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Alexandre at 23:30 PM on 29 April 2010Common graphical tricks and the Medieval Warm Period
Arkadiusz #7 What happens when you put all those in a statistical, comprehensive reconstruction (global or at least hemispheric)? To cite local reconstructions is like cherry picking 100 Chinese companies that are having bad results to "prove" that Chinese economy is not growing. -
silence at 23:16 PM on 29 April 2010Common graphical tricks and the Medieval Warm Period
I assume "They are showing you that the last decade was warmer than any 50 year period on the graph including the MWP." is meant to read: "They are not showing you that the last decade was warmer than any 50 year period on the graph including the MWP. -
Ken Lambert at 23:06 PM on 29 April 2010Tracking the energy from global warming
Typo in #88 "If you average *Jason* you get a linear fit from +14mm to +26mm in the period 2003-2010 say 7 years. This is 1.7mm/year not 3.2mm/year." -
Ken Lambert at 23:04 PM on 29 April 2010Tracking the energy from global warming
Chris #86 We indeed have different eyesight. Your graph in #76 has two distinct sections - Topex to 2002 and Jason 2002-2010. If you average Topex you get a linear fit from +14mm to +26mm in the period 2003-2010 say 7 years. This is 1.7mm/year not 3.2mm/year. There is a jump from +6mm to +12mm at the transition between Topex and Jason, likely indicating a calibration error. 1.7mm/year is consistent with the number mentioned in Dr Trenberth's Aug09 paper. Interestingly the CSIRO paper cited in Dr Trenberth's discussion finds a much better fit of sea levels with a model including volcanic forcings than not; which indicates that these might be more significant than the transient effects hitherto assumed. -
CharlieAus at 23:01 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
Could we get some more info on you talking at UQ? Do you need to be a student to attend?Response: Just got the final details myself - will add a post later today giving details. You don't need to be a student to attend. -
nautilus_mr at 22:45 PM on 29 April 2010Common graphical tricks and the Medieval Warm Period
Nicely done Brendon. This thread goes straight into my "saved" list. A quick comment on the Sicre-2008 link: I'm not sure I agree with you that the Labeling of MWP on the chart is misleading. CO2 Science do use the actual SST chart, including labels, from Sicre et al. They have altered it though, by adding their own green "modern temperature line". They put the line at 9°C -a modern day "average' of their own selection to be sure. I couldn't find a modern day SST average for the seas around Iceland, but This paper by Jiang et al demonstrates on page 2 that the peak warmth of the medieval period was a good 2-3°C lower than recent peaks. I am not in a position to calculate averages from this data, but I would suggest CO2 Science's 'thin green line' deserves some skepticism. -
Arkadiusz Semczyszak at 22:33 PM on 29 April 2010Common graphical tricks and the Medieval Warm Period
Oh well. 1950 y - proxies finished? Let me quote (one of the most recent - 2009.) 2 publications that I was able to quickly find: 1. von Gunten, L. et al. 2009. A quantitative high-resolution summer temperature reconstruction based on sedimentary pigments from Laguna Aculeo, central Chile, back to AD 850. The Holocene 19 : 873-881. „Von Gunten et al. developed a continuous high-resolution (1-3 years sampling interval, 5-year filtered reconstruction) austral summer (December to February) temperature reconstruction based on chloropigments derived from algae and phototrophic bacteria found in sediment cores retrieved from Central Chile's Laguna Aculeo (33°50'S, 70°54'W) in 2005 that extended back in time to AD 850.” "... quantitative evidence for the presence of a Medieval Climate Anomaly (in this case, warm summers between AD 1150 and 1350; ΔT = +0.27 to +0.37°C with respect to (wrt) twentieth century) and a very cool period synchronous to the 'Little Ice Age' starting with a sharp drop between AD 1350 and AD 1400 (-0.3°C/10 years, decadal trend) followed by constantly cool (ΔT = -0.70 to -0.90°C wrt twentieth century) summers until AD 1750." It is obvious here, that max. warmth of the MWP is about 0.5°C higher than that recorded for the past two decades (!!!) of the 20th century ... 2. Oppo, DW, Rosenthal, Y. and Linsley, BK 2009. 2,000-year-long temperature and hydrology reconstructions from the Indo-Pacific warm pool. Nature 460 : 1113-1116. Here MWP was about 0.4°C warmer than the Current Warm Period. Well, it is worth mentioning: Grudd H, (2008): Torneträsk tree-ring width and density AD 500 – 2004 [!!!]: A test of climatic sensitivity and a new 1500-year reconstruction of north Fennoscandian summers. Climate Dynamics, 31: 843-857. “The new data show generally higher temperature estimates than previous reconstructions based on Tornetra¨sk tree-ring data. The late-twentieth century, however, is not exceptionally warm in the new record: On decadal-to-centennial timescales, periods around AD 750, 1000, 1400, and 1750 were EQUALLY WARM, OR WARMER.” These are just some "cherry picking" from my references. Which is interesting: the recent - later works - the MWP warmer ... -
aj1983 at 22:23 PM on 29 April 2010Common graphical tricks and the Medieval Warm Period
What they will usually propose as a counter argument is that 1) the proxy dating can be off somewhat, 2) the proxy data is a >50 year average, so you have to compare it with the >50 year average now, which is (not yet?) the highest. If the temperature keeps on rising it will be a waiting game until the latest 50 year average will be above those of the previous 1000 years. They should include the resolution of the proxy data in the graph so that you can find out if the "peaks" are for example 5 year, or 50 year "averages". -
Brendon at 21:38 PM on 29 April 2010Common graphical tricks and the Medieval Warm Period
mautilus_mr, here's the main part. Note this is part of an argument about MWP. -------------------------------------------- CO2Science is pretending to be thorough and systematic by listing a lot of research and categorising them by wether they are warmer than today or not. And thus they prove MWP was warmer ... but do they really? Well it's not hard to debunk them. It's taking me far longer to write this up than it did to see their errors. And I'll also point out how some of the graphs are trying to Not only that, there's some examples of misleading graphs that are obscuring the fact that the data for their MWP is not warmer than today. Temperature reconstructions are done using a lot of studies from around the world. Each one contributes a small picture of what it was like in that part of the world, depending on the geography this can be a very localised effect, or it can be representative of a much larger area. What CO2Science are doing is looking for any warm part in each of localised data, then labelling that as the MWP, regardless of the dates involved. Firstly take notice of what is commonly regarded as the MWP period, a time from AD 950–1250, that's 300 years centered around AD 1100. Now lets examine a few of the examples from CO2Science that I listed earlier. Sicre-2008 notice that their label for the MWP sits over the AD 1000-1300 and avoids the lower temps in the 950-1000 period. Take that into account and the average temps are below CWP. Look at the smoothed red line (running average) and it sits below modern day temps for almost the entire MWP. Paulsen-2003 – they have the MWP centered around AD1300. For the actual MWP, 950-1250 the average is well below todays temp (shown on the left). Althoug even if you did take their proposed relocation of the MWP, it still would be cooler than today. Kitagawa-1995 – (note graph is inverted here – warming is downwards). On initial viewing this show mostly good warming but some radical cooling amongst it too. So what's up with that? Well firstly have a look at the number of samples used to construct this graph. It contains very few samples and hence you can't get good confidence from it. The graph only goes to 1950 so it doesn't include more recent decades of warming. It also has a baseline (horizontal line) that is well below (temp-wise) the CWP, but this baseline is not the CWP. The average person might be fooled ito thinking the basline was "normal" temps, but if you look closely you'll see todays temps are higher than the average for the MWP. Zhang-2003 – the label for MWP is again off by a couple of hundred years in order to make the reader think it includes the higher parts of the graph rather than one high and one low. Abcde would also probably point out that this is tree-ring data, hence the large variation would also attract large error bars. Loso 2008 sadly for you this one completely fails to provide evidence that the MWP was warmer than today. Even though they did their best to move the MWP away from AD950, the warming it shows doesn't compete against the decade upon decade of recent warming. -
nautilus_mr at 21:28 PM on 29 April 2010Common graphical tricks and the Medieval Warm Period
Brendon, your link denied me access! 'tis a shame, I'd very much like to check that stuff out. Perhaps a different pathway into the thread? CO2 Science is a slippery example, isn't it? Not as blatant as the example in Mark's article - it looks like a duck, walks like a duck, only when you listen closely it's saying "woof". -
nautilus_mr at 21:25 PM on 29 April 2010Common graphical tricks and the Medieval Warm Period
A very clear and useful article, Mark. I think that Durkin, Plimer, Monckton et al are extended an undeserved courtesy by being called 'skeptics', however. These people are not within a bull's roar of real skepticism. It is appropriate to call them deniers. Yikes, it seems the trouble with 'skeptics' these days, is they'll believe anything! -
Brendon at 21:23 PM on 29 April 2010Common graphical tricks and the Medieval Warm Period
CO2science do a similar dodgy job with their analysis of the various studies into temperature reconstruction of the MWP. They classify each localised study by whether it (MWP) was warmer than the current period (CWP) or not. But for each study they vary the time period they call the MWP. They pick out the highest part of the data near the MWP and then label that as the MWP even if it's a few hundred years away from other studies. Sometimes they label the MWP as being centered around 1300AD, sometimes at 800AD. Good description with examples in Whirlpool thread -
MarkR at 21:14 PM on 29 April 2010Common graphical tricks and the Medieval Warm Period
If anyone can pick holes in my approach, please let me know. I added the lines to the graph using pixel counting and may have made a mistake there so I'll double check later but if you notice a mistake, do shout out! -
Riccardo at 21:13 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
Argus, explicit or not, there are always assumptions when talking about the future. Here comes the physics of climate, which we cannot ignore so easily. -
JulianRGP at 21:12 PM on 29 April 2010Why are there fewer weather stations and what's the effect?
Hi, can you clarify for me the statement near the end of the article, which says "More importantly, the dropped stations do not cause a spurious warming trend." At first, it seems like it's saying "The dropped stations when considered by themselves do not cause a spurious warming trend." In the context of this article, I think you don't mean that. Do you actually mean "More importantly, removal of the dropped stations does not cause a spurious warming trend."? Apologies for being picky, but it puzzled me when I looked at it at first. Thanks for fixing the glitch that prevented comments being added (after #10).Response: Good point, your wording is an improvement and I've updated the text in the final paragraph. Thanks for the feedback. -
Argus at 20:59 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
#15 Berényi Péter I would very much like to know the background for the 'LOL' in the editorial response to his graph: ''Response: LOL, can I ask what value you used for the total ice mass of the Greenland ice sheet and your source?'' As far as I can see his figures are correct (also noted by #22 CBDunkerson), and it would take 10000 years for the ice to completely melt at the present rate. Of course if we assume various kinds of increased ice loss rate, it will take less, but such assumptions are nothing more than assumptions based on a very small number of years. Why worry when we can do nothing about it anyway?Response: The LOL wasn't meant to cast doubt on BP's graph - I just thought it was cool that he went to the trouble to track down the Greenland ice sheet total mass and draw a graph about it. -
kdkd at 19:52 PM on 29 April 2010Has Arctic sea ice returned to normal?
Just to follow up from Riccardo #62, the polar amplification has been a prediction of warming caused by greenhouse gas pollution for a very long time. Run the models with e.g. a solar cause of warming, and the polar amplification doesn't happen, but with increased greenhouse gasses, and TADA there it is. I'm afraid I can't provide a reference without going and digging on my bookshelf, but I can assure you that it's a clearly stated prediction in at least one of the ~ 20 year old environmental science textbooks in my possession. And being in a textbook, that makes it a mainstream prediction. -
Riccardo at 19:17 PM on 29 April 2010Has Arctic sea ice returned to normal?
Not exactly in topic but related. A new paper in Nature used the latest ERA reanalysis product (called ERA-interim) to study the possible causes of the well known polar amplification. They found that the impact of sea ice reduction is the largest contribution to the effect, more than atmospheric transport which is commonly believed to be dominant. They also considered humidity and cloud cover as possible causes. One of the improvements of ERA-interim reanalysis is a more realistic troposheric temperature derived from satellite based irradiance measurements, which overcomes the lack of land based temperature measurements. -
Paul D at 19:03 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
Gallopcamel said: "Can mankind control sea levels? I don't believe we can but I am open to persuasion if you can explain how to do it." The Ville: 1. I don't see why anyone is obliged to persuade you. 2. No one has suggested that they want to control sea levels directly, which is what you are implying. 3. The issue is the control of human influences on the environment that they inhabit. That we do have a responsibility for. -
Paul D at 19:00 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
GallopingCamel said: "TOPEX is providing really accurate measurements. Currently the rate of sea level rise is averaging ~3.2 +/- 0.4 mm/year." The Ville: And those rates are changing and have been changing. Also the proportion attributed to thermal expansion and melting ice has changed over a relatively short period. -
Paul D at 18:52 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
@52 and GallopingCamel: "At the present rate it will take 1,000 years for the seas to rise 3 meters. If that rise happens, our distant ancestors will have plenty of time to move to higher ground." As pointed out, current rates will not be maintained. So the scenario is unlikely. But to clarify your point. Time is what most skeptics and deniers ignore. You yourself are proposing to ignore the problem because you believe it to be a distant problem. The result of such a stupid philosophy is that the infrastructures that are permanent will be expanded and in 1000 years from now, under your scenario they will have even bigger problems then if the same occurs in only 200 years. The longer you leave it, the bigger the problem gets. Your attitude is the problem, not the time scales or the science. -
barry1487 at 18:03 PM on 29 April 2010Why are there fewer weather stations and what's the effect?
A question that skeptics often ask, and which I can't quite answer, is - why can't a small team be supplied to collect the huge amount of weather data available online. Example is La Paz, which is not included in recent GHCN, but which has an online weather portal with mean/max/min temps, precipitation etc. My initial response is that it takes time to sort the online data into GHCN format - there's no one chip catches all computer program that can be utilised to translate data from a variety of websites with a variety of formats. GHCN rely on participating Met stations who provide the monthly data in the format required. But I'm not dead sure that this description is precisely accurate, just what I've gleaned from reading blogs. It would be nice to get a straightforward but detailed description of the challenges the data collectors face, especially so skeptics can understand why, in the age of light speed information and broad access, it is not a simple matter to retrieve the abundant, daily updated online data for many stations/met services not covered by GHCN. -
gallopingcamel at 17:02 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
scaddenp (#59), You will find that my numbers in (#57) are consistent with those in the link that you sent me. Look closely at "Figure 3" and you will see 1,900 mm of sea level rise by 2010. If the rate of sea level rise is going to increase by a factor of more than six during the 21st century, something dramatic needs to happen very soon. I don't disagree with your qualitative arguments; the problems appear when one tries to quantify them. Likewise, Phila (#60). Let us suppose that you could reduce the amount of CO2 in the atmosphere by a factor of 2 (to 194 ppm). This would be close to the concentration that will cause most plants to die but what would be the effect on sea levels? -
nautilus_mr at 16:56 PM on 29 April 2010Why are there fewer weather stations and what's the effect?
re # 18, sorry, but I don't see how the D'Aleo article you link to shows at all that "if you look at only the U.S. temperature sensors that remain in a 'rural' environment, you will not see the 'hockey stick' increase." The claim is false in any case, but your source doesn't even support you. In fact, the D'Aleo article is confused about many of the same matters already discussed in this thread. I strongly recommend any readers of this site check out the US EPA's response to these questions. The EPA, following its recent "Endangerment and Cause or Contribute" findings, was obliged to respond exhaustively to over 300,000 emails -many objecting to the findings. For the UHI, start from page 16 of the PDF: EPA RTC Volume 2 ) It is a thorough and methodical treatment. A resource to keep. (EPA report previously reported here, by the way: EPA Report -
Phila at 16:18 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
#52 gallopingcamel "Can mankind control sea levels? I don't believe we can but I am open to persuasion if you can explain how to do it." Echoing scaddenp (#51), if temperature can influence sea level, and GHGs can influence temperature, and human beings can influence GHG emissions, then it seems logical to say that human beings can influence sea level. For which of these propositions do you feel there is "no credible scientific evidence"? -
JRuss at 14:48 PM on 29 April 2010Why are there fewer weather stations and what's the effect?
If you look at only the U.S. temperature sensors that remain in a 'rural' environment, you will not see the 'hockey stick' increase in global temperature. Most of the 'hockey stick' increase is due to sensor contamination of human heat sources. sensor contamination You also might find the following interesting: Space & Science Research Center -
scaddenp at 14:47 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
gallopingcamel - your questions about future sea level rise predictions are better placed in sea level rise predictions -
scaddenp at 14:39 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
Nor does modelling expect there to be. What is expected is acceleration as ice melt gains pace, albedo reduces and sea temperature rise bring rain onto icecaps. Try looking at sealevel rise rates over last millennium, compared to this century, compared to last 50 years. More in is sealevel rise exaggerated? Are you prepared to admit by the way that a greenland ice melt that contributes to a 1m rise by end of century might actually be a problem? -
gallopingcamel at 14:12 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
scaddemp (#56), TOPEX is providing really accurate measurements. Currently the rate of sea level rise is averaging ~3.2 +/- 0.4 mm/year. The rate of rise is not showing any kind of "Hockey Stick" tendency that should be evident if sea levels are to rise by 1,900 mm (AR4 worst case) in the next 90 years (21 mm/year). -
scaddenp at 14:11 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
Climate is not single-variable. Try the extremely strong correlation between temperature and all forcings. eg Benestad & Schmidt for an example of a statistical approach but the models are even better. The science has worked hard to estimate the size of all feedbacks and so far any globe-saving negative forcing has been extremely illusive. John Cook's summary on why GHG is the dominant forcing acting now is mighty good summary. If you have data to dispute this, then please post and continue the argument in the relevant place. So far this is a long way from your opening gambit that greenland's melting ice is a good thing. -
johnd at 13:49 PM on 29 April 2010Why are there fewer weather stations and what's the effect?
Phila at 12:05 PM, if anyone does follow up with a post perhaps they could illustrate it by using the Global Land Index, figure 2 above, with the base period set as 1880-1890. I don't know what period is used at present, I'm guessing 1960-70 as that was used for figure 3. A graphic illustration should be easier to demonstrate what difference, if any, different base periods make. -
gallopingcamel at 13:45 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
scaddenp (#54), The world is in an "Ice Age" as we still have polar ice caps. Currently we are fortunate to be experiencing an "Interglacial" period characterised by relatively high temperatures. Over millennia, sustained high temperatures cause ice to melt and oceans to rise. Hopefully we are in agreement up to this point. When you say that we are causing temperatures to rise by generating GHGs I still agree with you. When it comes to quantifying humanity's contribution to the undeniable "Global Warming" that has occurred since 1850 we may diverge. While basic physics can show that a doubling of CO2 concentration should increase global temperatures by ~1.2 degrees Celsius, there is the question of feedback. Do other natural processes increase or diminish the effect of radiative forcing? Given the poor correlation of global temperature with CO2 concentration I consider it likely that natural effects are overwhelming the "Anthropogenic" influence. -
scaddenp at 13:11 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
"Mother nature" is a very confusing term. Global sealevel responds to changes in temperature. I dont think you can postulate any other causes on time scale of million years or so. Do you seriously contest that temperature is NOT the cause of global sealevel temperatures? Since we are causing temperatures to rise thanks mainly to our GHG emissions, then of course we are influencing sea level. -
gallopingcamel at 13:03 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
Phila (#45), I can't prove that it is "impossible" to influence the rate of rise of sea levels. To the contrary, Mother Nature does it all the time, proving that it is possible. Can mankind control sea levels? I don't believe we can but I am open to persuasion if you can explain how to do it. -
gallopingcamel at 12:54 PM on 29 April 2010A visual depiction of how much ice Greenland is losing
The Ville, (#40), As you say, the consequences of rising sea levels will be "huge". I got a feel for this issue while living in Rotterdam on a street 7 meters below mean sea level. Today I live in Florida, less than 5 meters above mean sea level. At the present rate it will take 1,000 years for the seas to rise 3 meters. If that rise happens, our distant ancestors will have plenty of time to move to higher ground.Response: The key point is that sea level will not remain at the current rate - ice sheet melt is accelerating and past history tells us the ice sheets are very sensitive to sustained warmer temperatures. The latest peer-review analyses of future sea level rise, using various independent methods, predict sea level rise of 1 to 2 metres by 2100 (and don't forget that sea level rise will continue after 2100). -
nautilus_mr at 12:36 PM on 29 April 2010Why are there fewer weather stations and what's the effect?
Further to that topic, when I first got into the climate change issue, one of the things I initially found confusing was the term "temperature anomaly". Anthony Watts' site was one of the first that I read, which undoubtedly added to my confusion. For about the first 6 months, I was deeply skeptical about the temperature record. My background is in biology and philosophy of science, but I had to work very hard to grasp statistical principles. Once I got my head around the issues, I realised the whole approach of Watts et al is confused. The issue isn't whether a given weather station is close to buildings, while another one is in a forest. Obviously the first will be affected by urban heat production. What matters is whether the temperature trends differ widely, or indeed whether there is no trend at all. When the trend is similiar across a wide variety of stations, then there is clearly a general influence that is greater than the local, variable influences. You must explain the data, and the urban heat island effect just doesn't do it. That realisation was one of the first major steps for me in satisfying my skepticism. Watts' famous photos of weather stations are total red herrings. And let's think about this - if the actual trends in weather station data were chaotic, the skeptics would have been all over it like a rash. He really is dumbing down the debate. I suspect the use of temperature anomalies is actually inherently conservative, because it compares the current year's temperature to the average of the last century. As real temperatures increase, the average must increase slightly, thereby modestly reducing the difference between the two. I remember reading a study showing that, if we separate out the rural and urban weather stations, the rate of temperature change is almost identical. I don't have the article saved -perhaps somebody can help with a link..?Response: How urban heat island has little effect on temperature trends is examined in Does Urban Heat Island effect add to the global warming trend? -
gallopingcamel at 12:34 PM on 29 April 2010Why are there fewer weather stations and what's the effect?
Since debating this subject with Ned on another thread I posted a response relating to the station drop off problem in the Canadian Arctic: http://www.skepticalscience.com/news.php?p=2&t=81&&n=164 The above post is based on correspondence with Environment Canada and NOAA/NCDC that demonstrates John Cook made an incorrect statement at the head of this thread when he said: "The physical number of weather stations that are reporting temperature data has diminished......" There are 37 stations to GCN/WMO standards reporting in the Canadian Arctic. The data from all of them is available to the NCDC but only Eureka appears consistently in GHCN v2. I still don't know why the number of stations in the Canadian Arctic has fallen dramatically so I am planning a trip to NCDC in Asheville next month. If I learn anything I will let y'all know. If you still think that a very thin data set does not affect published results take a look at what happened on July 13, 2009 and March 29, 2010 (thank you, Berenyi Peter): [LINK] A temperature anomaly of 4 degrees Celsius for March 2010 should raise a few eyebrows!
Moderator Response:[DB] Shortened link breaking page formatting.
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Phila at 12:05 PM on 29 April 2010Why are there fewer weather stations and what's the effect?
#13 "Why is it that so many people simply don't understand what temperature anomalies are?" I suspect it's simply because so many people aren't used to them. They have a certain commonsense expectation of how temperatures should be measured; when actual scientific practice doesn't match that expectation, some people will get confused, and others will conclude that there's something underhanded going on. I don't think it's too late to do anything about it, though. Perhaps there could be a post on it here (or on arguments that exploit this misunderstanding). -
Jeff Freymueller at 10:59 AM on 29 April 2010Why are there fewer weather stations and what's the effect?
Why is it that so many people simply don't understand what temperature anomalies are? Is it something about the name? too late to do anything about it now, I suspect, but misconceptions abound. -
Tom Dayton at 09:20 AM on 29 April 2010Why are there fewer weather stations and what's the effect?
johnd, it doesn't matter what the base period is when you're interested in the trend in anomalies from the base period--the change in the anomalies over time. That's not an assumption, it's a mathematical fact. You can demonstrate it yourself, simply by adding or subtracting any number from all the anomalies and observing that the shape of the line over time is unchanged. The line merely moves up or down. -
johnd at 08:49 AM on 29 April 2010Why are there fewer weather stations and what's the effect?
HumanityRules at 19:25 PM, regarding your comments about the correlation from the 50's onwards. One of the problems? advantages? of plotting anomalies against one another is that they will naturally show good correlation at around the time of the base period selected. The base period is not shown on the graphs used here, it should be. A bit of digging indicates that a base period of 1960-1970 was used by one of the other analysis referenced, I haven't determined what base period was used by the others. First one has to assume that the same base period was used for both anomalies on each chart. Secondly one has to wonder why that particular period was selected. It is not the mid point of the time span. It however is the mid point of the post WW2 global cooling period. Would that be significant? Why not choose a period during the rapid warming pre WW2, or at the beginning of the time span. If that was done, then correlation would have been shown as best early on and getting worse as time progressed. Lastly, the use of anomalies against one another gives the impression that the raw data matches closely. However the two sets of data could shown differences of say 10 degrees, and the anomalies would still appear interwoven. -
kdkd at 07:50 AM on 29 April 2010Tracking the energy from global warming
Ken, You've hit the nail on the head there (unable to draw strong conclusions). You're right, we can't draw strong conclusions from the OHC/TOA data at this point, for all of the reasons mentioned previously. However there is a vast wealth of other data available that shows us the nature of the problem and it's magnitude. One small divergence of data and theory based on too little data does not a paradigm shifter make. -
scaddenp at 07:17 AM on 29 April 2010A visual depiction of how much ice Greenland is losing
"The sea levels are going to do whatever Mother Nature wants them to do and we need to stop whining about it. " Um, why do you think sea level rises? Mother Nature suddenly makes more water? There is nothing we can do about tectonic subsidence but this is local. However, sea level rises or falls globally in response to temperature change. Do you seriously dispute that there is no credible scientific evidence to support this? And we surely can change the main forcing in temperature change (GHGs). And are you still insisting that no rate of change in temperature is not dangerous? -
Phila at 07:12 AM on 29 April 2010A visual depiction of how much ice Greenland is losing
#45 "At the risk of upsetting some of you I consider that idea to be nonsense with no credible scientific basis." This would seem to be an example of argument by assertion. Presumably, if it's impossible that "mankind can influence the rate of rise of sea levels," there is some physical mechanism that makes it impossible. What might that mechanism be? -
Flowers blooming earlier now than any time in last 250 years
John, I added that article link under "It's not happening".Response: Much appreciated, thanks! The more peer-reviewed links we can include in the Global Warming Links directory, the more useful a resource it is. -
Riccardo at 05:47 AM on 29 April 2010Has Arctic sea ice returned to normal?
A few more points on sea ice and salinity. The layer below newly formed sea ice initially gets more saline but then tend to sink due to an increase in density. This contributes to the stratification of the Arctic Ocean. The solidification temperature of sea water decreases by about 0.28 °C for every 5 PSU increase in salinity.
Sea ice melting may play a role as a CO2 sink. When ice melts the resulting water is depleted in CO2 and then can absorb more of it from the atmosphere.
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Jacob Bock Axelsen at 05:31 AM on 29 April 2010Are we too stupid?
embb for individuals there is a higher authority, namely the state, that can punish defection and reward cooperation, Consider the fig tree/fig wasp symbiosis. If the female wasp invades an immature fig, the tree responds by cutting the fig off and thus both the fig and larvae perish. Tit-for-tat works because the defecting genes are purged and symbiosis is perpetuated. It was evolved thousands if not millions of years ago, and it does not involve an executive power. Taxes would not work if the state collected taxes only to avoid an uncertain catastrophe in 100 years Are there certain catastrophes? The tax would of course be used to further sustainable energy sources - immediate payoff in terms of environment and security. Your descendants will certainly appreciate it as it is evolutionary favourable. Examples would be the chemotaxis behavior of E. Coli or the sporulation of B. Subtilis both involving benefits only to future generations. Both mechanisms are extremely simple, stunningly robust and have been evolved millions of years ago. What I have are doubts. I am in this discussion to clear them You still have doubts, in spite of my reference to the fact that clever taxation and regulation have lead californian power plant companies to ask users to minimize their consumption? Please do not take offense, but your incapacity to quench these specific doubts seems suspicious and fits perfectly into Kingsley Davis' definition of someone who wish to obstruct reforms (from Hardin, 1968): "(...) worshippers of the status quo sometimes imply that no reform is possible without unanimous agreement, an implication contrary to historical fact. Hardin continues: (...) automatic rejection of proposed reforms is based on one of two unconscious assumptions: (i) that the status quo is perfect; or (ii) that the choice we face is between reform and no action; if the proposed reform is imperfect, we presumably should take no action at all, while we wait for a perfect proposal." So I ask, do you have any interest in maintaining status quo? If not, what is the best way to get states, individuals, companies etc. to cooperate about mitigating climate change? Please, do not be modest and claim that you cannot imagine it. -
CBDunkerson at 04:41 AM on 29 April 2010Has Arctic sea ice returned to normal?
Mike_Allen, sea ice is 'fresh water'... the salt is forced out during the freezing process. Thus, the melting of large amounts of sea ice can decrease the overall salinity of the underlying ocean water. I know cold water acidifies more quickly / to higher concentrations than warm water, but not how that impacts freezing point. -
chris at 03:12 AM on 29 April 2010Tracking the energy from global warming
Ken Lambert at 23:23 PM on 28 April, 2010 re your comment:If you can't draw strong conclusions against climate change based on warming from CO2GHG from *this* data, then neither can you draw strong conclusions *for* it
Well yes Ken, but I don't think anyone is drawing "strong conclusions" for climate change from this small snippet of temporal evolution of the climate system. I'm sure people here are very interested in what it might mean in detail. No doubt in a few years we'll be somewhat better informed about the apparent misaccounting of the Earth's energy budget; we may well know whether it's real or an artefact of measurement problems.... ... and of course "Strong conclusions about climate change" follow from the vast wealth of scientific knowledge and empirical observations, and a recognition of the nature of unceretainties. -
chris at 03:00 AM on 29 April 2010Tracking the energy from global warming
Ken Lambert at 22:21 PM on 28 April, 2010 We're probably geting into the "arguing fruitlessly" stage, which often an indication that the data under discussion is inconclusive (not surprising when assessing temporal evolution of observables with large inherent stochastic short term variability and relatively large measurement error bounds). I'll just make two points: (i) numerology. Of course the first law of thermodynamics is obeyed (a "scientific fact"!). The "numerology" relates to playing with tentative numbers as if they were perfect representations of the phenomena of interest and then drawing incorrect conclusions. We've been here so often before (e.g. with apparently solid evidence that the troposphere wasn't warming c/o Spencer/Christy; that the troposphere would dry as atmospheric [CO2] increased c/o Lindzen...). It's usually best to lay off making profound conclusions (e.g. Peter's "the climate system is not gaining energy, but losing it") until the measurements are solid, or if one feels compelled to look at the numbers, to do so with a recognition of the uncertainties. (ii) Your comments re Topex/Jason sea level measurements are apposite. I'm clearly looking at the graph (my post 76 above) with different eyes than you!. If the 60 day smoothed delta mean sea level (MSL) was around 5 mm in 2002 and looks likely to cross the 2010 line at a delta MSL near 25-30 mm at 2010, then it's difficult to argue that sea levels haven't risen during the last 8 years. Overall they've continued to rise something like (30-5)/8 mm.yr-1; i.e. around 3 mm.yr-1. That's really difficult to square with Peter's conclusion. If Peter was right we'd have to assume that the rise was solely due to the mass component (melting ice); however we are pretty certain that's not true. Somethng is wrong with Peter's argument, beautiful numbers notwithstanding. Incidentally, the sea level rise did seem to flatten for a while ( from around 2006ish to 2008ish). That's interesting, yes? Does it, as Peter infers "bring havoc to standard greenhouse theory"? Not really.. and it would be surprising if the solar cycle down-turn and extended solar minimum didn't have some effect in reducing the rate of increase of thermal energy into the climate system.
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