climate science
stoat | April 3, 2008Well, we knew that anyway, but there is some more stuff out on it, says the BBC: The Svensmark hypothesis is that when the solar wind is weak, more cosmic rays penetrate to Earth. That creates more charged particles in the atmosphere, which in turn induces more clouds to form, cooling the climate.
The solar folk tend to take this on a long term basis, which is fraught with problems because the cloud obs aren't good over those scales due to inter-satellite calibration etc etc. But Sloan et al. seem to have decided to take Svensmark seriously (which most people don't :-) and look to see if…
stoat | March 30, 2008Or nearly does, at least. It seems that the Wilkins ice shelf is hanging by a thread and bits are falling off. You'll have to forgive me for being late with this news, as I've been off in the Real World for a week or so, with only intermittent internet connections. The paper world seems to have ignored the story, which will have annoyed BAS's PR department. But there isn't all that much to it.
The Antarctic peninsula is warming, and we know that because we have thermometers that tell us so. Having ice shelves break off every now and again provides good visual appeal.
As BAS says in 1993 [DV]…
stoat | March 15, 2008Whether its post-IPCC-AR4 fatigue, or a foolish Michaelson-like assumption that we just about know whats going on, but things seem to be rather quiet on the climate front, in terms of real news and results.
Which leaves people footling around for something to talk about, and temperature trends over the past decade, or since 2001 seem to have become a favourite. Climate refuses to behave itself, and insists on having natural variability imposing on longer term trends, which means you can get almost any result you like if you pick your time period. Atmoz has looked at this a bit, but if you…
stoat | January 26, 2008Well, he says so himself: This is probably the most provocative hypothesis I have ever (and will ever) advance: The long-term increases in carbon dioxide concentration that have been observed at Mauna Loa since 1958 could be driven more than by the ocean than by mankind's burning of fossil fuels. Most, if not all, experts in the global carbon cycle will at this point think I am totally off my rocker. Hmm, this pic applies (it can't be rude, its Egyptian :-).
This isn't an interesting idea, or a procovative hypothesis, its just w*nky (don't worry, that link isn't rude). Why? Well, you can try…
stoat | January 24, 2008I've been putting off collating all the misc bets that came in. But here we go:
$333 (ie about 3p :-() against Joe Romm on an ice-free Arctic by 2020. P Farrington-Douglas, E200, same terms.
On next years Arctic sea ice being larger than this years record minimum: Nick Barnes, £10; Gareth, £20; Eli, £10 + 40 carrots; Steve Bloom, £20; Phil Hays, £10. And Raymond Arritt offers an indeterminate amount of beer. $100, Benjamin Franz.
Did I miss anyone? And is anyone else interested? - the book isn't shut yet.
stoat | January 16, 2008Why is climate modelling stuck? asked mt, and Bryan weighs in too. So I don't see why I shouldn't too. This is no kind of comprehensive list or manifesto, the way mt's is. Just some random thoughts.
First of all, there are too many GCMs, and some of them are cr*p, so much so that they should simply be thrown away. I suspect that certain countries simply built them because they wanted "their" model to appear in the IPCC reports. There are 20+ coupled GCMs in IPCC, and we don't need that many. I don't know how many we need - certainly more than one. In fact, I rather suspect that of the total…
stoat | January 5, 2008People constantly get polar amplification wrong. The most obvious mistake is to assume it applies equally at both poles. It doesn't in both models and observations: there is far more warming in the Arctic (at present, and expected in the future. This picture is somewhat complicated if you look back to, say, the last glacial, where climate change was amplified at both poles; but thats because it was for long timescales, hence the stabalising effect of the Southern Ocean doesn't apply (e.g. this RC post)).
But they also get the mechanisms wrong, too.
Hence, as OM points out in Natures blog, the…
stoat | December 12, 2007"Convection in the Antarctic Ice Sheet Leading to a Surge of the Ice Sheet and Possibly to a New Ice Age" is a 1970's Science paper by Hughes. Its all superceeded stuff now - the idea that the ice might (very very slowly) convect was current once, but no more (or else the cores wouldn't work very well :-).
The abstract is: The Antarctic surge theory of Pleistocene glaciation is reexamined in the context of thermal convection theory applied to the Antarctic ice sheet. The ice sheet surges when a water layer at the base of the ice sheet reaches the edge of the ice sheet over broad fronts and…
stoat | December 11, 2007Everyone has their own spin on things, but its still not nice to be misrepresented, especially in support of someone elses agenda. RP Sr would like the 2003 heat wave to be unrelated to GW. It may well be; it was such an exceptional event that it would remain outside the stats even if you factor in GW. Rather than looking at sfc T, which seems to be the natural thing to do, Chase et al (inc RP) looked at 1000-500 hPa depth, which is a broad measure of temperature in this layer. They find that by this measure that 2003 in Europe wasn't exceptional: similar anomalies have occurred elsewhere. I…
stoat | December 10, 2007The issue of reconciling tropical temperature trends at the sfc and in the troposphere rumbles on, although in a not very serious way: its a good subject for research, but it doesn't seem to be a major septic playing point, probably because the issue is too complex to get much traction.
A brief recap: once upon a time the satellites said the trop, globally, wasn't warming. That disappeared ages ago. We're now looking only at the tropics, which are warming too, and the remaining issue is whether the trop warming is compatible with the surface warming. Models and (we believe) basic physics says…
stoat | December 5, 2007Those anxiously awaiting my detailed reply to RP's reply to my reply to RP's attack on the IPCC are doomed to disappointment. I'm afraid its fallen into the lifes-too-short category.
In summary: RP has forgotten the T^4 radiative feedback; and the IPCC figure is a difference from 1750.
Now, who to vote for, or against?
stoat | December 2, 2007Enough mawkish maudlin sentiment. Time to jump on the wackos again. This time its UnSciAm, who are foolish enough to publish a letter from Singer without fact-checking it first (I don't think you can blame Singer for getting his facts wrong, since thats the entire point). You can (and I do) blame SciAm for not checking first. Its not as if the data is obscure or hard to find or anything.
Singer claims "the models predict that temperature trends will increase with altitude by 200 to 300 percent" (and then goes on to say "the data from both weather balloons and satellites show the opposite";…
stoat | November 30, 2007RP Sr's one-man kamikaze attack against the IPCC continues. RPs point appears to be that the IPCCs forcing-since-1750 of +1.6 W/m2 is not compatible with a current imbalance of about 0.85 W/m2. Sadly RPs link to the Hansen paper concerned is currently broken so I'm somewhat guessing what this figure is; I think its probably the earths current radiative imbalance. RP calls it the "the total observed radiative forcing and feedback" but I think he's got this wrong. If it was, it would need to have a start date on it; and since its based on deep ocean temps it would be tricky to start from 1750.…
stoat | November 28, 2007RP Sr sez: "We have shown in several studies that the downscaling of multi-year global model predictions by regional climate models is very strongly dependent on the lateral boundary conditions of the parent model". Good grief, really? Well you'd hope so, wouldn't you, since thats exactly what is supposed to happen.
It looks like rumours of RPs blog retirement have been greatly exaggerrated, though alas he is following in Pat Michaels footsteps by not allowing comments. And if you're going to talk tosh like my quote from him above, thats a very good idea indeed.
And we all love pre-…
stoat | November 26, 2007When I was a wee mustelid, I wrote about this; and there is an RC piece, and as far as I know, its all still valid.
But this post is aimed at those who put an "s" into poles in "What exactly is the mechanism that causes the poles to warm faster than the tropics as a result of climate change?" when they mean the real world, as opposed to a simplified or equilibrium one. Mind you, since the ar4 sez Models of the 21st century project that future warming is amplified at high latitudes resulting from positive feedbacks involving snow and sea ice, and other processes (10.3.3.1) you can hardly blame…
stoat | November 23, 2007Thaas outrageous, big Mammy refers. We had it as our journal club today, and the outcome was, no-one thought Hansen had done a convincing job.
The paper itself is confusing ("like being inside Hansens head", as someone put it) and its not clear what its really supposed to be about. My pdf attempts to understand it. The only slide that won't make sense is the last one; the 3-models-pic is number of AR4 models in the sresa1b scenario with sfc temperature in January above -5 oC. The conclusion of that (and other opinions in the room) is that substantial sfc albedo change is unlikely.
[Update:…
stoat | November 21, 2007So, the question was, how much effect does removing the Arctic sea ice make to the rest of the world? In particular, what is the direct effect, ignoring all the feedbacks that would occur on SST and so on? Happily, an atmosphere-only GCM can answer this question, and happily I had one to hand, viz HadAM3.
Happily also it runs fairly fast nowadays - about 20 years/day on 8 opterons - so here are results from 12 years of run, compared to 50 years of control run. The difference between the two is that I've wiped out the Arctic sea ice (in all seasons). It gets replaced with sea at (I'd guess) -1…
stoat | November 20, 2007I have got complained at for responding to "The impact on the stability of the Greenland ice sheet as well as on global weather patterns would likely be nearly unimaginable" with "...as for the impact on the weather, there is no reason to suppose any problem." This in the context of the recent loss of Arctic sea ice. So maybe its worth discussing a bit.
The refs for this are the press release containing a pretty pic that is a bit misleading; the Stroeve et al paper that started it; and my somewhat dismissive take.
Stoeve et al get obs trends (for September, ie ice minimum - no-one is…
stoat | November 9, 2007A pointer to The Real Truth About the Revelle-Gore Story because I came across refs to this just recently... where?
Oops, sorry, Eli did it ages ago. Good.
stoat | November 8, 2007Wild excitement, and local at that: A tidal surge in the North Sea has sparked severe flood warnings and evacuations on England's east coast. We shall see.
[Update: it was a bust -W]