According to a recent article in Eos (Doran and Zimmermann, ‘Examining the Scientific consensus on Climate Change‘, Volume 90, Number 3, 2009; p. 22-23 – only available for AGU members – update: a public link to the article is here), about 58% of the general public in the US thinks that human activity is a significant contributing factor in changing the mean global temperature, as opposed to 97% of specialists surveyed. The disproportion between these numbers is a concern, and one possible explanation may be that the science literacy among the general public is low. Perhaps Sherry Seethaler’s new book ‘Lies, Damn Lies, and Science’ can be a useful contribution in raising the science literacy?
The book is about science in general and about how science often is miscommunicated in the media. It addresses a range of issues, such as how statistics often is misused, how scientific progress is made in general, that the ‘scientific method’ is not always as straightforward as one might like to think, the influence of stake-holders, the importance of knowing the context of the research, relationships between science and policy, and ploys designed to bypass logic. Many of the points made in the book are probably well known for the RC readership – albeit used in different situations to the case studies discussed in the book. There is also some discussion about AGW, amongst other subjects.
One little paradox is that the book claims (p. xx) that it will empower people of all ages and educational backgrounds to think critically about science-related issues and make well-balanced decisions about them. To me, that sounds like a big promise, and after having read the book, I started to wonder whether that statement is just the sort of claims it tries to make people become more skeptical about? Or maybe Seethaler really did succeed after all – because I saw how the arguments in her book could be applied to this promise?
The book touches on AGW, and does in general do a good job in my opinion. However, I cannot avoid bringing up some small details to pick at: The description of the greenhouse effect is not quite correct, as the reader gets the impression that it involves reflecting infrared radiation back to space (p. 84). That is not the case, as the energy from the sun lies mainly in the visible spectrum, and the infra red light from the Earth is a product from the absorption of the sunlight and a re-emittance due to Planck’s law.
Another point that I think is that the book discusses the controversy around AGW, but this can be a bit misleading. If you look in the climatological field, you may not see much controversy, but if you search the web, you may see something that looks like one. But I think that this controversy to a large extent is constructed out of thin air, an impression I feel is supported by Doran and Zimmermann’s, Eos article.
I get the impression that ‘Lies, Damn Lies, and Science’ has much in common with the older book ‘Lies, Damn Lies, and Statistics’, and that they try to convey similar take-home messages.
‘Lies, Damn Lies, and Science‘ gives a nice collection of anecdotes and general tips. The book has a nice index and overview, so it’s easy to find your way through the book. I think the book is very useful for a lot of people – especially students, scientists, journalists, politicians, bureaucrats, and the voters.
You’ve just shown yourself to be smarter than 99% of the people who come by here questioning some aspects of climate science.
Now, if you or someone else could just teach Alastair to have the same attitude …
RE #226
Then BPL, I feel you are unlucky, I don’t recognise this lack of access to information that you find. I’m surprised that the libraries you mention have been – what’s an appropriate word – Bushed (?). If this is what you experience then I take your word for it. An outsider might accuse both of us of having cherry picked our data, but what else could we do?
Alastair Says:
“3 April 2009 at 12:06 PM There is no need for personal attacks, there is no place for it in science and as such I won’t be posting any more comments here.”
Alastair, in all fairness to the Real Climate regulars they appear to be more tolerant of differing points of view then many of the skeptic blogs.
Walter – I think it would be good to get a spreadsheet, in that it is a simple way to manipulate & plot data. I think there are some “freebes” out there. Maybe the web master might come up with a method to post a jpg, or image file, of limited size. Look back at my post, I can see why I got C’s in punctuation, and proofing.
Concerning tipping points and computer models… Let me first of all acknowledge my not having a clue. This increases my appreciation of you taking the time to provide this blog. I also had gotten the idea that computer models predicted a tipping point. I’d read somewhere (I know that isn’t helpful but I really don’t remember where I picked this up) that 450 ppm of CO2 was the level at which CO2 induced warming would be irreversible, the tipping point. I’d thought that computer models were instrumental in coming to this conclusion. I have read further and found that the term tipping point in the realm of climate science can refer to many things such as ancient ice melting to the point of releasing additional greenhouse gases. With that long winded setup, I’ll ask my questions now.
Is 450ppm CO2 a tipping point and is this what VP Al Gore is referring to when he says we’ll reach the tipping point in 10 years (not sure I’m quoting him precisely).
If so, were computer models instrumental in determining this?
Is 10 years the time frame we are expected to reach 450ppm CO2 if we continue with business as usual?
I feel I’m coming late to the climate change issue. My grandparents were my greatest influence on how to live life. Living through the great depression they taught me to conserve (waste not, want not). Recycling, composting and conserving energy have been things I’ve always done but I have to admit, though I grew up re-using clothes from the salvation army, I’m not doing that with my children though we do donate. I now have a daughter taking AP Environmental science in high school. In addition to this class, they are covering climate change in world cultures and English/Literature. That is half of her school day. She’s asked her world cultures teacher why multiple classes are covering the same thing (though AP environmental is in much more detail). Basically the reply was it’s a very important topic and most freshmen are not taking AP science classes. This topic gets discussed a lot in our household now. It’s also given my oldest daughter another reason to chastise us for having brought into the world our youngest daughter (child number 3); because we are putting an undue burden on the planet by having had more than 2 children. (Though she complained about this long before being aware of CO2 induced climate change.)
Thank you for your time,
Tad
[Response: Try here for a start. – gavin]
J Bob,
You’re right about that–go to openoffice.org and you can download a complete office suite that includes an Excel-quality (or better) spreadsheet program.
#256 Thank You. There you go Walter. If you can use the spreadsheet to pull the info off of these posting, you can then plot the it and we have established a method of sharing data. I am now using the Visual Basic option in EXCEL to re-activate my old analysis programs, so we might find some interesting stuff. Will watch for you postings on this thread.
Take care.
jbob,
here’s the specific “tamino” link that has his interpretation of the data.
http://tamino.wordpress.com/2008/04/28/central-england-temperature/
i’ll see about learning how to use a spreadsheet to produce a graph. would i have to enter in all those thousands(?) of data points?
regarding spelling etc… i say it’s content that counts. as you can see, it appears the shift key for capital letters on my typewriter is broken.
How to post a picture here:
1) put the picture on a web site that hosts pictures.*
2) post the URL here.
________
* Google
[Response: You can use <img src=”http://…” > html as well. – gavin]
258- How about a demo?
I meant 259 for a demo. Walter, you normally can cut and past data to a spreadsheet, just like moving text in a word processor.
> demo
Sure. Open the Advocacy thread: https://www.realclimate.org/index.php/archives/2009/04/advocacy-vs-science/
Use ‘View Page Source’ (Firefox)/whatever it’s called in your browser.
Use ‘find’ for this string: 3 April 2009 at 1:17 PM
Scroll down to the following line after you find that.
You’ll see where Gavin put the tags on the link I posted, so it displays the picture inline.
It can’t be pasted in here or you won’t see the code. You have to view the page source to see the HTML code before and after the URL for the picture.
Or use View Source in this thread and look at what follows:
Forgot to close the html tag. IF you use a left angle bracket it has to be followed eventually by a slash right angle bracket; Preview won’t show it so you just types your best guess and tries it out. Maybe:
Nope. What if we actually type in exactly the same code?
Flickr wants it to be called this, so we mention their name a lot, but it disappears when used at RC:
See? What followed the colon just disappeared.
That might work this way, still using the direct link Flickr wants; at least the following line does show up in Preview here:
That’s hand typing in exactly the same HTML Gavin described, and links to a screenshot of the HTML
[Response: fixed. You need to link directly to the img file (i.e. the jpg), not the flickr www address, and you need to use the angle brackets and quotes rather than the html rendering of them. – gavin]
When you start working with spreadsheets — make sure you read about the research _about_ spreadsheets. The study of the kinds of errors people make in spreadsheets is extensive, and humbling.
A few places to start:
http://www.eusprig.org/
and http://panko.shidler.hawaii.edu/SSR/Mypapers/whatknow.htm
Hank and Gavin,
I am not able to get the “img src” tag to work, either. However, that may be a good thing. Imagine people linking to images on slow servers. Perhaps deliberately doing so. The blog would load much more slowly if at all. Imagine people linking to large images, say five megabytes in size. Some people still have rinky-dink computers or connections to the web. Just providing a link to the image should probably be enough for the commenters. Then its “Let the clicker beware.”
Sincerely yours,
Cautious
Alistair says “It’s not arrogant to ask critical questions.”
Nope, it ain’t. However, if you will go back to your initial post in this thread, can you find a single question mark in anything you typed? I couldn’t. Not one. Rather, I find a whole bunch of ignorant assertions, which, given that you are addressing them to scientists who have been studying climate for decades, was pretty arrogant. What is more, you evidently realized that your approach was aggressive, as you said you expected abuse.
So if your purpose was to increase your understanding, you chose an odd manner to go about it. Even in your current post, you assert:
“There are many climate scientists who are skeptics,…”
Really? Care to name them? I’ll help. Here’s a list of the most cited authors on climate change. So… where are they?
“Barton Paul Levenson Says:
2 April 2009 at 3:54 PM
I’m reading this exchange over Antarctica melting and I feel like banging my head against a wall. Does our “scientist” not understand the primacy of evidence over argument? The GRACE satellite says the Antarctic ice cap is losing mass. If it’s not melting, where is it going?”
I found this question to be very interesting and have two possible alternatives to an increased rate of melting. The first is that the models depicting the rate of land mass rising in the antarctic are mistaken. The second is that precipitation is lessening.
Now that you have a hypothesis, steve (#268) go see if either is correct. The second one should be easy to check.
This is called “science”.
Steve, using your approach, it’s also possible the fish are drinking more water, or the Earth is expanding. That’d explain it too.
But you need more than just a notion. You need some credible mechanism — some way your notion could be happening; you need some observation that supports what you think is happening; and you need some way to explain away the observations that support the ideas other people have. The GRACE satellite isn’t a model and the observations aren’t models.
You have to go beyond models, else it’s just turtles all the way down.
I’m not going to bother suggesting you look up the science yet.
But there’s a very good section on fairy tales in the children’s library.
#255 – Thank you for the link Gavin. To make sure I’ve understood your 2006 article correctly, Dr. Hansen’s 10 years to a tipping point is an educated (very educated) estimate of how long we have to stop increasing CO2 ppm (to prevent it going over the dangerous 400ppm level) as opposed to the result of calculations from a computer model.
Also, I suspect from what I’ve read here now that VP Al Gore’s recent mention of us having 10 years until we reach the tipping point was probably a re-iteration Dr’ Hansen’s statement made in 2006.
As just a member of the general public, I’m trying sort out what is real and what is not in the body of information I’m getting from my daughter’s high school classes and elsewhere. Our local tv news and newspaper often have reports on how climate change is, or could affect our lives here in Washington state.
Thank you for being available to help fill in the missing pieces of information.
Tad
Barton Paul Levenson wrote in 227 three days ago back on 2 April 2009:
steve wrote in 268:
Land rising will be a fairly gradual effect, taking millenia, not decades — to result from ice loss. Therefore I strongly doubt that the “rising” of the land has any appreciable bearing upon our estimates of ice loss in Antarctica, whether they are based upon gravity measurements via satellites or laser altimetry.
steve wrote in 268:
Actually global warming is supposed to increase precipitation in Antarctica, not decrease it — as raising the temperature puts more moisture in the air for precipitation. Moreover, in terms of precipitation, for all intents and purposes, Antarctica is already a desert. Difficult for precipitation to go down from there.
Besides — we know that it has been losing mass by means of melting by tracking the flow of glaciers — which is happening well inland.
Please see:
I submit that when the ice flows out into the ocean most it melts sooner or later. And I submit that when it flows into the ocean that is mass loss. Moreover, we know that it is of roughly the same magnitude as is required to explain the mass loss as measured from space.
When a conclusion receives justification from multiple, largely independent lines of investigation, the conclusion generally acquires far more justification than it would receive from any single line of investigation considered in isolation from the rest.
*
The scare marks “” around “scientist” were there for a reason. When I was “debating” evolution vs. creationism in DebunkCreation with creationists, every few weeks we would have a creationist come by with only a first name claiming to be a scientist but would refuse to even mention what his speciality was — and it soon became quite clear that the “scientist” knew very little about the scientific method or any area of science he chose to discuss, and as such was clearly not a scientist.
As such, Barton’s question was rhetorical.
And I am afraid that you have been chasing unicorns.
hank!
“the earth is expanding…” gosh that is SO funny! but, seriously it COULD be. get gavin to check out the satellite measurements. of course, those COULD be off too, i mean you never know. and look into that fish-drinking theory too…
and thanks for your (and gavin’s) efforts in facilitating jbob’s posting that graph. i can’t wait to see it.
Timothy Chase Says:
“Land rising will be a fairly gradual effect, taking millenia, not decades — to result from ice loss. Therefore I strongly doubt that the “rising” of the land has any appreciable bearing upon our estimates of ice loss in Antarctica, whether they are based upon gravity measurements via satellites or laser altimetry”
Timothy I’m not a scientist but I do find certain things interesting for the strangest of reasons and one of those things was the idea that Scandinavia was rising rather quickly due to having lost the ice from the last ice age. From Donald Blanchard’s the ABC’s of Plate Tectonics I see that Scandinavia is currently rising at 90cm per century and the average it has risen over the last 8000 years is 68mm per year. The surface area of antarctica is about 14.2 million km. Unless I have made the unfortunate error of misplacing a decimal point I find this comes out to 14km squared for each mm of rising. Based on what is possible, it is certainly possible that the mass of antarctica can be affected by the rate of the rising land mass.
Hank Roberts Says:
5 April 2009 at 10:31 AM “The GRACE satellite isn’t a model”
But it does rely on a model to determine the rate of land rise. Correct?
Timothy Chase Says “And I am afraid that you have been chasing unicorns.”
I don’t mind chasing unicorns. You learn a lot during the chase.
Steve, the reason that Scandinavia is rising rapidly is because the glaciers melted relatively recently and the crust, abruptly relieved of a large burden, is rebounding. The same is true in Northern Canada.
By contrast, the Antarctic ice is still (mostly) there.
You ask if GRACE “uses a model” to determine the rate of land rise. Based on this source, I would say, “not in the sense you mean it.” But read for yourself.
steve wrote in 274:
Well, let’s see:
Yes, I suppose when you lose 3 km of ice (see above) at the end of an ice age (10,000 – 15,000 years ago) there will be some rebound. However, the last occurred primarily in the northern hemisphere, and to a much lesser extent in the southern. Some parts of Chile were affected, and so were some parts of New Zealand. (See Wikipedia’s Last glacial period.)
However, with ice core samples we appear to have a fairly good idea of what was going on in Antarctica. Its been pretty much a deep freeze. No kilometers of ice shaved off to cause rebound, although there does appear to have been a fair amount of sea ice loss earlier in the twentieth century, principally prior to 1975.
Sure there is going to be rebound — after a great deal of ice has melted. However, we are only at the beginning of the melt in Antarctica — with temperatures now rising along the West Antarctic Ice Peninsula more rapidly that just about anywhere else on this earth, and warming throughout nearly all of the surrounding Southern Ocean.
*
Now you have an argument regarding the area of Antarctica and whether the rise of this area might be sufficient to serve your needs without presumably having been already observed…
steve wrote in 274:
You also have an argument involving possibility…
steve wrote in 274:
*
Let me elucidate the nature of your argument involving possibility with a counterexample prior to turning to the question of surface area:
However, I am a male and therefore cannot become pregnant.
Now I ask: do you have any evidence that what you are claiming is “possible” is actually the case — given what we know regarding Antarctica?
*
Turning to the content of your argument, I am not exactly sure how you are doing your calculations, or for that matter entirely sure of what you mean by the mass of Antarctica being affected by the rate at which land rises. Are you suggesting that the land rises and then goes poof? Like a magic trick?
In both Newtonian and Einsteinian theories of gravity, internal to a thin, spherical shell of uniformly distributed matter there is no gravitational field, but external to that shell the gravitational field behaves the same as it would if its source were a mass point of no extension.
If Antarctica were to rise this would not lessen the gravitational field as measured from space — by means of the differential influence of the gravitational field on two satellites separated by some distance as in the Grace Experiment — except insofar as the rising of the land mass pushed water away from Antarctica’s coasts — but then the loss of mass would be in the waters surrounding Antarctica, not Antarctica itself. So I really don’t see why you are going on about the area of the entire Antarctic continent.
*
But setting all this aside — we have seen glaciers accelerating towards the coasts. We have detailed maps of glacier flow towards the ocean. We know that the glaciers are not piling up along the coastline, but that they are instead falling over it into the ocean.
Please see and acknowledge what I included and quoted previously but now emphasize:
Grace says that Antarctica is losing mass. Measured ice flow along the coastlines shows that Antarctica is losing mass roughly equal to what Grace measured.
Precipitation could have trended down as you suggest, but this would not in any way affect the fact that ice has been flowing out along the coastlines — and that this has been the cause of a loss of mass roughly equal to what the Grace Experiment shows. It would not eliminate observed and measured ice flow as a form of mass loss — roughly equal to what Grace measured. It would not be an alternative, but something in addition to what was lost by ice flow.
And then you would be left with the problem of why we didn’t detect this additional mass loss.
*
A few weeks ago, I wrote somewhat humorously in response to something I liked:
I would like to think that you are not simply trying to knock out a given line of evidence for a given conclusion simply by casting (unreasonable) doubt on that line of evidence — then ignoring the other lines of evidence (however strong they may be) which point to the same conclusion.
ref # 276 Thanks Kevin but although I may not have been making myself very clear I have little reason to doubt that I had the idea clear in my head. I have found a study recently published called Glacial Isostatic Adjustment over Antarctica from combined GRACE and ICESat satellite data which seems to me to agree with the basics of what I was saying. They say they have now determined that the GIA impact on GRACE-derived estimates of mass balance to be about 80GT/year. It’s from Geophysical Research Abstracts vol.11 2009. From reading this abstract one would conclude that it was a problem at least until 2009.
ref #277 No Timothy, actually I’m not arguing about anything other then if land masses rising at varying rates can mess up GRACE data. It seems that people are putting a considerable amount of effort into quantifying just how much it does.
Speaking of GRACE, which was my topic I thought, I have found several references to the deglaciation model and that is what I had read before. Unfortunately the best description of it I can’t find again but it basically models the earths crust and tries to provide a reasonable assumption of how much the crust would rise and this is used with the GRACE measurements to determine how much mass is ice and how much is land.
Timothy Chase Says:
5 April 2009 at 9:47 PM “Please see and acknowledge what I included and quoted previously but now emphasize”
I’m sorry Timothy, yes I have glanced at it. I really haven’t had time to try to digest it yet, I have been busy trying to prove that the rate of land rising was important to how GRACE functions. I am not ignoring it and will sit down and examine it at length some time.
Steve, 80 GT out of a total of how much?
http://scholar.google.com/scholar?q=%22Glacial+Isostatic+Adjustment+over+Antarctica+from+combined+GRACE+and+ICESat+satellite+data%22
The first of the 2 hits seems to be the paper you’re talking about; do you have the full text? The abstract ends:
“… The inferred GIA signal over the complete Antarctic continent supports Late-Pleistocene ice models derived from glacio-geologic studies, with important differences over the two main ice-shelves. The contribution of GIA mass change remains limited to less than 100 Gt/yr, which is considerably smaller than previously thought.”
steve wrote in 278:
More or less. Yes — with rebound there would have been displacement of water. It may also result in the flow of rock beneath the rebound where rock is denser than the ice the volume of which it was replacing. And you are right about Antarctica having suffered some glacial isolatic rebound since the last glacial period.
The following…
Last glacial period
http://en.wikipedia.org/wiki/Wisconsin_glaciation
… does not in any way indicate that Antarctica was strongly affected by isostatic rebound. However…
Post-glacial rebound
http://en.wikipedia.org/wiki/Post-glacial_rebound
… indicates that Antarctica was affected.
But as you have just pointed out, the signal of glacial isostatic adjustment is now smaller than the signal derived from GRACE. And in either case it would not have affected the measure of ice flow along the coastline.
Steve,
My apologies. I misunderstood your intentions — which sounded like someone arguing that we can’t really say for sure that Antarctica is experiencing a negative mass balance — even with all the evidence.
However, I might have to give you a link some time to my “Welcome to DebunkCreation.” My first post was a tongue-in-cheek Omphalosian argument — and people took it seriously for the next several hours.
Anyway, our interaction tells me I need to be a little more careful on a number of fronts — including keeping my “facts” straight.
ref # 281 no Hank I don’t have the full paper. I found the topic interesting but I believe they wanted to charge me for it and I didn’t find it that interesting.
ref # 283 No apology needed Timothy. If my comment would have been taken as intended I would have missed out an engaging conversation.
I almost dread saying this but can’t seem to stop myself, so let me prefix it with the comment: I don’t have any reason to doubt the antarctic is melting nor do I find if it wasn’t to be particularily strong evidence towards anything
wouldn’t the GIA mass being smaller then previously thought indicate the ice mass is greater then was previously thought
steve wrote in 285:
It is what it is, and identification precedes evaluation. The important thing is to figure out what is going on then go from there.
However, that said, there appear to be several studies coming out that are making use of similar sets of data but attempting to answer related questions.
One such study states in the abstract:
Digging deeper into the paper I found the following:
Eric Rignot most recent work in 2008 supported a larger, accelerating contribution of Antarctica’s ice mass balance to the rise in sea level. Which would mean that the results of this study are consistent with what we are observing in terms of ice flow along the coastline.
Hurray for us! Hey, wait a second… This isn’t good.
PS to the above…
The results I had been referring us to in terms of ice loss and glacier flow:
… was a product of Eric Rignot’s 2008 work:
Walter I think I got the images up. I checked the links and they look OK. http://www.imagenerd.com/uploads/temp_est_1-1v0Pu.gif and http://www.imagenerd.com/uploads/temp_est_2-AyTtN.gif
The first one gives a general view on how well the linear estimation looks. They were your base & slope numbers I believe. The actual flops around the trend line, but stays pretty close to it. Summed error from the line and actual data was less then a degree.
The second line is the error between the estimate and actual. One reason to plot the error is to get a unbiased look at the error. You are not influenced by the slope. I also filtered the error with a 1st order filter (Time constant of 8 mo. From the filtered error, one might get the impression there could be a downward trend. More work to do.
From Eric Rignot’s letter:
*
Captcha fortune cookie: letter bear
P.S – Thanks for all the help, in getting the graphs posted.
J. Bob, Congratulations, you seem to have reconstructed the hockey stick–your analysis shows that there is definitely something going on in the latter quarter of the 20th century that is inconsistent with the previous linear trend.
jim!
those are fantastic! great job. thanks so much. i can “see” (i’m visual…) how on both graphs about half the blue lines (temp) fall above and below the pink line (linear fit and filtered error) – like that pink line WOULD represent a good “averaging out” or “noise reduction” in the data. it looks very much like this one from tamino: http://tamino.files.wordpress.com/2008/04/cet1yrbig.jpg (i bet volcanos erupted around 1740 and 1880)
then he started doing some fancy statistical wizardry (taking 5, 10, 30 year averages http://tamino.wordpress.com/2008/04/28/central-england-temperature/) and the graph became more “severe” looking – like more warming has happened recently. i can’t exactly check his math…but does what he did make sense to you? i mean, does it look like he did it right? and is it a valid approach?
btw, i hope we both understand that central england’s climate trends are not necessarily reflective of the globe’s climate. in fact, i believe one of the long range things that’s “supposed” to happen is england may get COLDER eventually.
Walter Crain wrote in 292:
Fuego in Guatemala 1737 Aug 27 – 1737 Sep 24
Volcanic Explosivity Index: 4(?)
Krakatau in Krakatau Island, 1883 May 20 – 1883 Oct 21
Volcanic Explosivity Index: 6
(The island no longer exists)
from…
Global Volcanism Program: Large Holocene Eruptions
http://www.volcano.si.edu/world/largeeruptions.cfm
> img tag
OK, Gavin explains the problem at
4 April 2009 at 10:36 AM
Noting for the record, though I doubt they’ll complain, Flickr wants their URL used, not the direct link to the image — so I’d recommend people use some other image hosting service, not Flickr. I’ll consider the one attempt above fair use testing out what works and showing that Flickr’s terms of service render it useless for Realclimate purposes. I’ll find myself another image provider to use here.
But I agree with others too, that posting images is generally not a good idea, and pointing to them somewhere else is kinder.
Why? Because displaying images inline _really_ slows down people on dialup or with slow computers, not to mention anyone still using text (Lynx?) or anyone with vision problems using a text-to-speech converter.
“in fact, i believe one of the long range things that’s “supposed” to happen is england may get COLDER eventually.” – walter crain
Unlikely: this idea was based on the hypothesis that the Atlantic thermohaline circulation, which carries warm surface water to northern Europe, could be halted by the influx of fresh water from melting Arctic ice. This is now considered very unlikely – it may slow, reducing the warming of maritime Europe that would otherwise occur, but cooling does not seem to be on the cards.
thanks timothy,
so pinatubo was really ALL THAT, huh? i only saw 2 or 3 given a higher explosivity rating.
nick gotts,
oh, so that thermohaline theory’s “out” now. too bad…i secretly hoped to move to england if things got really bad snow-wise here in the virginia.
here’s what i do when it snows (speaking of flicker images): http://www.flickr.com/photos/58171957@N00/
Walter Crain wrote in 296
Pinatubo in 1991 was big, but Krakatau in 1883 was about twice the size.
Looking at:
Largest Explosive Eruptions Since 1400 AD
VEI Greater Than or Equal to 5
http://volcano.oregonstate.edu/education/facts/largest_erups.html
… there have been 33 eruptions at a V(olcanic)E(xplosivity)I(ndex) of 5 or greater since 1400 CA, including (?) and (+).
24 at a VEI of 5, 8 eruptions at a VEI of 6, and 1 eruption at a VEI of 7 — which was Tambora in Indonesia that began on 1815 Apr 5.
VEI is a base 10 logarithmic scale for measuring explosivity in terms of the “volume of erupted tephra” with a VEI of 0 corresponding to 10-5km3.
Please see:
Volcanic Explosivity Index
http://en.wikipedia.org/wiki/Volcanic_Explosivity_Index
Pinatubo from 1991 Apr 2 to 1991 Sep 2 was a VEI of 6 with tephra volume of 1.1×101km3.
Krakatau in 1883 was also a VEI of 6, but had roughly twice the tephra volume at 2.0×101km3.
Please see:
Global Volcanism Program: Large Holocene Eruptions
http://www.volcano.si.edu/world/largeeruptions.cfm
Hi Walter – Glad you got the graphs. They came through pretty good. You asked I believe what I thought. The first items again, is that it is from a single source, and we don’t know how accurate the thermometers were at recording realistic temperatures. That being said, it does provide a relatively long period of reasonable good thermal data. It may not be perfect but it’s a start.
Comparing the yearly and estimated temperature, gives us a long term temperature trend upward of about 0.3 deg./century, and that seems to be holding, looking at the way the data is bunched about the line. The more interesting chart is the 2nd one, showing the error between the estimated and actual temperature. It looks that the data is still clumped around the trend line, within a couple of degrees. Otherwise I think we would have seen more “bowing”. That is, if the middle of the line were 2-3 deg. below the estimate, while the ends would be 2-3 degrees above the line. If the “bow” was present, that would be a sure sign that something was going on. But for 350 years, with the extremes shown, I think it follows the trend line quite good, pretty much within 1.5 degree bounds. What happened before 1659, is very fuzzy. Along the way we see “bumps” (i.e. 1700-1750). Again 1815-1835, and a longer one from 1890-1950, and now the last, beginning about 1900 to about now. But a closer look comparing the raw data and filtered, seems to indicate a leveling off has taken place. I would be hard pressed to say the last 50 years would show a “hockey stick’. But 3 items did stick:
1-I didn’t see any sustained temperature increase in central England, during their industrial revolution.
2- Maybe a blip when Krakatora blew, and maybe a blip in 1737, when it was already on a run up.
3- Why do we see, wrt our current discussion on CO2, is what appears to be a leveling off in the raw temp since 2000? This is when CO2 levels are increasing. This is one of those cases you sometimes have to look at the raw and filtered data, to try and make sense as to what is going on.
So taking this one sample of data, I will have to repeat my original opinion, that I would not yet bet the farm on CO2 and temperature increases being strongly linked. That’s how I read the data, what do you think Walter?
However there is more information I think I can get out of those graphs. That will take a little more time, and there is more temps to go through. I think if we take this one step at a time, looking at the pros and cons, a clearer picture might emerge.
J. Bob writes,
CO2 isn’t the only thing that affects temperature. It is also affected by other greenhouse gases, changes in sunlight, aerosols both natural and artificial, albedo changes due to differences in land use, and vagaries of the ocean-atmosphere interchange. That’s why the definition of climate requires 30 years or more of data to find trends. “Since 2000” is meaningless.
Extrapolating to the world from central England data is a fallacy of composition. Global warming is talking about the mean global annual surface temperature. For that, ln CO2 accounts for 76% of the variance in temperature anomaly for 1880-2008.