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robert way at 17:25 PM on 14 February 20122000 Years of Climate Reconstructed from Pollen
I think that Kobashi et al (2011) might take issue with that final statement by Tom Curtis... If we're going to show Greenland temperatures we should show the work updated to present which Kobashi et al (2011) did... -
owl905 at 17:23 PM on 14 February 20122000 Years of Climate Reconstructed from Pollen
@Camburn - Misreading a response and pretzeling it back is sad. Your claim of a warmer arctic for a considerable amount of the past was bound to the pollen study (MWP), not to the 9kya Holocene peak. Your follow-on mish-mash of dates, adjectives, and claims only adds more embarrassment to the original fiction. Straight out - there is nothing in any of the proxies that makes the MWP warmer for a significant amount of time - quite the opposite, it shows brief spikes that matched the late 80s in some regions. To get a parallel to modern record levels, it's back to the Holocene peak - and that's a two-alarm observation. -
Tom Curtis at 15:44 PM on 14 February 20122000 Years of Climate Reconstructed from Pollen
Further to DB's comment (inline @14), here is the temperature record from Greenland (GISP2) showing modern temperatures for comparison:
As clearly indicated, by the green line, central Greenland temperatures where not warmer than current temperatures about 9,000 years ago. The green line should not be taken as an exact indicator, based on the methodology used to produce it. But it is accurate enough to show the 3 degree C difference was not universal in the Arctic.
Note also that by convention, reports of modern temperatures in paleo studies are based on 1950 temperatures unless otherwise specified, so the 3 degree difference reported by Camburn may in fact be a 0.5 to 1 degree difference from current temperatures in the 2000s.
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Norman at 15:29 PM on 14 February 2012NASA Mission Takes Stock of Earth's Melting Land Ice
Tom Curtis @53 "You quoted a figure from the total ground water used as irrigation and determined from that a projected increase in sea level. You did not mention recharge, and did not attempt to determine recharge before calculating the impact on sea level." Before my posting at 21, I had looked at this page. In post 21 I was not doing a highly detailed analysis, just demonstrating ball park numbers. "About 62 % of water used in agriculture, globally, comes from surface sources (e.g., rivers) while about 38 % comes from ground water (underground aquifers). However more of Earth's freshwater is in aquifers than in surface sources -- in fact, about 99 % of all liquid freshwater is in groundwater. (Issues in Ecol (9) 2001). Much (> 75 %) of this groundwater is "fossil water;" -- water that is not being recharged but is relic from wetter ancient climate conditions and from melting ice after the Pleistocene ice ages. Once we use it, it is "gone" for all practical purposes." source of quote. The Wikipedia article on irrigation gave the 545 km^3/year for irrigation. The above article made the claim that over 75% of the water used in irrigation was fossil water and is not being recharged at any appreciable amount (which is why I used the Ogallala Aquifier in my post to you, it is one of the types of Aquifiers that does not recharge very much and most the water withdrawn from it for agriculture will take a very long time to return). You call using the Ogallala Aquifier a "cherry pick", but I call it a demonstration of just how slow this type of aquifier fills up. The article I linked to above said over 75% of irrigation uses this type of aquifier. In your Post at 47 I am convinced that you and I are not making a communication link. "For what it is worth, the paper you link to estimates a global recharge rate of 15,200 km^3 per annum, and a withdrawal (abstraction) rate of 734 km^3 per annum. So withdrawal is only 5% of recharge globally, according to this paper. So, despite your continued cherry picking of the data, you have still not shown evidence that supports your claims, let alone establishes them." What I am talking about is removal of water from deep aquifiers that is not being replaced. If it is taken out from those aquifiers and not replaced, it is being added to the the surface water total amount. You are talking about groundwater recharge rate of 15,200 km^3 km/year (not recharge rates of deep aquifiers...a big difference) which makes sense it would recharge at this rate since this is the amount that is leaving the system (so it maintains balance)... "According to hydrologists and climatologists, about 15,000 cubic miles of water may evaporate from the earth's land sources each year. This includes water that moves through growing plants as transpiration. This value is less than 20% of the water that evaporates from all the seawater sources on earth." source. Finding the exact amount of water withdrawn from deep aquifiers minus replacement may not be possible. All sources I have researched would indicate it is much higher than the 61 km^3/year used in the paper KR linked to in previous posts but it has a large range. I can't agree with KR's sources as other peer-reviewed items state a much higher water removal. Tom, even when I completely explain the reason I gave you the Ogallala aquifier example you still call it a "cherry pick". Why do you keep making that claim and stating my intent is to mislead? The Ogallala aquifier was not used in my calculation. As you pointed out, they do not use any units on that web page. The purpose of bringing up that link was to give you a real example of the slow rate of recharge of a deep aquifier of which most irrigation uses (at least according to the source in the quote above making the claim over 75% of irrigation uses these slowly recharging wells). I think I have done a fairly decent job of research to show my point in global context. For reference check out the link in Post 43 and look at the table 7.4. -
Doug Hutcheson at 15:02 PM on 14 February 2012Peter Hadfield on Himalayan glacier melt
John Russell @ 3 et al Some of the comments to the Chivers article are priceless:I think its rubbish, and if it isn't, the cure is worse than the disease, I don't want to revert to the Stone Age.
If you want to know the truth about Arctic ice - check the blogs, don(t ask "the scientists"
If you, Tony, had been doing your job, you would have noticed a number of references to scientific work in the blogs, torpedoing the rising seas claims, papers and discussion about whether CO2 produces a positive feedback (the basis of the AGW scam) or negative feedback. The "consensus" is it is negative.
It's a regular 50-70 year cycle caused by the accumulation of iron in the ice.
We are putting more CO2 into the atmosphere, and the temperature is now gradually declining.
CO2 expands much more than air.
I inhabit SkS-space, because at least the comments appear to be rational. I struggle to understand the science, but at least I really do try. It is depressing how many people deny the science because they don't like what it says. Accumulation of iron in the ice? Riiiiight. -
andylee at 14:52 PM on 14 February 2012Peter Hadfield on Himalayan glacier melt
Thanks KR, that makes sense... but that ocean heat has to come out again somewhere as it is eventually distributed around the entire ocean through the various conveyor belts, nibbling (or munching) on ice shelves and glacier faces. -
owl905 at 14:27 PM on 14 February 2012Climate mythbusting at Lane Cove, Sydney on Feb 28
Best of luck with it. If you're looking for an intro grabber to frame the discussion, you might consider the cancellation of NOAA's detailed 20th-century climate reconstruction - because at a very fundamental level, this is a war about knowledge. http://www.scientificamerican.com/article.cfm?id=noaa-halts-reconstruction-past-climate -
Rob Painting at 14:18 PM on 14 February 2012CO2 is plant food? If only it were so simple
layzej- "Even if I were to trust that the four you selected are representative, I am not qualified to judge their merit." No need to rely on trust. You can search for yourself, just limit your search from 2010 onwards because that is representative of recent research (obviously). If you can find any paper that observes a net global benefit from increased CO2 I'd be interested. I haven't found one. "A source does earn credibility to the layman when he goes out of his way to point out when his own case is being overstated" There is no need for SkS to overstate things, the facts are what they are. The carbon cycle models assume a big CO2 fertilization effect this century, you can check the 2007 IPCC report for yourself. That this isn't being observed should be cause for concern, because we are talking about many decades worth of fossil fuel emissions (at today's burn-rate) staying up in the atmosphere. That there is a lot of extra warming if the CO2 fertilization effect doesn't pan out. I was surprised when he included this post among the ignorant.... As was I. Dawei's post is very well-balanced in my opinion - although it deals strictly with the effects on crops, rather than global vegetation. Nevertheless what John Nielsen-Gammon has written there is wrong. The man just hasn't done his homework. The tropics, and the Amazon in particular are in a precarious situation that could very rapidly turn the tropical forest carbon sink, the largest forest sink, into a source. Of course it may not happen, we are talking about projections after all, but the current trends are not encouraging. -
Camburn at 14:15 PM on 14 February 20122000 Years of Climate Reconstructed from Pollen
owl905@13. Thank for the links. Once again, the bow head whales confirm the Forest-Tundra was warm 1,000 YBP. Let me being by stating this is a paleo reconstruction is it not? When reading this paper, I think long term. When I state that the Arctic was warmer than present for a significant of time in the past, I deem several thousand years as significant. "During the first of these intervals (9000 before present) ice cores indicate that summer temperatures were about 3°C warmer than mid 20th Century." From the above link nrcan.gc.ca Think long term again folks. 3.0C warmer than the mid 20th century. DMI Arctic Temperatures: DMI Arctic Temperatures The temperature anomoly starts at 1958. Play around with it if you care to. You will see that Arctic Temps have not warmed 3.0C, according to this data anamoly set. The DMI is not to be used for actual temperature, it is an anamoly. With the anamoly, one can see the change in temperature, not the actual temperature. As I originally indicated, the Bowhead Whale proxy data suports the temp spike at approx 1,000 YBP provided by the pollin data. The Bowhead whale data supports the rangeing of the whales.Response:[DB] "During the first of these intervals (9000 before present) ice cores indicate that summer temperatures were about 3°C warmer than mid 20th Century."
In your rush to prop up your case you neglect the remainder of the quote (P. 5 of the linked pdf):
"There appears to be firm evidence from ice cores that the early Holocene was substantially warmer than the late Holocene in the northeast CAA (e.g., Fisher et al., 1995).
F. Koerner (pers. comm. 2000) estimates from melt-layer and isotopic records of the Agassiz Ice Cap that early Holocene summer temperatures were 3 ± 1°C higher than present. A strong early Holocene peak of bowhead bone abundance in the central and eastern CAA at 10 – 8 14C ka B.P. (Dyke et al., 1996a) may be explained by reduction of summer sea-ice cover due to that greater warmth.
However, changing ocean circulation patterns accompanying recession of the Laurentide Ice Sheet can also explain the bowhead peak (Dyke and Morris, 1990). It appears that neither increased warmth nor ocean circulation changes were large enough to clear summer sea ice from Norwegian Bay and areas north of there regularly during the early or the middle Holocene."
Emphasis added.
So it is noted that the numerical figures you quote
- were not a published figure
- were limited to only a portion of the Canadian Arctic Archipelago
- were not representative of even the Canadian Arctic as a whole
The use of DMI 80°N temps as being representative of the Arctic as a whole is a mis-step on your part. One, because it does not cover the entire Arctic and two, because summer melt and the nature of its gridding mean that it is biased low (resulting in it's misuse as a fake-skeptic's favorite toy):
The temperature series published earlier by Ranyl in this series is much more representative of Arctic temps, as can be seen here:
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citizenschallenge at 13:43 PM on 14 February 2012Fritz Vahrenholt - Duped on Climate Change
A couple days ago I had Vahrenholt's interview shoved at me with the implication being that here was further proof that the Global Warming conspiracy was finally being exposed. Reading it I was shocked at his transparent misrepresentations of IPCC and climatology in general. And disappointed that any thinking person would actually take his crazy-making seriously. Thank you for this thorough documentation of Vahrensholt's many misrepresentations. I look forward to sharing it ~ sadly though we can lead a denialist to information but, but . . . well we can always hope. -
layzej at 13:37 PM on 14 February 2012CO2 is plant food? If only it were so simple
Rob Painting @ 101, not scientific no, but I'm no scientist - just a mere mortal. There are about 27,000 hits on Google scholar for CO2 fertilization - more than I could possibly review. Even if I were to trust that the four you selected are representative, I am not qualified to judge their merit. For us mortals it really is a matter of trying to assess the reliability of our sources, and relying on them to honestly portray the literature. I look forward to reading the IPCC AR5 and finding out which of you came closest to their assessment. A source does earn credibility to the layman when he goes out of his way to point out when his own case is being overstated. Real Climate does a good job of this. JNG perhaps goes too far in this case. I recommended this SkS article to JNG's site as a source that gives an honest assessment of the effect of rising CO2 on plant growth. I was surprised when he included this post among the ignorant and/or [-preemptive snip-]. JNG may well have failed his own litmus test. I'll wait for AR5 before I judge. -
bill4344 at 12:55 PM on 14 February 2012Climate mythbusting at Lane Cove, Sydney on Feb 28
John Abraham don't much resemble a long-boiled crustacean in that graphic, do he? -
sauerj at 12:34 PM on 14 February 2012Climate mythbusting at Lane Cove, Sydney on Feb 28
John, do you plan on broadcasting the video of the event on SkS? This sounds really interesting; sure hope the rest of us will be able to see it!Response: [JC] I don't know if they're videoing the event and to be honest, I wasn't planning on going out of my way to ensure that happens :-) -
apiratelooksat50 at 12:32 PM on 14 February 2012Climate mythbusting at Lane Cove, Sydney on Feb 28
DB at 2 That's funny! -
sauerj at 12:23 PM on 14 February 2012Climate mythbusting at Lane Cove, Sydney on Feb 28
Note: First link (Climate Change: Busting the Myths) doesn't work.Response: [JC] Sorry, fixed the link which is to a PDF flyer of the event. -
Bernard J. at 12:10 PM on 14 February 2012Climate mythbusting at Lane Cove, Sydney on Feb 28
The truth is out there... -
owl905 at 12:05 PM on 14 February 20122000 Years of Climate Reconstructed from Pollen
Bowhead whale remains do not confirm a MWP Arctic warmer than the present from an early Dykes/England study: http://pubs.aina.ucalgary.ca/arctic/Arctic56-1-14.pdf (91K doc). There is a recent Swedish study that lays out proxy data for a double-spike around 1000 AD that exceeds modern values: http://www.medeltid.su.se/Nedladdningar/Poster_Ljungqvist_and_Grudd.pdf (328k doc) It doesn't appear to be a peer-reviewed publication, but the analysis seems solid. The most recent coverage available is based on the hypothesis that ice-core samples from 9kya parallel temps 4kya and 1kya - periods when bowhead whale remains have been found in the north-west passage (ergo it was ice-free in summer). http://www.nrcan.gc.ca/earth-sciences/climate-change/landscape-ecosystem/paleo-environmental/3947 Unfortunately for Camburn, "the Arctic was warmer during a significant amount of the past than present day temperatures." falls on its facia ... and the reconstructions also don't make a good case for the loss of Viking colonies collapsing due to falling temps. -
Daniel Bailey at 12:01 PM on 14 February 2012Climate mythbusting at Lane Cove, Sydney on Feb 28
Separated at birth???
Enquiring minds want to know...
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Camburn at 11:48 AM on 14 February 20122000 Years of Climate Reconstructed from Pollen
Sphaerica@4: You are correct, I was wrong. Thank you -
Pete Dunkelberg at 11:43 AM on 14 February 2012Climate mythbusting at Lane Cove, Sydney on Feb 28
I don't have any picture like that. Sigh. -
Camburn at 11:42 AM on 14 February 20122000 Years of Climate Reconstructed from Pollen
Tom@9: I have responded on the NW Passage blog. -
Camburn at 11:41 AM on 14 February 2012Northwest passage has been navigated in the past
Tom: I wasn't talking about the NW Passage, but that's ok. Bow head whale proxy data: Calgary Research Bowhead fossils Please note that the above paper mentions a period of low ice and expansion of bowhead whale domain approx 1,000 YBP which correlates well with the pollin proxy data of 2,000 years of Climate Reconstruction. -
Peter Hadfield on Himalayan glacier melt
andylee - That presumes all the energy imbalance goes directly into the ice. But only ~2.1% goes into the cryosphere.
80 * 0.021 = 1.68x (within a factor of 2 for back of the envelope), and given that recent years may have a radiative imbalance (not insolation) closer to 0.65 W/m^2, around 1.2x, so again fairly close for my rough numbers...
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robert way at 11:33 AM on 14 February 20122000 Years of Climate Reconstructed from Pollen
There are a range of indicators which show that the hypsithermal occurred in different places at different times because of the impact of ice sheets etc... Lets remember the ice sheets only disappeared in the NE portion of the Arctic about 6-7000 years ago. Anderson et al (2008) document significant ice melt 3000 years ago and before that on ice caps in the Eastern Canadian Arctic. There are many other papers which suggest such things. I preach caution when approaching this issue using the hypsithermal and insolation as analogues. -
Tom Curtis at 10:58 AM on 14 February 2012Northwest passage has been navigated in the past
Camburn elsewhere maintains that the N-W Passage was significantly warmer than current for long periods of the Holocene, citing as evidence Bow Head whale skeletons. My understanding is that bow head whale skeletons can be found across the length of the North West Passage during a period the preceding the Holocene Climactic Optimum:"The distribution and radiocarbon ages of whale remains indicate that during at least one interval of the Holocene, Bering Sea and Davis Strait bowheads could intermingle, (Figure 1b). The Bering Sea bowhead was the first to reach the CAA about 10,000 carbon-14 (14 C) years ago (11,450 calendar years B.P.). Bowheads entered via the Beaufort Sea about 1000 years after submergence of the Bering Strait, and they ranged up to the fronts of receding continental ice sheets [Dyke et al., 1996; Dyke and Savelle, 2001]. Until about 9500 14 C years B.P. (10,700 calendar years B.P.), by which time the Davis Strait bowhead ranged into the eastern Northwest Passage, the Bering Sea and Davis Strait stocks were separated by a glacier ice barrier. With dissipation of this barrier, the two stocks were able to intermingle, ranging well beyond historical limits. About 8000 14 C years B.P. (8900 calendar years B.P.), the Bering Sea and Davis Strait stocks were separated, as they are today. Thus, a year-round sea ice barrier must have become established at that time in the central part of the Northwest Passage."
(Fisher et al, 2006, my emphasis) In other words the NW Passage was open only for 1,800 year interval ending approx 9,000 years ago and there has been no skeletal evidence since for the intermingling of Atlantic and Pacific Bowheads. That strongly suggests any opening of the straits since then has been brief, and intermittent at best. For what it is worth, genetic evidence suggests the Bering Strait Variety of Bowhead are more closely related to the Hudson Bay stock than to the Davis Strait stock. It also indicates genetic separation of Hudson Bay and Bering Strait stock for at least 8,500 years; which is consistent with a forced separation by the closure of the North West Passage since before the Holocene Climactic Optimum. It should be noted that Atlantic and Pacific Bowheads have once again started intermingling. This evidence strongly suggests that the North West Passage and Canadian Archipelago was warmer than at present approx 10 thousand years ago at the last peak of northern summer insolation (red curve and figures):
However, it also strongly suggests it has not been warm enough in that region to maintain open waters since then, even though the Earth itself was warmer due to the gradually melting ice sheets.
Unless you have specific evidence of Bow Head populations intermingling in the North West Passage post 7,000 BC, you should stop using this evidence as though it suggested intervals of the passage being open throughout the Holocene. You frequently make that suggestion, but I see no evidence that supports it.
(Note: cross posted from here as I believe this to be the most germane place for this discussion.)
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Tom Curtis at 10:53 AM on 14 February 20122000 Years of Climate Reconstructed from Pollen
Camburn @3, my understanding is that bow head whale skeletons can be found across the length of the North West Passage during a period the preceding the Holocene Climactic Optimum:"The distribution and radiocarbon ages of whale remains indicate that during at least one interval of the Holocene, Bering Sea and Davis Strait bowheads could intermingle, (Figure 1b). The Bering Sea bowhead was the first to reach the CAA about 10,000 carbon-14 (14 C) years ago (11,450 calendar years B.P.). Bowheads entered via the Beaufort Sea about 1000 years after submergence of the Bering Strait, and they ranged up to the fronts of receding continental ice sheets [Dyke et al., 1996; Dyke and Savelle, 2001]. Until about 9500 14 C years B.P. (10,700 calendar years B.P.), by which time the Davis Strait bowhead ranged into the eastern Northwest Passage, the Bering Sea and Davis Strait stocks were separated by a glacier ice barrier. With dissipation of this barrier, the two stocks were able to intermingle, ranging well beyond historical limits. About 8000 14 C years B.P. (8900 calendar years B.P.), the Bering Sea and Davis Strait stocks were separated, as they are today. Thus, a year-round sea ice barrier must have become established at that time in the central part of the Northwest Passage."
(Fisher et al, 2006, my emphasis) In other words the NW Passage was open only for 1,800 year interval ending approx 9,000 years ago and there has been no skeletal evidence since for the intermingling of Atlantic and Pacific Bowheads. That strongly suggests any opening of the straits since then has been brief, and intermittent at best. For what it is worth, genetic evidence suggests the Bering Strait Variety of Bowhead are more closely related to the Hudson Bay stock than to the Davis Strait stock. It also indicates genetic separation of Hudson Bay and Bering Strait stock for at least 8,500 years; which is consistent with a forced separation by the closure of the North West Passage since before the Holocene Climactic Optimum. It should be noted that Atlantic and Pacific Bowheads have once again started intermingling. This evidence strongly suggests that the North West Passage and Canadian Archipelago was warmer than at present approx 10 thousand years ago at the last peak of northern summer insolation (red curve and figures):
However, it also strongly suggests it has not been warm enough in that region to maintain open waters since then, even though the Earth itself was warmer due to the gradually melting ice sheets.
Unless you have specific evidence of Bow Head populations intermingling in the North West Passage post 7,000 BC, you should stop using this evidence as though it suggested intervals of the passage being open throughout the Holocene. You frequently make that suggestion, but I see no evidence that supports it.
(Note: to moderators, I believe this post to be on topic here because, although I most frequently refer to the N-W Passage, the associated Canadian Archipelago temperatures are clearly on topic. I have also cross posted in the N-W Passage blog, and recommend Camburn responds there.)
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Bob Lacatena at 10:48 AM on 14 February 2012Satellites find over 500 billion tons of land ice melting worldwide every year, headlines focus on Himalayas
So... 500 billion tons = 5 x 1017 grams. 333 Joules to melt 1 gram of ice, or 5 x 1017 grams * 333 J/g = 1.665 x 1020 J Surface of the oceans of the earth is 360,000,000 km2, convert to square centimeters multiply by 10,000,000,000, or 3.6 x 1018. So Joules per square centimeter of ocean = 1.665 x 1020 J /3.6 x 1018 cm2 = 46.25 J, per year, per square centimeter of ocean. Energy to raise 1 g (roughly 1 cm3 of ocean at 4˚C) by 1˚C = 4.2 J. 46.25 J/cm2 / 4.2 J˚/cm3 = 11 ˚-cm Or enough energy per year to raise the top 11 centimeters of every inch of ocean on the surface of the earth by 1 degree. Alternately, enough energy to raise the temperature of roughly the top meter of the earth's oceans by 0.1˚C per year. Ten years of that and you've raised the temperature of the top meter of the ocean by a full degree. -
robert way at 10:40 AM on 14 February 20122000 Years of Climate Reconstructed from Pollen
The modern period refers to the 1961-1990 average. Yes the baseline refers to that period. The end dates and the start dates for the MWP and LIA are 800-1200 AD and 1400-1850 AD respectively. -
andylee at 10:34 AM on 14 February 2012Peter Hadfield on Himalayan glacier melt
@KR, I presume +0.9 W/m² is average insolation, but there must be a reason that it has taken 8 years and not 1.2 months to melt this amount of ice. This is a difference of 80x, so how to account for it? If this imbalance continues, then it has the capability to eventually melt most ice - if the ice goes, there'll be nothing holding back thermal runaway until the Earth reaches thermodynamic equilibrium again and reradiates as much as it receives. I don't see oceans boiling, but the increase of a few degress would definitely be a Bad Thing. -
Tom Curtis at 10:15 AM on 14 February 20122000 Years of Climate Reconstructed from Pollen
Robert Way, a very interesting post. To help me interpret it, 1) What are the start and end dates for the MWA and LIA periods used in the comparison in figure 2; and 2) Does the 0 degree baseline in the temperature anomaly graphs in figure 3 represent the average over the 1961-1990 "modern" interval. Also, it may be helpful to mention the modern interval within the post rather than relying on readers reading the abstract. -
andylee at 10:11 AM on 14 February 2012Peter Hadfield on Himalayan glacier melt
Rob @17, thanks - I'd like to think that most people can quantify an average 1GW power station, however nebulously. 1 million 1kW heaters is a lot of power! The UK has 75 GW of generating capacity, about 1kW per person. Humanity uses and wastes orders of magnitude more energy than it should need. -
Doug Hutcheson at 10:09 AM on 14 February 2012The Year After McLean - A Review of 2011 Global Temperatures
muoncounter @ 27 Thanks for the link to the video. I enjoyed the simple demonstration when it was first posted at SkS and use it as an example when talking to people. Cute doggy. KBow @ 26 Thanks for the link to the Khan Academy. I am excited by the prospect of breaking through the education barrier and that site looks very promising. I have the home page open as I write and many topics are jumping out at me to be studied. Looks like a great resource and it is now in my Favourites. "8-) -
ranyl at 09:26 AM on 14 February 20122000 Years of Climate Reconstructed from Pollen
True Camburb, but from the abstract the present day is taken as the 1961-1990 average temperature. Hasn't the arctic heated a little since then???
Response:[DB] Please limit image widths to no more than 500 pixels.
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Daniel Bailey at 09:22 AM on 14 February 20122000 Years of Climate Reconstructed from Pollen
Colour me skeptical, Camburn, but you make yet more unsupported assertions. Got any peer-reviewed sources from reputable journals that tie those two proxies into such an Arctic-wide presumptive statement? It's Ok, I'll wait... -
Bob Lacatena at 09:21 AM on 14 February 20122000 Years of Climate Reconstructed from Pollen
3, Camburn, No. The proxy shows temperatures at most 0.6 degrees C over about 1950, not present day. By contrast, annual temperatures in 2011 in that same region were 1 to 4 degrees warmer than 1950-1980 baseline. Today's warming is very frighteningly beyond what the proxy says. Robert Way, To clarify things for Camburn... what is the latest date on the proxies for that region? -
Tristan at 09:17 AM on 14 February 2012Melting ice isn't warming the Arctic
If more energy has been 'used' to melt ice than predicted, does it follow that less energy will have gone into heating the ocean/atmosphere than predicted? If so, how much less 'heating' would we have seen since the ice decline parted company with the IPCC predictions? -
Tristan at 09:12 AM on 14 February 2012Temp record is unreliable
Any word on how much HadCRU4 will rectify this discrepancy? -
Camburn at 08:30 AM on 14 February 20122000 Years of Climate Reconstructed from Pollen
One item of note is the temperature of the forest-tundra area, figure 3. The pollen proxy data is confirmed by bowhead whale proxy data in that the Arctic was warmer during a significant amount of the past than present day temperatures. -
Yvan Dutil at 08:14 AM on 14 February 20122000 Years of Climate Reconstructed from Pollen
I am always amaze hot much scientist can do with fragmented data! Nevertheless, I wonder how figure 2 and 3 refer to the same values? -
Peter Hadfield on Himalayan glacier melt
andylee - On the other hand... At a TOA imbalance of 0.9 W/m^2, with an Earth surface are of of 5.1x10^14 m^2, the imbalance adds up to 459 TW (not GW)! Or sufficient energy to melt that ice in 1/10th of a year. -
william5331 at 06:33 AM on 14 February 2012Peter Hadfield on Himalayan glacier melt
Nice comment by John Russell (I'm paraphrasing) on how the air stays the same temperature in the vicinity of ice as latent heat keeps the whole system at or around 0 degrees C. Once the ice is gone, the incoming heat can warm the air. How much truer in the case of the Arctic ocean. As long as the ice is there in large quantities, the Arctic ocean will stay around 0. When it is gone we should see some real temperature rises. Watch the clathrates break down then. -
David Lewis at 06:24 AM on 14 February 2012Peter Hadfield on Himalayan glacier melt
Ice doesn't have to melt to contribute to sea level rise Eg: Williams et.al.: Evidence for iceberg armadas from East Antarctica... -
Roger D at 06:09 AM on 14 February 2012Peter Hadfield on Himalayan glacier melt
Very informative video on the significance of what the study implies regarding sea level contribution and contributions from different melt sources – thanks. If I can, I’d appreciate any input from people on something I’m not clear on. I’m enquiring because I anticipate that a – cough- “skeptical” friend of mine, a very nice person, but who seems to be unaware of the difference between science and a headline in the Telegraph, might bring this up soon. Question: In hindsight it does not seem surprising to me that the ratio of shrinking to growing glaciers documented for observable/ measurable glaciers that are comparatively accessible to researchers would not match what this study found using GRACE data for higher elevation glaciers in the Himalayan Range. In short, I’m wondering if anyone can say whether or not the “answer” that is derived from the GRACE data could have, should have, or may was expected simply based on temperatures in the high Himalayas. Or are there gaps in temperature coverage for the Himalayan range that might have made such a seemingly logical expectation (i.e. the % of glacier shrinkage at comparatively lower altitude is greater than at very high elev.) less straightforward than what it seems to the layman like me? Hope that made some sense and sorry for the basic-ness of the question. -
David Lewis at 05:58 AM on 14 February 2012Peter Hadfield on Himalayan glacier melt
Tad Pfeffer, one of this paper's co-authors, was recorded on video as he gave the Nye Lecture at this year's AGU. He noted that the status of glaciology as a science has changed somewhat since 1960, when its definition was included in "Mrs. Byrnes Dictionary of unusual, obscure and preposterous words". "We're in the spotlight now" He talked about the strengths, weaknesses, and limits of glaciology. The importance of sea level rise to civilization makes glaciology an "applied science", as opposed to the more purely intellectual endeavor it once was, he said. He called attention to the great efforts scientists in his field are making to provide global data and analysis at this crucial time: "Up until recently our inventory, our knowledge of where the glaciers are in the world and how big they are - this isn't just a matter of the total area or volume of ice in the world, but what's the area and elevation of distribution - we only knew that for about 48% of the glaciers in the world and even that was brought up from about 40% - 48% ... in 2009. This increase from 48% to nearly 100% has been accomplished by this group of about 40 contributors... in one year in anticipation of AR5 and I think its a magnificent accomplishment" One thing I found when comparing the chart of data from the Jacobs et.al. study that was published in the Guardian (I haven't been able to get the actual paper yet) to Hansen's estimates for what is going on published in his Earth's Energy Imbalance and Implications paper, i.e. his Figure 14, was that Hansen's mean value for the total contribution from Antarctica and Greenland to sea level rise was 0.85 mm/yr, whereas what Jacob et.al. found was 1.06 mm/yr. I.e., Jacob et.al. find that in the regions where most of the remaining ice on the planet is, ice mass loss is greater than what Hansen recently thought. -
John Russell at 05:31 AM on 14 February 2012Peter Hadfield on Himalayan glacier melt
It's also worth remembering that it takes 80 times more energy to melt a block of ice at 0 degrees C into water at the same temperature, as it does to raise the temperature of the same amount of water by each subsequent degree C. This phenomenon is called the 'enthalpy of fusion'. It means there is an inherent 'inertia' in temperature when a large amount of ice is present in an area. Air temperatures will then tend to rise much faster in an area once the ice has gone, as it requires less energy to warm it up. -
Rob Honeycutt at 04:38 AM on 14 February 2012Peter Hadfield on Himalayan glacier melt
andylee... "Context: It would take a 1GW power station 45,439 years just to melt this much ice! " That's a fantastic way to state it. -
owl905 at 04:24 AM on 14 February 2012Peter Hadfield on Himalayan glacier melt
@Dr Joju - thanks for explaining the different percentage references. -
owl905 at 04:20 AM on 14 February 20122000 Years of Climate Reconstructed from Pollen
If this means another addition to the hockey team, give them the sweater with #10 on it - that was Guy La Fleur's tag. -
Neven at 04:15 AM on 14 February 2012A prelude to the Arctic melting season
gpwayne, you are absolutely right. I will put a colour bar showing percentage of sea ice concentration in next time (you can see it here at the source). Of course, the emphasis in this post was on ice cover vs open water. -
Tristan at 04:09 AM on 14 February 2012Measurements show Earth heating up, think tanks & newspapers disagree
I'm trying to find the met office release that the daily mail cited, but I cannot locate it, any help would be much appreciated (it'd probably be good to link to it in this article as an example of how to misinterpret research).
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