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  2507  2508  2509  2510  2511  2512  2513  2514  2515  2516  2517  2518  2519  2520  2521  2522  Next

Comments 125701 to 125750:

  1. 1998 DIY Statistics
    RSVP, good point. I happen to comment on this problem a lot of times with friends. It appears that people more easily grasp temperature than other often more important effects. I think this is because we all are directly affected by temperature and we have a feeling of it; it's a direct measurement as opposed to indirect measurements such as sea level rise, tree line shift, etc.
  2. 1998 DIY Statistics
    nofreewind, use whatever data set you like but do not be fooled by short term trends, they are statistically meaningless. Based on what you claim that UAH is superior to HadCRU? It's worth recall that surface air temperature data set (GISS, HadCRU, etc.) are not the same as lower troposphere dataset (UAH, RSS). They measure similar but different things, you should not expect to get exactly the same results. Each has its own problems and strengths, their overall agreement is reassuring of the similarity but your sort of conclusive claim is totally unsupported.
  3. 1998 DIY Statistics
    It is curious that the level of mercury in a glass tube seems to be more relevant to decision makers than the actual measurable effects of global warming (i.e., sea level rise, sizes of glaciers, water supplies, etc.) Just as the Earth is a giant magnet, it is also a giant thermometer; you just have to know how to read it.
  4. 1998 DIY Statistics
    nofreewind: Such a short time period is 'wrong' if you assume that things like the Sun affect climate. If the Sun affects climate, then there is a cycle in heat flow with a period of 11 years (same time as the solar cycle). The entire point of my post is that if you take a trend over 1 cycle or less (in fact, you can even do the same with longer periods too), then you get spurious 'trends' that say nothing about greenhouse gases or longer trends, because they're dominated by the short term one. Eg a 1 year trend would be dominated by summer/winter, a 24hr one by day/night. You can get big positive or big negative trends from cycles that have no real trend if you pick your starting period well enough. Eg the linear regression of the cycle Sin(x) in the period [0, 2pi] is negative: http://www.4shared.com/file/184278813/5069ef42/SineNeg.html If you took the trend in the period [-pi, pi] then you'd get an equal and opposite positive trend. However, the 'real' trend is zero. The 'it's cooling' types tend to rely on tricks like this.
  5. 1998 DIY Statistics
    yocta, not sure i understand what you're asking for. If you are curious about how the average absolute climatology is obtained I'd suggest this review by Jones et al.; in section 6 you'll find how they do. This is the "HadCRU method", details vary between research centers.
  6. It's the sun
    Another point. Even with historic low sunspot numbers, global temperatures have still remained above +0.5 degrees over the 1951-1980 mean for the last decade. What happens if we see a sudden surge in sunspot numbers over the coming 22-33 years? Will we see an increase in the rate of warming-per decade-to as much as +0.3 to +0.4 degrees per decade? Its uncertainties like this (& the positive feedbacks of CO2 release from oceans & increased levels of water vapor) which makes me think we should engage in the precautionary principle-namely to immediately begin making sensible changes in our generation & use of electricity to reduce the CO2 emissions associated with our economies (not by reducing GDP, but by reducing both the KW/$ GDP & the tCO2e/$ of GDP.)
  7. 1934 - hottest year on record
    Also, if you look at the US-only graph, you see that after peaking in the 1930's & 1940's, temperatures fall off again (in line with the rapid rise in average sunspot numbers, followed by a sudden dip), but then start to rise again quite quickly-in spite of the fact that average sunspot numbers haven't risen again since the 1950's. Nor do average US temperatures show any sign of falling-as they did in the 1940's!
  8. Temp record is unreliable
    What galls me is this-in spite of the fact that Dr Roy Spencer (of University of Alabama, Huntsville) has been shown that his adjustment for diurnal variations is in error, as far back as 2005, he still persists in using this method, which generates a long-term trend of +0.035 per decade lower than what is should be. If this error is accounted for, the long-term trend for UAH satellite data is around +0.2 degrees per decade (the same order of magnitude as RSS, which was around +0.23 degrees per decade). What's interesting is that *both* of the satellite data-sets give values which are *higher than for surface-based measurements (+0.187 degrees per decade). Another point is this, why do skeptics refuse to pillory Dr Spencer (a skeptic) for his errors, yet are quick to attack any apparent errors made by climatologists with CRU or GISS? That smacks of hypocrisy to me!
  9. 1998 DIY Statistics
    Oh, & my point is further highlighted by the fact that the R^2 value for the trend-line is a mere 0.0027, i.e. too small a correlation to signify a trend.
  10. 1998 DIY Statistics
    So I've been over the RSS data &-though I still say its too short a time period to show concrete trends either way-I come out with a weak warming trend between 2000-2010 (around +0.02 degrees for the decade), in spite of a massive drop in sunspot numbers over that time. Which just reaffirms the strong role of both the sun & GHG's in global warming.
  11. 1998 DIY Statistics
    Nofreewind, what is of particular interest is in plotting sunspot numbers for 1997-2010: http://www.woodfortrees.org/plot/sidc-ssn/from:1997/plot/sidc-ssn/from:1997/trend which shows a massive downward trend in sunspot numbers over the 13 year period(from 100 to almost 0 from 1997-2010). Yet over that same time period, average global temperatures still manage to increase-even in spite of the El Nino event of 1998.
  12. It hasn't warmed since 1998
    Mizimi & others seem to not understand the concept of the Energy Balance. Average Global Mean temperatures for all of 2000-2009 is +0.512, which is a full +0.18 degrees greater than the period of 1990-1999. This is in spite of the fact that the 1990's were dominated by rising sunspot numbers, wheras the current decade has been dominated by record low sunspot numbers (0 for almost the entirety of 2005-2009). Not only that, but the data shows that the rate of warming-per decade-is *accelerating*, not *decelerating*. Lastly, its all very well saying that Global Mean Temperatures will *only* rise by about 2 degrees over the next century (assuming no accelerating in the warming trend), but that is a GLOBAL MEAN. Actual temperature differentiations will be *much*, *much* higher at different parts of the year & at different points of the planet. Winter temperatures might only increase by an average of +0.1 to +0.5 degrees, wheras summer temperatures might increase by an average of 3 to 4 degrees-or more. Some parts of the globe may see a much sharper increase in mean temperatures-& see an increase in heat related disasters. Australia has had 3 record heat waves in the space of only a year, what can they expect in 10 to 20 years time? Also, I'd like to remind you that at least 2 civilizations were wiped out due to a total increase in global mean temperatures of only +0.6 degrees-over the space of almost 600 years. Tell the Anasazi & the Khmer Empire how unimpressed you are by a *mere* 1.8 degree increase in global mean temperatures over the next 100 years, Mizimi. Oh, thats right, you CAN'T because they got wiped out! Seriously, try quoting science instead of regurgitating fossil-fuel industry propaganda, I might then start taking you a little more seriously.
  13. 1998 DIY Statistics
    Hope you guys can tolerate another grade school comment from me, but why not just plot 1938-1979 CRU then switch to UAH because CRU was the best we had until satellites. So there was basically no warming from 1938 to 1997, then we had an enormous step up during the El Nino and we have been wallowing in such since. Very similar to what happened to Alaska with switch of PDO in 1997.
  14. 1998 DIY Statistics
    Excuse me fellas, the above is way over my head. But what is so wrong about simply plotting the 1997-2010 RSS? Or if I must, 1997-2010 CRU?
  15. It hasn't warmed since 1998
    Actually, Mizimi, when you graph the numbers, & draw a trendline, you see the rate of change for 1910-1944 was +0.013 degrees per year, wheras the rate of change for 1964-2005 was +0.016 degrees per year. So this 2nd warming period has been faster than the first one-even though average solar activity during the 2nd warming period has remained unchanged.
  16. Temp record is unreliable
    Mizimi, I have to tell you that your claims regarding the Siberian stations is just plain wrong. If you can provide *proof* of this wild allegation, I'd be happy to entertain it though. As for your claim regarding the satellite data post-2002. Even if what you said was true, 2003-2009 represents too small a sample group to be of any real benefit for determining trends-especially when that period is dominated by abnormally low sunspot numbers. That said, if we look at temperatures from AMSU-A for 1st July, we see that 2003 was -14.42, 2004 was -14.19, 2005 was -14.13, 2006 was -13.94, 2007 was -13.86, 2008 was -14.39 then 2009 was -14.11. This is only a single date, of course, but a look through the entire year shows that, if anything, the trend has been towards *warming* between 2003-2009, not cooling as you claim. As I said, though, picking on these dates-to prove either case-is the worst kind of cherry picking.
  17. Temp record is unreliable
    WA. 1951-1980 was not the *coldest stretch in a century*. The 30-year average of 1901-1930 was a good .24 degrees *colder* than 1951-1980-& is by far the coldest 30 years of the the 20th century. 1931-1960 average is almost identical to 1951-1980, & the 1961-1990 average is slightly warmer than either 1931-1960 or 1951-1980, so I don't see why you think GISS is in error for using this period as a base-line. The satellite data is from 1979-2000 because 1979 represents the start of the satellite measurement period.
  18. It's cooling
    selti, you are wrong about the IPCC projections being disproved. See Comparing IPCC projections to observations. If that's not detailed enough for you, click on the link that's in that post, to Tamino's related post.
  19. Temp record is unreliable
    Wondering Aloud, would Energy & Environment be the same "journal" that published that awful "paper" by Beck-the one claiming that, based on measurements of the day, CO2 levels in the 19th century were higher than in the 20th century? When you look at the results used by Beck, you see they have *massive* margins of error (around +/-200ppm) because most of the samplings were taken in urban environments, were measured without internal controls &/or were measured with equipment with sensitivities 10-100 times worse than modern equipment. Yet E&E still accepted this paper, even when no other respectable journal would touch it, because it fit into their ideological agenda. I suspect the same is true with their "analysis" of monitoring stations.
  20. 1998 DIY Statistics
    Hey MarkR, great post. As I said in posts #4 & #5, I've tried plotting the rate of change in average global temperatures myself, & have come up with a value of +0.108 degrees per decade for 1949-2009, & +0.163 degrees per decade for 1979-2009 (both with greater than 70% correlation). Now I wanted to do the same thing with RSS but, when I downloaded the dataset, I confess the whole thing looked like complete gibberish! Could you quickly explain how I can make the RSS data more....legible? Thanks in advance.
  21. 1998 DIY Statistics
    Ah coolthanks. I think I've done it, though rather crudely I got something like this. Year Jan 1880-1890 -0.136363636 1891-1901 -0.406363636 1902-1912 -0.354545455 1913-1923 -0.153636364 1924-1934 -0.026363636 1935-1945 0.035454545 1946-1956 0.000909091 1957-1967 0.019090909 1968-1978 -0.04 1979-1989 0.306363636 1990-2000 0.4 2001-2009 0.691111111 I understand the need to use temperature anomalies rather absolute temperatures but I am interested in specifically how they work them out. Rather than waste alot of time telling me, if you know of a paper or two that would be handy. (perhaps you know Ricardo?) This page has some info but it is a bit basic but their description reminds me of Excel Solver. http://data.giss.nasa.gov/gistemp/abs_temp.html
  22. 1998 DIY Statistics
    #17 yocta I used excel because it's simple! Your GISS data set is commonly used and the experts say it's fine, so feel reasonably confident using it. :) If you're particularly interested, it's worthwhile taking a look at the satellite data as well (UAH & RSS are the names of the sets). You get some interesting squiggles from them; they seem more sensitive to El Nino for example, and it takes a bit more work to get an idea of what might be going on!
  23. It's cooling
    IPCC projections disproved. As a result, CO2 has nothing to do with global warming.
  24. High CO2 in the past, Part 2
    http://en.wikipedia.org/wiki/Ordovician#End_of_the_period More detail. The Ordovician is a geologic period and system, the second of six of the Paleozoic era, and covers the time between 488.3±1.7 to 443.7±1.5 million. It ended with the Ordovician–Silurian extinction event, about 443.7 ± 1.5 Ma (ICS, 2004) that wiped out 60% of marine genera." Also of note and very relevant is the fact that dry land during the end of this period consisted of one great continent known as Gondwana. And, of most importance, these land masses were sitting over the during the time of this glacial period. Just imagine what impact on climate earth we would see if Antarctica with a current mean temperature of -57degC, was 10 times its current size. I think this glacial period was started, mostly as a byproduct of the location of Gondawana! The amount of snow which would have resulted from a land mass the size of Gondwana being located at the South Pole, both in the sea and on land, would have had a truly enormous impact on the amount of solar radiation which was being reflected back into space! In addition, sea water acts as an enormous heat reservoir. During this period of extreme glaciation, as much as 1/3 of the ocean could have been removed and deposited atop of Gondwana. The result would be less heat in the oceanic reservoirs.
  25. High CO2 in the past, Part 2
    >>>> Late in the Ordovician period, the Earth experienced glacial conditions at a time of high CO2 levels. Observe the thin grey line around 443 to 445 million years ago. How could glacial conditions occur with such high CO2 values?<<<< Answer is really quite simple. During that period of time, the earth was almost entirely covered with ice. This extremely high albedo of white ice reflected nearly all Short Wave solar energy back into space. Since no (very, very little) SW energy was being absorbed, there was virtually NO long wave IR energy being radiated from the eath. Also realize that CO2 can only absorb energy from an (8% to 20%)portion of the IR (long wave) energy spectrum. If there is no (little) LW IR energy being radiated into the atmosphere, atmospheric CO2 would have very little impact on global warming. Also think about the reality that the extremely cold air ducring this period would have also been extremely dry air. Therefore, the normal greenhouse gas impact from H2O would have been close to Zero during this period of extensive glaciation. Geological evidence indicates that what shocked the earth out of this "snowball" state was almost certainly a period of hyperactive volcanic activity. The volcanic activity served to darken the earth's surface which reduced the albedo affect and allowed the sun to warm the earth a bit. This hyperactive volcanism also put a lot of subterranian heat into the atmosphere and oceans, along with vast quantities of ash and CO2 and other gases. As the albedo effect of snowball earth was diminished over 10s of million years, the atmosphere slowly began to heat up because CO2 was there to trap some of the newly available IR energy. Also, as the earth reheated, the amount of H20 om the atmosphere increased which served to accelerate the warming process. In this instance, we can say "thank you Co2, for being there when we needed you the most!" End
  26. 1998 DIY Statistics
    RE:# 11SLRTX That looks like an excellent book, i'm requesting my library for it now... A general question about the data sets for Mark or anyone...I'm assuming the GISS data set I've linked below is one that I can use. Also is Excel a good enough program to do the analysis? http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt
  27. 1998 DIY Statistics
    NEILPERTH: You said, "I have been told that the earth is suffering from 'unprecedented global warming' as a result of man-made CO2 emmissions since about 1970." No one has ever said that. What is unprecedented in at least 10,000 years is radiative forcing, NOT temperature. There are a few other things that are unprecedented, such as temperature in at least 400 years, glacier melting in some areas, etc. See for yourself. Do a search for "unprecedented" in the AR4: http://ipcc-wg1.ucar.edu/wg1/wg1-report.html
  28. 1998 DIY Statistics
    Ned, starting from the raw data, the more you smooth the lower the chance that you get spurious short time trends. This is the zeroth order treatment of the time series, i.e. no other statistical test on uncertaintiy or significance. On the contrary, if you can manage some stitistics, you'll probably want to use the raw data. But even in this case, sooner or later you'll end up smoothing and looking at residuals.
  29. 1998 DIY Statistics
    I think woodfortrees.org is a good source to mention in this connection. It is both a DIY (though only basically univariate) analysis/checking/plotting site and data source, for example... I'm a lot more pessimistic than you about basic statistical skills and global-warming-is-over fallacies, Mark. Remember the saying: "Statistics is often used the same way a drunken man uses a light-pole: For support rather than illumination." Sadly, we can't presuppose sound reasoning, and we must be prepared to document all sorts of things that should be rather obvious by now. Tamino has just done the modeling exercise "the statistical way", without sun, but with volcanic activity and the multivariate ENSO index: http://tamino.wordpress.com/2009/12/31/exogenous-factors/#more-2150
  30. 1998 DIY Statistics
    Ned: the target I had in mind for this method was someone who has barely been introduced to statistics, so probably wouldn't think of things like uncertainty. I can't see how someone conversant in beginner stats could fall into the 'it's been cooling since 1998' -> 'global warming is over' trap anyway! Of course, there are thousands of people much better at stats than I am and maybe they'll show up my naivety...
  31. 1998 DIY Statistics
    This is nice, but it leaves open the question of the significance of the trend. By using a running mean to smooth the data, the autocorrelation will be increased dramatically. My concern with this kind of DIY thing is that someone will repeat what you've done here but then make the leap to naively interpreting the variance around the trend estimate as an actual confidence interval, which would be a big mistake. There's actually much more uncertainty in the estimate of the trend than one would think based on the smoothed data. I like Tamino's approach of looking at the temperature data many different ways -- using annual data and correcting for autocorrelation, and then just taking straightforward decadal means (NOT running means, literally plot the average from the 1970s, the 1980s, the 1990s, and the 2000s). The latter isn't as exciting, because you can't update it very often, but it does a nice job of eliminating all the autocorrelation issues. Anyway, this is all just nitpicking. Thanks for the interesting and informative post.
  32. Skeptical Science housekeeping: Translations and Comments Feed
    I must confess that Google Translator is pretty good into Spanish, but, still, you will miss some details and find some incomprehensible sentences.
  33. 1998 DIY Statistics
    Mark, Excellent post. "I tried the same trick with a quadratic equation and yet again, the averaging trick works" Be careful using the word "trick." ;-) Deniers like to use their own "tricks" to manipulate the charts to their own meaning. Unfortunately, most people don't understand how to read these charts, so they only see what they want to see. As I tell them, if you look hard enough, you can find an image of Jesus in a piece of toast. It's not enough to say there's a trend. Any trend must be supported by real-world evidence in order to properly interpret that trend. A minor point the deniers conveniently miss. To them, a trend is just a trend. One of my favorite books is "How to Lie With Statistics" by Darrell Huff. I like how Huff lines up these fallacies and explains how to filter them out. http://en.wikipedia.org/wiki/How_to_Lie_with_Statistics http://en.wikipedia.org/wiki/Misuse_of_statistics Keep up the good work! I'll keep sending folks your way!
  34. 1998 DIY Statistics
    #3: I made up the values using 0.2cos(At)cos(Bt). A and B were calculated to give periods of 4 and 8 years, and I chose an amplitude of 0.2 because peak to peak swings of 0.4C seem to have been observed before. Eg 1996-98 was a 0.4C swing in HadCRUT3 and I think it's reasonable to assume most of that was ENSO related.
  35. 1998 DIY Statistics
    neilperth, there are some problems with your procedure. You cannot use unadjusted data, if by unadjusted you mean the raw data. There are several reasons and tons of papers on the need to adjust the raw readings. You can use a single station to look for the trend; although the statitstical significance of the results will probably be rather poor. Neverthless you can try. Or, you might want to look at global averages. In this case you can not simply pick up a random and rather limited selection of stations. You need to homogenize the time series first and check for the geographical distribution, the random selection criterion do not apply in this case. A final statistical test must be applied for the significance of the result. In other words, you must make a choice local vs global (or regional), then use the right data and the appropriate procedure.
  36. What ended the Little Ice Age?
    batsvensson, what you call bandwidth (i'd call it variability) is not known a priori but can be extracted from the measurements. The signal, again, is not know a priori but can be extracted from the measurements. In practice, take the temperature data, smooth with the algorithm of your choice, take the residuals. The standard deviation of the residual is the bandwidth, the smoothed line is the signal.
  37. Climate's changed before
    As a total layman I can follow the arguments in my simple way to the point where I see that GHGs amplify warming and cooling periods, so more co2 in the atmosphere increases amplification. But when I look to see what the science says about what initiated pre-industrial inter-glacial warm and cool periods i get a bit stuck in debates about solar activity, a plethora of weather oscillations between negative and positive and now feeback loops and planet earth knowing and adjusting its own temperature because it is conscious of an energy imbalance. Global warming doesn't get any easier to understand.
    Response: Hang tight, I'm at this moment working on a post on the whole ice age/interglacial mechanism, the emphasis on making it easy to understand. Hopefully online within a day or two.
  38. 1998 DIY Statistics
    #6 & #7, global warming seems to be most easily evidenced by nighttime temperatures The above post is about trends in averages; the post I linked is about trends in record temperatures. They're really quite different things.
  39. What ended the Little Ice Age?
    RSVP and SNRatio, My comment is not considered about how well models are at making a curve fit with actual measurement or why the measured curve has the shape it has. What I am asking about is how well our understanding is of the behavior of the actual measured signal. There is no rocket science involved in this really and no reference need to be done to reality for this, but just a couple of standard test. Bern , Why do you think it is meaningful to compare variations in global mean with variations in temperatures for local weather?
  40. 1998 DIY Statistics
    neilperth: Why are only "unprecedented" temperatures seen as being significant? Which data set(s) did you use? How many stations were in the data, total? How far back did your data go? Why select 20 stations out of N? How was your "random" selection done? What results do you get if you looked for "unprecedented" readings across all stations, and what % of hits (highest value in that 10-year window) would you consider significant to prove your hypothesis? For that matter, what was your hypothesis? You can access temp graphs and a bunch of other energy and climate graphs on a page I put together: http://www.grinzo.com/energy/graphs_v3_beta.html The temp graphs my page loads (all from NASA GISS) show a pronounced upswing beginning around 1975.
  41. 1998 DIY Statistics
    What concerns me is the following : I took unadjusted data for a “randomly” selected set of weather stations around the globe up to around the year 2000, and looked at the data. I looked at the data for 20 stations and asked myself : “from the data is it seen that the temperature in any of the last 10 years of data is unprecedented”. In only one of the stations ( Hawaii ) was the highest ever recorded temperature in the last 10 years of data. I have been told that the earth is suffering from “unprecedented global warming” as a result of man-made CO2 emmissions since about 1970. But from this simple and quick investigation of mine, I don’t see that.
  42. Climate's changed before
    Quietman. Even if we ignore the impact of past climate change on animals, look what slower-less extreme-warming events had on human civilizations. Two come quickly to mind-the Anasazi & The Khmer Empire both died out because they failed to adapt to a relatively small warming of the planet during the Medieval Warm Period. Another thing-the feedbacks may not be boundless, but evidence of past climate suggests the situation could get very bad if we let it. Throughout much of the pre-Quaternary period, the planet was a good 4-8 degrees warmer than what it was at any point in the Quaternary period. Is it mere coincidence that this higher temperature was at a time when CO2 levels were 10 times higher than today? I seriously doubt it.
  43. 1998 DIY Statistics
    Here's another point worth considering. Look at the data from AMSU-A, comparing the temperature of mid-July, at roughly 2-year intervals, for the last 11 years & you get the following results: 1999: -14.35 2001: -14.29 2003: -13.98 2005: -14.00 2007: -14.06 2009: -13.65 Though the numbers bounce around a little bit, what we see is a definitive +0.7 degree warming trend at 1km above the planet's surface (the so-called "near surface layer). Looking at other parts of the year shows similar trends. Again, that this has occurred during a period of a record solar minimum just beggars belief-unless you accept greenhouse gas theory. Also, the fact that these measurements are occurring at 1km above the Earth's surface must surely discount the myth that any differences are due to the placement of weather stations!
  44. 1998 DIY Statistics
    If I use GISS data & plot it against the year, I still come up with a trend line of y=+0.0102x for the period of 1998-2008. For 2000-2009, the trend line is y=+0.012x. Also the average temperature anomaly for 2000-2009 is +0.515, compared to +0.32 degrees for 1990-1999. That the first decade of the 21st century is a clear 0.18 degrees *warmer* than the 1990's-in spite of falling solar irradiance-suggests to me that CO2 is playing a *very* important role in increasing the underlying temperature of the planet.
  45. 1998 DIY Statistics
    Well written, Mark, thanks. Out of curiosity, what data source did you use for your ENSO values in Figure 1? Made-up values, or real ENSO data? Your solar cycle looks like a nice 11-year sine wave... :-)
  46. It's freaking cold!
    @djb95054 Watts' attempt isn't much of a debunking. Everything he mentions is addressed in the original paper. I mean what do you think is the more robust analysis, a weatherman's report of the records across a few dozen states or the actual record from 2000 stations over decades. See the y-axis above that's 5e+05! 500,000 measurements! Watts' plots show maybe 50 self-reported measurements. The statistical error on that alone is > 10%. Ask Watts to put this in excel and tell us the error on the slope. And he says things like there were 10 lows and 8 highs in 1930s or something like that. Do yourself a favor, read the original paper--you'll find the analysis 5e+05 times more robust.
  47. 1998 DIY Statistics
    Nice explanation, bookmark, bookmark!
  48. 1998 DIY Statistics
    Good, simple explanation. I tried a similar thing here last year.
  49. What ended the Little Ice Age?
    We must never forget that 'sensitivity' is _not_ well-defined as the net result of a complex of mechanistic processes. It is just the expectation value of something that may be considered a stochastic process. We will eventually get to know what the realized value in our current experiment will be, but we may not know exactly how close a second, more or less identical, experiment would come in. As most estimates of pdfs for the sensitivity seem to have rather fat upper tails, we might expect the observed results to differ quite a bit from case to case - but we will never be able to repeat the current experiment even approximately. This is not a weakness of AGW theory, it is a strength. And one consequence, is that if somebody should come up with an analysis showing another decomposition in natural and anthropogenic components than Meehl's estimate presented here, it would actually -in principle- strengthen the case for AGW. The more models consistent with physics and with the observations, the more robust the paradigm. Surely, the denialosphere will be thick with statements about "debunking" whenever an alternative reconstruction is introduces (just see what happened to Knorr's paper). But that will be like someone triumphantly saying: "Got you! Yesterday, you tried to tell me that nine is six plus three. But now, I can prove you wrong. Here I have obtained conclusive evidence that NINE IS FOUR PLUS FIVE."
  50. Is the airborne fraction of anthropogenic CO2 emissions increasing?
    The network of in-situ CO2 measurement stations ( http://gaw.kishou.go.jp/wdcgg/ ) provides a good record of global and coarse-scale variation in atmospheric CO2 over time. Satellite measurements provide information on finer spatial scale (regional) variation in CO2 over time. There really is no question about any of the following three statements: (a) human activities (fossil fuels and land use) are adding CO2 to the atmosphere, (b) natural biogeochemical sinks are removing some but not all of that excess CO2 from the atmosphere, and (c) because only a fraction of the anthropogenic CO2 emissions are removed, the CO2 concentration in the atmosphere is increasing over time. All of this is very well understood, and not even remotely controversial. With all due respect, the comments made in this thread by ralphiegm give a quite misleading picture of uncertainty in an area where no such uncertainty exists. [If he/she has been relying on the work of EG Beck, that is quite understandable....]

Prev  2507  2508  2509  2510  2511  2512  2513  2514  2515  2516  2517  2518  2519  2520  2521  2522  Next


The Consensus Project Website

THE ESCALATOR

(free to republish)


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