. The danger is that generating AGW by adding CO2 may or may not disrupt other natural sources of warming. In the case of periodic volcano eruptions it wouldn’t. Likewise if there’s a group of remarkably spaced CO2 comets it wouldn’t. In the case of things like water vapor (pro warming), clouds (anti warming) it may or may not. The problem is that while the last million years may look like there’s no problems that thinking is flawed for two reasons:

1. Things that were big problems thousands of years ago have been forgotten. Who cares if NYC’s coastline shifted back and forth 50 miles 250,000 years ago. If it happens tomorrow the cost is trillions.

2. AGW was not part of the equilibrium back then. Adding it to the system may short out control mechanisms that were in place before humans came alone. My simple volcano/plant model is meant to illustrate that. Looking at it from far away, it seems logical that life has been mostly a net carbon sink during the earth’s life…..hence all the stored carbon we enjoy today in the form of things like coal and oil. We’ve started to eliminate that and are making life a net carbon producer. The leap of faith that is being asked here is to assume that has no negative consquences.

The point being that the cause of warming trends is apparently not well understood. It’s not “predictable”. In fact, the cause of the current trend, for example, ongoing for 400 years now … what is the cause of the trend? Historical records should be good enough to isolate and identify the causes to which you suggest anthropomorphic CO2 is adding its part. So what is that cause?

To be honest I think these variables are so complex and noisy that you’re not going to get a simple function that relates CO2 to temperature. You’re going to just get an estimate and unless things go very badly you’re not going to get something as clear cut as Chicago having a winter where the temp never goes below 70 degrees.

. It’s only early December … it could be a very long hard winter, eh?

It feels like two years now in NJ we had snow storms in December, which is a bit unusual, but the winters themselves turned out to be duds. My brother-in-law plows so every crappy dusting of snow is $800 or more lost income for him…..

The point being that the cause of warming trends is apparently not well understood. It’s not “predictable”. In fact, the cause of the current trend, for example, ongoing for 400 years now … what is the cause of the trend? Historical records should be good enough to isolate and identify the causes to which you suggest anthropomorphic CO2 is adding its part. So what is that cause?

I should add that this an amusing topic for discussion today when I drove to work with 20 mph winds and 1 F on the mercury. My youngest was grousing about waiting at the bus stop. It’s only early December … it could be a very long hard winter, eh?

Suppose also that every 20-40K years there’s massive emmissions of CO2 from volcanic eruptions.

Then you should be able to point to a massive volcanic eruption which triggers right at the start of the warming period. Your hypothesis leads to testable predictions … do they bear out?

You need to find the cause of the past warming events. Then you are in a better position to evaluate the current warming trend. In the past weeks I’ve linked to posts with graphs showing that the current warming trend began in the 16th century … a problem for the CO2 as the key. Some CO2/AGW critics suggest that warming causes the CO2 rise not the reverse (warmer oceans release CO2). Correlation is not causation. You need to identify causes.

Well your long term 500,000 temp graph would look like it does. Temps slowly fall over thousands of years as life sucks carbon out of the air. Then the eruptions replace the missing carbon allowing temps to shoot up again. This is a nice comfortable system, granted only one that’s been in place for a relatively recent period of 0.5-1M years. We know that deep in the past the climate has gone through much more radical swings. So while this is ‘stable’ for life as we know it. But we know from millions of years in the past other, dramatically different, equilibriums are possible.

Now if this is the case would the graph tell us not to worry? On the contrary, we should be very worried. Human activity having reversed the natural drawdown of CO2 means no more gradual cooling….good in that we can avoid ice ages which most people would say is a bad thing. But since the natural increasers of CO2 are not impacted by human activity they will continue to add CO2. The result is an escallation of temp. beyond the stable climate regime of the last half million years.

While the MWP or the fluculartions in temp back in semi-deep time (1 million years or so) might have very well been non-man made and more dramatic than AGW estimates today that is a long way from making the skeptics case.

I understand your 0.02 degree counter-hypothetical but I don’t agree with it. The question is how much is AGW. If human activity is generating 2 degree or 0.02 the question is what is the cost of that 2 degrees or 0.02 degrees. A CO2 comet may give us twenty times as much warming ten years from now or maybe it did 1000 years ago but that’s not the crux of our problem. Assuming a CO2 comet (or volcano or solar increase or whatnot) is totally outside our control its costs are therefore totally unavoidable.

Now this is simplistic because the question of ‘how much does 2 or 0.02 degrees cost us’ is not really specific enough. 2 degrees on top of 8 degrees almost certainly costs us a lot more than 2 degrees on top of zero. Likewise 2 degrees over 100 years is very different in terms of cost than 2 degrees over ten years.

There is also the feedback question. Assuming humans had no important activity we might expect our temps to go up and down over the very long period. This would imply some periodic cycle of warming setting off cooling process that eventually ‘bend the curve’ setting off a cooling period which then sets off warming processes and so on. What if, though, AGW has or is swamping the natural cooling processes that would normally bend the curve downwards? Maybe this would break the rollar coaster of recent warming-cooling and leave us with a stable warm period…..AGW in that sense might actually be good since we don’t need an ice age anytime soon. But what if the warming cycles that had been breaking the cooling cycles still show up? Instead of the curve flattening out it might bend upwards setting off warming much faster than anything we’ve dealt with in our history…..

Conservatism says since we don’t know the implications of so dramatically increasing CO2 we should hold off doing it as much as we can. If it turns out CO2 is either not a big deal or it turns out that the AGW is helpfully keeping us from what would have been another mini-Ice Age….well we can always turn around and burn all that oil and coal to make more AGW if we really need it.

As for the MWP, the question remains is this a European event or a global one. We clearly know its a European event but we remain unclear what it was in terms of the globe. In global terms it might have been a MWP, or maybe just a MSWTUP (Medieval slightly warmer than usual period)…or even a net MCP (Medieval cooling period)