Arguments
Recent Comments
Prev 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 Next
Comments 127451 to 127500:
-
Mizimi at 07:44 AM on 21 September 2009Is the U.S. Surface Temperature Record Reliable?
#23...a nice demonstration Chris of how x+ 0.2 - x =0.2 but are they real figures? I doubt it. So just for some indication I went to GISS dataset and abstracted annual mean temps for 20 stations picked at random across the globe from 1980 - 1990. Of those 20, four stopped sending data in 1990/1991 (Madrid, Riga,Fugin, Minqin). Constructed a simple mean 'global' T series from the data, then did it again dropping out those 4 stations. The result? With all stations included the ten year 'trend was 0.2C...not too far from established results. But the trend when they were removed fell to 0.12C. Not conclusive in absolute terms but enough I would say to demonstrate that both the number of stations and the area covered are vital to getting the trend right. -
Steve L at 02:07 AM on 21 September 2009Measuring Earth's energy imbalance
Manuel, see if this thought experiment helps: Say you have a stove in a very leaky one room cabin with broken windows and the door off the hinges. The stove always puts out the same amount of heat (the energy going into the stove is always equal). It's cold, with the heat energy quickly escaping from the cabin, so you nail boards over the windows and fix the door. At first the heat from the stove escapes less quickly, and the cabin starts to warm ... but it doesn't warm forever. Eventually a new equilibrium is reached. Again, the added heat from the stove is balanced by the heat escaping the cabin, but because of the extra time spent by the heat in the cabin, you're more comfortable there. If you continue to improve the insulation, then the equilibrium temperature in the cabin will continue to increase. There is a slow down in the heat leaving the cabin with each increase in insulation, but that only lasts until the temperature inside has increased. Eventually the rate of heat production by the stove is still equal to the rate of heat emitted by the cabin. I hope this analogy is more helpful than harmful. -
Manuel at 19:40 PM on 20 September 2009Measuring Earth's energy imbalance
John, Thank you very much for your clarification. I think I can follow the idea of energy imbalance and why it requires a higher equilibrium temperature, or more specifically, a combination of higher local temperatures that make the radiation going out equal to the radiation getting in. I say combination of temperatures and not global temperature, because it is still very hard for me to understand the physical meaning of an average temperature. I still don't understand the term "outgoing radiation" on figure 3. On your reply to my comment you say: "What is happening is the energy coming in is relatively constant but the energy radiating back out into space is being partially trapped by increasing greenhouse gases. Hence less energy going back out = energy imbalance." What is then, the "outgoing radiation" shown on figure 3? I hope this clarifies my previous question. And, in any event, I am going to take advantage of your offer to get the full paper.Response: The outgoing radiation in figure 3 and the outgoing radiation that gets trapped by greenhouse gases are one and the same. The earth radiates longwave radiation. As the earth gets hotter, it radiates greater amounts of longwave radiation. Greenhouse gases partially trap the longwave radiation on the way out to space. -
thingadonta at 12:21 PM on 20 September 2009Measuring Earth's energy imbalance
A couple of points: 1) If the earth has been heating since the 1970s due to other factors than greenhouse gases (eg less low level clouds due to eg long term solar magnetic trends, delayed tipping points/feedback loops from longer term solar lag effects etc), the apparent 'energy imbalance' (ie the factors used to calculate it) would still be there(Figure 1). E.g. less clouds- warmer earth/ oceans/atmosphere= 'apparently' more energy in than out. If the oceans warmed due to less clouds, this would absorb heat coming in, without it going out, but greenhouse gases would not be producing the warming. 2) The warmer oceans from 1950s for example could be eg either 1) a lag effect from long term temperature trends, or 2) a result of less low level cloud cover. Figures 1,2,3 are models/interpretations, not data. Figure 4 appears to be data. 3)One would have to check the papers and data in more detail etc, but one suspicion is, is that ocean/land heat/atmoshpere content etc has been measured correctly, but modelled using assumptions about greenhouse gas forcing and not other possible factors, to create an apparent 'imbalance' that is not there. (The also the attached Murphy 2009 paper requires subscription).Response: To answer your points:
1. I intentionally don't go into much detail on what's causing the energy imbalance (apart from touching on it briefly in Figure 2). That's a topic for a future post or two (or more). I'm taking baby steps here - just to accept that there's an energy imbalance is a big step for some :-)
2a. The increasing energy imbalance since the 1950's cannot be a lag effect. In my response to Comment #1 and the climate time lag post, we see that if there's a change to the planet's energy imbalance (eg - increase in solar activity, increase in greenhouse gases), the planet will gradually approach equilibrium. This is not the case here - we're seeing the energy imbalance actually increasing in time since the 1950's.
2b. Figure 1 is based on direct empirical observations of heat content. Narry a model is seen or used. Figure 2 is based on radiative line-by-line calculations, not climate models - nevertheless I only touch on this in passing as my main point is the overall energy imbalance, not the individual contributors. The various factors of Figure 3 are all calculated from empirical observations apart from stratospheric aerosol forcing which again is calculated from radiative line-by-line calculations. Nevertheless, my main point from Figure 3 is to compare the heat capacity of ocean to atmosphere which is hardly a controversial point to make.
3a. Ocean/land/atmosphere heat content is based on empirical measurements. Modelling or greenhouse gas assumptions are completely irrelevant. We're talking about direct observations here. With all due respect, thingadonta, you need to switch off the cognitive dissonance here.
3b. Sorry, I've been unable to find a link to the paper online yet, it was emailed to me. If anyone would like to read the full paper, contact me and I'll email it to you. -
Steve L at 11:01 AM on 20 September 2009Measuring Earth's energy imbalance
Hi John, I also had a bit of a hard time following everything, but for a different reason than Manuel. For me the steady increase in cumulative forcing from solar and from ozone are problematic. In addition I'm surprised that most important negative forcing ("aerosol direct + indirect + other forcings") doesn't get a fuller description. Is the paper explicit about these things?Response: The stratospheric and tropospheric ozone forcing is taken from NASA GISS data - there's a page on the NASA website going into details on how this is calculated. Re "aerosol direct + indirect + other forcings", this is actually one of the major points of the paper - I chose to concentrate on the simpler issue of energy imbalance (the reasons become evident if you read comment #3).
Aerosol forcings are one of the major areas of uncertainty with climate models. So what this paper does is place empirical constraints on aerosol forcing by working out the total energy imbalance, then pruning away other forcings that we know with greater certainty. What is left is "aerosol direct + indirect + other forcings".
If you'd like the full paper, contact me and I'll email it to you. -
Manuel at 07:40 AM on 20 September 2009Measuring Earth's energy imbalance
Hi John, I don't follow completely the reasoning behind this paper (or maybe that of your excellent summary). You start your post saying: "When the Earth is in energy imbalance, with more energy coming in than radiating back out into space, we experience global warming." But then, you say: "Note that outgoing radiation is on the increase - another indication that the planet is indeed warming and consequently radiating more energy back into space." But if Earth is both warming and also radiating more energy out, it means that the energy coming in is also increasing. Where does this extra energy come from?Response: Very good questions and apologies for the confusion. There is a lot more to the paper than what I outlined above - I focused on just a few of the main points of the paper in an effort to be concise and accessible - perhaps not successfully!
No, the energy coming in isn't increasing. In fact, that's another important point to make. We have satellite measurements of incoming solar radiation and it shows little to no long trend over the past 50 years. What is happening is the energy coming in is relatively constant but the energy radiating back out into space is being partially trapped by increasing greenhouse gases. Hence less energy going back out = energy imbalance.
In fact, the paper explains some of the basics of this process by imagining what would happen to global temperatures if there was a sudden increase in greenhouse gases (a hypothetical simplified situation for the purpose of understanding the physics involved):
If greenhouse gases suddenly increased to a new level, the planet would suddenly be in energy imbalance. The energy out would be less than the energy in and the planet would start accumulating heat. Hotter objects radiate more energy. Therefore, as the planet gets hotter, it radiates more energy so the energy imbalance lessens. Eventually the planet will have accumulated enough energy so that the energy out approaches the energy in. Eg - the system approaches equilibrium.
This is why we talk about there being 'warming in the pipeline'. Even if we completely stopped all our CO2 emissions right this moment, we would still be left with a significant energy imbalance. It would take several decades of warming before the planet reached equilibrium. And that's a best case scenario. Of course we're not going to immediately stop CO2 emissions so the energy imbalance will only increase in the years to come.
I tried explaining this process in the Climate Time Lag post but people seemed confused there too - I might have to rework my explanation of the whole process :-) -
BKsea at 06:37 AM on 19 September 2009The growing divide between climate scientists and public opinion
One of the overlooked aspects of this discussion is what the question means: "Do you think human activity is a significant contributing factor in changing mean global temperatures?" To a scientist, this may mean "Is there a correlation between human CO2 release and global temeperature change that exhibits a p-value less than 0.05?" To a non-scientist, it might be interpreted as "Is human activity directly impacting my life through changing temperatures?" I think this is part of the big challenge for scientists. We communicate and interpret through our scientific filters. But those filters may be distorting the message received outside the scientific community or our interpretation of the messages coming in. -
chris at 20:41 PM on 18 September 2009Is the U.S. Surface Temperature Record Reliable?
re #26 Not really WA. I don't think you've made an effort to investigate the US Climate Reference Network (USCRN). One can learn about the history of the development of this network here: http://www.ncdc.noaa.gov/crn/ and more specifically, here, for example: http://www1.ncdc.noaa.gov/pub/data/uscrn/publications/annual_reports/FY08_USCRN_Annual_Report.pdf In a nutshell, the USCRN was set up following a recognition starting in the mid-90's that it would be very useful to set up a network of US climate monitoring stations that would give a very long term (50-100 year) uninterrupted data set for high quality US climate analysis into the future. The network is part of the continuing role of the NOAA, enshrined by legislature to do climate monitoring. In other words it's a major role of the NOAA to continually assess its products and consider improvements/updates, much like any organization with a defined role. The essential nature of the USCRN was defined in a consultative period which came up with a set of principles by around 1999. There then began the process of planning, site acquisition, testing, quality control etc., with the first stations going "live" around 2001. There are now around 130 of these. Now that's all very well documented. The network was a response to careful analysis and planning and didn't have much to do with people "making a fuss".....nor did it have anything to do with "tooth fairys". -
chris at 20:38 PM on 18 September 2009Is the U.S. Surface Temperature Record Reliable?
re #25 You're not really addressing the data Mizimi, and what you "think" isn't a good basis for addressing science. That's a theological position (see WA message above). After all you "think" that that web site you linked to is useful when it's demonstrably rubbish (see my post #23). So if you don't "think" that 100 stations is enough to determine the temperature anomaly "over a 1200km sq cell" you should give some evidence why. In fact you've misunderstood the 1200 km correlation point. The fact is (this can be ascertained by examining station data output [*]) that the temperature anomaly is well correlated between stations even if these are separated by quite large distances (up to 1200 km in middle to high latitudes). That means that data from stations separated by medium and even large distances can be combined to give high spatial coverage with apparently sparse sampling to determine the gridded anomaly. Obviously this wouldn't work if we were interested in some spurious notional "average temperature" since the absolute temperature varies markedly on the small spatial scale. But we don't pretend to be interested in that (whatever dodgy web sites say!); we're interested in the referenced spatially-averaged temperature change (the anomaly). If you don't understand this fundamental point you're simply not going to be in a position to comment meaningfully on the data. Do we have scientific evidence that this is valid? Yes. We can calculate the profile of temperature anomalies using sub-sets of the total data. This has been done numerous times. An example is given in Figure 2 of John Cook's top post in which the temporal temperature anomaly profile for the contiguous US is calculated using a subset of the 70 best stations. It's very similar to the profile determined from the full record. That's not surprising since while absolute temperatures are highly non-correlated on the local scale, the temperature anomaly is rather well correlated. So we don't need a vast number of stations to determine the temperature anomaly. In another theological argument you say you don't consider 100 stations since 2001 as being significant". In fact the US Climate Reference Network has constructed around 130 stations in the new network covering the entire US since 2001. If a representative anomaly can be reconstructed from a subset of 70 temperature stations (see John Cook's Figure 2 above), I wonder what lends you to consider that 130 optimally sited stations with carefully optimised spatial coverage isn't even "significant". Note that 130 sites covering the US (2% of Earth surface) is equivalent to 6500 sites averaged over the earth’s surface. That’s a good coverage. In fact the real difficulty in obtaining full spatial coverage in the past has been the large areas of ocean that were poorly represented. However with the advent of satellite sea surface temperature measures, and improved networks of in situ sea surface measures….that situation has changed and there is now good ocean coverage. Re your comment: “obviously NOAA concedes there is a problem …”, that also needs some qualification. There is a continual drive to improve methodologies and analysis (e.g. see [***] for the most recent improvements in NOAA surface temperature analysis). That’s an on-going process in science. The existing met station network and other records has produced useable data since the late 19th century and the methodology for analysis and quality control has been continually improved as described in many dozens of papers over the past 20 years. If the advent of satellite sea surface temperature measurements can improve SST coverage then why not include this vast resource into the surface temperature analysis…improved in situ sea surface measurements from buoys and disposable instruments has been made – why not include those? If we can construct an improved network of met stations in the contiguous USA, then great. None of this means that pre-existing networks and analyses were not adequate. But given decent funding and scientific inventiveness, we can always make things better, and that’s done in climate-related science as in any scientific endeavour. If you’ve got some substantive criticism of these methods then address them specifically. Referring us to dismal websites that are rather obviously designed to mislead the poorly informed isn’t “skepticism”. [*] see papers describing NASA Giss methodologies here: http://data.giss.nasa.gov/gistemp/ [**] papers describing Hadley Hadcrut methodologies here: http://www.cru.uea.ac.uk/cru/data/temperature/#sciref [***] see this paper for example, for recent improvements in the NOAA surface temperature record: Smith TM, Reynolds RW, Peterson TC et al (2008) Improvements to NOAA's historical merged land-ocean surface temperature analysis (1880-2006). Journal of Climate: 21, 2283-2296. http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F2007JCLI2100.1 -
chris at 20:30 PM on 18 September 2009The growing divide between climate scientists and public opinion
Shawnhet, your post doesn't address the subject of this thread, but instead is about a sort of made up denialist fantasy. John Cook's top article and the paper under discussion addresses two quite specific things, the most general being the disconnect between informed opinion and public opinion in the US , and more specifically the response to two straightforward questions about (i) whether the global temperatures have risen since the late 19th century, and (ii) whether human activity is a significant contributing factor in changing mean global temperatures. There is nothing in these questions or analyses that have anything to do with GCM's and one wonders why you wish to attempt to introduce a denialist "stalking horse" where it doesn't belong. The evidence that the global temperature has risen (point i) has nothing to do with GCM's (it's the result of direct observation of land, sea and tropospheric temperatures, mountain glaciers, high latitude ice sheets, sea levels, seasonal climate effects, trends in the biosphere etc.). The evidence for the contribution of human activities (point ii) also has little to do with GCM's (it's the result of basic empirical and theoretical knowledge of the greenhouse effect and greenhouse gases, understanding of natural contributions to temperature change, and empirical knowledge of the variation of greenhouse gas concentrations and of natural factors). So your curious notion that the top article lends us to consider a "choice" between GCM's and some "alternative hypothesis", is doubly bogus in the context of the top article and the paper being discussed. (I wonder what your unstated "alternative hypothesis" might be!). Your last sentence/paragraph is a contrived "forced sequitur", where you've chosen to drift from the clear and explicit (points i and ii) to the vague and undefined. Specifically, the question addressed in the survey that both scientists and public responded to is "Do you think human activity is a significant contributing factor in changing mean global temperatures?". The evidence is strongly on the side of a response in the affirmative, wouldn't you say? However you've chosen to elide from the specific to the vague ("hypotheses A and B" which you say are "equally likely to be true"!). Which hypotheses might these be?! Obviously if you postulate two imaginary undefined hypotheses of which you've made up a notion that they are "equally likely to be true", then obviously we might question whether expert opinion can reliably distinguish these. But, of course, that's not what the thread, the top article or the paper under discussion is about, which is something quite specific. Denialism is largely based on the presumption of ignorance and relies on a withdrawl of sufficient information from the debate that a self-serving interpretation can be induced using specious "arguments". Unwittingly or not, that’s what you’ve done. You've taken a specific and well-defined question and its responses, withdrawn all the specifics from this and substituted an information-free notion of imaginary "hypotheses" within a logical construct that forces the conclusion that you've built into it. Interesting! -
georgebailey2 at 07:13 AM on 18 September 2009Is the U.S. Surface Temperature Record Reliable?
First post, please don't attack. Some thoughts crossed my mind as I read this and the various responses and I hope I can make those thoughts clear. With regard to the temperature anomaly, I understand the concept and that the change is important in trying to determine directional temperature trends. There was a point I think that thingadonta was trying to make in #5 with regard to Tom Dayton that Former Skeptic tried to counter in #7. If the absolute temperature error is constant, and the dynamics of that particular station are constant, then there is no effect on the anomaly. First, let\'s leave the dynamics of a particular station alone. If, in a perfect measurement, the station should read 32.0 degrees F, but it reads 32.2 degrees then for the anomaly to be unaffected, on a 95 degree day, the station should read 95.2 degrees. I would hazard to guess that the differential goes up in correlation with the increase in temperature above some certain level (e.g. the initial .2 degree difference may be unchanged until the real temperature reaches 50 degrees then begins to increase slightly thereafter due to external radiative influences). My question is whether there are similar influences that could make it go the other way, such as ice/snow on a 40 degree day and, even so, would that extend to temperatures below freezing? Also, I don\'t know if I should read anything into the fact that Figure 2 is in Fahrenheit while the NCDC ratings for range of error are in Celcius. Just thoughts about this topic and this topic only. -
Water vapor is the most powerful greenhouse gas
Something to consider. The global dew point has been rising faster than global temperature. At the same time the pan evaporation rate has been dropping with an increase in global temperature. -
Former Skeptic at 02:04 AM on 18 September 2009It's Urban Heat Island effect
Paravantis: So, from your econometric training, are you saying that UHI is NOT affected by wind? -
Cryptonomicon at 00:30 AM on 18 September 2009The correlation between CO2 and temperature
I can see your argument about the dips being about a trend but I still have several concerns with the data. As you mentioned you can not look at just a small piece. The same argument also holds for the pro global warming argument. You can't just look at the last century. You need to put the current temperature profile into the context of the whole of the Quaternary. Believe me doing so is non trivial. The issue I have is the unusual "flat spot" if you want to call it that of the last 10,000 years. Historically as you would know the Holocene we are in is an extremely unusual interglacial in the middle of the Quaternary glacial period. The argument is that the reason humans were able to develop civilization in the first place is because of this unusual warm flat temperature range. Simply put we got lucky. We evolved for far tougher conditions and the nice comfortable range of the current interglacial meant that humans were able to spend less time just surviving and more time thinking. The crux of my problem is that the flat range is unusual. It was due to end thousands of years ago based on the periodicity of the data - which btw simply screams Fourier Series. So how do you demonstrate absolute causal dependency between CO2 and temperature and disprove the possibility of a bigger problem - the end of the Holocene - or worse the end of the Quaternary period driven by massive effects that we have no hope of controlling. Remember temporal dependency does not imply causal dependency. Just because things occur at the same time does not imply one causes the other. If it did you could correlate your temperature rise to the amount of music played on the planet - which also increased over the 20th century. Why are you so convinced that the correct response is to try and fight change rather than adapt to it? Why would global warming be bad? Think of the consequences of a reduction in human population versus an increase? It seems a rather arrogant echo of King Canute to think that man can make the Holocene last forever simply by commanding it so -
shawnhet at 02:02 AM on 17 September 2009The growing divide between climate scientists and public opinion
Am I the only one here who thinks that polling scientists to find out their *opinions* is silly. Science is about making *predictions* about things that we haven't observed yet IMO. Regardless of what the opinion of scientists working with them, they only get to claim superiority of their *hypotheses* when they are able to demonstrate some valid *risky* predictions of the phenomena they consider. While the GCMs haven't been falsified yet (at least IMO), that doesn't mean that they have enough evidence to allow us to choose them over one of the alternative hypotheses. If hypotheses A & B are equally likely to be true(based on the evidence), then the fact that most scientists believe A to be valid and most plumbers believe B to be valid, doesn't mean that we should take the *beliefs* of scientists to be more likely true. Cheers, :) -
Wondering Aloud at 01:24 AM on 16 September 2009Is the U.S. Surface Temperature Record Reliable?
Sub set etc... does a different subset have different results? I espect so but it doesn't even matter the point is that the uncertainty is much larger than people pretend and indeed larger than the entire signal. I am still hopeful for significant warming but belief... As to fixing the stations... Do you think that would have gotten funded if no one had made a fuss about the problem? If so do you also believe in the tooth fairy? We were doing corrections with a "algorythym based on low resolution satellite photos. -
thingadonta at 00:15 AM on 15 September 2009The growing divide between climate scientists and public opinion
re 22: Chris Thanks for the well reasoned post. My experiences as a scientist and as a human being at university, and also in government, has been extremely disillusioning at times. And no this isnt the after- taste of a talent-less good fo nothing. Some of my most bitter experiences within science were very similiar to those I experienced growing up within religion- I would say EXACTLY the same. My experience in industry has given me the impression of a system that is more self-regulating and slightly more akin to reality than either academia, government, and certainly religion. There IS a dark side to science, because it is practised by people, and because there is a dark side to people (just like there is a dark side to governmnet and religion). 'Science' is not a perfect process or system by any means, and I think that humans have several hundred more years before 'science' matures to the point where it at least partly addresses some of its weaknesses (all other things being equal). As for some of your post, there was a strong shift within earth sciences away from industry-based research to non-industry based research in the 1990s, I know because I saw it first hand. It is still going on. I dont have specific details here, but thanks for your post. Re 27: No I didn’t get a copy of the questionaiire, but I suppose I would have if I conformed more to the disgraceful goings on I saw at university. -
hans at 02:20 AM on 14 September 2009It's aerosols
Here is a NASA study about aerosols affecting the Arctic: http://www.nasa.gov/topics/earth/features/warming_aerosols.html "Clean air regulations passed in the 1970s, for example, have likely accelerated warming by diminishing the cooling effect of sulfates" So without our pollution in the sixties global warming would have started much earlier. -
Mizimi at 05:06 AM on 12 September 2009Is the U.S. Surface Temperature Record Reliable?
Chris, I do understand the difference between temperature and temperature anomaly. As you rightly point out in order to obtain a reasonable assessment of the anomaly you require a reasonable coverage of the earths surface. Taking a sample over a 1200km sq cell only requires about a 100 stations (for land temps. I don't think anybody would consider that to be enough. " So it's very surprising that you don't know that the NOAA, despite limited funds, has been underway with a very significant programme to address the problem of surface station siting since 2001. They have already constructed well over 100 sites in a new network to give high US surface coverage using optimal placement criteria.\" A couple of things...(1) obviously NOAA concedes there is a problem and (2)I would not consider 100 stations since 2001 as being significant. (but maybe since we only need 100 stations on a 1200km grid to get an accurate reading of the temp anomaly it will be more than enough). -
Philippe Chantreau at 03:28 AM on 12 September 2009Is the U.S. Surface Temperature Record Reliable?
Chris, not to be a downer, but methinks you're wasting your time. Confusion between temp and temp anomaly is rampant and obvious with some commenters on this site. So is the confusion between the various reference periods used to compute anomalies, which are not the same for GISS and HadCRU; that's the only reason why some prefere HadCRU (that and the lack of Arctic consideration), it looks better to them, while in fact it says exactly the same as GISS. Satellite records have a different baseline still, which gives a different absolute value to the anomaly, yet shows the exact same trend. Also source of confusion is the fact that satellite records include stratospheric components. Etc, etc. All stuff that was discussed here at some point or another but then gets forgotten so the same talking points can be recycled ad nauseam. -
chris at 01:08 AM on 12 September 2009Is the U.S. Surface Temperature Record Reliable?
Re #19 I'm not going to dignify your site it by re-citing it, Mizimi, but I'd expect a skeptic would not be taken in by the essential flaw in the presentation which is based on a confusion of "temperature" and "temperature anomaly". What’s very odd is that the practitioners of your dodgy site have elsewhere made great play of the essential meaninglessness of the concept of an earth “average temperature” or “global temperature” when in fact proper scientists don’t use this anyway…however on your site that’s the concept that is presented to attempt to portray something odd with the surface station data. Let’s have a look: Your site presents a graph of some form of an averaged station temperature (ordinate) as a function of year (abscissa) and overlays this with the number of stations. However this data tells us nothing about the effect of station loss on the global temperature anomaly trend which is actually what we’re interested in (and what NASA GISS and Hadley Hadcrut and NOAA determine). Your dodgy site asserts that: “Graphs of the 'Global Temperature' from places like GISS and CRU reflect attempts to correct for, among other things, the loss of stations within grid cells, so they don't show the same jump at 1990.” However that’s not why Giss/Hadcrut etc don’t show “the same jump at 1990”. These data don’t show the same jump because they don’t plot the meaningless “average temperature”, but the temperature anomaly. If one doesn’t understand the difference between these then one is likely to be taken in by the sort of plot on your dodgy site (perhaps that’s what its author is hoping for). We can look at some model data to illustrate what’s actually going on. Let’s take 10 surface sites located randomly around the world and look at their temperatures and temperature anomalies.Local average temperature (oC) Site 1985 1995 1 13.1 13.3 2 8.3 8.5 3 9.5 9.7 4 18.6 18.9 5 12.4 12.6 6 10.6 10.8 7 17.4 17.6 8 9.2 9.5 9 21.3 21.4 10 11.0 11.2If we take the change in temperature at each site as the anomaly (that’s what an anomaly is, although in reality it is relative to a base year range) then we can calculate the (meaningless) “global temperature” and the global anomaly: “global temperature” (1985) = 13.14 oC “global temperature” (1995) = 13.35 oC global anomaly (1995) = 0.21 oC (relative to 1985). Now we remove the five coldest sites from the 1995 data set due to “collapse” of the Soviet Union (say) in 1990: “global temperature” (1985) = 13.14 oC “global temperature” (1995) = 16.76 oC global anomaly (1995) = 0.20 oC (relative to 1985) Interesting, yes? The world has apparently got hotter while the global temperature anomaly is essentially unchanged. Do you see why one doesn’t use the meaningless “global average temperature”, but rather the temperature anomaly Mizimi? The temperature anomaly has a number of other excellent qualities. One of these is that while absolute temperature between distant sites is non-correlated (some might be at higher altitudes or in different local environments) the temperature change over time between sites is highly correlated even at high distances (up to 1200 km). Therefore the temperature anomaly allows one to get a rather accurate global scale assessment of temperature change even without full surface coverage. And (as we’ve just seen) the use of the temperature anomaly means that changes in coverage (loss or gain of stations) doesn’t materially affect the measured global temperature change so long as there are sufficient overall stations. Another quality is that additional temperature measures (e.g. from satellites) can be seamlessly incorporated into the temperature anomaly analysis. -
chris at 00:58 AM on 12 September 2009Is the U.S. Surface Temperature Record Reliable?
You don't seem to have researched this subject very well WA, and are somewhat misinformed: So it's very surprising that you don't know that the NOAA, despite limited funds, has been underway with a very significant programme to address the problem of surface station siting since 2001. They have already constructed well over 100 sites in a new network to give high US surface coverage using optimal placement criteria. As time proceeds data from this network (the US Climate Reference Network) will merge with the pre-existing surface station data. So contrary to your assertion, "the government" is "coming up with the bucks" to improve the network of surface sites. I hope you're happy that your tax dollars are being put to good use! You can read about this here: http://www.ncdc.noaa.gov/crn/ You also seem unaware that despite a photo-campaign to attempt to discredit the US surface measurements, a reconstruction of the US surface temperature record employing only the sub-set of good or best-sited stations, yields a temperature anomaly record that is hardly distinguishable fom that created from the full set. You can read about this in John Cook's top post on this thread (see Figure 2 above). It desn't matter if some sites are poor - this is taken into account in the analysis of the temperature record and corrected for. So again it's silly to say that "correcting these issues is something that has not been done". In fact correcting these issues has been the subject of a huge amount of effort and has been done doubly (firstly by careful assessment of the pre-exisiting data network, and secondly by construction of an entirely new network). it's your tax dollars WA - you should make a better effort to determine how they are utilised! -
Wondering Aloud at 23:33 PM on 11 September 2009Is the U.S. Surface Temperature Record Reliable?
Chris The greater than 3 degree etc. scale is NOAA's own scale, it has to do with what the errors are in the site location and what measurement error these are known to introduce; as determined by NOAA itself. For instance with something like 9% of US sites located adjacent to sewage digestors that run at about 35 C all the time we are going to have some considerable distortion especially when the outside temperature is -35 C. The rating scale attempts to quantify this error based on distance to things that introduce bias. You can get a pretty darn good idea of these problems through a survey of the site. And indeed this type of survey is the prescribed method from NOAA for determining site compliance. It isn't something Watts made up. The problem is correcting these issues is something that has not been done. Because they don't know? No. Because with all the billions spent on AGW by the government somehow they won't come up with a few bucks to get these fixed. I hope WUWT will force NOAA to fix this network. -
snowman1955 at 07:03 AM on 11 September 2009Does Urban Heat Island effect add to the global warming trend?
I don't know about the results in China, I would have to examine the data set involved, but in the Western US, specifically in more Arid regions...the Urban Heat Island effect has been great (on the order of 10 F increases in annual mean temperature)since 1970, and the number of stations involved is increasing due to Urban Sprawl. NASA has not corrected for this....nor have then excluded Urban areas in their computations. Also please note that they have been greatly overestimating the SST Anomalies over the Pacific by arbitrarily changing the long term mean temperature downward...by close to 1 C. Not a skeptic, just a scientist looking for the truth. -
snowman1955 at 06:18 AM on 11 September 2009Does Urban Heat Island effect add to the global warming trend?
Since when did a Gas become bad? -
Mizimi at 05:40 AM on 11 September 2009Is the U.S. Surface Temperature Record Reliable?
It is worth watching the mpeg file at the Delaware site showing the loss of stations from 1950 onwards, especially in 1990 when the Russian Federation collapsed. http://climate.geog.udel.edu/~climate/html_pages/air_clim.html you will have to logon (free) to access the data. -
Mizimi at 05:22 AM on 11 September 2009Is the U.S. Surface Temperature Record Reliable?
'#14...Philippe....I am sure that datasets are analysed and configured to minimise the impact of losing stations within a grid. My point is that when you lose a massive amount of stations ( such as in Russia) then it must have a deleterous effect on overall data reliability. There is an interesting article on the subject here... http://www.uoguelph.ca/%7ermckitri/research/nvst.html' -
floyd at 14:29 PM on 10 September 2009Human CO2 is a tiny % of CO2 emissions
@chris and mizimi Re: posts 14-17: I googled 'dynamic equilibrium' and was easily able to find not only many definitions but also a host of examples from biology and physics where it applies. I'm no expert on scientific communication, but I think it is critical to have a common conceptual and terminological corpus in order to exchange information with any degree of efficiency. It seems that many of the posters here rely on Chris to provide a rudimentary overview of the science (I mean the stuff that has survived peer-review and been published in reputable journals, not your uncle Jesse's theory of faerie-dust driven tropospheric warming, which he posted last Sunday after a few cold ones on some random website somewhere). There's nothing necessarily wrong with that, unless said posters are arguing passionately that the mainstream science is wrong. After all, what better way to undermine your own credibility than to take a vigorous stand against a position that 1. you do not really understand and 2. is supported by 90% of experts in the field - people who do actually do understand the science? On what basis can you disagree with the majority of professional scientists in a given discipline if you don't even have a handle on something as elementary as the terminology they use? -
chris at 01:44 AM on 10 September 2009Is the U.S. Surface Temperature Record Reliable?
not really WA. The notion that one can "look at" a load of photos and "know that the bias is overwhelmingly positive" is simply non-scientific and indicates a pre-conceived view point that is also non-scientific. Science is about measuring and analyzing . As the NOAA showed (they're scientists who measure things!) calculating the temperature profile based on the "best" set of sites results in a data set that is barely distinguishable from the profile calculated from the full data set with bias corrections based on comparison with local rural sites (see John Cook's fig 2 above). It's astonishing that Mr Watts didn't do such an analysis; however it's perhaps understandable since Mr Watts isn't a scientist and apparently has non-scientific reasons for pursuing his photo campaign. Anyway, I don't understand how you can determine that a site has a "likely error of 3 degrees" by looking at a photo. What exactly are you measuring WA? And why not answer Philipe's straightforward questions? What scientific paper(s) has presented this "warm bias" that is "overwhelmingly inflating temperatures"? How can the US surface temperature data be inflating temperatures, when the surface temperature is consistent with that determined from satellite data, and with independent measures of temperature increase (e.g. temperature profiles calculated from the rates of mountain glacier retreat)? One of the problems with "stripping out" quantitative analysis and relying on qualitative descriptions (e.g. photos) is that the latter are heavily prone to subjective interpretation and ripe for misuse by propagandists. Theological arguments are subjective/qualitative whereas scientific arguments are quantitative. Less theology please WA; let's see your quantitative analysis or a link to a published relevant version. -
Wondering Aloud at 23:14 PM on 9 September 2009Is the U.S. Surface Temperature Record Reliable?
Never mind. If you don't understand that a site with a likely error of 3 degrees cannot produce quality data than I am wasting my time. If you can look at the thousands of photos and not know the bias is overwelmingly positive... If you can look at site records where the warm bias has clearly been growing over time due to facility changes yet the corrections reduce past temperatures and increase recent temperatures. A pattern that has been shown many times with specific documented cases at the Surface stations project. Then you are apparently talking theology. -
Philippe Chantreau at 01:29 AM on 9 September 2009Is the U.S. Surface Temperature Record Reliable?
"A look at the corrections..." You need to substantiate and specify that accusation, it makes no sense under this formulation. "Analysis of the effects of the discovered problems is a further step." Which has been preliminary taken by John V and completed by NCDC. The purpose of WUWT was never to check data quality, because they never closely looked at data. They took pictures of sites then went on wildly speculating about the significance of it. The significance is shown by data analysis, which is the part they never did. The state of the stations is not news to NOAA and NCDC, they were working on it before Watts. This statement "The sample size at present means that at least 2/3 of US stations have likely error greater than 2 degrees C, and that the error is overwelmingly inflating temperatures." is total nonsense, as was demonstrated by the data analysis. What paper has demonstrated the "overwhelming" warm bias? If that was the case, how is such agreement obtained with the satellite data? Even 3 minutes spent on WUWT is a waste of time. -
XPLAlN at 01:27 AM on 9 September 2009The growing divide between climate scientists and public opinion
Interesting data but not very surprising. Thanks for posting. I fall into the darkest blue category. What about you thingadonta? Did you get sent a questionnaire by the authors of the report? -
Wondering Aloud at 01:18 AM on 9 September 2009Is the U.S. Surface Temperature Record Reliable?
I don't know why my response to dorlomin is not here but I did say that yes some stations are found to have a cool bias though the numbers are not even and most have a bias that would tend to show warming. Phillipe I think you misunderstand the purpose of the project. It was to check data quality. Analysis of the effects of the discovered problems is a further step, go ahead and start on that I'm sure it would be welcome. I think a finding, that 89% of the stations in the USHCN (which is supposed to be the best data set) don't meet even minimal quality assurance standards is important news in and of itself. The sample size at present means that at least 2/3 of US stations have likely error greater than 2 degrees C, and that the error is overwelmingly inflating temperatures. A look at the corrections introduced by NASA on a site by site basis shows that the corrections do not fix the problem and often make no sense. If the raw data is off by more than 2 degrees and the corrections don't correct isn't any analysis or comparison using that data to look at fractional degree temperature changes simply rubbish? Can we assume the rest of the world data set is good? -
NewYorkJ at 17:04 PM on 8 September 2009The growing divide between climate scientists and public opinion
For Robbo... Latif is co-author of the 2008 Keenlyside study, which predicted slight decadal cooling, with no changes to the long-term outlook (see year 2030). http://www.realclimate.org/index.php/archives/2008/05/global-cooling-wanna-bet/ I'm not convinced of their short-term outlook, though. Global mean temperature had already overshot their earlier hindcast, and ocean surface temperatures are beyond record levels for June and July. http://www.noaanews.noaa.gov/stories2009/20090814_julyglobalstats.html It's interesting that while ocean cycles (PDO, AMO, NOA) are in or moving towards their negative phase, and solar sunspot activity has been at near century-low levels for about 3 years now, global mean temperature is near record levels. Kind of makes you wonder how very rapid the warming will be when these phases reverse. Sorry for the off-topic response. Back to the topic... "Does it matter if there is a consensus of like minded twits - if the consensus is incorrect?" I think it does. The folks over at Wattsupwiththat and other pseudoscience blogs could use a large dose of critical thinking encouragement, as groupthink is prevalent in such places. In addition, our society suffers when large groups of individuals are blinded by ideology and willing victims of the Dunning Kruger Effect. -
Robbo the Yobbo at 12:11 PM on 8 September 2009The growing divide between climate scientists and public opinion
Does it matter if there is a consensus of like minded twits - if the consensus is incorrect? The planet is still cooling and will continue to do so for another decade or 2. See this form Fred Pearce in New Scientist. http://www.newscientist.com/article/dn17742-worlds-climate-could-cool-first-warm-later.html Warm later indeed. Is there something here about flogging a dead horse. -
Philippe Chantreau at 01:00 AM on 8 September 2009Is the U.S. Surface Temperature Record Reliable?
Thingadonta is going at it again with the diurnal "thermal inertia" nonsense, while it has been shown to him already that there is no such thing. The very premise to Watts' web site existence was invalidated fist by John V, and now by NCDC. Nothing more needs to be said. Actually, yes, one more thing: the data analysis done by John V and NCDC should have been done by Watts if he had any real intention to demonstrate the very thing he believes in. But he did not. Despite the clamored, iron-clad confidence that it was so bad, not once was there a true, mathematical data analysis of the surface stations data on WUWT. I wonder why. Mizimi, if you think that gridding is not properly done in the analyses, you have to substantiate. Take the papers, look at how they do the gridding and tell us how it's wrong. Your statement here is very vague and does not seem to refer specifically to how any given anlysis was done. -
Philippe Chantreau at 00:42 AM on 8 September 2009The growing divide between climate scientists and public opinion
Well said Chris. Indeed a functioning society needs both industry and governement funded research, fundamental and applied science. But in both cases, the education necessary to the people conducting it is acquired in universities. I'm still reeling from the astrology=socialism thing, I thought I had heard it all, but this one is out there. Silly caricature indeed. -
Philippe Chantreau at 00:41 AM on 8 September 2009The growing divide between climate scientists and public opinion
Well said Chris. Indeed a functioning society needs both industry and governement funded research, fundamental and applied science. But in both cases, the education necessary to the people conducting it is acquired in universities. I'm still reeling from the astrology=socialism thing, I thought I had heard it all, but this one is out there. Silly caricature indeed. -
chris at 23:20 PM on 7 September 2009The growing divide between climate scientists and public opinion
Thingadonta, your politicisation of everything scientific leads to misunderstanding that is not far off conspiracy theorising! The government doesn't "fund research that is outside "industry" by default". That's simply not true. "The government" strongly supports science that has industrial links, and especially that is part-funded by industry, and in our grant applications we have to indicate the benefits of our research to beneficaries including potential industrial applications as well as to society and so on. The government (and charities) fund "technology transfer" grants in which academic ideas with potential industrial applications are supported to facilitiate research at pre-application stage that can be exploited by interested industrial partners downstream. One can examine the NSF budgets and find, for example, that, in the US, climate science is funded around the same level as nanotechnology research. Nanotechnology has huge potential industrial applications, and the US government supports basic research in this area largely (apart from basic scientific interest) as "seed corn" for downstream applications that will be of expected industrial benefit. Much of the pharmaceutical industry feeds off the basic research (in the US) of the government-funded National Institutes of Health…they effectively get a "free ride" off the basic understanding of molecular and cellular biology developed in "academic research"….and so on. Obviously there is a large generalised arena of science that has to be funded by governments since it relates to the general interests and well-being of the population but is of little direct interest to industry, at least initially. The basic understanding of AIDS virology, for example, was gained by government funding initially to understand the disease and develop therapies, but with huge downstream benefits for the pharma industry in sales of antivirals. Pharma is not very interested in developing new antibiotics (not very profitable) and this essential task is funded by government….etc. etc. And obviously science that relates to the environment pretty much has to be funded by governments, outwith those aspects with direct industrial applications (oil, gas, mineral, forest, hydro exploitation). If we want to know the effects of sulphurous emissions on lakes and forests industry likely isn't going to do that; likewise with the effects of releasing chlorofluorocarbons in large amounts, or of massive greenhouse gas release – industry is about making money wouldn't you say? That's the bottom line…no problem with that obviously, but let's not pretend that we can learn about many fundamental things of interest to our well-being without serious efforts from government-funded scientists. We either decide we should know about these things…or not. And we don't pretend that the laws of physics should yield to our political sympathies just because we don't like the research outcomes. In fact I suspect most informed individuals recognise that government-funded and industrial research are two interlinked aspects of a mature society, and that we need both. Your silly caricature (for which you give zero evidence!) that government funding ensures " the development of a generation of researchers who are fundamentally opposed to industry" sounds like a political mantra to me. As for your notion of a poor industry "which is supposed to magically train and look after itself", I think you'll find that industry benefits from a vast resource of government-funded research (see above) and a massive resource of educated and trained individuals, the training and education of which they get largely without direcly paying for. Industry, by and large, doesn't pay for those BScs, MScs and PhDs. And of course if things go pear-shaped (financial industry…auto industry) who's there to sort things with huge bail-outs? The nasty government! Again nothing necessarily wrong with that… but let's not pretend that there is some sort of "industrial/government-funded" dichotomy about which one has to choose sides…that sort of thing is for political fanatics and propagandists! Sadly (getting back to the subject of this thread!) there are some rather well-funded organisations ('specially in the US) that consider it politically expedient and profitable to present the false picture of government-funded science that you portray so well.... -
canbanjo at 22:51 PM on 7 September 2009The growing divide between climate scientists and public opinion
re the conspiracy theory, I asked a doctor in oceanography friend at southampton uni what scientists thought of this and he replied as follows: "this is an oldie, and actually one some people in the field sometimes agonise over from a different direction, in particular the argument can go 'we (scientists) know that potentially dangerous global warming is just around the corner, but by continuing to do endless research into the magnitude, side effects, feedbacks etc. etc. (and so further our careers) we are actually just distracting the politicians/public from the key message which is that something needs to be done now to drastically cut emissions. Consequently we should all quit until the world gets it's act in order and starts taking things seriously, which they clearly aren't at the moment'. Anyway, the way the sceptics tell it is much more common (because they have an agenda). and yes actually I am sure there will be a lot more climate scientists now than 20 years ago and they will consquently be spending more tax payers money (their salaries). But that would be the same if it was a real problem or an exagerated one wouldn't it? If it's a real problem then resources are needed, so more jobs for the boys I'm afraid... Anyway, all comes back to integrity, peer review, scientific method etc., any scientist would get really shitty with anyone claiming they are falsifying or exagerating their results, it amounts to accusation of professional misconduct, this is why most won't even bothering to stoop low enough to engage with this one." -
canbanjo at 16:57 PM on 7 September 2009The growing divide between climate scientists and public opinion
These polls are useful for non scientists, eg the general public, politicians, the press etc to realise that the AGW skeptics are small minority. It shows that a layman skeptic is saying either that they believe that the vast majorty of scientists have got it wrong (without any scientific understanding / basis), or that there is a giant global science conspiracy to make us believe something that isn't true. -
Steve L at 14:54 PM on 7 September 2009The growing divide between climate scientists and public opinion
And Gallup is an agent for Communism, right? Spin all you want, but remind me never to take anything you write as honest/serious commentary. Here's what I found on Gallup's website: "Results for knowledge of global warming are based on telephone and face-to-face interviews conducted between 2007 and 2008 with about 2,000 adults in most countries (and a sample size range of 500 to 8,256). Results for perceived causes of global warming have a sample size range of 150 to 5,273. Confidence intervals thus vary widely based on the sample sizes of specific groups. However, for the scores for public awareness of global warming, confidence intervals for all countries were always less than ±6 percentage points. In addition to sampling error, question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of public opinion polls." -
Mizimi at 05:26 AM on 7 September 2009The correlation between CO2 and temperature
#27...try this... http://chartsgraphs.wordpress.com/2009/08/13/excel-chart-misrepresents-co2-temperature-relationship/ -
Mizimi at 05:02 AM on 7 September 2009The growing divide between climate scientists and public opinion
#16, Steve L....my comment was directed at the 3142 earth scientists, not joe public and perhaps I should have made that clear. What is interesting is that there appear to be no figures for the public...are we talking substantial numbers here or what? According to a certain shampoo manufacturer 9 out 10 women surveyed prefer their product...but when you check the small print they only questioned 300 women. Hardly a good statistical sample. On another note, the European Union didn't like the Irish 'No' response to a referendum. Their reaction? Well you'll have to vote again until you get it right....... What is illuminating is that DESPITE all the political/media/evironmentalist hype there are still (apparently) a large number of people who don't believe in any 'significant' effect. -
cce at 03:45 AM on 7 September 2009The growing divide between climate scientists and public opinion
The tobacco industry used the exact same arguments to discredit "establishment" studies showing what they and everyone else already knew. It is useful to read this speech from Colin Stokes, then CEO of RJR, introducing Frederick Seitz (he of Oregon Petition fame) in his role as the director of their research program. He repeats industry talking points, each one of them with a direct analog to the arguments posed by so-called AGW skeptics. It's the same game, with higher stakes. http://tobaccodocuments.org/ness/29154.html Take, for example, "the American Cancer Society has concentrated its efforts on developing a cancer cure and on claiming that lung cancer would be virtually elminated by the elmination of smoking. We firmly believe that their claims are a dis-service to society in that they discourage people from seeking out the true causes of cancer" "many both inside and outside of the scientific community feel government has proven itself a biased, restrictive sponser." "H-E-W [now HHS] direct study under the preconceived idea that smoking causes cancer, emphysema and cardiovascular disease, and therefore is spending the majority of its anual twenty million dollars in smoking-and-health research money for finding methods of smoking prevention." Now, consider the credibility of these claims: "prominent medical authorities lining up on each side of the arguments" "For every charge that has been made against cigarettes, there has emerged a strong body of scientific data or opinion in defense of the product" "It is not possible ... to distinguish between the lung of a smoker or a nonsmoker" "why do many nonsmokers fall victim to lung cancer, while the disease is never contracted by ninety-eight percent of those so-called heavy smokers who consume a pack-and-a-half a day or more" "One study, for instance, has indicated that light smokers and ex-smokers are less prone to cardiovascular illness than smokers." "There is no medical proof that nonsmokers exposed to cigarette smoke in ordinary relation with smokers suffer any damage." Also, if anyone can point me to a report from the National Academy of Sciences advocating Communism, Eugenics, and Astrology I'd like to see it. And it had better be an authoritative consensus report urging policy action and not the extra-curricular activities of cranks. -
Steve L at 03:11 AM on 7 September 2009The growing divide between climate scientists and public opinion
Mizimi #9, your complaint about question two makes no sense to me. If the question is unanswerable except by "yes", then why so many "no" responses? If the question is too vague, then why so few "I don't know" responses? It seems to me, given your opinion of the question, that the results are very impressive -- people with the least understanding of the issue (and the least understanding of the caveats you note) think human activities have nothing to do with significant changes in mean global temperatures. Almost 40% of the general public responded "no" versus about 6% "not sure"! This staggering response to a question unanswerable except with "yes" should receive more attention. Thanks for blogging it, John. -
Mizimi at 07:45 AM on 6 September 2009Climate time lag
Just a small point Chris...the hypothesis that CRF effects cloud nucleation ( principally at low level) does not require CRF to vary. If you vary WV concentration whilst CRF remains constant you would achieve the same result - a variation in cloud nucleation. -
Mizimi at 07:31 AM on 6 September 2009It's microsite influences
An idle thought....we tend to think of 'bad' stations giving higher readings than 'good' stations as they respond to surrounding heat emitters such as buildings. In cold weather the opposite can occur...the 'bad' stations will respond more slowly to increasing T due to the thermal inertia of those same buildings. In other words, the T swing max-min could be greater in the 'bad' stations but dis-appears in the averaging process. So maybe there is an element of self-compensation here which could be determined by looking at more detailed data. -
Mizimi at 04:49 AM on 6 September 2009Models are unreliable
#114 "Is it really true that there is a direct causal link between human activities and climate? " Certainly there is. In the same way that vulcanism or other factors have an effect on climate. But the real question is to what extent do human activities affect climate..and that we have yet to quantify. And therein lies another problem; those who wish to control us( for whatever reason) will turn tentative indications into cast iron certainties in order to achieve their purposes..and both sides are equally guilty of this. -
Mizimi at 04:30 AM on 6 September 2009The growing divide between climate scientists and public opinion
#14 Define sceptical..... "are human activities contributing to global warming?" Most certainly. As do many other processes. To what degree? Now that is the question which we are really debating/trying to quantify. And for me, here begins scepticism. Ask the same scientists if they consider GCM's to realistically model climate in all its complexity and you will likely get an answer along the lines of..." in accordance with our present understanding of..."
Prev 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 Next
