climate science
stoat | May 10, 2007There is a fairly weird paper entitled Suggestive correlations between the brightness of Neptune, solar variability, and Earth's temperature by Hammel and Lockwood. Why is it weird? Various reasons, which I'll try to explain here as best I can, but it really needs someone who knows more about it. These are more notes in case anyone out there feels interested to look.
First off, none of their correlations are significant, a fact which does rather disappoint them: Although correlations between Neptune's brightness and Earth's temperature anomaly--and between Neptune and two models of solar…
stoat | May 9, 2007An interesting pointre TGGWS comes my way:
We have concerns regarding the use of a graph featured in the documentary
titled "Temp & Solar Activity 400 Years". Firstly, we have reason to
believe that parts of the graph were made up of fabricated data that were
presented as genuine. The inclusion of the artificial data is both
misleading and pointless. Secondly, although the narrator commentary
during the presentation of the graph is consistent with the conclusions of
the paper from which the figure originates, it incorrectly rules out a
contribution by anthropogenic greenhouse gases to…
stoat | May 2, 2007JF points out Arctic Ice Retreating More Quickly Than Computer Models Project, which says "Arctic sea ice is melting at a significantly faster rate than projected by even the most advanced computer models... the Arctic's ice cover is retreating more rapidly than estimated by any of the 18 computer models used by the Intergovernmental Panel on Climate Change (IPCC) in preparing its 2007 assessments". Its here if you have access.
Of course the question is what does this mean? The press release goes for "This suggests that current model projections may in fact provide a conservative estimate of…
stoat | April 30, 2007Unless I haven't been paying attention, the mighty Madhav Khandekar's "Questioning the Global Warming Science: An Annotated bibliography of recent peer-reviewed papers" has been met with total indifference. Until now... Its supposed (I think) to be a sort of Peiser-done-properly.
He saith: "a large number of studies questioning the GW science have appeared in peer-reviewed International scientific Journals" and "This Document presents an annotated bibliography of selected peer reviewed papers which question the current state of the GW science." So we'd better start at the beginning, "1.…
stoat | April 24, 2007While I still have a possible bet in the pipeline, Brian Schmidt now has a real bet lined up for a total of $6-$9k. Personally I think that 0.15 oC/decade is more likely than not, but that less is a realistic possiblity given natural variablity. So while its good from an expected return view it could potentially be bad from a PR view. I wonder how important the latter is... probably not very, in 10 years time.
Brian has a spread of bets across 10, 15 and 20 years which is an interesting way of doing things. I'm still looking forward to making big money (a-la James :-) when a real market for…
stoat | April 19, 2007 Thin day today, and anyway my plane leaves at half five. Some friends are off to see Mozarts grave but I opt for a sit in the cafe in front of th Dom. The pic follows in the tradiation established last year and shows Me relfected in Something; in this case the entrance to the Albertina. Which is OK but not up to the kunstmuseum.
I shall follow that up with a lunchtime session on Insurance and Climate in the hope that it might be interesting, and a little bit of Feedbacks this afternoon.
stoat | April 18, 2007Rowan Sutton: on the amplification of warming over land. That the land warms more than the oceans is well know; but as RS points out the *why* is somewhat less well known. I would have said, unthinkingly, its because of the ocean heat capacity. But... you get the same effect (or similar) in equilibrium runs so its not that, or not all that. He says its because the oceans are wet and so can lose heat through evap, which is harder for the drier land, and this seems likely. Its interesting how well-known-things like this turn out not to have been much investigated.
Some talk of precipitation and…
stoat | April 17, 2007RP Sr has been pushing his favourite climate change metric - ocean temperatures - and hyping one paper - Lyman et al, that appeared to show a cooling in that metric. It seemed to me rather imprudent to do this based on one untested paper; now unexpected support comes from Lyman et al themselves who have discovered biases in their data. So... RPs argument collapses. This is rather reminiscent of the "lets use the MSU" crowd, who touted its suerior reliability over the sfc record, before discovering - oops - that their favourite Spencer+Christy version was wrong.
Also rather amusingly, RP used…
stoat | April 17, 2007Its EGU time again. Monday was a bit of a blur (technically I got to my hotel on monday, about half past midnight. Travelling Air Austria is a lot more pleasant than RyanAir, though).
Tuesday was better, partly because I gave up on the stupid "personal programme" stuff the site lets you build on-line and simply got one of the huge book-blocks of sessions.
Morning: global dimming/brightening. More stuff pretty well confirming the old: that GD masked increasing GHG forcing up till 1980 ish; and we've seen "brightening" since then (e.g. Wild). nb the conf search engine is here.
Ray Bradley…
stoat | April 5, 200710Be evidence for the Matuyama-Brunhes geomagnetic reversal in the EPICA Dome C ice core slipped by me when it was published last year (Nature 444, 82-84 (2 November 2006)). If they are correct, then its nice for the ice core folk because it provides an absolute tie-point into the marine records. Its also interesting for the rest of us, because of the potential connection to the clouds-solar stuff: together with the 41 kyr "event" it provides some test as to whether cosmis rays do affect climate.
If you look at cosmocr*pology, you'll notice (somewhat buried in the S "paper") some handwaving…
stoat | April 4, 2007"The warming of other solar bodies has been seized upon by climate sceptics; but oh how wrong they are, says Oliver Morton". But then he is writing in that dodgy rag Nature, so what does he know? "If the shooting of fish in barrels offends you, look away. The publication this week of a Nature paper on global warming on Mars offers a fantastic opportunity to kill off one of the silliest climate-sceptic arguments, and I'm more than happy to be pointing the gun at the water. The sceptical 'argument' -- using the word loosely -- in question is that global warming on Earth should be seen as a…
stoat | April 1, 2007Nature has Climate sensitivity constrained by CO2 concentrations over the past 420 million years (subs req, of course). Its interesting for two reasons: firstly as yet another way of getting the same range for climate sensitivity (they get 2.8 oC as a best guess). And secondly as an antidote to the septics who assert no correlation of CO2 and T over geological time. Not that the match presented here is perfect, but it does exist.
[Update: FP has a link+pix for those without direct nature access -W]
stoat | April 1, 2007CarbonTracker is cute (though poss not as much as CarboTracker, which google suggested I might have meant. I wonder how long the explicit "What does CarbonTracker tell us? North America is a source of CO2 to the atmosphere. The natural uptake of CO2 that occurs mostly East of the Rocky Mountains removes only ~30% of the CO2 released by the use of fossil fuels" will stay so prominent.
stoat | March 28, 2007 Following my previous post there has been discussion in the comments on "which graph to believe". Sadly this becomes ideological, for some. I think the major point is that the HPS '97 graph (the one here) just isn't used anymore by anyone, except the septics who want to see a MWP. The graph has never been explicitly disowned, but the authors of it have published plenty more since then, all only going back 500 years (and AFAIK no-one else before or since has tried to use boreholes back that far), and showing a different timing of the cold bit. Naturally, if you're paranoid, this is because…
stoat | March 24, 2007
In 1998, there appears Climate Change Record in Subsurface Temperatures: A Global Perspective (Science 9 October 1998: 279-281) (subs req: sorry; abstract probably free) by Henry N. Pollack, Shaopeng Huang, Po-Yu Shen. The take-home message from that paper is pretty much the graph from http://www.ncdc.noaa.gov/paleo/borehole/core.html, which I'll inline here (and its the same as used in the TAR). And that is: a 500y record, showing a temperature rise in line with the instrumental record where they overlap (and somewhat colder than most other reconstructions around 1500; but thats not the…
stoat | March 13, 2007OK, so we're back to the question of whether T leads CO2 in the ice cores, the skepics favourite talking point. The std.answer is "OK, so there is a lead (maybe) but..." (Stoat passim). The "but" is a good enough answer, and I suspect most people skip over the (maybe). But its important, because the lag/lead is not at all easy to establish, because the T comes from the ice (via d-o-18 proxy) and the CO2 comes from the bubbles. 800y+/-600 is the current "best guess", but not certain.
Thanks to GH for pointing out Loulergue et al. [Meh, dead link. Try http://www.clim-past.net/3/527/2007/cp-3-…
stoat | March 12, 2007Guest posting by (or rather, ripped from) Eric Wolff.
It is indeed a very fundamental question about whether the CO2 leads or lags the temperature. If there was somewhere in the ice core record where CO2 increases and temperature does not, then our understanding of the greenhouse effect must be faulty. However, so far we don't find such a place. [*]
[*] Eric is a scientist, not a lawyer. His words, whilst essentially still valid, were not carefully enough framed. He writes (2012/4): I should have carefully included the words "all othe things being equal" and "significantly" as in: "If there…
stoat | March 10, 2007Well thats what RP Sr sez. Although he immeadiately gets cold feet and adds "Or, At Best Cherrypicking". I think he should make up his mind - if he is going to throw around a rather hard term like "errors" in the title he shouldn't wimp out to "or at best..." a moment later.
So, first off, does he find any errors? No, of course not. None of the 4 things he lists are wrong. And the person cherry picking appears to be RP.
The first one is about "... snow cover have declined on average in both hemispheres." Which of course it has (fig SPM-3). Or, if you prefer, the graph RP directs you to. His…
stoat | March 10, 2007Its evident that some people are still confused by the T/CO2 relationship, so I'll have another go in fairly simple terms.
Let me start with the "official" position, if you like. There are two cases: the current one, where we're pumping out CO2; and the ice age one, where CO2 varies naturally. There is no reason to expect them to have the same timescales.
In the first case, we know that CO2 is going up quickly - on geological scales, its going up vertically (see inline from wiki). This is then expected (basic physics, simple and GCM models) to lead to T increases more-or-less immeadiately -…
stoat | March 9, 2007 Thanks to BG, we have a screen capture of the solar graph from the silly "Swindle" prog; I've inlined it. Now this is nice, because it says S+C as source. Which means we can look-up the ever useful Damon and Laut. First off, notice that the data plotted *isn't* solar variation directly, but an index of solar cycle length. There was speculation that it might be related to solar variation, but this was never clear. Now notice that the solar graph stops in 1980. Why could that be? Look at D+L's figure 1c: when the correct data is used, the upturn after 1980 disappears and the correlation with…