The medieval...whatever you want to call it

We touch on this often in discussing paleoclimates here. I don't mean to pick on AustinGreen particularly, but he has recently voiced the idea that calling it M. Climate Anomaly is a disingenuous change from M Warm Period. I think this is quite important to think about, and its 'mirror' the Little Ice Age (LIA; which no one has thought to rename yet )

Free link to a review paper well worth a look:

http://blog.lib.umn.edu/stgeorge/geog5426/Diaz%20Bulletin%20of%20the%20American%20Meteorological%20Society%202011.pdf

Even though the hated Mann is among the authors, I would suggest that it is a comprehensive overview of the studies that have attempted quantifying the thing. Can't be bothered to read? Then you are stuck with my summary. It was warm and dry some places, and cold and dry in some others. Both M... and LIA were quite unusual states, to the extent those can be known from paleo records. Diaz' review (and others) suggest that oceans act differently to redistribute heat sometimes.

I don't see that as flailing or 'we can't think of any other cause'. It is simply a reflection that oceans have massive heat-sink and heat-transfer capabilities, far greater than the atmosphere. But when the ocean will choose to exercise those capabilities in the future, I guess we haven't a clue.

Here's how I think all this relates to anticipating climate for the rest of this century. Do these past anomalies mean that more IR-absorbing gases in the atmosphere don't absorb IR? absolutely not; that is pure physics and it happens above the oceans. Increase the IR-trapping and you increase the total energy of the system. It can't be waved away.

BUT, where does that heat go? Not much to the atmosphere where it can be easily seen as temperature increases. Mostly to Davy Jone's locker. But that apportioning can change. Heat flow changed in the Medieval, and it changed a different way in the LIA. Thus it changes on the 1000 to 100 year time scale. Also, looking at the shorter instrumental air-T global record, we see two 'pauses' in air-T increase since 1850. Thus it changes on the 100 to 10 year time scale as well, and I have talked about them here before.

In this way, I think that climate prediction/projection models are whacked. Because we haven't a clue as to how the oceans will handle added heat in 21st century. The models present a smooth upward T, which follows from an assumption that the ocean sloshes won't change.

The elephant is in the room, and we are missing it. If the oceans decide to sink a lot more heat, we could get much less than 3 oC per CO2 doubling in air T. That would be great. Or, if they choose the other, we could get more on this time scale. The elephant is in the room, and it doesn't matter whether you get your facts from Henry Diaz (above) or from Sallie Baliunas.

The climate models in IPCC AR4 were wonderful, and no doubt those in AR5 will be even more so. But I believe that they all miss the elephant. I believe that we are flying blind into our temperature future. It could be mild (+ or -), or highly disruptive.

This is why the precautionary principle is so often invoked. Trim added atmospheric energy absorption (CO2 burn) down as quickly as possible, within economic and political constraints. It's not like we can't burn it all later, if that looks like the best plan.

What does anyone else think that we can learn from the Medieval?

 

No, I was not being sarcastic about wonderful AR4 AR5 models. I think it is wonderful that they include so many processes at so many scales. I am not sure what other types of giant models might compare - computational fluid dynamics?

But I think they are not complete in the sense that they appear to exclude changes in the patterns of ocean heat uptake and re-distribution. It would be difficult to include those things, because it seems to me we don't have the mechanisms worked out.

I'd be more than pleased to be wrong about that. As it stands, I think that the oceans could suppress or enhance the 3 oC per CO2 doubling, on time scales of their choosing. Clearly not in human hands. The part that is in human hands is to control the rate of CO2 increase.

Corwyn, I completely agree that the heat goes somewhere. But with vast heat capacity, the ocean T does not increase nearly as fast as air T, per megajoule added. The big impacts on steric sea-level rise and enhanced ice melt are probably on >100 year time scale, when (maybe) we will be better able to adapt. I really can't say much more than that, except reduced ocean pH may sooner hit some groups of marine life. Outside the scope here though.

Mojo adds some to our reading list, which is all to the good. As far as cherry picking (which I'd rather call selective citation), here's the test I'd use: Which cites only examples of warming? which cites examples of both warming and cooling? See how simple that is? You don't even have to care about the authors' names or whether the list came from an affinity website or whatever.

'Cause in graduate level courses (like this one here), we don't care. We just see who's got the data, the strong analysis. Or who fumbled the ball on the 3-yard line.

I really feel that I am sticking my neck out here, but telling climate scientists how they ought to think about things. Because I am sure I don't know all the things that they do. I'll just but some unconventional ideas forth and ask you to hit the books.

 

...

double post

 

In my real life, I look for what makes soil accumulate C or blow it off as CO2. The findings are quite different from mainstream literature, and I'd be well advised to focus on them rather than PriusChat. Is tying me down here your real goal, mojo?

Climate (modeling) scientists have only the faintest idea of what soils 'do' and not even the faintest of the microbes that cause it. If, in the next 10 years, we can bring that in, then I might become a climate scientist by way of contributing to climate modeling.

But mostly here lately, I have been questioning matters far outside my expertise, what the oceans do with heat and when. It is not my area, but I set aside the strong voices from both sides and just ask, what might the oceans do?

I do not ask this because PC readers will find the missing truth. Rather, because I want them to somehow get interested in reading the lit. At least the review papers. It is a transparent ploy on my part, only justified because I want y'all to know what's happening. Work by you would be required for this.

The alternative is sheep-mode, where we all trust the warming advocates and deniers and policy makers to somehow choose the best, low-regrets future. It is only the fear of that, that keeps me bothering y'all here.

Because all of them suck at planning our future.

 

AG@13 "Alley chose the most naïve model"
What other options were available? please tell.

 

Anyway, I am very happy that mojo has led us to
C3
because that site links to published papers (at least a chosen subset). Y'all should read them. Whether you accept the interpretations posted in front is up to you. Not for me to call.

Gaps between what papers say, how they are spun in press releases, and how they are respun at affinity websites and in the media is, well, a problem. But there may be no cure other than reading enough, and thinking enough, to sort it out on your own.

 

“Using data to attribute episodes of warming and cooling in instrumental records”
Ka-Kit Tung and Jiansong Zhou
PNAS in press, doi:10.1073/pnas.1212471110

This paper so related to my ‘the ocean sloshing is a big player in air-T trends’, that some might suppose I took it as inspiration. I just found it this morning, honest. I think we are going to be hearing a lot about it, so why not start here. First a quote from the summary:

“The observed global-warming rate has been non-uniform, and the cause of each episode of slowing in the expected warming rate is the subject of intense debate. To explain this, non-recurrent events have commonly been invoked for each episode separately. After reviewing evidence in both the latest global data (HadCRUT4) and the longest instrumental record, Central England Temperature, a revised picture is emerging that gives a consistent attribution for each multidecadal episode of warming and cooling in recent history, and suggests that the anthropogenic global warming trends might have been overestimated by a factor of two in the second half of the 20th century. A recurrent multidecadal oscillation is found to extend to the preindustrial era in the 353-y Central England Temperature and is likely an internal variability related to the Atlantic Multidecadal Oscillation (AMO)…” (emphasis added by me)

We see that they used HadCRUT4, and the (tightly regional) CET. Did not use BEST, and I assume that was because it has not yet been peer-reviewed published. It should be on their to-do list.

The AMO record they use is longer than I was aware of. I guess this record comes from comparing barometric pressures at low-and high-latitude sites (That’s how ENSO is done, but there it’s east and west). Mercury column barometers have been around for a long time, and are very accurate if used carefully. So, fine there as well.

Tung and Zhou used wavelet analysis to separate signals of different timescales. I cannot explain that technique at all, so perhaps someone else here could help?

Beyond what I highlighted in the quote above, the authors also assert that AMO going negative could lead to slowed air-T increases in coming decades. That total solar irradiance (even though only varying from 1365 to 1366.5 watts/m2) is in synch with the long-term T trends, to which they attach meaning, although a mechanism to amplify that still eludes us. I think you can see why I expect these ideas will ‘stimulate lots of discussion’. All climate watchers here ought to read the thing. Your pirated copy is only a ‘private message’ away.

Dr. Judith Curry, on the climate etc. website, has lamented that PNAS has lost all credibility by publishing any tattered thing that supports the warmist team. We might be looking soon for a retraction (restatement) of that.

+++

Meanwhile, I would not hope that anyone here thinks that a long-term T sensitivity to CO2 doubling of 3 oC only comes from Alley’s best guess. There are many such analyses from different ‘paleo records’ by different authors. AustinGreen certainly knows them, but has been slow to reveal. Mojo may not want to know them; it doesn’t matter to me.

 

It would take little effort for anyone here to find the many papers using paleo proxies to constrain the CO2 doubling to 3 oC, They don't all say 3, and the range may be of some interest. That is why I called back to AustinG, because Alley is often not an author and none of them are guesses. They are somebody's best informed shot. And I think that AustinG knows of them. We highly value here his reasoned assessments of carbon and energy policies, so we don't want him to fall off the cart.

More to the point is dynamics; how fast things happen. This has been my topic recently. Paleo-analyses, by anybody, are poorly poised to help us with that. We care about that because we want to know the T trends for the next 2 decades. Probably less so, for the following 6 decades, and much less for the century after. So we have 3 oC per doubling, and it is +/- a lot, but we want to know how fast it comes to us.

Paleo doesn't say. Climate models, driven by radiative transfer, say they do, but I think they are poor with the ocean. I thought they failed with the instrumental-T records, and Tung and Zhou (above) may have put a finer point on that. But still, nobody is able to tell us how the ocean may mitigate IR-heat trapping in the near future. NOBODY, and I think that puts us in a poor position.

So, what's the plan? Do more energy conservation that will save money regardless of CO2 and T? It is amazing to me that we are not. Do more renewable E that looks costly now, but might look very wise in a future where CO2 and T begin to bite? Sounds 'precautionary', but global economics are sluggish just now. It would require strong leadership.

I think that there is a fair chance that the oceans could suck it down and make the next 2 decades T increase slow. The intentionally self-misinformed may take that as proof that CO2 does not absorb energy. Even more exciting, the oceans could suck down even more and ruin my 'every decade warmer than the previous' idea. More important, it would make the IPCC models look stupid. It would challenge us all, very severely, to plan a good CO2 path going forward.

Because as the oceans have stored heat in the past, later they have released it. On any time scale you might care to look. So if we get some slower warming soon, we will get faster later. Could cause problems.

Which reminds me, I should trouble you all someday with a thread here that 'Gaia is whacked'. Plants on earth are evolving on a suicide mission to create an environment where they cannot ultimately survive (4 big evolutionary jumps since the oxygen revolution). Volcanoes (we should say plate tectonics) oppose that, in a complicated way, but neither could possibly 'care' about the other. Meanwhile, Milankovich cycles just continue, and the oceans follow thermodynamics as well as they can within flow limitations. None of these care about the others. Briefly, there is no Gaia, and we are all just damn lucky to be on a planet where several amazing coincidences have prevailed.

You wanna massively mess with that, by quickly putting fossil C back in the atmosphere? Good idea? Are you SURE? What makes you sure?