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Comments 106601 to 106650:
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The Inconvenient Skeptic at 00:39 AM on 19 October 2010Throwing Stones at the Greenhouse Effect
Craig, I apologize for causing you to feel insulted by my feeling insulted. :-D I suppose that this website would see plenty of claims that the GHE isn't real. I accept the need for articles like as a result. Three cheers for Calculus!!! -
Craig Allen at 00:01 AM on 19 October 2010Throwing Stones at the Greenhouse Effect
TIS #3 A quick Google search pulls up 31,000+ pages with people claiming that the greenhouse effect is bunkum because (they claim) it violates the second law of thermodynamics. I feel insulted by your pretence at feeling insulted. -
muoncounter at 23:55 PM on 18 October 2010Despite uncertainty, CO2 drives the climate
#18: See the graph here. Projection for China's nuclear energy in 2020 is given as 150 billion kwH; this works out to 17 MW of generating capacity. -
CBDunkerson at 23:41 PM on 18 October 2010Throwing Stones at the Greenhouse Effect
TIS #3: Your lack of awareness of people who deny the greenhouse effect is not the same as them not existing. It is an exceedingly common claim amongst 'skeptics'. Indeed, I thought you'd been on some of the threads where people were claiming that the greenhouse effect contradicts the first and/or second law of thermodynamics. If not, just do a search on 'thermodynamics' and you'll get more than your fill. Might have been something to try BEFORE accusing the author of making up an "inaccurate" straw man argument that no one really uses. -
jorgepeine at 23:33 PM on 18 October 2010Throwing Stones at the Greenhouse Effect
Thanks for the excellent example: MOON ... it is just striking, and actually it would be nice to know about the distribution of temperature on the surface of the moon. Does anybody know where to find those data? What is the heat capacity of the rocks of the moon? Anybody knows?? -
The Inconvenient Skeptic at 23:29 PM on 18 October 2010Throwing Stones at the Greenhouse Effect
I am not aware of anyone saying there is no greenhouse effect. I certainly agree that there is a greenhouse effect. The atmosphere certainly keeps the Earth much warmer than it would be otherwise. It is the importance that CO2 plays in the greenhouse effect that we disagree about. The total greenhouse effect includes all energy going into the atmosphere. Convection and evaporation also play an important role in transferring energy into the atmosphere. I will gladly mock anyone that says the atmosphere doesn't insulate the Earth and keep it warmer. However, this article is inaccurate as I am not aware of anyone claiming that the atmosphere doesn't have an effect. This article seems intentionally written to insult people that disagree with the theory that the currently increasing CO2 is going to significantly alter the Earth's climate. They are separate and independent issues in every way.Response: Sadly, there are many who deny the greenhouse effect and there have been many comments on this site to that effect. Just the other day, someone emailed me an article purporting to disprove the greenhouse effect. There are various levels of climate skepticism and unfortunately, we have the job of addressing them all. -
Roger A. Wehage at 22:45 PM on 18 October 2010Throwing Stones at the Greenhouse Effect
JMurphy, there can be only two ways of life: What we do and what we must do. Unfortunately what we do makes us feel good and what we must do does not. Why are nearly 75% of Americans, American news media, and American politicians deniers? Because acknowledging the truth would make us feel guilty for not doing what we must. Make us feel guilty for condemning our offspring to unimaginable futures. But that's not all. What are the other 25% of non deniers doing? Mostly a lot of lip service and hand waving? Are we really changing our lifestyles, or could we even if we tried? What significant changes and sacrifices are we making to lead the way? 350.org is a great concept, but it barely scratches the surface. The world will need thousands of proactive groups like 350.org if we are to overcome the momentum of life as it is. -
CBDunkerson at 22:11 PM on 18 October 2010Despite uncertainty, CO2 drives the climate
Joel wrote: "I'm currently reading "Proofiness" by Charles Seife and one of his first example of a misleading graph is setting the index at a place where the reader doesn't expect it." Which is entirely subjective. Most readers expect the baseline for temperature anomalies to be an average over the timeframe of the data series or some portion thereof. Your apparent expectation that it would be the average over the year 2010 (which isn't over yet... so, what, recalculated daily?) is highly anomalous. Your claim that a graph which doesn't conform to YOUR assumptions is intentionally "misleading" says alot more about you than it does the graph. In short, you're looking for excuses, and incredibly thin excuses at that, to find fault... so, of course, you will. -
JMurphy at 21:18 PM on 18 October 2010Throwing Stones at the Greenhouse Effect
I still can't understand how anyone could dispute such basic science facts, unless it's a trend among some to reject all science unless they themselves can prove results by personal experience alone. Some even seem to think that they are more intelligent than anyone else and are able to discard scientific proof because they know the 'true facts' - as opposed to the facts produced by 'elitist' scientists who are only out to enrich themselves and help governments enslave us all, apparently. The reality is, of course, that such people - deniers of any science they don't like, not just AGW - are arrogant, self-deluding and blind to reality. -
bgood2creation at 16:02 PM on 18 October 2010DMI and GISS Arctic Temperatures: Hide the Increase?
"In the Arctic Summer when the surface ice is melting, it is known that the air temperature close to the surface is limited by this ice melt temperature to just above zero degrees C, (Rigor 2000)." This basically has to do with the heat of fusion, right? Anyway, regardless of the Arctic Summer temperature trend, the length of the melt season grew longer by an average of 6.4 days per decade from 1979 to 2007, according to NASA. http://www.nasa.gov/topics/earth/features/longer-melt-season.html -
Steve L at 15:40 PM on 18 October 2010Climate Change Impacts on California Water Resources
There's already a lot of acrimony over trying to keep Californian River flows high and cool enough for salmon. Regardless of scenario, I guess it's good-bye to California's salmon. -
dana1981 at 15:35 PM on 18 October 2010Despite uncertainty, CO2 drives the climate
archiesteel #15 - you didn't miss anything, the baseline is completely unimportant. -
CoalGeologist at 14:53 PM on 18 October 2010Despite uncertainty, CO2 drives the climate
This discussion may be trending off-topic. Nevertheless... The advent of of natural gas production from shales, made possible through the improvements in drilling and hydraulic fracturing technology, has radically altered the notion of "peak oil". The resource potential of shales is immense. Electricity generation from natural gas results in approximately 37% less carbon emissions than coal, for an equivalent amount of energy... but that's still 63% more than zero. At this point, energy supply is driven by market economics (not quite "free"-market!), and coal remains an economically viable energy resource. Even if world oil production begins to decline, there's still plenty of fossil carbon available to generate energy... and... .er.... CO2 as a by-product. Environmentalists who were counting on "peak oil" to reduce the rate of carbon emissions will likely be disappointed, despite the environmental benefits of natural gas. It will require some sort of artificial "meddling" in the marketplace to substantially alter this trend. -
Rob Honeycutt at 13:00 PM on 18 October 2010Despite uncertainty, CO2 drives the climate
muoncounter @13... That's interesting that China is shooting for 75MW (surely they mean GW) by 2020. They're shooting for 230GW in wind by the same time. -
Doug Bostrom at 12:56 PM on 18 October 2010Despite uncertainty, CO2 drives the climate
Oil's part of the problem, Joel, coal is the biggest. Here's some data on where coal is headed:From United States Energy Information Administration Notice that population does not track coal consumption; your correlation is specious. The swerve you see post-2002 continues; for 2008 production was 7,271,249 thousand short tons. There's lots more coal available, dirtier going forward, but plenty to burn unless we choose to do otherwise. This business of changing the baseline seems simply an exercise in politically correct thinking.
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Chris G at 12:51 PM on 18 October 2010Despite uncertainty, CO2 drives the climate
Joel, Take a step back and try to understand that you are not the first person to understand the problems with extrapolating current trends into the future. BTW, isn't this what you are doing by predicting a date for when China will have more nuclear plants than coal plants. You should also realize that does not mean that they will have less coal plants than they have now. Also try to understand that there is more than one scenario in AR4. These predictions of the future are much more, 'If A happens, we can expect B to be a result.' than they are a prediction that 'A will happen'. Lastly, please explain your math. Pre-industrial levels of CO2 were about 287 ppm. Currently we are at about 388 ppm. So, we are about 1/3 of the way to a doubling already. The levels are increasing by about 2 ppm currently. Even if the current levels of production stop growing immediately, at the current rate, we'll reach a doubling by around 2010 + ((287ppm*2) - 388ppm)/(2ppm/yr) = 2103. Wow, that is _so_ far off from 2100. However, if you look up the levels of CO2 in the atmosphere, there is every indication that the rate of increase is increasing, and not decreasing. So, there is every indication that a doubling will be reached before then, and no indication that any reduction will occur without some form of intervention. Peak oil will happen; it's just a matter of when, but there are plenty of other sources of fossil fuel around. Incidently, if you look at US Department of Energy predictions, there is no reduction of fossil fuel use expected. Regarding, "there shouldn't be any need to reset the baseline". Umm, you are right, and most of the baselines were established 30 years ago or more. Then again, as has been pointed out repeatedly, if the audience can read a graph, why does it matter? -
archiesteel at 12:35 PM on 18 October 2010Despite uncertainty, CO2 drives the climate
Uh, maybe I missed something, but what difference does it make where the baseline is? -
Joel Upchurch at 12:32 PM on 18 October 2010Despite uncertainty, CO2 drives the climate
If you set up the spreadsheet correctly, there shouldn't be any need to reset the baseline. You should be able to set it up to draw the X and Y crossings corresponding to the current date. An alternative would be to have the spreadsheet draw a symbol at the current date. Sort of like the You are Here symbol on a mall map. -
muoncounter at 12:03 PM on 18 October 2010Despite uncertainty, CO2 drives the climate
#10: "since it assumes it is actually possible to triple out production of fossil fuels. ... Ever hear of peak oil?" Have you ever heard of coal? China is #1 in CO2 emissions (total, not per capita) for the past few years, primarily due to their most abundant source of energy: Coal. Coal's CO2 emissions per kwh of electricity generated is much higher than petroleum. See Table 1 here. As far as China's nuclear industry, they are shooting for 75 MW by 2020, up from 9 MW now. That's still a drop in the bucket, especially if you go with per capita energy needs for a 'developing' nation. -
Joel Upchurch at 11:57 AM on 18 October 2010Despite uncertainty, CO2 drives the climate
#8 When I looked at the reference you gave, Figure 1 explained in the first sentence what the baseline was, so saying that scientists don't have to explain that seems kind of spurious. Why don't you use the graph that explains explains the baseline? -
Chris G at 11:51 AM on 18 October 2010Despite uncertainty, CO2 drives the climate
Incidently, Stephen Schneider at one point thought that particulates would dominate the effect of CO2 and that cooling would prevail. This was one source, if not the main source, of the media splash on 'global cooling'. Not very much later, he retracted that position with the admission that he'd gotten some of the math wrong. This was in the 1970s. So, it's not an easy determination to make, but more is known now than it was then. -
Riduna at 11:43 AM on 18 October 2010Climate Change Impacts on California Water Resources
http://www.onlineopinion.com.au/view.asp?article=11063 provides information on the findings of the GRACE satellites. Although the importance of California’s Central Valley to US agricultural output seems over-stated, the fact is that dwindling water supplies have already resulted in population/agriculture competition for the inadequate supply available. Outcome to date is that population needs are being met. Those of agriculture are not. Aquifers are already being pumped at unsustainable rates in a bid to overcome shortage of water for agriculture and yields are falling. This is happening in 2010. With predicted population growth and the effects of climate change by 2050, agriculture in its present form will no longer be possible. As in Australia, farmers will have to learn to use water in a more cost-efficient and effective manner, growing those crops which provide the best returns, given the price of water. Farmers do not have until 2050 to learn how to make best use of water. They must do so now. Those that do not will go out of business and crop yields will fall further as population increases. -
Joel Upchurch at 11:01 AM on 18 October 2010Despite uncertainty, CO2 drives the climate
#4 & #5 lets me use another section of "Proofiness" that the author call "regression to the moon". The example was some scientists that analyzed men and women sprinting records and did a linear projection and concluded that women would beat the men in the 100 meter in 2154. This paper actually got published in Nature. Doing a linear projection of carbon emissions for 10 year would be fairly reasonable assumption. For 20 years, not so much. For 90 years, it is gibberish. The way I see it, we have three kinds of countries. Developed countries Developing countries, and not so developing countries. In rough numbers, since I'm too lazy to look it up, call it 2 billion developed, 2.5 developing and 2.3 NSD. The developed counties are all at ZPG or below. The developed countries have fairly flat carbon emissions per capita and they will have less people by 2100, so their carbon emissions will be flat or decrease by 2100. The NSD counties will have a lot more people, but they won't be able to use a lot more fossil fuels, because they don't have the money to buy or the infrastructure to use a lot more fossil fuels. If fuel prices go up a lot, then they might actually be using less. Developing counties eventually become developed counties, like former developing countries like Taiwan, Korea and Singapore. I figure China gets there about 2040 and India by 2060. At that point their emissions per capita flatten out and their population decreases. China is already at ZPG and India should be there in 10 years of so. Above is rather simplistic, since it assumes it is actually possible to triple out production of fossil fuels. Does anyone actually think we will producing three times as much petroleum in 2100? Ever hear of peak oil? We would be extremely lucky to maintain our current production. Part of this will be addressed by tar sands and shale oil, but at much higher prices. This also opens opportunities for renewables to grab part of the market and makes hybrids and electric cars a reasonable purchase without tax subsidies. There is also a reasonable case that we can't triple our production of coal either. China has already started importing coal, but the are limits to how much coal they can practically import. China has a nuclear power program that is growing by leaps and bounds. They will have more nuclear plants than the United States by 2025. By 2040 nuclear plants will be displacing coal plants. That is about the year when China estimates that the CO2 emissions will flatten out. A few years after that it will start go down. -
Riccardo at 09:45 AM on 18 October 2010Despite uncertainty, CO2 drives the climate
There are a few requirements to define the baseline for the temperature anomaly, the first being that it cannot be any single year. Being it an average over 30 years, it's better if temperature didn't change much over that period. Finally, you want the best data possible, and this excludes any 19th century period. The three decades 1950-80 look very appropiate. -
dana1981 at 09:35 AM on 18 October 2010Despite uncertainty, CO2 drives the climate
Joel, I find your argument that something which is the norm and which everybody is accustomed to is "misleading" very hard to swallow. Anyway the figure is from a peer-reviewed scientific paper and used in an Intermediate level rebuttal. In both cases the audiences should know how to read a simple graph, and if they don't, they can always ask. -
Doug Bostrom at 09:18 AM on 18 October 2010Despite uncertainty, CO2 drives the climate
Not to sound overly reactive, but how often should we reset the baseline, Joel? Every year? And by your recommendation, why should the baseline not be set to any arbitrary year we choose, as opposed to 2010? What's so special about 2010 in the statistical record? The cynic in me imagines that trying to shorten the longitudinal perspective this way has an objective of comfort as opposed to cold-hearted assessment. -
Joel Upchurch at 08:52 AM on 18 October 2010Despite uncertainty, CO2 drives the climate
#3. I know that is a common convention and it is always misleading, especially when you clip the graph out of context, so we don't know what the 0 degrees represents. You said "Note that even with the lower climate sensitivity, the model shows the planet warming 3°C by 2100 in this emissions scenario.". Did you mean 2010 or 1950-80? Most people reading it weren't born in 1950 and a lot of them weren't born in 1980 and are going to assume that you meant it was going warm 3 degrees between 2010 and 2100. If you can't re-normalize the data to the current year, then at least mark an X and label it 2010. -
Peter Hogarth at 08:05 AM on 18 October 2010DMI show cooling Arctic
HumanityRules at 01:18 AM on 18 October, 2010 Thanks, I have corrected this now. -
Peter Hogarth at 07:57 AM on 18 October 2010DMI and GISS Arctic Temperatures: Hide the Increase?
The Inconvenient Skeptic at 22:27 PM on 17 October, 2010 Atlantic Multidecadal Oscillation (AMO) is derived from detrended North Atlantic SST variation. So your point is regional SST and Surface air temperatures correlate? We would intuitively expect some correlation, but what is driving the SST in this area upwards (as we see if we leave the trend in) and what is driving the multidecadal variations? SST in the North Atlantic appears to be driven by a combination of atmospheric forcing and possible meridional heat transport. What is the source of this underlying increasing thermal energy in both cases? You may consider the facts that the North Atlantic SST variability is strongest at the surface and is also strongest at higher latitudes. I will try to get time to dig out recent work in this area, but here is some more inconvenience for you, as it does not appear that AMO leads surface temperature. If anything the reverse looks likely, though I would be cautious here. The AMO is de-trended North Atlantic SST from NOAA ESRL and I have de-trended the HadCRUT3 surface temperatures also to allow comparison. -
scaddenp at 07:30 AM on 18 October 2010DMI and GISS Arctic Temperatures: Hide the Increase?
TIS - can you explain to me your proposed mechanism by which the positive phase of the AMO manages to increase winter temperatures please? No problem explaining this of course within mainstream climate theory. Also, what is your calculation for increased heat flux from AMO and how does this compare with the increased radiation flux from GHG? -
CBDunkerson at 07:20 AM on 18 October 2010Despite uncertainty, CO2 drives the climate
Joel #2: It should be noted that the IPCC projected a range of different emissions scenarios. The point of using the high end A2 scenario in this writeup is presumably to show that even in such a 'worst case' scenario the possible mitigation effects of controlling these other pollutants are significant. That said, the A2 scenario actually projects 836 ppm at 2100, which is more than double the current 390 ppm and just over three times the 'historical baseline' value of 278 ppm. As others have noted, this is based on the assumption of continued industrial development around the world. You should also note that the 'population will stabilize between 9 and 10 billion' it is just one of a range of projections. -
muoncounter at 06:13 AM on 18 October 2010Despite uncertainty, CO2 drives the climate
#2: "To reach over 6ppm would require a big increase in average carbon output per capita" Isn't that what happens when developing nations develop? See Wikipedia: China, India, Vietnam, all have short doubling times for their per capita emissions. -
Peter Hogarth at 05:47 AM on 18 October 2010DMI and GISS Arctic Temperatures: Hide the Increase?
barry at 23:21 PM on 17 October, 2010 Thanks for that. I've looked at the ERA-40 and the T511 model data in the approx eight month overlap period during 2002 and there is evidence of a small bias. -
Peter Hogarth at 05:45 AM on 18 October 2010DMI and GISS Arctic Temperatures: Hide the Increase?
kwinters79 at 13:17 PM on 17 October, 2010 Thanks, fixed that. -
dana1981 at 05:32 AM on 18 October 2010Despite uncertainty, CO2 drives the climate
Joel, setting some part of the 20th century as the baseline for global temperature anomalies is the norm. That's what everyone does. And in a business as usual, high emissions scenario as employed in Figure 3, atmospheric CO2 will double from pre-industrial levels before 2100. You appear to be neglecting rather large developing countries like China and India. That's a rather large omission. -
Joel Upchurch at 05:03 AM on 18 October 2010Despite uncertainty, CO2 drives the climate
A couple of things bother me about Figure 3. The first thing is that zero is not set to the temperature for 2010 or at least 2009, but for what looks about 1960. I'm currently reading "Proofiness" by Charles Seife and one of his first example of a misleading graph is setting the index at a place where the reader doesn't expect it. If you look at 2010, then the temperature increase is only a little over 2 degrees. It also looks like the graph assumes that CO2 will double between now and 2100. That would mean an average increase of about 4.3 PPM per year and increase of between 6 and 7 PPM per year by 2100. That seems questionable considering current demographic projections to the world reaching ZPG around 2040-50 and population stabilizing between 9 and 10 billion. To reach over 6ppm would require a big increase in average carbon output per capita, which also seems unlikely since most of the carbon hog countries are looking at declining population. -
archiesteel at 04:37 AM on 18 October 2010Animals and plants can adapt
@johnd: in order to invalidate *any* model, we'll need to have sustained greening over a significant area of the desert. It's a bit early to start calling out specific models. Your last paragraph is simply an attempt to invalidate climate models in general by introducing a bit of FUD about their precision. However, as the article clearly spells out, it is *North Africa* that is difficult to model. Models tend to agree a lot more about other regions, and there's no reason to believe that the models that eventually get it wrong on North African impact are any less accurate in the rest of their predictions. It seems to me you're fishing for a pretty convoluted argument, here. -
johnd at 04:28 AM on 18 October 2010Animals and plants can adapt
I think one of the points being made by the article goes back in part to what was quoted by archiesteel at 06:35 AM, that being "Half the models follow a wetter trend, and half a drier trend." Whilst some may feel that this greening is not causing problems for AGW, however it certainly must be causing some problems for some of the modelers. If anyone now accepts that the trend of increasing rainfall validates those half of all models that are predicting a wetter trend, then they must also be accepting that it also invalidates those other half of the models predicting a drier trend which obviously have been built around some rather incorrect assumptions. If those assumptions are now being found to be incorrect, which one must now be willing to accept in this particular case, then wherever the same assumptions have been inputted into other modeling makes those outcomes produced perhaps somewhat similarly suspect also. -
KeenOn350 at 03:43 AM on 18 October 2010Skeptical Logic Can't Save Greenland Ice - for that you need to stop climate change
@boba10960 #6 Do you know if the presentation by Dorthe Dahl-Jensen at icp10 is accessible as video anywhere? -
DSL at 03:15 AM on 18 October 2010Animals and plants can adapt
"Nevertheless that which has taken place,whilst not condemning outright AGW and its proponents, is however at odds with mass media output." As others have pointed out in different ways, Sahel greening will never "condemn" AGW outright or implicitly. You need to work on larger processes if you want to try to find evidence against a warming planet. If you want to be taken seriously, point to single instances, but do so by looking at the single instances within the context of the whole. "ie we haven't had any glowing reports of this (benign) change in the Sahel. When brought to the attention of Joe Public, invariably his first utterance is "Why haven't we heard of this?"(because he still depends for the most part, but increasingly suspiciously, on the mass media for his information)" Invariably? Where is your evidence for this response? And if you think mass media news is in collusion with climate science, you aren't paying attention. "I think you may have problems like this in the future. Time is wearing on, after all. Time was always a bit of a problem for soothsayers and fortune-tellers." Ahhh, the old "modeling a complex system is impossible" game. You do note that you're playing the game, too, yes? You make the implicit claim that the planet is not warming--and certainly not because of humans--because the Sahel is greening. And yet you make this claim without any sort of evidence. Soothsaying indeed! Don't be so provincial. The Sahel may be greening, but the oceans are dying and pine mountain beetles are munching my bloody pine trees. -
HumanityRules at 01:18 AM on 18 October 2010DMI show cooling Arctic
In the advance article the trends in Fig5 are tenfold less than Fig6. Should that be per year? -
jsam at 01:17 AM on 18 October 2010Uncertain Times at the Royal Society?
Only a denier could read the RS report and deny that it supports the warmist position. And they will. -
muoncounter at 00:16 AM on 18 October 2010DMI and GISS Arctic Temperatures: Hide the Increase?
"peak positive excursions are being limited by the ice melt temperature in Summer." That's a key point, explaining the strange look of the seasonal buoy maps as well:Lots of red except in the summer, where one would have expected the most red. Can anyone with a shred of credibility see a cooling Arctic and a simultaneously melting Arctic?
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barry1487 at 23:21 PM on 17 October 2010DMI and GISS Arctic Temperatures: Hide the Increase?
I recently emailed DMI with a query about summertime temperatures and got a reply a couple of weeks ago. Here are the relevant bits. My comments are in italics.I am curious about the temperature profiles for the Arctic, 80 degrees North from 1958 to present... I have read quite a few studies on Arctic summertime temperatures indicating that the temperature trend for the region has been significantly positive over the last few decades. The University of Alabama satellite record maintained by Roy Spencer and John Christy has a trend of 0.47C/decade since 1979. I realize that the circle of the Arctic your graph covers is a smaller area than many other assessments of Arctic temperatures... ...would you be amenable to providing a brief reply? I plan to disseminate it responsibly, unless you state otherwise. 1) It would appear at a glance that summer time temperatures have increased little over the past few decades going by the DMI graph set. Do you hold this to be the case? From the link to WUWT, that you've attached below[*], it seems that a cooling temperature trend in the Arctic summer is present, throughout the past approximately 10 years. Where 'summer' is defined as the period where the +80N mean temperature is above 273K. However, I very much doubt that a simple conclusion can be drawn from that, as there are complicating aspects to that analysis, e.g.: 1) The surface in the +80N area is more or less fully snow and ice covered all year, so the temperature is strongly controlled by the melting temperature of the surface. I.e. the +80N temperature is bound to be very close to the melt point of the surface snow and ice (273K) and the variability is therefore very small, less than 0.5K. I am sure you will find a much clearer warming trend in the same analysis applied to the winter period. The winter period is more crucial for the state of the Arctic sea ice, as this is the period where the ice is produced and the colder the winter the thicker and more robust the sea ice will become. 2) The +80N temperature data after 2002 are based on the operational global deterministic models at ECMWF, at any given time. Before 2002 the ERA 40 reanalysis is used. I.e. the +80N temperatures are based on 4 different models, the model used for the ERA 40 data set and the operational models T511, T799 and T1279. The point is that there can be a temperature bias in one or more of the models, that can cause the lower temperature level since approximately 2002, where the shift between the ERA40 data and the operational model data occur in the WUWT-plot from the link below. 2) Can you help me understand what appears to be a discrepancy with other reports on Arctic temperature trends? I do not think one can give a general comment on that - i.e. such discrepancies have to be discussed in a 'case by case' manner 3) Are there any published studies done by DMI researchers on Arctic temperature trends - for reference? No - unfortunately, we have not had time to look deeper into this.
* The WUWT link in my email was this one. http://wattsupwiththat.com/2010/08/05/dmi-polar-data-shows-cooler-arctic-temperature-since-1958/ -------------------------------------------------------------------------------------------------------------- Looks like you've done a very good job, Peter. My correspondent was Gorm Dybkjær. -
The Inconvenient Skeptic at 22:27 PM on 17 October 2010DMI and GISS Arctic Temperatures: Hide the Increase?
This article does show the weakness of the station data. 1200 km interpolation is not the best for analyzing the Arctic. Since 1979 the DMI and the satellite data are showing the same trends though. The strongest warming is taking place during the winter, but the summer is warming in the satellite data as well. The satellite trend is weak until 1997, but after 1998 the trend is clear. Of course 1998 is also the year the AMO went strongly into the warm phase and that makes distinguishing the cause of the warming very difficult. So I agree with the warming, just not the cause. It is too bad the DMI data does not extend back to 1930. -
Doug Bostrom at 21:08 PM on 17 October 2010DMI show cooling Arctic
What a chewy article. Thanks, Peter! -
MarkR at 20:49 PM on 17 October 2010DMI and GISS Arctic Temperatures: Hide the Increase?
Very interesting Peter! I haven't had the time to look into this myself, but once again our friend Steven Goddard has shown a severe lack of skeptical thinking and maintained his unbelievable ability to cherry pick. -
archiesteel at 17:25 PM on 17 October 2010DMI show cooling Arctic
It is also worth nothing that the DMI acknowledges the reality of rapid warming on their website about the Arctic: "Since the 1970s the extent of sea ice has been measured from satellites. From these measurements we know that the sea ice extent today is significantly smaller than 30 years ago. During the past 10 years the melting of sea ice has accelerated, and especially during the ice extent minimum in September large changes are observed. The sea ice in the northern hemisphere have never been thinner and more vulnerable." -
archiesteel at 14:33 PM on 17 October 2010Animals and plants can adapt
@AWoL: I'm sorry, I have a hard time understanding your point. The fact that AGW is apparently causing some greening of the Sahara desert due to increased rainfall is *not* an argument against AGW theory. I'm also unaware that the Sahara is often cited in Mass Media stories about AGW. Furthermore, this is another piece of evidence showing that AGW is real. I don't see how this could "cause problems" for AGW proponents. To the contrary, it goes to show that we are, in fact, having a serious impact on our environment through CO2 emmissions. I also don't get your comment about soothsayers and fortune-tellers. I suggest you stick to the science and not try to divine how public opinion will react to an observed greening of the Sahel. -
kwinters79 at 13:17 PM on 17 October 2010DMI and GISS Arctic Temperatures: Hide the Increase?
Great article, but your trend line equations in Figure 3 are mislabeled or off by a factor of 10. They should either say yearly or the decimal point shifted right.
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