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Eric (skeptic) at 13:06 PM on 20 December 2011Models are unreliable
scaddenp, you are right, I was confused. Fig 2a shows both the raw observation which is -0.5 peak cooling and the ENSO-adjusted which is -0.7 UAH shows a bit over -0.4: http://www.drroyspencer.com/wp-content/uploads/UAH_LT_1979_thru_November_2011.png -
Tom Curtis at 12:36 PM on 20 December 2011The End of the Hothouse
TIS @18, a more likely cause of the drop in CO2 was the collision between the Indian Sub-continent and Asia which was occurring at that time. The consequent raising of the Himalayas resulted in massive erosion, a process which absorbs CO2. The cooling of the Ocean due to the opening of the Magellan straight (the gap between Antarctica and Australia) would also have resulted in increased absorption of CO2 into the ocean, but based on the correlation between temperature and CO2 levels observed in the Vostock Ice Core, that would have reduced atmospheric CO2 levels by around 150 to 250 ppmv, and could not account for all, or even most of the 700 - 1200 ppmv reduction observed. -
Ger at 12:02 PM on 20 December 2011The End of the Hothouse
There is a more likely candidate for the faster melting than GHG alone and that would be the dumping of the heat which will be transported to the poles. Not only dumping but also the release of methane and its reduction in the air to carbondioxide + water will release quite an amount of heat. If permafrost is escaping lots of ch4 that might be quite a good reason why the north cap is melting faster than the south pole. -
John Hartz at 11:50 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
@chriskoz: Tamino did an excellent job of defining the scientific terms and acronyms in his analysis of the same paper. I believe his approach was superior's to Dana's in this particular regard. -
The Inconvenient Skeptic at 11:23 AM on 20 December 2011The End of the Hothouse
So what caused the CO2 to drop? Could it be the formation of the Southern Ocean that was taking place as the Antarctic Circumpolar Circulation started at the same time. Interesting that a 10 C drop in the 100m of the Southern Ocean would be enough to absorb large amounts of CO2 and cause the levels to drop.Response:[DB] Link to non-science blog snipped.
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Tom Curtis at 11:07 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
Chriskoz @19: AOD is aerosol optical depth, and is a measure of the reflectivity of the atmosphere due to sulfate aerosols including those emitted by volcanoes. TSI is the Total Solar Irradiance, and is a measure of the total power received from the sun across the full range of the electromagnetic spectrum falling on a one meter squared area in orbit and held at right angles to the incoming sunlight. ENSO is the El Nino Southern Oscillation and is the actual physical phenomenon observed in the equatorial Pacific ocean. MEI is the Multivariate ENSO Index, and is one of many measures of the strength of the El Nino Southern Oscillation. -
chriskoz at 10:43 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
John Hartz @1 Frankly, of all of acronyms on the figures above, the only one I clearly understand is ENSO (I didn't enven know ENSO could still be double-abreviated to MEI when talking about its measure!) rest of them are pure magic. But I can deduce their meaning from the context, i.e.: TSI must be the sun output variability (? Sun Index) and AOD must be the volcano eruptions. Even without those guesses, the term 'exogenous factors' makes the things understandable. Overall, Dana's article and the statistical analysis in the paper are well understandable, even by untrained people like me. I have a suggestion about those acronyms: make a list of them, for example in Newbie's section, in alpha order. Could be explained, if required, in one sentence each. Or even if not explained, it's nice to have them here at SkS, rather than looking up at wikipedia, discriminate them from incidental idents, etc. Has anyone got such list? If not, I can start sth up: AGW - Anthropogenic (man-made) Global Warming OA - Ocean Acidity ENSO- El Niño Southern Oscillation GHG - Greanhouse Gases SST - Sea Surface TemperatureModerator Response: [DB] A list of acronyms is in the works already. But thanks anyway for the suggestion! -
skywatcher at 10:36 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
#13 skept.fr, I'm not sure I agree with you on your point #1. ENSO is the variability, not the rising trend, and so removing the ENSO signal will not remove any of the increasing trend in global temperatures. It would only do so if ENSO showed a trend over the same period. GHG forcing might affect the pattern and strength of ENSO, but that would show up in the ENSO signal oscillations, which are then removed. For your #2, AFAIK, AMO and PDO are not large enough to have a significant effect on global temperatures. For example, when PDO is in a 'cool' phase, a significant part of the North Pacific is in a 'warm' phase as part of the oscillation - the net effect on global temperatures is thus very muted. The PDO is also likely the integrated product of ENSO variations, and so is not a forcing in its own right. The AMO's definition has a linear global warming signal removed from it too. But this discussion (if there is one) is probably best on another thread. -
John Hartz at 10:29 AM on 20 December 2011Arctic settles into new phase – warmer, greener, and less ice
ManOfFireAndLight: The Independent(UK)article that you have provided a URL for is based on the paper "Recent changes in shelf hydrography in the Siberian Arctic: Potential for subsea permafrost instability" which I cited in my post #14. -
scaddenp at 10:19 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
I am not aware of any solid evidence that ENSO, PDO or AMO are forced at all. One of the conundrums awaiting better models is what effect GW will have (if any) on ENSO (and thus on regional weather patterns). -
skept.fr at 10:17 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
#14 Bert : yes, most (80-90%) of the warming trend is stored in ocean as heat content, so the LT or surface 1979-2011 trends are just a "small picture" of the real effect of forcings on Earth energy balance. For the "signal-noise", I've used the terms of FR : "the global warming signal becomes even more evident as noise is reduced" (noise being here ENSO, volcanoes and sun). #15 Stephen Baines : "There is no apparent long term trend in this index with time. So the index acts as if it were an exogenous factor, with respect to GHG warming signal at least" I agree, to be precise there is a small and negative (but poorly significant) trend for MEI, see table 3 : -0.014-0.023 K/dec. Whatever this trend, it is the "physical logic" that I try to understand, if I can say : the difference we can do theoretically between a noise and a signal in a forced climate. For AMO and PDO, I have not understood your point. As FR have not treated at all these oscillations (or others), we don't know from their paper what is their signature on 1979-2011. -
Stephen Baines at 09:34 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
Skept.fr The MEI uses 6 variables, only two of which are temperature variables and one of which is SST. There is no apparent long term trend in this index with time. So the index acts as if it were an exogenous factor, with respect to GHG warming signal at least. As for AMO and PDO, the efefct of such long period cycles should have become more apparent in the residuals after removing the effects of short period cycles and sporadic eruptions. That didn't happen, which suggests there is no cyclical variability on decadal time scales to be explained. -
skept.fr at 09:33 AM on 20 December 2011Renewables can't provide baseload power
Not much time right now, but I continue with some general views from the SRREN 2011. First, orders of magnitude. Readers must recall that we currently produce 492 EJ/y, but with 197 EJ/y losses in production, transportation and conversion of energy, so we actually consume 294 EJ/y. On this table, IPCC authors give the technical potential of RE, minimum and maximum, as estimated by literature. Technical potential is what we could produce from renewable sources (wind, sun, ocean, geothermia, biomass) with current technology.
So, the good new is that even the minimum estimates of RE potential total as high as approx 1900 EJ/y, that is nearly five times what we produce now (at 80% from fossil). As this estimate results from actual knowledges and devices: it is not an optimistic projection of what we could do in an hypothetical future with an hypothetical progress, but an assessment of what we could do now.
This figure helps to see where the biggest potentials are and are not. For example, hydropower estimate are convergent but low, 50 EJ /y for minimum and 52 EJ/y for maximum. So, we should not rely to hydro as a baseload power, because it too low for our needs, except in some very well endowed countries like Norway (99% of electricity production from hydro).
Wind and mostly solar have the highest potential for producing electricity and heat. I’ll try to adress later these two energy sources. Production of primary energy or electricity is one thing, but the real challenge is of course to satisfy our final uses in society, so to transport, store, convert this energy.
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Bert from Eltham at 09:33 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
skept.fr my understanding is that the Global Temperature Anomaly looks 'noisy' because it has other real variabilities superimposed on it. This is NOT noise but real signals that can be evaluated and accounted for. This paper by Foster and Rahmstorf has done just this and they have even adjusted for time dependant effects albeit approximately. All this was done using real physics not number fudging! The remaining real noise is within measurement errors. Your third point about equilibrium is quite valid as the majority of the heat is going into the oceans and thus the situation is far more dire than the GTA suggests. We are all falling off a very high cliff and we are arguing whether we have reached terminal velocity yet. Bert -
skept.fr at 08:59 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
The 3 points I don't clearly understand in FR 2011 paper is : • ENSO signal (from MEI) notably consist in SST change. But SST are forced by GHGs as we know (and of course by all other forcings). So, part of the ENSO noise they removed also contains part of the signal they want to identify. I don't see ENSO as an "exogeneous factor" (legend 3, figure above), because GHGs and feedbacks do influence temperature and circulation of oceans. • On a 32 years period, they remove the sole ENSO noise but there are other "natural" modes of variability on such a period. (But the problem is the same : as ENSO, PDO, AMO and others "O" are also forced, no more just "natural", so it is unclear for me how we can distinguish signal and noise when dealing with these "natural-and-forced" oscillations.) • Climate is never on equilibrium, and response time is long for ocean. So we don't know what part of the 1979-2011 trend results from response to previous forcing, and this point doesn't seem adressed in the paper. By the way, it is a physical rathe than statistical point, so maybe FR just leaved it. I think FR get the broad picture with their choices, but I don't know if the decadal trends they obtain from their removals are very precise. Maybe lower, maybe higher. -
ManOfFireAndLight at 08:55 AM on 20 December 2011Arctic settles into new phase – warmer, greener, and less ice
@John Hartz Hopefully you can find out a bit more (including some actual data) about this: http://www.independent.co.uk/news/science/methane-discovery-stokes-new-global-warming-fears-shock-as-retreat-of-arctic-releases-greenhouse-gas-6276278.html -
Bert from Eltham at 08:51 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
The take home message from this paper is that cherry picking even a ten year interval to show 'cooling' has completely gone. The other often mentioned 'it is impossible to describe a chaotic system' now rings very hollow as well. The image of the situation has now come into very clear focus. Any further denial would only be due to blindness or ignorance maybe both. Bert -
John Hartz at 08:43 AM on 20 December 2011Arctic settles into new phase – warmer, greener, and less ice
The findings of "Recent changes in shelf hydrography in the Siberian Arctic: Potential for subsea permafrost instability" cited in my previous post are incorporated into a new SkS article, "Abrupt Climate Change - Causes" by Agnostic that will be posted in the near future. -
John Hartz at 08:31 AM on 20 December 2011Arctic settles into new phase – warmer, greener, and less ice
funglestrumpet; The paper you are referring to is: "Recent changes in shelf hydrography in the Siberian Arctic: Potential for subsea permafrost instability" JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 116, C10027, 10 PP., 2011 doi:10.1029/2011JC007218 The "Key Points" of the paper: •Our data provide evidence of drastic bottom layer heating over the coastal zone •We attribute this warming to changes in the Arctic atmosphere •Recent climate change cannot produce an immediate response in subsea permafrost The Abstract and additional information about this paper is available here. -
John Hartz at 08:05 AM on 20 December 2011Arctic settles into new phase – warmer, greener, and less ice
cRR Kampen: If you have not already done so, you may wish to peruse “As Permafrost Thaws, Scientists Study the Risks” published in the New York Times on This in-depth article portrays in words and in photos what's happening to the permafrost in the Arctic. It is part of the NY Times' Temperature Rising series. To access “As Permafrost Thaws, Scientists Study the Risks”, click here. -
cRR Kampen at 07:49 AM on 20 December 2011Arctic settles into new phase – warmer, greener, and less ice
#11, the methane thing in the Arctic becomes the single and by far most alarming change in existence re AGW - if we see methane concentrations rise sharply on a global scale in the next couple of years. Personally, I fear for the absolute worst. -
dana1981 at 07:43 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
KR @7 - in general I don't find Bob Tisdale's analyses very good either, but I do give him credit for criticizing poor posts on WUWT like this one quite frequently. He's one of the few 'skeptics' willing to point out the errors made by his fellow 'skeptics'. -
John Hartz at 07:41 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
Joe Romm over at Climate Progress also posted an article about the Foster and Rahmstorf paper. Romm's Dec 13 post includes a reprint of the Tomino article cited by Dana. The title of Romm's post is: Sorry, Deniers, Study of “True Global Warming Signal” Finds “Remarkably Steady” Rate of Manmade Warming Since 1979. To access it, click here. -
Stephen Baines at 07:33 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
Sphaerica, This is a statistical approach to removing the effects of exgenous variables. As such it is rather "stiff" in how it implements lags. In reality, dynamical considerations could shift the effective lag in any one instance of ENSO forward or backward from the mean lag. As a consequence, I think one can only hope to remove some of the natural variation using these methods. Only a proper dynamical model would truly be able to account for ENSO effects and the such. However, what Foster and Rahmstorf sacrifice in statistical efficiency is more than made up for by the clarity such an approach affords. Clearly warming has proceeded pretty much apace once much of those effects have been removed from the data. The average lags make sense based on modeling as well, I believe. That's a nice consistent picture. -
Foster and Rahmstorf Measure the Global Warming Signal
John Hartz - Takeaways? My personal opinion here, but I see the takeaways as: * Major portions of mid-term climate variability can be attributed to (with statistical significance) various exogenous (outside) factors. * Accounting for those exogenous factors shows a very clear linear warming trend over the last 32+ years, with all temperature records in agreement. * Not incidentally, accounting for the exogenous factors shows a warming trend demonstrating statistical significance of warming over periods as short as 11 years, since 2000! * Related skeptic memes that this is evidence against: It hasn't warmed since 1998, Climate is chaotic, "It's internal variability", It's a natural cycle, etc.Moderator Response: [DB] Fixed text per request. -
Foster and Rahmstorf Measure the Global Warming Signal
dana1981 - I would have to agree. I've read through that WUWT thread, and the singleton removals are numerically invalid for a multiple contribution case like this. You really need to perform a multiple simultaneous regression, or you overemphasize the contributions of the factor(s) you identify first. Interestingly enough, Bob Tisdale (a person whose work is sometimes criticized on Tamino's blog) has been posting on that WUWT thread objecting to Lansner's analysis on much the same grounds. It's good to see that at least a few of the people considered 'AGW skeptics' are willing to critique the opinions of others with that worldview. -
John Hartz at 07:20 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
dana1981: In plain Englsih, what are the take-away points of your post?Response:[dana1981] The main point is the last sentence of the post - the warming trend has remained very steady when these short-term factors are filtered out. I've added a concluding statement from F&R to clarify this point.
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dana1981 at 07:13 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
Somebody left a comment which was deleted due to a violation of the Comments Policy - it was just a link to a post on this paper by Frank Lasner on WUWT, suggesting that people should read his post for the sake of 'balance.' I don't agree - Lasner's analysis was extremely poor. For example, he tried to remove the factors one at a time rather than simultaneously (as Foster and Rahmstorf did) with multiple linear regression. This is a statistically poor approach. And in the end his results were effectively the same as F&R. Most of his criticisms of the paper were not valid. Another was the F&R use of TSI rather than sunspot number, but F&R clearly stated that they also did the analysis with sunspot number (and SOI rather than MEI, and a different measure of volcanic activity) and it didn't change their results significantly. As I said, it's a very poor analysis, and shouldn't be read just for the sake of "balance." -
sidd at 06:52 AM on 20 December 2011The End of the Hothouse
C B Dunkerson writes at 23:44 PM on the 16th of December, 2011: "But, in my hypothetical, there are these people who deny it is happening and oppose any action to address it." Not so hypothetical: http://www.washingtonpost.com/national/health-science/virginia-residents-oppose-preparations-for-climate-related-sea-level-rise/2011/12/05/gIQAVRw40O_story.html To paraphrase Haldane: People are not only more stupid than we imagine, they are more stupid than we can imagine. sidd -
funglestrumpet at 06:51 AM on 20 December 2011Arctic settles into new phase – warmer, greener, and less ice
This all fits with the report of giant (one kilometer dia) methane plumes rising to the surface in the Artic that have been discovered by Russian scientists. That's the trouble with tipping points, they slip by so silently - a bit like crossing the event horizon of a large black hole, you don't realise until it's too late. (I have never put a hyperlink in before and after reading in the tips section that if I get it wrong, it will screw up the page, I won't try this time either. The address off my computer is: http://news.yahoo.com/blogs/sideshow/giant-plumes-methane-bubbling-surface-arctic-ocean-163804179.html. I imagine that there is a more academic report somewhere.) -
Bob Lacatena at 06:36 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
A few observations of interest, looking at the animated graph: 1) Tropospheric temps (RSS and UAH) seem much more susceptible to ENSO events. The smoothing brings them much more closely in line with the surface observations in terms of variability. 2) Even after adjustment, the tropospheric temps still seem to be more susceptible to "dips" (particularly UAH). 3) MEI is clearly not a perfect indicator of ENSO events, as the timing of those peaks and valleys is still somewhat visible in the final graph. I wonder whether another measure of another ENSO-related variable would smooth things further. I'm not asking you to do the work (Dana), but now that I look at it and try to appraise it... it would have been nice to see the graphs from figure 2 and figure 3 separated and stacked (much like figure 2), but with the x-axis lined up, to let one visually see the factor, before and after graphically. -
cRR Kampen at 06:32 AM on 20 December 2011Arctic settles into new phase – warmer, greener, and less ice
Given the Arctic ice volume trend, it appears the ice cannot exist other than purely seasonal at present climate conditions already. I disagree with the title "Arctic settles into new phase" entirely. There is no 'settlement' - yet.Moderator Response: [John Hartz] The headline was written by NOAA's press office. -
scaddenp at 06:23 AM on 20 December 2011Models are unreliable
Eric - I am not sure where you see 0.3 on Soden. It says ~0.5K (text above Fig1) and that seems to match Fig 2a as well. The GCM predictions are helpfully on the same graphs and seem to match my assessment of "very accurate". -
Daniel Bailey at 06:18 AM on 20 December 2011Sea level fell in 2010
In addition to Tom's comment above, mace, please note that it can take several months to years for rainwater deposited into catchments and watersheds to return to the sea. A compounding factor is the replenishment of depleted aquifers. A nice, open-access, recent review is by Church & White 2011: Sea-Level Rise from the Late 19th to the Early 21st Century John A. Church • Neil J. White Surv Geophys (2011) 32:585–602 DOI 10.1007/s10712-011-9119-1
[Source]
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arch stanton at 06:01 AM on 20 December 2011Infrared Iris Never Bloomed
EOttawa @18 – That Seed article is very relevant. Gavin’s comment hit the nail – Lindzen sounds like a contrarian but he actually agrees with most of the mainstream science. Like many others that seek to sew doubt, he likes to throw stuff in the fan in the hopes… -
Yvan Dutil at 04:56 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
I have two questions: do you have the data in excel file (I don't want to run de R script even it is on the web) and do you know if there is a database of spatial temperature anomaly. I think there is some residual signal that could be removed from the data and I would like to check what it might be.Response:[dana1981] I have the data provided by tamino, which includes the raw and adjusted data. Some of it was in the Excel file he provided, and some was in a .dat file. I didn't run his R programs.
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John Hartz at 04:51 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
Dana: Is the version of Figure 2 with "Enso, Volcanic, Solar Removed" identical to Figure 1?Moderator Response:[dana1981] Almost but not quite. The points in Figure 1 are annual averages. For Figure 2, I just took a 12-month running average. So rather than having 1 point per year, Figure 2 has 1 point per month, each point being the average of the surrounding 12 months.
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John Hartz at 04:48 AM on 20 December 2011Foster and Rahmstorf Measure the Global Warming Signal
Dana: SkS readers who are not well-versed in climate science acronyms and terminology will have a hard time understanding the information presented in this article. -
Bob Lacatena at 03:57 AM on 20 December 20112011: World’s 10th warmest year, warmest year with La Niña event, lowest Arctic sea ice volume
44, mace, The NOAA has a simpler approach. Here is their ENSO Education page. Here is their general ENSO page. -
Bob Lacatena at 03:55 AM on 20 December 20112011: World’s 10th warmest year, warmest year with La Niña event, lowest Arctic sea ice volume
44, mace, This isn't the one I was looking for, but this post at Real Climate is a good introduction. -
Bob Lacatena at 03:50 AM on 20 December 20112011: World’s 10th warmest year, warmest year with La Niña event, lowest Arctic sea ice volume
44, mace, There's a lot to be learned about ENSO events to be able to answer your own question. I suggest you start with the National Weather Service Climate Prediction Center, although it's a bit "thick." I recently saw a simpler tutorial (there are a few around), but I can't remember where. If I dig it up, I'll add the link. -
mace at 03:35 AM on 20 December 20112011: World’s 10th warmest year, warmest year with La Niña event, lowest Arctic sea ice volume
What's causing this La Nina effect? Is the effect intermittent in some way. The dates in the article don't seem right. Looking at the records, it doesn't look like she kicked in until December 2010 and finished her merry dance in March 2011:- August 2010 3rd warmest September 2010 8th warmest October 2010 8th warmest November 2010 2nd warmest December 2010 17th warmest January 2011 17th warmest February 2011 17th warmest March 2011 13th warmest April 2011 7th warmest May 2011 10th warmest June 2011 7th warmest -
Tom Curtis at 02:59 AM on 20 December 2011Sea level fell in 2010
mace @16, the inland area of Eastern Australia, approximately the entire area of Queenland, New South Wales and Victoria inland of the Great Dividing Range, consists of three very large flood plains. The largest is the Murray Darling Basin, with an area of just over a million square kilometers. The Darling and tributaries drains nearly all of inland NSW, and a large section of southern Queensland, with a river system that drains into the Murray, and then into the sea in South Australia. Next largest is the Cooper Creek Catchment, with an area of 297,000 km^2. The Cooper Creek Catchement reaches as far north as my birth place, Mount Isa and drains into Lake Eyre, a normally dry salt pan below sea level. The area in Queensland drained by Cooper's Creek and the Diamantina (a tribuatary) is called the channel country because of the very large number of normally dry river beds that cross it.
(Click on picture for full sized photo, which is well worth the look.)
North of the Cooper Creek Catchment is the Gulf Country, a wide area drained by a number of intermittently flowing rivers into the Gulf of Carpentaria. The area of the gulf country is about 186,000 km^2.
Combined, all three flood plains have an area approximately half of the Mississipi Basin, but unlike the Missisipi basin, most of the area is arid with only intermittently flowing rivers. It is also exceptionally flat. Floods in the Cooper Creek in Queensland take 9-10 months to travel its 1,300 km length to Lake Eyre. The land is so flat that raging floods travel at the glacial pace of 0.2 km/hour. Water traveling to the Murray down the Darling takes a similarly long time. Consequently much of the 2010 Queensland flood is either just now reaching the mouth of the Murray, or reached Lake Eyre a month or so ago, where it will now sit until it evaporates away. The land was so wet that the rivers in the channel country still have water in them.
In addition to this natural storage, many of Australia's dams where at very low capacity before the floods, but are now very full. Wivenhoe Dam near Brisbane, for example, would have captured a volume of water close to that of Sydney Harbour (mostly during 2010). Combined that means a truly staggering quantity of water is being stored in Australia's river systems and dams which was not there 2 years ago.
Dikran Marsupial is correct. The amount of water involved is not enough to account for the dip in sea level in 2010 by itself (and Australia was certainly not the only area flooded in 2010). Never-the-less, that water which is stored in Australia's rivers will not return to the sea as quickly as it was taken from it. It will be five or more years before Australia dries out (assuming we do not have ongoing rainfall, which we currently have). I suspect similar stories can be told in many other regions of the world, so while I expect sea levels to resume their inexorable rise, it will not be an immediate turn around.
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mace at 01:28 AM on 20 December 2011Sea level fell in 2010
Hi Daniel Bailey, thanks for letting me post on more threads but I think I'll stick to just this one as I need to internalize my thoughts. The topic's about sea level falling, and the articles saying that this is because of more rain falling on the land than is normal. Obviously, rain would normally run off the land in to the rivers and oceans pretty quick, so I'm trying to think up why this hasn't happened in 2010. It dawned no me that it might be that it's being sucked in to the land, so I looked at the countries in figure 2 of the GRACE diagram, and Australia looked a likely candidate for this sponge effect. There definitely seems to be slightly more dark blue than dark orange in that picture, and the two can't be convoluted because the dark blue indicates higher quantities of surface lying water but it doesn't factor in how much has been absorbed in to the earth. The direct link is here:- http://grace.jpl.nasa.gov/news/index.cfm?FuseAction=ShowNews&NewsID=53 A Nasa climate scientist, Josh Willis, has put it more eloquently than I can, but I reckon he's saying the same thing. I guess we'll have to wait until next year for an update of the sea level data. Even if it doesn't show a bounceback, I think this could be due to a lagging effect as the water has to penetrate through the rock to get back to the sea. -
Daniel Bailey at 00:51 AM on 20 December 2011Sea level fell in 2010
mace, you are welcome to post comments to as many threads as you feel capable of carrying on a dialogue on with any who participate with you, provided you are on-topic for that particular thread and that your comments comply with the Comments Policy (here). That being said (per Dikran above), for better internalization of things learned, fewer is probably best. Also note that this is a science-based website, so any hypothesis one wishes to float would need be accompanied by supportive references to the peer-reviewed literature. -
Daniel Bailey at 00:04 AM on 20 December 2011Arctic settles into new phase – warmer, greener, and less ice
CBD, I believe you refer to the Tietsche et al 2011 paper. Note that a limitation of Tietsche is that the presumption is that stable CO2 concentrations have been achieved and equilibria with temps then reached. We are far, far from those conditions. Tietsche thus remains an academic construct. -
mace at 00:00 AM on 20 December 2011Sea level fell in 2010
Sorry about that Dikran. I kind of see your point now about Australia but I read the article and previous posts so just wanted to launch a hypothesis out there to see if any fellows felt it was plausible. The article also identifies Columbia, the US, Brazil and Pakistan as having some heavy flooding. I don't think it's quite so dry in those places, though, so I agree my hypothesis is probably falling down. I think I've only posted to 2 threads, so far but apologies again. I will confine my posts to just 1 thread in the future. -
Dikran Marsupial at 23:40 PM on 19 December 2011Sea level fell in 2010
mace@12 Please try to use some self-skepticism when putting forward a new hypothesis and at least apply a sanity check before posting. The surface area of the worlds oceans is ~3.6×10^8 km2, the surface area of Australia is only 7,617,930 km2, 1/47th of the surface area of the oceans. So for Australia as a sponge absorbing a 6mm rise in seal levels would be equivalent to absorbing 282mm of rainfall over its entire surface (most of which doesn't get much rainfall). Do you think that is at all plausible? If mean sea level were that sensitive to local flooding, it would bounce up and down like a yo-yo. Also I would suggest that you should confine yourself to discussion on a smaller number of threads. Your posts rather suggest a lack of basic knowledge on a number of basic topics, and posting wild theories like this gives the impression of trolling/spamming, especially when posted to multiple threads. This is intended as friendly advice, there is plenty of time to discuss these topics, and science is better served by depth of discussion rather than breadth. -
CBDunkerson at 23:24 PM on 19 December 2011Models are unreliable
mace wrote: "Can we conclude, that if the ice melts in Greenland, rather than the sea level increasing as many may expect, the global warming will cause seawater to evaporate and hang in the atmosphere." No. A warmer Earth does mean more water vapor, but the increased atmospheric water vapor content is much smaller than the increase in liquid water due to ice melt. The planet would have to get very hot (c.f. Venus) in order for that to stop being true. As to cloud feedbacks... there has been alot of research on the positive and negative feedback effects of clouds which you elude to. The exact net value is still uncertain, but it has been narrowed down to 'small'. That is, whatever the exact value it isn't going to have a major impact on the climate compared to the more prominent factors; CO2 forcing, water vapor feedback, and ice albedo feedback. -
CBDunkerson at 23:16 PM on 19 December 2011Arctic settles into new phase – warmer, greener, and less ice
I don't think there is any chance of the Arctic 'stabilizing' to a 'new normal' any time soon. Even if greenhouse gas levels magically leveled off we'd continue to see continued ice loss and related changes for decades, if not centuries, to come. I recall a study a year or two ago which concluded that if Arctic temperatures/conditions returned to 'normal' the sea ice could recover and therefor there was no 'death spiral'... which never made much sense to me because it should be obvious by now that there isn't going to be any 'return to normal'. That 'normal' is gone. The conditions which allowed it no longer exist.
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