Sea ice: What I do in my spare time :-)

In the small amount of spare time I have in between blogging, editing wikipedia, posting to sci.env, bringing up two children and looking after the garden and occaisionally talking to my wife and... so on... I sometimes manage to find some time to do actual real work. And this post is about that.

Also: I (and others) frequently decry the medias habit of only reporting sensationalised science; yet I think I probably spend most of this blog discussing such myself. Admittedly in an attempt to explain rather than sensationalise. But as a (possibly rather boring) antidote, here I shall discuss my most recent paper: Connolley, W. M. Sea ice concentrations in the Weddell Sea: A comparison of SSM/I, ULS, and GCM data. GEOPHYSICAL RESEARCH LETTERS 32 (7): art. no. L07501 APR 2 2005. The figures here are taken from the paper.

So: the issue: we run coupled ocean-atmosphere GCMs, which produce (amongst many other things) a field of sea ice concentration and depth in both hemispheres, and we would like to know whether they are right or not. I only do the SH. A simplifying factor there is that we have so few observations of sea ice depth that there is rather little hope of verifying the model depths, so we can stick to ice concentration, which since 1979 has been observed by satellite (there are earlier obs by sat, since 1973, but pretty well everyone agrees that these can't be merged consistently into the later series). This is done by SSMR/SSMI, which is special sensor microwave radiometer or imager, and you can read more about it at wiki. Basically you observe the upwelling microwave radiation in a couple of frequency bands (microwaves are good because they mostly go through clouds and stuff), and their horizontal and vertical polarisation, and from various ratios you then have a quantity that can be related to sea ice concentration. This then gives you a daily field of sea ice concentration.

But, there is more than one way to do this. There are various issues (weather filters, tie points, etc etc) but the man point is that there are two main algorithms, viz the Bootstrap and the NASA Team (there are lots of others too: change the tie points and you can have your own. But its chosing what to ratio to what that is more interesting). I won't tell you the technical differences for the very good reason that I can't remember them. There is (rather well hidden underneath) some politics in all this: and if you probe people carefully they tend to tell you that intercomparisons favour the Bootstrap, but since people had worked on Team that they weren't about to give it up. Certainly the intercomparison papers I read and ref'd in the paper favour Bootstrap, but, err, they were written by the Bootstrap authors. OTOH if the Team folks wrote similar intercomparisons I failed to find them.

Anyway: the other thing about Team is that until fairly recently it was the only one I had access too, and that my model (HadCM3) produced sea ice that had higher ice concentrations than Team (it also produced ice in a pattern around Antarctica that was somewhat wrong, but for the purposes of this I'm going to ignore the pattern and talk only about the concentration). Then I got access to Bootstrap and discovered that Bootstrap concentrations were higher than Team (though still a bit less than HadCM3). Imagine my delight: we could abandon those efforts to make the model produce less ice and just change the obs. But... this is a bit unsatisfying. We need some obs to verify the obs. So bring on... ULS (upward looking sonar) which sit under the sea for a year or two, going "ping!" every now and again and (after being retrieved and a whole pile of clever data processing to remove wave heights etc) producing a signal for "is there any ice above me" every 5 mins or so. Which can be averaged, over a month, into an ice concentration at a point. And there were about 8 of them in the Weddell sea - see pic. So, spiffy, we can compare them to the Bootstrap and Team data.

Incidentally, note that this is a thing that happens: I didn't set out to write a ppaer about different sea ice concentration datasets, it just became obvious that I needed to know about this to validate the model and (inconveniently) no one else had done it already.

And... we discover that the ULS doesn't fit brilliantly to Team *or* Bootstrap, but it does fit better to Bootstrap. The pic is a scatter plot, with ULS values on the x axis and SSMI (contemporaneous and colocated) on the y. The one-to-one line is where we want all the points to be. The thicker dashed line is a least-squares fit of all these points, using Bootstrap data. The thinner dashed is for Team (and to confuse you, the points are not plotted for Team, just the line). The grey (gray?) lines are what happens when you do the least-squares fitting at just the individual ULS's, instead of aggregating them.

On the whole, I (and most people I spoke to) tend to assume that the ULSs are probably right, and therefore interpret the scatter on the plot as a measure of the SSMI retrieval being wrong. OTOH, there is a difficulty in meshing the ULS (point measurements with fine temporal resolution averaged up to monthly scale) to the SSMI (which has a 25 km^2 footprint, which I've averaged up to about 100 km^2, and is daily but I've averaged up to monthly). Quite how much scatter you expect from this, if the ULS and SSMI were both exactly "right", I don't know. But I haven't yet found a good reason why there should be a *bias* between them (ie, why the dashed line on the plot isn't 1-to-1). If you know a good reason, its safe to tell me: the paper is now published, and any new ideas can be fed into a new publication :-).

So the end result of all this? The paper says that sea ice concentrations, at least in the Weddell sea, are probably higher than most people thought they were, and quite possibly even higher than Bootstrap says. And that consequently we can stop worrying much about HadCM3 concentrations. Sadly, it looks like HadGEM concentrations are rather lower... but you can't have everything.

ps: I've decided I'm vaguely keen on explaining my work, so, if anything in the above is not explained, baffling, obviously wrong, whatever, do feel free to comment and I'll try to expand.


Tackling Climate Change in Cambridgeshire

Tackling Climate Change in Cambridgeshire is a report (pdf) for Cambridge County Council. Its interesting to see stuff coming down to our local level. But is it any good? Surprisingly, yes: at least on the words. They also have long lists of actions but I rather suspect that the cumulative total might be small.

(BTW, I've abandoned the "more" stuff... it was too annoying).

Point number 1, they get the science pretty well right (The average global surface temperature has increased by about 0.6°C in the last 100 years, and there is strong evidence that most of the warming over the last 50 years has been caused by man. This is mainly because of the release of greenhouse gases leading to an ‘enhanced’ greenhouse effect. The gases accumulate in the atmosphere and remain there for many years, driving climate change. Scientists think that if we do not limit the release of these gases, temperatures around the world could rise by between 2° and 6°C by 2100). Perhaps this isn't too surprising - septics have got nowhere in UK climate science or govt science policy making, or even in general policy making (see my prev analysis here). They are only present by default in that the UK govt action doesn't really measure up to the words.

Point number 2, they tell you where Cambridgeshires CO2 comes from, via an analysis by CERC (who?). And the answer is, as of 2002: electricity 32%; waste 16%; transport 16%; manufacturing and construction 12%; residential 10%; industrial 6%; agriculture 5%; commercial/institutional 3%. This isn't quite as useful as it could be, because presumably the "electricity" term would be better split up amongst the various classes of users. In fact... is this data presented as you would want it? Shouldn't it be split amongst the user classes (residential/ind/ag/manuf/commerce) and then the three "creation" classes waste/elec/transp (with heating and lighting then needing to be extra classes). Anyway, we end up with 15 tonnes/person/year.

So what about the action bit? They have decided to adopt the "ambitious" target of 20% less than 1997, by 2010, which is the same as the national targe, which... err... we're not going to make. They also promise to "work towards" a 60% reduction target. Hmm. The council is going to do things to its own energy usage. It buys a lot of its electricity (80%) from renewable suppliers. It designs in energy efficiency into new buildings. It runs some vehicles on LPG (which is says is both cheaper and produces 20% less CO2). It makes efforts to avoid its staff having to drive (though moving its HQ out to Cambourne didn't help me: I used to cycle when it was in Cambridge, now I must drive. To be fair, now I think of it, it was South cambs that moved, not the County, which is still inside Cambridge). And much more, if you read the report. But... there isn't a lot to say quite how this is going to get them to their county-wide 20%-less-by-2010 target. Which is only 5 years away.

Theres also a section on "adaption", where again they get the science right, in that they notice that even present levels commit us to more climate change in the future.

So... all in all quite good words, time will tell for the action.


Recommending Rahmstorf

Stefan Rahmstorf has an article about climate sceptics (trans from German) at http://www.pik-potsdam.de/~stefan/.... Theres lots of stuff there, nothing too novel to anyone who reads here or RealClimate, but its well presented.

One thing it mentions as wrong is Jaworowski’s article in ESPR, which is taken to pieces by Some are Boojums (as well as Hans Oeschger on SaB). In fact I shall add SaB to my list.


Confusion from Tim Worstall

Tim Worstall (of ex sci.env fame) has been going down in the world, and now writes for TCS. His latest is Things Look Brighter on Planet Earth, a rather confused take on the global dimming/brightening which is rather better reported :-) at http://www.realclimate.org/index.php?p=154.

The papers aren't really joint, just coincident. But more importantly, it isn't really about albedo either. If changes this big were due to albedo, ie the changes reflected top-of-atmosphere chnages in fluxes, they would be so enormous as to be readily detectable in the temperature record. They aren't. So they are, more, changes in the distribution of energy within the climate system. As it happens there is a paper in the same issue looking at albedo changes, but thats different.

But the meta-issue above this, which TW attempts to use these for, is: uncertainty, and/or how much should we trust the IPCC reports. TW sez:

As I say above, the first thing I take from this is that we do not, in fact, know everything about this subject yet. The IPCC report is, quite clearly, not the last word on the subject, for if it were, no one would be able to find something to publish on the subject, right?

This is stupid, because its trivially true, and indeed acknowledged by anyone sensible: the IPCC TAR wasn't the last word, which is why thousands of people are currently working on the AR4. But what TW appears to be saying, or trying to imply without actually saying it because its a logical non-sequitur when said out loud is: "and so what is in the IPCC reports is wrong, and/or too uncertain to trust". But TW is so pleased with his vacuous comment that he repeats it at the end of the article.

More not-betting; James' empty blog

JA is doing more septic-teasing by discovering that when they say "no reasonable offers refused" what they really mean is "we refuse to put our money where our mouth is", this time Pat Michaels at WCR (WCR, the "blog" that is so frightened of you it doesn't allow comment on *any* of its posts...).

Since I've added him to my blogroll, I won't be recommnending his posts again: I'll assume you can see them yourself.

I've also slightly revised the blogroll tagline, to "other blogs", since I'm now quite fond of this one.

JA's betting-on-climate is turning out to be quite entertaining. None of the septics are prepared to put up. I thought that maybe some would, just to shut him up. But then I suppose they would have to watch, year by year, as their bet unravlled, and that would be embarrasing. But the current situation is going to get embarassing for them too, soon. At the moment its below general public notice (George Monbiot against Myron Ebell was the most public its got) but that is likely to change.

ps: more blogger "more" pain: I now discover that if I *don't* put in the span tags, then it still puts in a ...more... message, even if there is no more! Argh


70's cooling again: but why?

The good old "1970's cooling" stuff comes up again, this time over at Slate about an article by Chris Mooney. CM blogs about this with "Here We Go Again Over in the "Fray" at Slate, they're having a pointless argument over global "cooling" in response to my recent piece. Will the misinformation ever end?". But in fact, things aren't that bad at all...

Because the comments end up with the right answer: which is to refer to the RealClimate post on the same subject. Excellent.

But re-reading that, and my page http://www.wmconnolley.org.uk/sci/iceage/ I find that one thing is missing, or there only by implication, which is to answer "OK then, so why was there a cooling trend from the 40's to the 70's, if CO2 was increasing?". Which is a fair question. The right answer above answers it about right:

Firstly, the cooling was fairly small, and if it wasn't in the middle of warming periods it probably wouldn't even have been called cooling. The cooling was stronger in the NH (which fits the aerosol explanation), and even there it isn't (in retrospect) nearly as large as some of the datasets of the time seem to have implied.

Secondly, its quite explicable within the standard theory: as usual, its all in the IPCC TAR, specifically SPM and figure 4 and fig 12.7 . Which is to say, its mostly the sulphate aerosols. Those figures can be over interpreted though: as it says elsewhere " These results show that the forcings included are sufficient to explain the observed changes, but do not exclude the possibility that other forcings may also have contributed". Which is to say... that modelling will get better, we may well tighten up these results, and may even discover something unexpected: but its certainly wrong to say the cooling is inexplicable.

Learning how to do more

I've finally (I think) discovered how to do "...more..." with blogger. Its a bit of a pain, involving edits to the template and each post. To find out how...

...read on! So, its all explained at Blogger advanced help and its rather harder than wordpress (where you just put <!--more--!> or somesuch into the post.

Hmmm... forgot to edit second template... try again...


Looking at... David King on OpenDemocracy

Over at OpenDemocracy.net they are running a special feature on debate on climate change. The "kick-off" pair of articles were by David King presenting the std.consensus view, and one by Benny Peiser who, lacking much to say, is obliged to puff up uncertainty. I ripped that up here. But what of David Kings contribution? Is that any good? Lets take a look...

Oops, first a caveat: I'm a climate modeller. So I can do that bit. I'm not so good at "impacts" and I try to steer clear of it. I'm going to be obliged to mention them in what follows, because DK does, but remember to devalue my opinions in those bits.

Headline: "Global warming: a clear and present danger". I'm a bit unhappy about that (see RealClimate post here) but I'll try to stick to the science (and its possible he didn't choose his headlines; but based on what follows, this is unlikely).

Bit of history (this-isn't-new) then "...global temperature increases of 1.5-6C for a doubling of carbon-dioxide levels". This may be the wrong numbers (see here) or maybe not - I'm not certain.

Mentions IPCC and Kyoto.

Nonetheless, it is often reported that scientists themselves cannot agree whether climate change is really happening, whether it is influenced by human activities and whether, even if both things are true, it really matters that much. The bad news is that this is for the most part a pseudo-debate. Tempting as it may be for some to believe that “it’s just the environmentalists doom-saying again”, the reality is that the overwhelming majority of credible scientific opinion is clear on all three points. Well, you have my opinion of the consensus via the RC link above. I think it includes the first 2 points, and a third (cl ch will continue) but is weaker on the fourth, impacts.

Beyond any reasonable doubt, climate change is happening. Fair enough.

Unmitigated climate change will both magnify humanity’s existing scourges – poverty, disease, famine – and add to these new ones, such as through increasing climatic extreme events, rising sea levels and flooding on a scale beyond human experience. Yeeeeeeesss ish. Less happy here: as above. Sea level is the only one I'm reasonable sure about: the IPCC mid value is about 0.4 m to 2100.

Part of the answer is in the nature of the media itself, which likes to present two sides of a story. “Scientists agree” is not such a great head line as “scientists at loggerheads”. Definitely agree.

There is also an issue that some, including some politicians, simply do not want to hear the evidence, regarding the implications as just too unpalatable (and politically unpopular) to be faced. Again, agree.

DK then goes on to examine groups of skeptics.

1: those basically scientists, but doubting. Lindzen as example. OK, as far as L's science writing goes; not true for his "popular" works.

2: small group of scientists who appear at every meeting but are not seriously regarded. Not familiar with this grouping.

3. very vocal group of professional lobbyists. Yes.

Summary: the balance of international scientific opinion is enormously in support of the conclusion that climate change is a real and present danger, requiring urgent and committed action. As above, I'd prefer a different description on the impacts side, but agree on the basic science side. [T]he arguments put forward by the sceptics gain publicity and influence far beyond that which can be justified by the standing of the individuals concerned, by the validity of their arguments, and by the scientific credibility of the evidence that they are able to put forward. To this I wholeheartedly agree.

Someone asked in particular about a French scientist who claims from a study of records of tea plantation companies in Tanzania that there has been no temperature increase around Kilimanjaro despite the loss of 85% of its ice cap (which has been dated back to the last ice age) over the past 100 years. I'm not familiar with this. From what I've heard, Kilimanjaro isn't a great example of anything: Kaser et al. suggests that the retreat of K's glaciers isn't directly temperature related. Others (no ref; sorry) suggest otherwise. But... so what? DK is correct to say that we shouldn't pay much attention to anyone "disproving" GW by looking at K; K is just one place; and whatever the mechanism for the glacier retreat there - T related or not - it won't say much about GW. For that, you want to look at glaciers globally: Eric Steig at RealClimate did that recently.

Estimates of future climate change

Current estimates of future climate change are quite uncertain - the IPCC TAR headline figure was 1.4 to 5.8 oC. But that doesn't mean quite what most people think it means, because it includes uncertainties in CO2 emissions, which themselves are large. So if you're interested in the uncertainties just from uncertainties in the models, or the change at 2*CO2, then you need a different number. This is then the climate sensitivity (equilibrium at 2*CO2) or more usefully (and somewhat smaller) what the IPCC call the Transient Climate Response or TCR, which is the temperature change at CO2 doubling following a 1% CO2 trajectory. The number would varies a bit, but not much, if you followed a different plausible trajectory. It is 1.1 to 3.1 oC IPCC, here. This needs to be said with the standard caveats: that the global figure conceals regional variations, and that the model range may or may not encompass the true range.

I mention this in particular because David King may have made this mistake over in his piece at Opendemocracy, saying: The most recent calculation, based on enormous computer programmes at a number of world centres, including the Hadley Centre for Climate Prediction and Research, yields global temperature increases of 1.5-6C for a doubling of carbon dioxide levels. So if by most recent he means IPCC, I think he has the wrong numbers. Unfortunately he doesn't source his statement, so he may well mean some more updated numbers.


Global warming is not from waste heat (2)

A little while ago, I proved conclusively :-) that the recent temperature increase isn't from waste heat. In essence, its obvious: the energy from waste heat is about 1/100th of the radiative forcing from GHG's.

When I wrote that, I had forgotten about Nordell 2003 (subscription required, but you can see the abstracts, and the people commenting on it), which has recently resurfaced amongst the comments at RC.

Thomas Palm succinctly summarises it thus:

I've read the paper by Bo Nordell and it is junk. Here is as summary I wrote in sci.environment after having read it:

The difference between the surface of the Earth and space is 33 degrees.
Geothermal heat produces about 0.07 W/m^2 heat. And if this causes 33
degrees heating the climate sensitivity must be 470 K/W/m^2. Thermal
pollution is 0.02 W/m^2 and will thus give a heating of 0.02*470= 9 K.
The mathematics he uses reduces this by a factor of 3, but essentially
this is his argument

If Nordell *were* right, we'd be seeing huge fluctuations in global temperature as a result of the small variations in solar forcing.

Only just recently, two letters have been sent to the journal Nordell published in (Global and Planetary Change) saying pretty much the same, but more politely, as befits a scientific journal: the first by Curt Coveya, Ken Caldeiraa, Martin Hoffertb, Michael MacCrackena, Stephen H. Schneiderc, Tom Wigley; and the second by J. Gumbel and H. Rodhe (the latter are pretty fierce by academic standards, saying This paper is seriously flawed and contradicts basic principles of physics. The paper contributes wrong and misleading arguments to the important discussion about human impact on the Earth’s climate).

Both of these point out the obvious, as I did: that the thermal pollution term is tiny by comparison with the GHG term. They also point out that Nordells model is far too simplistic to be any use: As these basic assumptions by the author are in error, all subsequent conclusions are also in error. We would also like to comment on the atmospheric model used by the author to obtain his radiative results. This model is based on simplistic assumptions that make it inappropriate for any quantitative calculations (G+R again).

The original Nordell paper, in its intro, makes a couple of characterisic septic-type mistakes: repeating the debunked wv-is-98% claim (OK, so *we* hadn't debunked it when Nordell published, but it was just as dodgy then); quoting Lindzen *1992* on models (how they got away with ref'ing that in an alleged scientific journal I don't know).

Nordell then responds to the comments, but to my mind unconvincingly.

Tear our pleasures with rough strife / through the iron gates of life

If SC can quote Marvell, so can I. Mine is only a fragment:

...Now therefore, while the youthful hue
Sits on thy skin like morning dew,
And while thy willing soul transpires
At every pore with instant fires,
Now let us sport us while we may;
And now, like am'rous birds of prey,
Rather at once our time devour,
Than languish in his slow-chapp'd power.
Let us roll all our strength, and all
Our sweetness, up into one ball;
And tear our pleasures with rough strife
Thorough the iron gates of life
Thus, though we cannot make our sun
Stand still, yet we will make him run.


Beekeeping and changing agricultural practice

I'm a beekeeper. You might have noticed. In the long-ago, about this time of year, people would be leaving their bees to get on with it. But in the UK nowadays rape plants are commonly grown for the rape seed oil, and in the spring time these produce vast acreages of bright yellow flowers (I think it looks quite pretty: many people hate it). They are also very good for nectar flow, and produce large amounts of honey. But. The honey very rapidly granulates. So much so that you can't leave the bees to cap it over, it has to be taken out (about now; and perhaps again a few weeks later), spun out and bottled. If you don't, it just granulates in the comb and its uselss to the bees, and then you have to melt the comb down, which is messy and painful.

The photo shows a corner of a frame left in a bit too long (I should have done it on sunday, but we were in Oxford for M to take part in a piano competition (round 2). She came second (a close second we thought...)). Over on the right, the darker cells are liquid. Rightwards, paler brown are partly granulated; some white ones are solid. I spin it, most of the liquid comes out, put it back on a hive and hope the bees will turf some of the granulated stuff out. If you look closely, you can play spot the wax moth larva.

Comments on Prometheus

RP wrote:

In the discussion motivated by Oreskes' Essay, I have seen one claim made that there are more than 11,000 articles on "climate change" in the ISI database and suggestions that about 10% somehow contradict the IPCC consensus position.

This claim is so wacky I couldn't even place it. RP didn't seem to either. It turns out (see Peisers reply to my comment (side note: is it weird that Peiser is supplying the references for Pielkes articles?)) that this is ref'd to Timo Hämeranta, another std.septic, and it isn't even correct: even TH only claims to have 4,000 abstracts, and I would guess that his categorising ability is no higher than Peisers. What exactly is the point in giving prominence to stupid claims like this one, except to give them credibility?

OTOH, RP *does* say:

Like Oreskes, I am happy to take the IPCC as the best assessment of state of climate science, and its conclusions as an accurate measure of the central tendency of views among the climate science community. The work of the IPCC, including its certainties and uncertainties, is plenty good enough for the development and promulgation of a steady stream of policy options on climate

which is confirmation of his non-skeptic status, should one ever doubt it (ahem).

But RP then continues:

But so what? If that number is 1% or 40%, it does not make any difference whatsoever from the standpoint of policy action.

This is wrong. If 40% of papers doubted the consensus, there would be no consensus.



Since Christmas (when Jessica first showed me a fiendish one, which I failed to solve over several days) I've been keen/addicted to Sudoku number puzzles. Here is one, not too hard, in case you don't know what they are:


You then have to fill in the numbers 1-9 in each row, each column, and each 3x3 sub-square. Note the symmetry of the initial placement: this doesn't appear to be essential, and doesn't imply any symmetry in solving it.

They first appeared in the UK in the Times, then the Torygraph, and I grew annoyed that the Grauniad (which we get) didn't have them, I was reduced to scrounging Times's from various places (notably CB1, where it is now traditional for Rob not to do them...). Then the Grauniad just a week ago succumbed, good, about time too, pity they had to ponce around with stuff about how theirs were human-generated hand hence much better (they are slightly different in style, but not clearly any better). Apparently they are even in the Sun, though presumably not the difficult versions :-).

And... they originate in Japan, land of mystic east (cue tinkly glasshopper type music). Except... I asked JA at EGU if he had ever seen one (he works in Japan) and... no, he never had.

I can do the fiendish ones now. Half an hour, on a good day.

More flexible and agile funding...

...and I'm sure you all know what *that* means! I don't pay much attention to NERC finances, and indeed didn't understand all that much of todays presentation, but it looks like the much-vaunted uplift to the science budget that the govt announced a year or so back has all melted away, to no-ones great surprise.

Meanwhile, we are still world leaders at renaming things, with SOC now called NOC, hurrah!

Do I sound bitter and cynical?


Talking to children

Back in March, I posted about a general-cl-ch talk I gave at Cafe Scientifique. After that, a student at Hills Road Six Form College (err, for non-UK folk, thats pre-university) invited me to give the talk there, which I finally did today, to an audience of 18 people (16-years-old-ish, I guess, and 2 teachers) at the "physics club" lunch time talk series.

This time, instead of a 10 minute talk that burst at the seams into a 15 minute talk, it was the same set of slides expanded to about 30-40 mins and 10 mins questions. And I was delighted with the questions, because they were far better, more interested, more aware than those from 70+ of the general public.

And those questions were... some discussion of THC collapse, aka "Day after tomorrow". Its fairly clear people are still keen on it as a concept, no matter how much I try to downplay it. Q: "didn't it happen in the past, 13 kyr ago?" (internal answer: well done, right date, you don't get that often): A: yes, but linked to the Laurentide ice sheet, that mechanism can't happen now. Q: "but what about glaciers in the Urals etc? Is that in the GCM runs?" A: snow in the Urals may be in there but glaciers too small to represent in GCMs; but then the amount of water from those sources is probably too small.

I explicitly mention impacts/politics at the end (largely to say: not my job guv; and trade-offs), so some Qs on that: "do economists try to value the environment?" to why my A: yes, papers in Nature etc, but its hard to do in a way that anyone will agree on (and there are at least 2 types of value: direct-econ-benefits that may not have been counted (e.g. water catchments), and pleasure-value (hiking in the hills)). Also Q: "but do your scenarios count the emissions from rapidly-industrialising India/China, and should/can we stop them?" A: yes the pessimistic ones do (I show the SRES range from the TAR SPM, I think); and how we end up with a vaguely equitable distribution of GHG emissions I don't know; tech transfer perhaps; obviously they are likely to want our material standard of wealth, but hopefully they don't want all the crap we've got: I don't want to give up decent dentistry or doctors, but they are welcome to the M11.

Q: "what about uncertainty/surprises (I'd talked briefly about the W Ant ice sheet collapse as an unquantifiable possible effect): shouldn't they be factored into the political calcs?". A: yes, but its tricky to see how to do that. A sane system would: in our insane system the major GHG emitter won't even accept the clear and obvious science, let alone the unknown bit (its all right, I didn't say "insane").

Global dimming got asked about (a hang-over from Horizon): see RC for that, which I parrotted. "Committed change" too: yes, about 0.6 oC according to the most recent Hansen et al. (See RC again).

So, a good session overall. My "public outreach" for the day, or PUS as we call it here (Public Understanding of Science).


Thermohaline collapses. Or not. Again.

People often pick up on the risk of future cooling over Northern Europe as a "paradoxical" consequence of global warming: most recently in the Times: Britain faces big chill as ocean current slows. I think that people get too enthusiastic about this, because of the exciting "paradoxical" features. One way to tell whether such reports are dodgy or not is by seeing if they reference "The Day After Tomorrow" without pointing out that the film was... just std.hollywoodjunk.

A little disclaimer here: all of this is outside my immeadiate professional expertise, so for these purposes I'm just an interested amateur.

My own view on this (and it was number 7 before) is that its all oversold; that a THC collapse is unlikely (based on the GCMs, of course: ...the probability of a THC shutdown is not high: in fact, it doesn't happen "by itself" in coupled models runs, you have to force it to happen; what you get is instead a slight slowdown and although there is a cooling tendency from the slowdown, the overall effect is warming, even over northern europe. The TAR, section Thermohaline circulation changes is good, as always... was what I said before); and even that the role of the gulf stream is over emphasised.

To take that last point on, try Is the Gulf Stream responsible for Europe’s mild winters? by Seager et al. in QJRMS (google "Seager gulf" if you want the pdf, and other interesting links). They say:

Is the transport of heat northward by the Gulf Stream and North Atlantic Drift, and its subsequent release into the midlatitude westerlies, the reason why Europe’s winters are so much milder than those of eastern North America and other places at the same latitude? Here, it is shown that the principal cause of this temperature difference is advection by the mean winds. South-westerlies bring warm maritime air into Europe and northwesterlies bring frigid continental air into north-eastern North America. Further, analysis of the ocean surface heat budget shows that the majority of the heat released during winter from the ocean to the atmosphere is accounted for by the seasonal release of heat previously absorbed and not by ocean heat-flux convergence. Therefore, the existence of the winter temperature contrast between western Europe and eastern North America does not require a dynamical ocean. Two experiments with an atmospheric general-circulation model coupled to an ocean mixed layer conŽfirm this conclusion. The difference in winter temperatures across the North Atlantic, and the difference between western Europe and western North America, is essentially the same in these models whether or not the movement of heat by the ocean is accounted for. In an additional experiment with no mountains, the flow across the ocean is more zonal, western Europe is cooled, the trough east of the Rockies is weakened and the cold of north-eastern North America is ameliorated. In all experiments the west coast of Europe is warmer than the west coast of North America at the same latitude whether or not ocean heat transport is accounted for. In summary the deviations from zonal symmetry of winter temperatures in the northern hemisphere are fundamentally caused by the atmospheric circulation interacting with the oceanic mixed layer.

Now, this isn't the end of the story, because "minor" effects like a 5 oC change can still come from changes in the ocean circ, and Robert Kunzig tells us:

Other scientists are surprisingly willing to concede much of Seager's challenge to the Gulf Stream myth. Michael Vellinga of the British Meteorology Office's Hadley Centre agrees that the currents do not warm Europe preferentially. But he and others emphasize that they do warm both sides of the Atlantic in winter, by roughly 5 degrees. Although Seager calls that a "modest" effect, it's more than the difference between today's climate and that of the Little Ice Age, from the 16th century to the 19th century, when both Europe and the United States endured many a rude winter. "If you switch [the currents] off, you get massive cooling," says Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research in Germany.

But shutting down the THC wouldn't shutdown the Gulf stream anyway, since its a Western Boundary Current driven by the winds in one of those odd mysteries of ocean dynamics.


Weasel words from Peisner

What a lot there is to write about at the moment...

So, the excitement is over at Deltoid: here, where the discussion of Peisners abstracts continues, with P trying to defend himself. His latest line is:

Even if there is disagreement about any of these papers, it is highly improbable that all 34 are ambiguous.

Which is appalling, though I think it now explains why he has so many dubious abstracts in there: he is trying to say, OK, so I was wrong about most of them, but is it likely that I was wrong about *all* of them? Ie, scattershotting as many as possible in the hope that something might stick.

He has also found the "missing" abstract, of which he sayeth:

The attached abstract includes a statement stressing that the "development of alternative, environmentally safer energy production technologies will benefit society whether or not global climate change actually occurs." I interpret this statement as a weak form of scepticism about what Oreskes defines as "consensus position".

Err... which is nonsense: see Deltoid for the full abstract. Peisner has thrown in the towel on Deltoid, without even trying to defend his choice of abstracts: very poor work. It was also pointed out to him over there why he got the wrong number of abstracts: he has failed to answer that, or to retract his now obviously false claim that Oreskes was wrong about the number.

Detecting anthro change

A little while ago (before Cmas?) there was excitement about a Barnett study, reported at a conference, showing detection of an anthro signal in the worlds oceans. A Barnett study is available (here; thanks HET) but since this is from 2001 its presumably an earlier one. Anyway, to quote:

Application of optimal detection methodology shows that the model-produced signals are indistinguishable from the observations at the 0.05 confidence level. Further, the chances of either the anthropogenic or observed signals being produced by the PCM as a result of natural, internal forcing alone are less than 5%. This suggests that the observed ocean heat-content changes are consistent with those expected from anthropogenic forcing, which broadens the basis for claims that an anthropogenic signal has been detected in the global climate system.

A more recent paper (again in Science, this time lead by Hansen (see his comments about political interference with his press releases here)) is commented on by RC (by Gavin, since he is a co-author).

The Hansen paper gets tagged with the tedious "smoking gun" idea again, which I have come to believe is just not sensible. John Fleck touches on the point here, and says most of what I mean, but not quite in the same words. What I think is now clear is that the evidence, objectively considered, for anthro climate change is now somewhere between incontrovertible and very strong. But, in certain quarters, this doesn't matter, because its not objectively considered. For these people, who very strongly *don't* want to be convinced, there may well never be a "smoking gun" - because the "gun" is always a complex matter of observations and modelling that needs patience to understand: and if you don't have or want this patience, there will always be a septic out there with simple, easy-to-understand (but wrong) arguments for why there is no problem. There are, after all, still people who can't accept things like relativity - and there isn't even any politics/money tied up in that.


More betting on climate. Or not, as the case may be.

Read Betting on Climate with Richard Lindzen by James Annan over at sci.env, containing the interesting Richard Lindzen's words say that there is about a 50% chance of cooling. His wallet thinks it is a 2% shot. Which do you believe? James really ought to get his own blog. Or at least post to the one he has sometimes :-)

Peisners 34 (33) abstracts

Peisners consensus-busting abstracts are now on display at Deltoid and... no, they aren't convincing. Some of them are so obviously not that including them is surreal.

He seems to have included things just because of the word "uncertainty"; or "testing models", or... well, I don't know. Lets look at one of them:

24. Regional climate change: Trend analysis of temperature and precipitation series at selected Canadian sites Clark JS, Yiridoe EK, Burns ND, Astatkie T Canadian Journal of Agricultural Economics-Revue Canadienne d Agroeconomie 48 (1): 27-38 Mar 2000
Abstract: Global climate change does not necessarily imply that temperature or precipitation is increasing at specific locations. The hypothesis of increasing temperature and precipitation trends associated with global climate change is tested using actual annual temperature and precipitation data for nine selected weather stations, spatially distributed across Canada. Vogelsang’s (1998) partial sum and Woodward et al’s (1997) bootstrap methods are used for testing for trend Both methods suggest no warming in the Canadian temperature series except for Toronto, Ontario, which had significant increase over time, along with Moncton, New Brunswick and Indian Head, Saskatchewan, which had marginal increases. There is no evidence of increasing trend in precipitation except for Moncton, New Brunswick, which had a significantly increasing trend, thus, public policies designed to address the regional effects of climate change need to be adapted for a particular ecological zone, based on knowledge of the climate trends for that region, rather than on general global climate change patterns.

Why is this in there as rejecting or doubting the consensus? There are many others of the same ilk.


Consensus, again

I'm going to do an EGU wrap-up post when I have a moment; in the mean time the Oreskes study is back in the news, since Peisner is challenging it. Both Tim Lambert and Chris Mooney have the details and links (actually TL's post is mostly about the Bray survey, but also includes some P stuff). TL is currently winning the whose-blog-should-we-post-comments-on war :-)

My contribution is (a) to say that the easiest way to settle this is to check the 34 abstracts that Peisner says contradict the consensus, and (b) my bet is that when (if) he reveals this list, most people will agree that he has miscategorised most/all of them. I suppose I could add (c) all the evidence from EGU is that Oreskes was right.