Even more thinking about this, and re-reviewing the latest surface and satellite temperature trends…

It seems more likely that the 50% probability for “do nothing” in the next 50 years would put the warming at more like 0.8 degrees Celsius (not 0.6 degrees Celsius, as I’ve previously stated).

Therefore, comparing the 50% probability for “do nothing” to the Alternative Scenario (AS) for the next 50 years would be more like 0.8 degree Celsius versus 0.5 degree Celsius temperature rise from present, respectively.

I’d consider that (a 0.3 degree Celsius difference) “perceptible”…though just barely.

So here are alternatives to your sentence that I’d suggest:

1) “No emissions reduction policy currently under discussion – from changes in personal behavior to those proposed under the Framework Convention on Climate Change – even if successfully implemented will have more than a barely perceptible effect on the global climate system for at least 50 years.”

2) “No emissions reduction policy currently under discussion – from changes in personal behavior to those proposed under the Framework Convention on Climate Change – even if successfully implemented will have a perceptible effect on the global climate system for at least 30 years.”

Note that the second sentence shortens the time frame from 50 years to 30 years. This is important, because I estimate that even the “do nothing” approach would result in only about 0.5 degree Celsius temperature rise in the next 30 years…and no policy currently under discussion could cut that rise enough to be “perceptible.”

I might not have made what I’m thinking very clear.

I agree with your statement, “No emissions reduction policy currently under discussion – from changes in personal behavior to those proposed under the Framework Convention on Climate Change – even if successfully implemented will have a perceptible effect on the global climate system for at least 50 years.”

I also agree that Gavin Schmidt set up a straw man for contrast. But where I think you’re 180 degrees wrong is the direction of that straw man. You said that the straw man was on the low side…the Alternative Scenario. But as you yourself can see, the climate forcing to date has been closest to the Alternative Scenario (of all 5 scenarios in James Hansen’s AGU presentation).

The strawmen that Gavin Schmidt gave so that he could claim there was a significant difference were the “business as usual” scenarios he chose. He gave the scenarios of the A2 and A1B. But if you go to Figure 1 of the paper he referenced:

http://pubs.giss.nasa.gov/abstracts/submitted/Hansen_etal_1.html

http://pubs.giss.nasa.gov/docs/notyet/2005_submitted_Hansen_etal_1.pdf

…you’ll see the that A2 and A1B both have a CO2 concentration in 2050 of a whopping 533 ppm. And the methane concentrations are even more ridiculous: approximately 2400 ppb for A1B and 2600 ppb for A2.

In order for the CO2 concentration to be 533 ppm in 2050, the AVERAGE annual increase between now (~382 ppm) and 2050 would have to be approximately 3.43 ppm. That’s almost DOUBLE the average increase over the past 25 years. That is simply not credible.

The methane concentration likewise require AVERAGE increases of >10 ppb per year. The average increase over the past 5 years has been…essentially ZERO ppb.

So the A2 and A1B scenarios are obviously nonsense. It’s not surprising that the Alternative Scenario will be different from two scenarios that have essentially ZERO chance of happening.

In contrast, from that same figure, the Alternative Scenario values for CO2 and CH4 in 2050 are approximately 440 ppm and 1550 ppb, respectively.

These values can be compared to my “50% probability” values for 2050 of 477 ppm and 1810 ppb, respectively, for “do nothing.” The difference in temperature between the two would not be perceptible (probably a little more than 0.1 degree Celsius).

So you’re right about the straw man. But the straw man scenarios are A2 and A1B…not the Alternative Scenario.

And you’re also right that the difference would not be perceptible. There will probably be about 0.6 degrees Celsius increase for “do nothing,” and a little less than 0.5 degrees Celsius for the Alternative Scenario.

Mark

You write, “Thanks, but you are asking me if I can read a graph. The answer is yes.”

No, I was not asking you if you could read a graph. I was asking you what scenario on that graph most closely follows climate forcing to date.

You continue, “Yes, to date the emissions path has followed what Jh now calls his AS.”

Finally! Why didn’t you simply answer that in the first place?!!

BTW, you STILL are slightly (but importantly) wrong; the graph has climate forcing, not emissions. That’s important, because there is very important scientific uncertainty about methane emissions versus the change in methane climate forcing. The change in methane *climate forcing* (i.e., the increase in methane atmospheric concentration) has essentially gone to zero:

http://www.cmdl.noaa.gov/gallery/ccgg_figures/ch4_tr_global

…but the trend in methane emissions is far less certain.

So…if you agree with me that the past trends in climate forcing have most closely resembled Hansen’s Alternative Scenario (AS), don’t you agree that you were wrong when you said (to Gavin Schmidt),

“…I am aware of no policy proposal being discussed that comes close to your AS”?

How can you not be aware of any policy proposal being discussed that comes close to the AS (Alternative Scenario), if you agree that the TRENDS TO DATE have been closest to the AS??!

Mark

But your statement could be made irrelevant if we faced reality. Gavin states above, “A second point is alluded to above; efforts that aim to control CH4, CFCs, trop O3 or black carbon have much shorter concentration response times and so will impact climate all the faster if changed. Your statement applied to them is even more flawed.”
No policy or proposal that I am aware of addresses these factors. If so, then Gavin is wrong in saying that ‘your statement applied to them is even more flawed”. But he is certainly right in saying that these factors can be controlled enough to disprove your 50 year outlook.
If Hansen and NASA had stood up to the environmemntal lobby a few years ago and pushed for control of these gases as they proposed, then the pop press might now be yelling, “Hey folks, these are true pollutants, we can do something about them now and we should see results quickly” Add to this other forcings such as land use, and new focuses such as actual earth regions rather than abstract globes, etc. and we find a lot can be done. Who knows, if we were pragmatic realists, we might even eliminate the climate problem in 50 years.
But it won’t happen, folks would rather have their point of view prevail then see results. All hail the great CO2 monster!

Thanks, but you are asking me if I can read a graph. The answer is yes. For the upteenth time, we discussed Hansen’s scenarios at length and documented this a few weeks ago. Yes, to date the emissions path has followed what Jh now calls his AS. As far as predicting the future, I’m not convinced that the IPCC has covered the full range of possibilities, nor Hansen, you, or anyone else. There is uncertainty about the future, there is no single “truth.” Hope this is what you are looking for. Thanks.

It’s now been more than 12 hours since I last asked my very simple question, that has a very simple one-word answer, and which should take you less than 5 minutes to answer. You haven’t answered…even though you’ve found time to comment to multiple times on the “hockey stick.”

I’ve got to admit that I’m very disappointed. It seems to me that there are two possible reasons for you to write this new essay you’re apparently writing:

a) you want people to follow the policy recommendations that I presume you’re making, but only because you’re telling the truth about the current situation, or

b) you want people to follow the policy recommendations that I presume you’re making, even if you are not telling the truth about the current situation.

Based on the evidence of your lack of reply–again, all I asked for is a one-word reply, that would take less than 5 minutes of your time–it seems to me that the reason you’re writing the essay must be “b.” That is, you want people to do what you recommend, even if you are not telling the truth about the current situation. That’s very disappointing; I thought much more of you than that.

FYI…the answer I was expecting was “Alternative Scenario.” That is, the “Alternative Scenario”–the one resulting in 1 degree Celsius warming in the 21st century–is the scenario from the graph that most closely represents the climatic forcing to date.

If you think the correct answer is *not* “Alternative Scenario,” please let me know. I DO care whether whether or not I’m telling the truth about the current situation.

Sincerely,
Mark Bahner

1. You write: “Roger, are you saying that the only policy worth discussing is one that commits governments to a fixed approach for the next 50 years plus.” No, of course not.

2. You write: “We look at the evidence now. We take a decision based on that evidence, looking forward to the next 100 years but only specifically committing to actions over the next 15.”

Sounds good, though we could quibble over the number 15, but as a frmaework, it is great.

3. You write: “in fact, it’s the one agreed upon” — By whom? To do what?

Kyoto did not have any discussion of future commitments. It is failing on its own terms. Discussions about post-Kyoto are in gridlock.

4. You write: “adaptation is a feature of life in Kyoto signatory nations but not in non-signatory.” Well maybe semantic, but non-Kyoto countries have an awful lot of climate adaptation efforts going on. It is a way of life. The issues are less “psychosocial” in my view than economic. The big question is how to create mechanisms to transfer wealth, knowledge, know-how, capacity, lessons, etc. from well-adapted to vulnerable communities in developed and developing contexts. I’ll stand by my assertion that the FCCC is an obstacle in this process, despite “adaptation” efforts under it.

Thanks!

How about this as a policy: We look at the evidence now. We take a decision based on that evidence, looking forward to the next 100 years but only specifically committing to actions over the next 15. Then, after 15 years, we revise the commitment in the light of new knowledge. I think that’s a good policy (in fact, it’s the one agreed upon), yet not one of the interim policy commitments will, on its own, have a discernable/meaningful effect on climate.

(BTW, regarding your point on adaptation, I know your views. But it’s ironic that adaptation is a feature of life in Kyoto signatory nations but not in non-signatory. “Impossible” but true. The reasons, of course, are psychosocial rather than legal. The question is to what extent the process of advocating mitigation impacts psychosocial factors thereby creating an environment that also fosters adaptation).

You well described what I would call “faith-based policy”;-)

Given the performance of Kyoto, is it really a good idea to assume that “something” will come next? What?

If we (as a globe) are having this much trouble with Kyoto, how can we think anything is coming next?

Perhaps I should cahnge the sentence as follows (OK tongue in cheek, but still!;-):

“No emissions reduction policy currently under discussion – from changes in personal behavior to those proposed under the Framework Convention on Climate Change – will have a discernible effect on the global climate system for at least 50 years, but something is bound to come up.”

I apologize for the tone of my last remarks, but I really have what I think is a quite simple question, for which I think you ought to be able to give a quite simple (one word) answer, without much effort at all on your part.

You wrote, “Hansen’s graph has observations on it, so I’m not sure what you are looking for beyond that.”

What I’m looking for is a one-word answer to my question. Please look at slide 43 (page 57 of 64) of James Hansen’s Keeling Lecture:

http://www.columbia.edu/~jeh1/keeling_talk_and_slides.pdf

Now, please look at the figure in the bottom right-hand corner of that page, titled, “Forcing Growth Rates, W/m2/year.”

There are 5 labeled scenarios on that figure:

1) “Alternative Scenario,”
2) “B1″,
3) “2 deg C”,
4) “A1B,”
5) “A1F1″.

Which one of those 5 scenarios do you think comes closest to the actual climate forcings observed to date (the solid curves)? Your answer can simply be one word, e.g.,

“A1F1.”

Thanks,
Mark

P.S. Of course, if your answer **is** “A1F1,” I’ll be contacting you (confidentially) to ask about getting some of that great stuff you’re smoking!