Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings

All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

Recent Comments

Prev  2217  2218  2219  2220  2221  2222  2223  2224  2225  2226  2227  2228  2229  2230  2231  2232  Next

Comments 111201 to 111250:

  1. Climate change: Water vapor makes for a wet argument
    johnd - I am sorry but I can make no sense of that. Firstly, the water vapour in the atmosphere is mostly from evaporation out at sea and surface sea temperature is what is important. If the feedback from temperature didnt have an equilibrium point (k<1), then we would have runaway. To change climate and create trends, then you have to perturb the system. You cant do that by suddenly finding a way to add water, but you can if you increase the radiation received by the surface. Can you honestly believe that extra W/m2 of radiation is somehow NOT going to warm the surface?
  2. Quantifying the human contribution to global warming
    A very, very good article that lays out the facts in clear, logical terms. A suggestion and a nitpick: I would drop the final paragraph regarding the conservative estimate of the sensitivity -- it doesn't really fit the article and, as you correctly point out, the low sensitivities have been pretty much discredited. If you are going to keep the paragraph, however (and this is the nitpick), one would expect that the warming delay caused by thermal inertia would apply to this estimate as well, so CO2 under the low sensitivity model would account for less than 0.5 degree C of the total increase over the past 150 years. Again, though, really good article.
  3. Climate change: Water vapor makes for a wet argument
    Chris G @21 Assuming GHGs are the prime cause of atmospheric temp increase, then the greater their presence, water vapor increases. But the more water vapor present means an increase in clouds, reducing the level of solar radiation reaching the surface of the earth. Is it not true to argue that increased atmospheric water vapor acts not only to amplify temperature increases caused by GHGs but also acts to limit that increase by reducing solar energy reaching the earths surface?
    Response: Tricky question - clouds not only limit the amount of incoming sunlight but also trap more infrared radiation coming up from the Earth's surface. The amount of heat trapped depends on the altitude of the clouds. The evidence currently indicates a slightly positive feedback from clouds (eg - a net warming effect) but this is an area with much uncertainty. Certainly a worthy topic for a more detailed future blog post!
  4. Quantifying the human contribution to global warming
    40%! Perhaps I heard that figure before, but to see it stated so precisely here, and with mounds of data to back it up, that certainly makes the situation sound dire. 40% is a lot, especially when the increase takes place so fast. 150 years is a blink of the eye on a geological time scale -- which is precisely the time scale that is most relevant.
  5. Climate change: Water vapor makes for a wet argument
    scaddenp at 17:36 PM, water vapour feedback or forcing is almost a chicken and the egg question. Evaporation of surface moisture, and the resultant water vapour, depends on a number of factors, however the two that drive it most are solar radiation and wind. Ambient air temperature whilst a factor is not so nearly important as soil temperature which in turn responds directly to solar radiation. The depth of heat penetration of the soil is dependent not only on soil composition, but soil moisture levels with moist soil allowing the heat to penetrate as much as 3 times the depth as with dry soil. This reservoir of both moisture and stored heat is then most responsive to wind which without on a day of high solar radiation causes soil temperatures to rise, but with wind, even on a day with lower solar radiation will rapidly remove soil moisture. Wind is perhaps the most important single factor in evaporation. Ambient air temperature, or surface temperature is generally understood as not being that on the actual surface, but that at a point above the surface, in the case of instrument readings, 1.4 metres IIRC is the standard height. It as this standard height that a person can quite comfortably stand fully clothed whilst frying an egg on a steel plate on the ground heated solely by solar radiation, as long as the surface is protected from the wind. When the question of correlating water vapour content with atmospheric temperatures, it needs to be looked at from at least two different perspectives. Firstly what drives the change of state process that results in water vapour entering the atmosphere in the first place, and secondly what drives the process that causes it to change state again in the atmosphere and complete the hydrological cycle.
  6. Climate change: Water vapor makes for a wet argument
    Just some general thoughts: Without more water vapor, there will not be more clouds. Else, what are the more clouds made of? With higher temps, water vapor will stay in gas phase longer than with cooler temps. Water vapor is always a GHG; there just isn't very much of it above the tropopause. Water vapor has a tendency to precipitate out of the atmosphere; CO2 does not precipitate at conditions commonly found on earth. Regarding the overlap of water vapor and CO2, I've found these links to be useful. Basically, there is enough non-overlap for CO2 to have effects. http://webbook.nist.gov/cgi/cbook.cgi?ID=C7732185&Units=SI&Type=IR-SPEC&Index=0#IR-SPEC http://webbook.nist.gov/cgi/cbook.cgi?ID=C124389&Units=SI&Type=IR-SPEC&Index=1#IR-SPEC We are mostly interested in what CO2 does around the 667 wavenumber. I like to switch the graphs to absorbance for clarity. An alternate view of the same information http://en.wikipedia.org/wiki/File:Atmospheric_Transmission.png
  7. Climate change: Water vapor makes for a wet argument
    Doug... There is a good piece on the Spencer/Braswell paper here at Real Climate.
  8. Climate change: Water vapor makes for a wet argument
    What's your take on the Spencer/Braswell paper in Journal of Geophysical Research questioning the cause and effect assumptions of the water vapor feedback theory?
  9. It's the sun
    sun tzu - MORE to the point - why should any consideration be given to uninformed opinion? What affecting climate... well without moving the earth's plates around you have four ways to influence climate. 1 solar - amount and distribution. Stable or dropping 2 aerosol - stable 3 albedo - actually replacing forest by agriculture increases albedo and so a net cooling affect. 4 GHG - increasing and unsurprisingly, so is temperature.
  10. The surprising result when you compare bad weather stations to good stations
    Omnologos, Scientists say warming is unequivocal. What part of unequivocal do you not understand? Menne is just saying that it is interesting that station siting has no effect on the trend and that he expected to see some type of effect. That does not mean that the trend no longer exists as you suggest. It is not necessary to determine why station siting has no effect on the trend to prove that there is a trend. GISS, HADCRU and other scientists have checked their data for this type of error for decades and were not suprised by the result. The key point here was that the deniers chose the good stations so they cannot claim now that the good stations were cherry picked to give the desired result.
  11. Earth's five mass extinction events
    #68: "this link has taken the reader far back in time to the Ordovician to draw a correlation between rises in CO2 and mass extinctions. " No, you've missed the point. That 'CO2 levels were higher in the past' (all the way back to the Ordovician) is a denier argument. This argument requires that one make direct comparisons between the distant geologic past and today based solely on reconstructed atmospheric CO2 -- and that is what stimulated the discussion of plate tectonics, ocean circulation, completely different fauna, etc. However, this does nothing to negate the current CO2-climate issue. That's been discussed on many other threads here. I don't recall anyone here claiming that CO2 is an "insidious scourge", but if you have some new insight as to why it is not a significant climatologic concern, please be specific in your argument. "When anyone tries to draw vague parallels to climate changes associated with wandering land masses and global conditions alien to those of today, it only reinforces the skeptic’s position. " Once again, trying to draw those parallels is exactly the skeptic position -- and you point out quite elegantly just how ludicrous that position is.
  12. Climate change: Water vapor makes for a wet argument
    Rob, I'd say you have it pretty well covered. Water becomes vapour because the heat excites the vibrations between different molecules. These are low energy: 20 times smaller than vibrations of the atoms within a molecule. Excite them enough and individual molecules will start "breaking free", Dah Dah: water vapour. Some people get confused about the fact that the feedback from water vapour doesn't explode, giving infinite heating, especially if they are told that the heating contribution from H2O is greater than CO2. A good way to explain that is to use the factor 2/3 as an example. So a 1 degree rise due to CO2 gives an extra 0.66667 due to H2O, which in turn induces 2/3 of that (i.e. 4/9 of the original). So already by the second iteration the total contribution from water vapour is greater than CO2 (1.1111 or 10/9) but, because the numbers at each iteration are smaller than the previous one the feedback is not explosive.
  13. How climate skeptics misunderstand past climate change
    CO2 concentrations in the upper atmosphere increase with an increase in temperature and not the other way around.
    Moderator Response: This argument is addressed on the page "CO2 lags temperature".
  14. Climate change: Water vapor makes for a wet argument
    robhon, even at ~30 C lower global temperatures there ought to be regions along the equator which were still warm enough to have some water vapor in the atmosphere. Possibly billions of years ago when solar output was significantly lower it could have resulted in 0% absolute humidity worldwide (c.f. 'Snowball Earth' theory). Otherwise your explanation matches my understanding.
  15. Earth's five mass extinction events
    There appears to be a desperate need to tie CO2 to the GW litany. To this end, this link has taken the reader far back in time to the Ordovician to draw a correlation between rises in CO2 and mass extinctions. This is beyond the pale of ludicrous as the comments discuss the rise and fall of corals, reefs and the insidious scourge of CO2. 1)Ancient reefs 560 mya were primarily cyanobacteria which trapped sediment and secreted calcium carbonate, forming large structures (up to 450m thick, but more usually less than 5m thick) known as stromatolites. 2)The first scleractinians, or modern day hard corals, turned up during the Triassic period about 230 mya 3)Coral reefs were almost replaced by bivalve reefs in the early Cretaceous period - rudist bivalve reefs dominated corals for around 30 million years. 4)Changes in the configuration of the continents limited or expanded coastal shelves influencing reef growth 5)Volcanism and plate tectonics have resurfaced the earth 6)The reefs divers are most familiar with are only 10,000 years old 7)When looking at the fragility of reef systems and the oceans biomass natural and man-made hazards have impacted their growth and health but NOT FROM CO2. The geologic record in many cases is quite explicit. When anyone tries to draw vague parallels to climate changes associated with wandering land masses and global conditions alien to those of today, it only reinforces the skeptic’s position. When I was a kid I made a very detailed model of a Werewolf. It was painstakingly painted and dramatically presented. In the end it was a beautiful model of a fictitious creature. It too was art not science.
  16. CO2 was higher in the past
    mmckinstrie, calculations of past solar output come from solar physicists. By studying stars of various sizes and ages they've been able to get a very detailed picture of how stars change throughout their lifetime. See info on the Standard Solar Model for details.
  17. Greenland is gaining ice
    Sorry, I messed up two hyperlinks. Here they are: ... mentioned in e.g. the IPCC 2007 report. There's another, somewhat older research, ...
  18. Greenland is gaining ice
    New research on the GRACE results argues there's exaggeration of the ice loss in Greenland and Antarctica data. The current estimates are supposed to ignore isostatic rebound caused by the weight reduction pressing down on the bedrock through the lost ice mass. E.g. this new report claims that the true loss in Greenland is only half of the previously reported 230 Gt per year. This spectacular reduction is, ofcourse, trumpeted around in the media and denial blogs as exiting news, but 104 Gt per year brings it right into the IPCC 2007 ballpark of 100+ Gt per year. It is, however, much lower then the latest GRACE numbers as published by Velicogna et al. 2009 and 2007, but in the same ballpark as GRACE numbers from Luthcke et al. 2007. The concept of isostatic rebound effecting the GRACE mass numbers isn't new either as it was already mentioned in e.g. the . It just puts some numbers to it. There's another, somewhat older, that delves into the apparent GRACE overestimation by comparing IceSat to GRACE results. But instead of isostatic rebound it seeks to explain the differences with ice density uncertainties. It also gives an IceSat number of -138 Gt per year for Greenland which is roughly equal to the results of this new research. So I don't know exactly what the great joy of this report is supposed to be for the contrarians. It just seems to me as confirming, refining and consolidating the science behind the apparent shrinking ice sheets.
  19. Climate change: Water vapor makes for a wet argument
    I've always tried to explain this one to people this way (maybe someone can correct me if it's wrong)... Water vapor in the atmosphere is dependent on temperature. Warmer air holds more water vapor. Cooler air holds less. Absent all greenhouse gasses the earth would cool by ~30C. If you were to remove all the OTHER greenhouse gasses (CO2, CH4, etc.) other than water vapor the moisture would quickly freeze out. It would have no mechanism to remain in the air. Solar irradiance does not provide enough warming to hold water vapor in the air on it's own. Slowly add the other "trace" GHG's back into the atmosphere and you get incremental warming, which allows water vapor to stay in the air. A little more CO2 then feeds back more water vapor, etc. This is Richard Alley's "Biggest Control Knob." Dial up CO2, more warming. Dial down CO2, less warming.
  20. CO2 was higher in the past
    Good article.. very insightfull.. One question, how was the percentage of solar output derived. You said that "solar output was about 4% less than current levels.", but there are no sources and no further information as to how the number came about
  21. Urban Heat Islands: serious problem or holiday destination for skeptics?
    More followup to friend BP, who writes: Anyway, the SEDAC/GPWv3 gridded population density dataset is really useful. Thank you for the pointer, I have not known about its existence. You're welcome. I agree that it is useful, although not without its shortcomings (there are some apparent artifacts in places). In particular, it probably isn't that great a match for the GHCN stations, due both to the coarse resolution of the GPW data set (in many places the population density estimates seem to be based on averages over particular local administrative units, rather than being grid-cell specific) and due to the poor quality of the GHCN metadata (station lat/lon coordinates may be off by enough to put the station in the wrong grid cell). I think Ron Broberg has looked into this a bit -- see his post GHCN metadata: Horseshoes and Hand Grenades? Also, supposedly GHCN Version 3 is coming out this year ... so you might not want to expend too much effort exploring the nuts and bolts of Version 2.
  22. Urban Heat Islands: serious problem or holiday destination for skeptics?
    Let's address the other point. In the second half of his comment, BP writes: Now, average difference of base 2 logarithmic population densities around stable stations is 0.218, while the same figure for abandoned ones is 0.057. In other words annual population growth rate around stable stations is 1.52% (well above world average) while it is 0.39% around abandoned ones. This selection bias alone adds several tenths of a degree to the warming trend on a century scale. So station drop out could have some effect after all, contrary to what people claim. Once again you're naively averaging stations without taking into account spatial autocorrelation or applying any kind of spatial weighting method. This is a completely invalid analytical method, as I've shown before. From that other thread:
    So ... a naive nonspatial analysis of these data give an erroneous "cooling" of -0.05C/decade. A spatially weighted analysis gives a warming of +0.18C/decade.
    This is why people use gridding, kriging, or other geostatistical tools for analysis of irregularly spaced sample data.
  23. Urban Heat Islands: serious problem or holiday destination for skeptics?
    Berényi Péter writes: Thanks for your work. However, we are not talking about global temperatures here with no further specification whatsoever, but land surface temperatures as they are measured by stations included in the GHCN (Global Historical Climatology Network) and about the bias the UHI effect may introduce into that dataset. Therefore your 3% is irrelevant. Well, I can only respond to what you actually write. In your first comment in this thread, you claimed about 0.4-0.6°C of the global trend is due to UHI. If we ignore the 71% of the world that is ocean, and apply the "Berényi Method" model with spatially distributed population growth, the estimated mean bias from UHI over land areas only would be +0.16 to +0.24 C/century. For comparison, over the same period, the mean of various land-only temperature reconstructions is +2.8 C/century.[1] Thus, over land, the "Berényi Method" suggests that UHI would be responsible for somewhere between 6% and 9% of the observed warming trend. ----------- [1] Based on averaging the trends from 1990-2009 annual land-only temperature reconstructions by CRU, NOAA, Jeff Id/RomanM, Zeke Hausfather, Joseph at Residual Analysis, Nick Stokes, and Chad Herman. The GISSTEMP "land stations" temperature record is not a true "land only" reconstruction.
  24. Climate change: Water vapor makes for a wet argument
    Andrea, the FACT that CO2 and other greenhouse gases slow the rate at which infrared radiation leaves the atmosphere was first PROVEN by John Tyndall in the 1850s. You will not find a single remotely respected scientist, even amongst the global warming skeptics, who disputes this. No one claims that CO2 'holds heat' within itself... that simply isn't how the greenhouse effect works. The fundamental flaw in your argument is that it assumes this is the ONLY way heat can be retained within the climate system. Greenhouse gases absorb and then re-emit infrared radiation. Thus, radiation which WAS traveling from the planet's surface out towards space instead gets 'bounced back' down towards the surface... which has lots of rocks and trees and water and all sorts of other things which can 'hold' that heat just like water vapor does. The more greenhouse gas in the atmosphere the more this heat has to bounce around before it eventually makes its way out to space and thus the hotter the planet's surface.
  25. Berényi Péter at 02:04 AM on 3 September 2010
    Urban Heat Islands: serious problem or holiday destination for skeptics?
    #28 Ned at 22:51 PM on 2 September, 2010 I used his own model with actual spatially-distributed population growth data, and found that his model actually estimates a global mean UHI bias of around 3% of the observed warming trend. This took a fair amount of work on my part. Thanks for your work. However, we are not talking about global temperatures here with no further specification whatsoever, but land surface temperatures as they are measured by stations included in the GHCN (Global Historical Climatology Network) and about the bias the UHI effect may introduce into that dataset. Therefore your 3% is irrelevant. Anyway, the SEDAC/GPWv3 gridded population density dataset is really useful. Thank you for the pointer, I have not known about its existence. At least using that dataset some light could be shed on an old mystery. As all we know, the majority of GHCN stations were abandoned between 1990 and 2000, at least those outside the US of A. For USHCN (US Historical Climatology Network) this mass extinction process took somewhat longer, it was only completed by April, 2006. As SEDAC for some unknown reason fails to provide the datasets in plain ASCII beyond 2000 and I would rather not toil and moil with arcane binary formats, I have considered the decade between 1990 and 2000 and only GHCN stations outside the USA, because I was interested in the station drop out issue. There are 1152 such stations worldwide that provided some data both in 1990 and 2000. Let's call them "stable". On the other hand there are 1760 such stations that quit some time between these two dates, these are the "abandoned" ones. Now, average difference of base 2 logarithmic population densities around stable stations is 0.218, while the same figure for abandoned ones is 0.057. In other words annual population growth rate around stable stations is 1.52% (well above world average) while it is 0.39% around abandoned ones. This selection bias alone adds several tenths of a degree to the warming trend on a century scale. So station drop out could have some effect after all, contrary to what people claim. There is a wealth of information in this GHCNv2/GPWv3 pair, and the result above is only a preliminary one, needing further, more careful study. But now there is hope to be able to answer a lot of interesting questions. I wonder if there are some peer reviewed papers as well on GHCN quality checks using this dataset. Pointers are welcome.
  26. It's the sun
    sun tzu, I see where you are being side-tracked now. From your links : The BBC one is a blog post from a year ago; The Canada Free Post one is an Opinion piece from 6 years ago; The Telegraph article (by an Environmental reporter) is about a report, published in Wiley Interdisciplinary Reviews Climate Change, which confirms what you could find by sticking to the actual science; The Yahoo Answers link is not worth the paper it's not printed on ! Don't rely on blogs, opinion or the mass media. Try the links I gave above, plus : Scientific American The Discovery of Global Warming Science Science News Science Daily Physics World New Scientist Nature National Academies, and here Knight Science Journalism Tracker Climate Central Climate Data
  27. The empirical evidence that humans are causing global warming
    svdwal, have you read both basic and intermediate versions of this?
  28. The empirical evidence that humans are causing global warming
    What I am missing in this explanation is how much it is warming, and how good the different models are at predicting the measured warming over time. The way to disprove a model (which is a theory) is to show that it cannot predict observations, so one has to show that the models actually make accurate predictions.
  29. Water vapor is the most powerful greenhouse gas
    daisym, there is a good explanation of clouds and climate at the NASA Goddard site.
  30. Sea level rise: the broader picture
    HR writes: Ned's post does say 5.4mm/4.9mm "compares very well" with 3.3mm. More generally with regard to acceleration we are arguing over a change in SLR of ~1.5mm/year, I was just saying on Ned's basis 1.8mm "compares very well" with 3.3mm. First, the main point of my comment was to show that the Jo Nova post cited by Miekol was deeply misleading. Ms Nova was trying to convey the impression that satellite measurements of sea level rise are contradicted by data from in-situ sea level monitoring stations in the Pacific. This is quite wrong. Anyone looking at the data Ms Nova refers to, or reading the annual reports from the station network in question, will quickly see that all of the stations in that network show rising sea levels, and that the text of the annual reports explicitly states that the observed sea level rise is consistent with measurements from satellites. It would be nice if Miekol, or HR, would recognize that. With that out of the way, HR does seem very interested in the claim that a mean sea level rise of ~5 mm/year at various South Pacific stations is "consistent" with a global sea level rise of 3.3 mm/year from satellites. HR uses this comment to claim that a lower rate of 1.8 mm/year (over the 20th century as a whole) must also therefore be considered "consistent" with the current rate of 3.3 mm/year ... the point being, apparently, to establish that there hasn't been any acceleration in sea level rise. Now, IMHO that is a very confused argument, one that will probably not stand up well to dissection. The "consistency" between 5 mm/year at Pacific island stations and 3.3 mm/year in the global satellite record comes from the fact that sea level is known to be rising faster in the Southwest Pacific than the global average. In fact, if you look at the map shown in Figure 3 of Peter Hogarth's excellent post here, you will see that from 1993-2008, sea level rose by 5 cm to 15 cm in this region. That works out to a satellite-derived estimate of 3.3 to 10 mm/year for regional sea level rise in the Southwest Pacific. It seems to me that 5 mm/year (from the island stations) is perfectly consistent with 3.3 to 10 mm/year (from the satellite record). Does that make sense now, HR?
  31. Arkadiusz Semczyszak at 23:35 PM on 2 September 2010
    The empirical evidence that humans are causing global warming
    @neilrieck - high solar activity also reduces the number of 14C atoms and because of the nuclear explosions, we do not have data for recent decades. Until then, the activity of the Sun definitely growing. Effect Suess can be determined only by the delta 13C.
  32. The surprising result when you compare bad weather stations to good stations
    @Dappledwater - "impossible to be false" - not sure what you are talking about. The "reason why station exposure does not play an obvious role in temperature trends" is not known to Menne, Meador, John Cook, me, you or anybody else. As things stand, it is not known to science. Wouldn't you want to see it investigated? Of course if somebody would properly (scientifically) investigate it, then we would be able to exclude the "alternative hypothesis".
  33. Sea level rise: the broader picture
    Ken Lambert (henceforth KL) @ 68 - "And Dappledwater (DW in short in future): pray tell us if the decent sized La Nina's are sending heat out to space or redistributing heat around in the Earth system (atmosphere, land, ice, oceans)?" Sounds like a silly question to me KL. The answer is of course - 42. Ever wonder why the global sea level rises and falls in response to ENSO KL?. Like El Nino for instance, wasn't that heat already in the ocean?. KL @ 60 - I'll just put to one side your misrepresentations of the satellite trends, that donkey is so dead it's fossilized. Others have explained that sufficiently IMO. As to the energy budget, yeah looks to be a lot missing (maybe) Looks like you're not the only one concerned about the inability to account for it (yet). Kevin Trenberth: Where's the missing heat? KL if the missing heat is way down deep (I recall Chris steering toward some papers on the topic) then it'll soon be coming to an atmosphere near you. (The word "soon" being very subjective - and no relation to Willie)
  34. Arkadiusz Semczyszak at 23:12 PM on 2 September 2010
    Urban Heat Islands: serious problem or holiday destination for skeptics?
    I complete only Berényi Péter It is worth to make such a comparison for Africa. He soon joins the population - in particular cities - escape from poverty (shockingly fast - as fast as forests are cut or burn), leading to significant changes in the Earth's albedo and evaporation, the local "dry" glacier - eg Kilimanjaro (Between a logging and fire, Kilimanjaro has lost a third of its forest Since 1929. ) create strong NBL ... - because all this is also UHI ... particularly UI- warm effects. Of course most clearly in Africa.
  35. Sea level rise: the broader picture
    HumanityRules at 02:23 AM on 1 September, 2010 The overall satellite trend offers true global coverage, but it is a relatively short record, though Wenzel 2010b has made an an interesting attempt to bridge the gap between Topex and GEOSAT altimeter data (1986 to 1989). The recently re-processed (corrected) altimeter datasets from Ssalto/Duacs which now includes GDR-C reprocessing for Jason 1 are now available. The overall 17 year trend, which must include GIA corrections if we are to compare with the corrected tidal values, is around 3.3 +/-0.4mm/yr. Peter B and Ken, for the record (once again), Topex/Poseidon runs to Autumn 2005, Jason 1 runs from beginning 2002 to present, Jason 2 runs from half way through 2008. Thus there is overlap which allows correction for (some quite large) offset biases. The real absolute raw offsets make any talk of “offsets” in the accessible data more than a little academic. The trends for Topex/Poseidon, Jason1, and Jason 2 (including GIA) are 3.5mm/yr, 3.0mm/yr, and 3.1mm/yr respectively. Peter Bs figures showing a split between Poseidon and Jason1 data, (and hence the trends and offset) are incorrect. In addition the uncertainties in these separate trends will certainly be greater than the 0.4mm/yr error bars for the overall series. Any suggested decrease in overall trend is therefore not significant from this data. Nevertheless, why might the interannual trends vary over short periods? As Dappledwater has mentioned, ENSO. From Nerem 2010 showing de-trended Global MSL compared to MEI (Multivariate ENSO Index). The correlation of MSL interannual variations with ENSO is significant at the 95% level over the altimeter period. This kind of variation is also observed in the tide gauge records, whose interannual variations follow global and local regional climate patterns. This is why we must take the overall satellite record and use all of the data, rather than chop the record into arbitrary mini-trends. This is why we should if possible look over longer periods than the 17 year satellite record to determine MSL acceleration (which is significant over the tidal record we have). Ken Lambert at 23:33 PM on 30 August, 2010 The GDR-C altimeter re-processing is also relevant because (from Nerem 2010) the “GDR-B bias error in Jason1 was large enough to cause GMSL from GDR-B data to be nearly 1 mm/year too high for the period from July 2003 until June 2007, which partially explains the misclosure of the sea level budget between Jason-1, GRACE, and Argo (Willis et al. 2008; Leuliette and Miller 2009)”. To some extent this answers your point (which quoted values from Sea level budget from Trenberth based on this same 2003 to 2007 data). If this is changed to something like the 1993 to 2007 value for thermal expansion (table 1 Cazanave 2010) the sea level budget appears to close, but I’m sure there will be a paper or two on this pretty soon.
  36. It's the sun
    "more to the point, without citing other people stats or research, what do you think is the cause behind climate fluctuations and why?" If you discount stats and research (ie, science), you're pretty much left with anecdotal data. Why, in this day and age, anyone would think that anecdotal data has any real standing in science amazes me. Looking for science information in the media also seems suspect to me. I'm not a climatologist, but I am a scientist, and the number of times that the media has gotten things wrong in areas I do know about are depressing.
  37. Urban Heat Islands: serious problem or holiday destination for skeptics?
    Let's be completely clear about what's happening here. BP proposed a model whereby there is a UHI-sourced bias in global temperature records. He claimed that this bias was large enough to explain much of the observed warming trend, but this claim was based on the unrealistic assumption of uniform population growth everywhere. I used his own model with actual spatially-distributed population growth data, and found that his model actually estimates a global mean UHI bias of around 3% of the observed warming trend. This took a fair amount of work on my part. Rather than acknowledging that inconvenient fact, BP is moving the goalposts around. I'm disappointed, frankly. This is not conducive to productive discussion.
  38. It's the sun
    my personal unaided view is chopping down the amazon, solar activity and increased agruculture have alot to answer for!
  39. It's the sun
    more to the point, without citing other people stats or research, what do you think is the cause behind climate fluctuations and why?
  40. Urban Heat Islands: serious problem or holiday destination for skeptics?
    Dappledwater, since BP prefers not to provide it, here's a good figure showing global sea surface temperatures. This is from Kelly O'Day: Source code and data are available via the link. Note the unsurprising similarity to the other surface temperature records.
  41. It's the sun
    ps. that was just a small cross section of some of the media reports etc, im not quoting any of them specifically
  42. It's the sun
    http://news.bbc.co.uk/1/hi/8299079.stm http://www.canadafreepress.com/2004/deweese121404.htm http://www.telegraph.co.uk/earth/environment/climatechange/7369339/New-evidence-for-man-made-global-warming.html http://uk.answers.yahoo.com/question/index?qid=20091123115037AAItLGF they are not scientific sources although they do cite them selves as such, however given the massive number of variables at play in the overal arena of 'warming' or 'cooling' whos to say they are any more accurate than anyone elses opinions? im sure next week will be another startling media discovery or discreditation to do with climate anomolies... from where Im sitting with the information presented to me via these forums, the internet as a whole not to mention having lived in many locations around the globe and witnessed first hand from real people discussing the way in which their environments have changed, eg lack of snow on peaks, reservoir depletion and also the opposite too, snow storms, floods etc all of which where loclalised events but none the less at each place I have been to every one seemed to agree that one way or another something is changing percevably with the climate. anyhow, I could fire up a supercomputer and feed lots of stats in and see what the results tell me, but even so, if I miss so much as one variable or miscalculate or use inaccurate results im going to be back at square one with 'im not sure'... however theres a good chance its this...
  43. Sea level rise: the broader picture
    HR#65 Dappledwater #67 Nice summary of the 2003-2007 SLR scene HR. Notice that the only paper which has the steric rise anywhere near the mass rise is Leuliette and Miller (2009) with a 0.8+/-0.8mm for steric and 0.8+/-0.5 for mass. I wonder at the value of a measurement which has error bars equal to the value. If I expressed my height as 1.8m +/-1.8m, you would not know if I were a giant or a midget. If the mass far exceeds the steric, the energy budget shortfall gets rapidly worse. And Dappledwater (DW in short in future): pray tell us if the decent sized La Nina's are sending heat out to space or redistributing heat around in the Earth system (atmosphere, land, ice, oceans)?
  44. Arkadiusz Semczyszak at 22:17 PM on 2 September 2010
    How we know an ice age isn't just around the corner
    “The change from glacial to interglacial occurs over thousands of years.” present interglacial in exactly,(!) three years (a major change; the whole - seven years), probably even the Sahara became the Sahara (with green, thriving savannah to desert - as today) in less than 100 years (movie: Man on Earth). I can present hundreds of works that the former changes were equally dramatic - not just warming. “H” events occurred during the life of one man - the main changes sometimes within one of the winter. Richard Seager (The Gulf Stream, European climate and Abrupt Change, 2009) says: “These abrupt changes - the Dansgaard-Oeschger events of the last ice age and the Younger Dryas cold reversal of the last deglaciation - are well recorded in the Greenland ice core and Europe and involved changes in winter temperature of as much as thirty degrees C!” Changes have always been violent - even those much smaller than the “H” events, because: „In its place we need serious assessments of how changes in ocean circulation will impact climate change and a new look at the problem of abrupt climate change that gives the tropical climate system and the atmosphere their due as the primary drivers of regional climates around the world.” (Seager, 2009.) Again, the tropics ... I think that the AMOC - “two-pole swing” - it's just delayed in time - delayed warming in the SH to NH - as the globally is warmer - is less. And after a period of warming to the 2030s, waiting for us again but slightly weaker LIA ...
  45. Climate change: Water vapor makes for a wet argument
    TOP #7, the fact that the IR absorption bands of water vapor largely overlap those of CO2 and methane does NOT prevent those gases from causing warming in those IR bands. That argument was first made by Angstrom in 1900 (who also thought water vapor overlapped entirely because instruments of the time lacked sufficient resolution). However, it has since been proven false; Water vapor is generally not found in the high atmosphere (see the discussion about jet contrails above for an exception). However, carbon dioxide and methane ARE. Which means that IR photons which manage to get through the 'water vapor layer' then get absorbed and re-emitted by CO2 and methane higher up. Without the CO2 and methane they'd all have escaped to space immediately once past the water vapor... with these other GHGs they get bounced around in the atmosphere more and this delay in radiating to space means more warming. So no, rising temperatures do NOT lead to decreased IR absorption by CO2. The 'band overlap' argument is simply false... though a reasonable mistake a hundred years ago.
  46. Urban Heat Islands: serious problem or holiday destination for skeptics?
    BP, got a plot of the global sea surface temperatures?.
  47. The surprising result when you compare bad weather stations to good stations
    Omnologos @ 54 - "Why? Because the evidence of the warming trend is for the time being only (as a matter of course) in the well-sited stations" And the "bad/naughty" stations too. Omnologos -"This can't be taken as evidence of a warming trend. It's an hypothesis, however well rooted, not a conclusion. And the alternative, however badly in need of extraordinary evidence, still can't be taken as "disproven" See I was right, Reductio ad absurdum "A common species of reductio ad absurdum is proof by contradiction (also called indirect proof) where a proposition is proven true by proving that it is impossible for it to be false."
  48. The empirical evidence that humans are causing global warming
    I recently attended a seminar where the presenter stated that overwhelming proof exists for industrial humans contributing to the increase of atmospheric CO2. One proof was based upon atmospheric ratios of C12, C13 and C14. Recall that all living systems incorporate C14 into their tissues, and that C14 has a half-life of 5,730 years, and that fossil fuels are so old that they contain virtually zero C14. This means that burning massive amounts of fossil fuels will result in much lower C14 in the atmosphere than the amount placed there by current/recent living processes (which also includes other stuff like burning wood, slash and burn farming practices, etc.) Apparently economic records exist for all fossil fuels sold since 1960 (on a country-by-country basis). These records can be used to compare fossil burning against the carbon isotope ratio for the same time period. Scientists can see the resultant dilution of C14.
  49. It's the sun
    sun tzu, stick to the science and the peer-reviewed literature, rather than opinion on blogs. There is plenty of information on this site : Start Here There is also plenty of information (and many sources) here : IPCC Summary for Policymakers Why aren't you more forthcoming as to the sources of your information ? Provide a few examples of where contrary information is being given that you believe is as believable as any of the information you find on this site.
  50. Arkadiusz Semczyszak at 21:02 PM on 2 September 2010
    Climate change: Water vapor makes for a wet argument
    FF - RF should be, very sorry ...

Prev  2217  2218  2219  2220  2221  2222  2223  2224  2225  2226  2227  2228  2229  2230  2231  2232  Next


The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us