A quick post for commentary on the new Solomon et al paper in Science express. We’ll try and get around to discussing this over the weekend, but in the meantime I’ve moved some comments over. There is some commentary on this at DotEarth, and some media reports on the story – some good, some not so good. It seems like a topic that is ripe for confusion, and so here are a few quick clarifications that are worth making.
First of all, this is a paper about internal variability of the climate system in the last decade, not on additional factors that drive climate. Second, this is a discussion about stratospheric water vapour (10 to 15 km above the surface), not water vapour in general. Stratospheric water vapour comes from two sources – the uplift of tropospheric water through the very cold tropical tropopause (both as vapour and as condensate), and the oxidation of methane in the upper stratosphere (CH4+2O2 –> CO2 + 2H2O NB: this is just a schematic, the actual chemical pathways are more complicated). There isn’t very much of it (between 3 and 6 ppmv), and so small changes (~0.5 ppmv) are noticeable.
The decreases seen in this study are in the lower stratosphere and are likely dominated by a change in the flux of water through the tropopause. A change in stratospheric water vapour because of the increase in methane over the industrial period would be a forcing of the climate (and is one of the indirect effects of methane we discussed last year), but a change in the tropopause flux is a response to other factors in the climate system. These might include El Nino/La Nina events, increases in Asian aerosols, or solar impacts on near-tropopause ozone – but this is not addressed in the paper and will take a little more work to figure out.
Update: This last paragraph was probably not as clear as it should be. If the lower stratospheric water vapour (LSWV) is relaxing back to some norm after the 1997/1998 El Nino, then what we are seeing would be internal variability in the system which might have some implications for feedbacks to increasing GHGs, and my estimate of that would be that this would be an amplifying feedback (warmer SSTs leading to more LSWV). If we are seeing changes to the tropopause temperatures as an indirect impact from increased Asian aerosol emissions or solar-driven ozone changes, then this might be better thought of as impacting the efficacy of those forcings rather than implying some sensitivity change.
The study includes an estimate of the effect of the observed stratospheric water decadal decrease by calculating the radiation flux with and without the change, and comparing this to the increase in CO2 forcing over the same period. This implicitly assumes that the change can be regarded as a forcing. However, whether that is an appropriate calculation or not needs some careful consideration. Finally, no-one has yet looked at whether climate models (which have plenty of decadal variability too) have phenomena that resemble these observations that might provide some insight into the causes.
Matthew, check into sources you rely on; as an example
http://www.google.com/search?q=appinsys+wilkinson
Get an idea of their agenda; don’t rely on secondary sites, go to the original science.
BPL –
{3 February 2010 at 6:14 AM
Vendicar,
That reminds me of another quote:
“Science makes everything sound painful, Spongebob!”
–Sandy Paws}
Now there’s a real scientist!
Thanx for the quote, it help to start my day off in the right mood.
And thanx to all who take the time to answer my queries, believe me, they are much appreciated.
CFU – I’ll see if I archived that statement, to see if I did indeed misinterpret it.
Off to work now, have a great day all!
RE: 290
Hey Barton,
Here in is a link to the last NCEP chart that the nomads server at ncdc provided. ( http://nomads.ncdc.noaa.gov/ncep-charts/hires/20091231/gdas.200.hgt.iso.nh.anl.00.20091231.gif )
I have been able to tweak the Systems Admin./Web Master for the last three years and get the Year field updated to the current year in the search window. This past year however, it appears that there is no longer any systems funding available to continue to support the system and it is no longer being maintained.
For me and my short stint at Elon University it has provided a great insight to the atmospheric processes. I have been able to watch the development of pressure waves at high altitudes and see them develop towards the ground. (The light green wave found in the former 250 mb isotach stn and now the 200 mb isotach stn apparently is a representation of the northern Jet Stream.)
When I couple the NOAA ENSO and NAO forecasts with the NH analysis the wealth of knowledge you can obtain by the visualization out strips any table or charting of the data set I had ever seen before in the last 40 years. However, times change as do the funding organizations so like most things eventually a wonderful resource must be retired. I would be very interested in seeing the results of your modeling.
The main point is when I tied the above data set into the Water Vapor data I was observing at the Unidata site on UCAR ( http://www.unidata.ucar.edu/data/suominet/loop/loop2/suomi_ani_zoom.html ) the ideas I have shared earlier quickly came into focus.
Well I think I had better cut this short, I know there are others that have their own ignorance to flout. I am just glad for the opportunity to share mine with the more tolerant technical team here then we first saw on the climate change Yahoo message boards a decade ago…
Cheers!
Dave Cooke
Re Comment by Didactylos — 3 February 2010 @ 8:55 AM:
“(It doesn’t help that so many weather forecasters keep their models proprietary.)”
Gasp!
Steve
Leo: “CFU – I’ll see if I archived that statement, to see if I did indeed misinterpret it.”
Check how Hank read the 70%, which may have been actually the reporter.
The problems with many take-away points in modern news reporting that relies on soundbytes is that you’re missing what the reporter means.
I.e. did that 70% mean 70% of the 40% or 70% of whatever part of the 40% is drought ridden (as opposed to desert)? Did that reporter add 40% to 28% and get 68% which is 70% “or good enough for government^W news reports”?
“297
Didactylos says:
3 February 2010 at 9:02 AM
BPL:
It is a little simplistic to attribute all drought to climate change.”
However, it won’t help, will it. Overall, it will get worse. Unless higher temperatures destroy deserts…
“294
Chris Dudley says:
3 February 2010 at 7:38 AM
#280,
Your explanation is not correct.”
Chris, it wasn’t an explanation of how venus was hot.
It was a possible way that someone could get “Venus is hot” and “High pressures at the surface of Venus” to mean “Venus is hot because of high surface pressure”.
This is a cart-before-horse problem because as you and others have mentioned, such heat is lost and therefore pressure by itself cannot cause high temperatures.
But high temperatures at the surface can cause high pressures, if the gas is dense.
T is big. P then big.
Whereas the report was P is big then T big.
“entire blogs dedicated to blog comments that were too stupid to be allowed. I mean, isn’t that about the saddest thing you’ve ever read?”
I don’t know about all of you, but I only post about half of what I write, consigning the rest to the void of “not worth saying”. RC has enough of a signal to noise problem as it is….. says me, adding to the noise.
Few posts are so great that they don’t benefit from a second look before clicking “Submit”.
BPL and others: Re: The Palmer Drought Severity Index (PDSI). I guess it’s beauty is that past PDSI’s can be calculated based on historic rainfall and temperature data. However, I’ve used it for years along with water level measurements in shallow basins and it’s definitely a blunt instrument. A much better indicator of drought or changing rainfall patters in my opinion is low flow stream volume. Not total volume where massive flooding can compensate for long dry periods, but base flow or summer flow or some other measure of low flow. For example: a graph of the days of a year where no flow or only base flow is present on the y-axis and year on the x-axis is enlightening. Of course irrigation and withdrawals need to be considered. I have found that gages on small streams without significant base flow is a good measure of what’s going on with local rainfall patterns. It’s all about finding the right stream and the right gage site.
Re #283: Barton, I find it very hard to believe 30 years of global warming has caused an 18% increase in the “dry” area of the Earth, using any reasonable measure. This implies a “drought sensitivity” of around 40% per degree of warming. Extrapolating this backwards is absurd; did deserts almost disappear during the Little Ice Age? Extrapolating forward is no better, the reconstructions of the Pliocene that I have seen, when it was about 3 degrees warmer, show an increase in vegetated area, not a decrease.
I suspect that internal climate variation noise is being measured (is the 1970 date cherry picked?), but I do not have access to the Dai paper. The Battisti paper is about high temperatures affecting crops, not drought, so it is not relevant to this question.
I try to follow the mods’ lead in keeping the discussion focus. But comments about RC post deletion/mutilation have kept appearing meaning they are being let through. Therefore…
I posted here earlier on this thread. Again, nothing abusive, certiainly not as bad as some material that has already appeared on this thread.
That post has gone down a memory-hole. It has not appeared here at all.
Doug:
You declared unilaterally that there is no supression of posts, implying a certain open culture. Yet Gavin says we’re supposed to be at a dinner party of sorts. There is obviously a disconnect. I have a lot of little rocks in my pocket now. :)
CFU, Ray and the others: You can understand why I have suddenly lost motivation to post on this forum now. Any user can reply to comments or ignore them and be in a discussion, but post discussion is something I have no control over and personally find very distateful.
Thanks for your time
And stop asking for climate money :)
Anand
L. David Cooke says: 3 February 2010 at 11:33 AM
“Here in is a link to the last NCEP chart that the nomads server at ncdc provided. ( http://nomads.ncdc.noaa.gov/ncep-charts/hires/20091231/gdas.200.hgt.iso.nh.anl.00.20091231.gif )
I have been able to tweak the Systems Admin./Web Master for the last three years and get the Year field updated to the current year in the search window. This past year however, it appears that there is no longer any systems funding available to continue to support the system and it is no longer being maintained.”
Well that just helped partially ruin my day. Talk about “for lack of a nail”; here’s data already being gathered, automatically processed for peanuts, but we can’t look at it because the interface is expired?
Arrrgh. We are just so screwed. FYVM, “Club for Growth”.
Sorry “post discussion is something I have no control over…”
should read
“post deletion is something I have no control over…”
CFU said: “Overall, it will get worse.”
Again, not particularly accurate. Precipitation changes mean that while some regions will suffer severe drought, others will get more water. Think a little about why the regions experiencing drought are significant in terms of human suffering.
You insist on using black and white, when reality is much more nuanced.
Few people ever seem to refer to the AR4 WG1 report which forms the scientific basis for all the AGW hysteria.. The key section is 8.6 which deals with the forcings and feedbacks and climate sensitivity.After reviewing water vapour and cloud cover the conclusion is as follows ” Moreover it is not yet clear which tests are critical for constraining future projections. Consequently a set of model metrics that might be used to narrow the range of plausible climate change feedbacks and climate sensitivity has yet to be developed.”
No sceptic would disagree with that perfectly good statement which clearly means that future temperatures cannot be predicted and all the forecasts of CO2 caused disaster are merely speculation with no scientific base. How this conclusion became distorted in the other sections of AR4 and the Policy Summary and was taken up by the Western politicians and chattering classes in the great anti CO2 crusade would form an interesting study of mass manipulation and delusion.
#307,
No, you are not getting it. The pressure is fixed by the mass of the atmosphere (and the gravity of the planet). The thing that changes in response to temperature in a non-condensing atmosphere is the scale height, how puffed up the atmosphere is.
In other words, the pressure at the surface is set by hydrostatic equilibrium and it cannot change so long as the mass of the atmosphere is conserved.
#292 CFU
I’m always ready to update in the face of new solid or well reasoned evidence :)
Justice is a dish best served with cold beer and good friends:
http://voices.kansascity.com/node/7482
http://www.nytimes.com/2010/02/04/science/earth/04climate.html
Hank Roberts, if that information was incorrect, and you didn’t say it was, link to better information. Everybody has an agenda, even scientists and peer-reviewers.
I assume this may address a relatively small portion of Trenberth’s comments about not knowing why the models don’t agree with the current lack of increase in temperature? During the era of measured temperatures, warming has been occurring since about 1970, but not in the last 10 years, right? So, we have 30 years of warming followed by 10 years with no clear warming pattern. In most fields of research, a data set in which 1/4 of the data do not fit the expected trend or in which the trend occurred at 3 time points but not at the 4th would be regarded as inadequate to make any predictions about future trends. Why is this regarded as sufficient in climate science, or is it?
Orbiting Carbon Observatory (atomized in launch failure) to be replaced. Yay!
News:
http://www.spaceflightnow.com/news/n1002/03smdbudget/
283 Barton Paul Levenson, thanks very much for the cite, I didn’t doubt your statement, I just like to have concrete sources. :)
283 Barton Paul Levenson: Great post! Do you have a URL for that 9th UN report? Published Where by Jim on Monday? A URL for that is exactly what we need. I’m forwarding your post to my US senators.
This is OT, but was posted at CA, posting it here in case CA decides to delete:
“this was posted at CA @ 12:29 am:
Mr. McIntyre,
Were you one of the complainants against Mann? If so, could we please see the correspondence that you sent to Penn State? Thanks.
So one can conclude that you would have no reservations with someone using FIPPA to see all your UofT emails (sent and received and cc’d and deleted) that may make reference to CA, Mann, CRU, CanWest, David Rose, Friends of Science, Tom Harris, IPCC etc.? Just to make sure that you are on the up and up; of course you are probably clean, just as Mann is, but people are asking questions. Same goes for your colleague McKitrick. The results of all such investigations should be made publically available, including transcripts of all interviews with you and Ross, should it come to that.
Given the important nature of your work here at CA, people have the right to see unequivocal proof that you were telling the truth when you stated that “Everyhting that I’ve [SteveM] done in this, I’ve done in good faith”.
With those important details out of the way, you and Mann could then return to advancing the science.”
OT admittedly but I am miffed that Greenpeace decides to call for Pachauri’s resignation at a time when we need solidarity. He may not be the best Chair for IPCC but he’s what we have got for now.
To point on Venus – CO2 thermal runaway amply demonstrated there. Need we have a better example?
If Sponge Bob was a Republican Speech writer who had close ties with high Republican office, I’d be equally concerned.
That reminds me of another quote:
“Science makes everything sound painful, Spongebob!”
–Sandy Paws
Original quote
“Science leads you to killing people.” – Ben Stein – Republican Speech Writer.
Thanks for the responses to my #279. UEA has a response worth reading (found via Deltoid).
“In most fields of research, a data set in which 1/4 of the data do not fit the expected trend or in which the trend occurred at 3 time points but not at the 4th would be regarded as inadequate to make any predictions about future trends. Why is this regarded as sufficient in climate science, or is it?”
Because the expected trend is still not voided.
You need longer than 10 years.
Here’s a “trick” for you to try on the data.
Remove the 1998 figure.
Then interpolate the two years either side to refill the gap.
Now have a look at the trend.
Your “missing on 1/4 of the data” is absolutely false and, if you’re not trolling, is merely an artefact of your pattern seeking brain.
Because taking that one year out (as denialists were parroting on about in 1999 when the record breaking year could have been used to “prove” AGW, you can’t use the 1998 figure to determine the change in climate) changes your pattern.
Rather than being 1/4 the data, it’s one year’s data out of 150.
“314
Didactylos says:
3 February 2010 at 1:32 PM
CFU said: “Overall, it will get worse.”
Again, not particularly accurate. ”
You didn’t say it was wrong either. Probably because it wasn’t.
And therefore YOUR “not particularly accurate” isn’t really particularly accurate itself.
Re 315: Norman Page, you are creating a false dichotomy between 100% certainty about the role of water vapor and clouds, which of course does not exist, and the alternative that we therefore know absolutely nothing. Future temperature and climate cannot be perfectly predicted, but adding carbon dioxide to the atmosphere creates a known and significant increase in heat added to the Earth system. Sure, people make unsupported claims of environmental disaster with false certainty, in fact I am challenging such a claim in 310. But it does not follow that we can keep adding CO2 with no effects on climate.
It’s a strawman. Climate science has never said that CO2-forced warming would lead to monotonically increasing temperatures suddenly absent of the kind of natural variation that has been observed in the past. Climate science has never said that CO2 in the earth’s atmosphere would suddenly cause variations in solar output to suddenly cease. Or ENSO to disappear. Etc.
All you need to do is to look at a graph of global temps over the last century. You’ll see there’s nothing unusual about the last decade (other than its being the warmest on record).
Re #320: Such a qualitative statement often leads man false. Suppose the simple function y(t)= at + sin t. You can easily find the 50% increaseing period and 50% decreasing period when 0<a<1 although y(t) has a increasing trend.
# 320: Such a statement does not make sense. Suppose a simple function y(t)= at +sin t (0<a<1). You can easily find 50% increasing period and 50% decreasing period even if y(t) has an apparent increasing trend.
Norman Page says of that uncertainty over forcing due to clouds “…clearly means that future temperatures cannot be predicted and all the forecasts of CO2 caused disaster are merely speculation with no scientific base.”
Wrong! While it is true that there remain significant uncertainties in forcing due to clouds–and aerosols, too, for that matter–in no way does this seriously hamper model development for two main reasons:
1)All the best information available to date suggests that forcing due to clouds is slightly positive.
2)We know that overall CO2 sensitivity is between 2 and 4.5 degrees per doubling based on about a dozen separate lines of evidence.
It is surprising to me that a PhD geologist would simply abandon hope of progress upon encountering a bit of uncertainty in his initial approach to the problem. It would seem to me that any decent scientist would look at other avenues for progress and bound the uncertainty that way. In effect that is what climate scientists have done. That is why they have been able to predict 3 decades of warming, while the denialists have managed to accomplish at last count…nothing.
#311 Anand
What is climate money? Or did you mean money for climate research ;)
So you don’t think the US military should have studied the upper atmosphere?
You think understanding climate to understand decadal shifts in natural variation for global agriculture is a bad idea?
Do you think understanding how plants react to increased Co2 concentration is not something we should explore?
Do you think, generally speaking, understanding the climate is something that should be dropped from the agenda?
Do you know anything about farming and what affects plant growth?
Do you think farmers should not understand climate?
Or are you simply against research in general of all sorts?
What are you advocating? Going back to hunter gatherer?
325, Richard C.: OT admittedly but I am miffed that Greenpeace decides to call for Pachauri’s resignation at a time when we need solidarity.
I don’t know whether Pachauri is too compromised to be an effective chairman, but what you call “solidarity” is also called “circling the wagons”, and it is not what the UN IPCC needs right now. What IPCC needs right now is a public rededication to excellence (I am not saying they haven’t, only that it is necessary.) Most of the actual mistakes are minor and easily corrected, but they should be openly acknowledged and corrected. What has been evinced by Pachauri is a record of denying and not correcting the mistakes, while concurrently reporters are reporting his conflicts of interest, and former members of IPCC are expressing dissatisfaction with the way IPCC mishandled contradictory information.
CFU: my criticism, again, is that you refuse to examine detail. You write your headline, and that’s all she wrote. Or, at least, all you ever write.
Please stop trying to score cheap points. Slow down, and have a more substantive discussion.
Hey Barton,
I just wanted to share a few additional links as relate to the polar “blocking” highs that I believe relate to the polar amplification and here are a few links related to tropical water vapor transport. (I admit I have to say I have not located a good replacement for my old nomads SRRS reference so if any have an updated alternative it would be welcomed.)
Polar Blocking High
http://earthobservatory.nasa.gov/IOTD/view.php?id=36972
http://www.igidl.ul.pt/Ricardo/Trigo_etal_block_2004.pdf
Water Vapor Transport
http://www.ccpo.odu.edu/SEES/ozone/class/Chap_6/6_5.htm
http://www.ssec.wisc.edu/data/geo/index.php?satellite=east&channel=wv&coverage=fd&file=jpg&imgoranim=img
http://wattsupwiththat.com/2009/12/16/nasa-says-airs-satellite-data-shows-positive-water-vapor-feedback/
General Reference for the un-initiated:
http://rammb.cira.colostate.edu/wmovl/VRL/Texts/SATELLITE_METEOROLOGY/CHAPTER-4.PDF
Cheers!
Dave Cooke
A warning to everyone. This is what happens when one asks blunt and awkward questions as CA:
“Jean S: I’ve checked your math skills, and they don’t impress me much. After checking your IP, I think you have no business of being rude and hostile on this site. Your comments are OT, and from now on I will simply delete all of your comments unless they are strictly on the topic. You’ve been warned.”
Remember why Pachauri has the job?
http://www.slate.com/id/2064611/
http://www.nrdc.org/media/docs/020403.pdf
Richard Ordway (242) , I know this has been discussed here before, but I guess I just didn’t focus or maybe missed the points. With this apology I have some questions on your answer to polar amplification.
The albedo difference between ice and water is large — but not that large: 30-40% for most ice and about 5% for water, except EM waves that come in at a low angle, like much of the arctic, can have albedo up to about 10-15%. Does this really make that much difference? Secondly, does Arctic ice melt from the top or the bottom? If from the bottom it sounds like ice is melting because the sea water is warming up because the ice melted. Sounds goofy. Though is it more of a positive feedback thing?
The same circular logic seems to apply to your point #2 (increased water vapor), though that, too, sounds like it might be a feedback mechanism.
Your #4: why would the latent heat transfer differ between ice and sea water?
Something sticks in my memory that ocean currents have a big effect on polar amplification. Isn’t that correct? Or is my memory failing me?
Norman Page: “…a set of model metrics that might be used to narrow the range of plausible climate change feedbacks and climate sensitivity has yet to be developed…” No sceptic would disagree with that perfectly good statement which clearly means that future temperatures cannot be predicted and all the forecasts of CO2 caused disaster are merely speculation with no scientific base.
It doesn’t mean anything of the sort. They want to narrow the range. They did NOT say the range was wide open, which is what you seem to think. Whether the Charney sensitivity to doubled CO2 is 2 K or 4.5 K, we’re still in big, vast trouble.
Stephen Pruett: “During the era of measured temperatures, warming has been occurring since about 1970, but not in the last 10 years, right? So, we have 30 years of warming followed by 10 years with no clear warming pattern. In most fields of research, a data set in which 1/4 of the data do not fit the expected trend or in which the trend occurred at 3 time points but not at the 4th would be regarded as inadequate to make any predictions about future trends. Why is this regarded as sufficient in climate science, or is it?”
BPL: Because climate scientists understand statistics, and you clearly don’t. ALL the points matter EQUALLY. If you get a significant trend (and “significance” is something that can be MEASURED), it doesn’t matter what a cherry-picked subset of the data is using–taking that subset together WITH all the other subsets still produces a significant trend.
And, BTW, it is still warming.
“A Penn State academic board of inquiry has cleared Michael Mann of scientific misconduct in the “climategate”.”
“A Penn State academic board of inquiry has cleared Michael Mann of scientific misconduct.
The major findings:
— When Mann said in an e-mail he had used a “trick” in a graph that showed global warming in the 20th century, he wasn’t manipulating data, as critics have loudly claimed.
The Penn State board found that, “The so-called ‘trick’ was nothing more than a statistical method used to bring two or more different kinds of data sets together in a legitimate fashion by a technique that has been reviewed by a broad array of peers in the field.”
— Mann didn’t destroy e-mail messages; the ones in question were produced to the Penn State board.”
What are you guys scared of? A big government takeover or losing oil, coal and gas profits? There might not be any government to takeover or oil, coal or gas profits even possible in 100 years if we don’t get this climate problem fixed soon.
Human-caused-global warming has a long latency (~40 years or so), or lag time, or huge heating in the pipeline, or climate commitment due to the oceans huge heat capcity (thermal inertial). It means there is a whole lot that are going to happen in 40 years in the future (unless you change the laws of physics) that we have utterly no control over because it is already here and takes 40 years to manifest because the oceans hide it delay it) for 40 years.
How many innocent scientists, just doing their jobs, have you tried to publicly slander…Tom Wigley (1996) and now Michael Mann.
Countries that suppress their scientists lose their world’s economic competitive advantage. It is a major reason why Portugal, of only a million inhabitants, became a world superpower in the 1500s.
Under Prince Henry, they started arguably the world’s first scientific research institute at Sagres, Portugal which used science to strip away superstition of the oceans and scientifically catalogued the ocean’s trade winds, routes and for the development of new ship designs and weapons.
The most brilliant people immigrated to Sagres from all over the known world in a brain drain from other countries. You guys are hurting your country and your kid’s future by attacking science and scientists.
Read a very readable pulitizer prize winner’s book showing the politics of what Tom Wigley and publishing climate science went through in the 1990s to today called “The Heat is on” by Ross Gelbspan (try Amazon.com).
http://voices.kansascity.com/node/7482
http://www.nytimes.com/2010/02/04/science/earth/04climate.html
What? No headlines about the outcome of the Mann investigation at PSU? Or would that be too obvious?
>>”OT admittedly but I am miffed that Greenpeace decides to call for Pachauri’s resignation at a time when we need solidarity.”<<
We don't need solidarity. We need competent scientists.
Stephen Pruett (320) — Those matters hae be thoroughly addressed in several recent thread’s over on Tamino’s Open Mind blog, linked on the sidebar.
Rod B says: 4 February 2010 at 1:02 PM
“The albedo difference between ice and water is large — but not that large: 30-40% for most ice and about 5% for water, except EM waves that come in at a low angle, like much of the arctic, can have albedo up to about 10-15%. Does this really make that much difference?”
Well if you work out the numbers that’s a huge difference, right? Let’s say for argument’s sake a perpendicular sun angle. You’re looking at absorption of roughly 950W/m2 for water versus 700W/m2 for ice, so 250W/m2 difference. Using some of the slightly less dramatic anomaly figures from the Arctic, that leads to a difference of about 350GW increased absorption during August when comparing the beginning and end of the Arctic ice anomaly record, not using 2007. Work that into joules captured in August and it’s a pretty staggering amount of heat. That number can be refined of course and I’m sure it’ll get smaller if the maths are done with actual insolation angles, but the point is how much area we’re talking about; seemingly small differences stack up pretty fast.
“Something sticks in my memory that ocean currents have a big effect on polar amplification. Isn’t that correct? Or is my memory failing me?”
Loads of good stuff on that, here:
http://www.cgd.ucar.edu/oce/pubs/03pubs_files/Holland-ClimDyn.pdf
334
Ray Ladbury says:
4 February 2010 at 10:59 AM
“1)All the best information available to date suggests that forcing due to clouds is slightly positive.
2)We know that overall CO2 sensitivity is between 2 and 4.5 degrees per doubling based on about a dozen separate lines of evidence.”
1. wrong. please cite these studies you claim to be the best information available. Spencer, who is an authority on cloud forcing is not doubt not one of your “best available” indicates in his research that clouds are a negative feedback.
2. Wrong again. There are just as many studies that indicate that co2 sensitivity is nowhere near that high. See:
Schwartz (2007) – 1.1 +- 0.5 K
Chylek and Lohmann (2008), GRL – 1.3 – 2.3K
[edit – stop with the tiresome cliches]
[Response: Plus note that neither of those studies have stood the test of time. Foster et al, (2008); Schwartz (2008); Annan and Hargreaves (2009). – gavin]
False dichotomy, Rod B: “Secondly, does Arctic ice melt from the top or the bottom? If from the bottom it sounds like ice is melting because the sea water is warming up because the ice melted.”
Why only one?
Warm sea: from the bottom.
Warm sun: from the top.
Chemical deposition: from any surface.
These are examples, not an exhaustive list.