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 Donate

Twitter Facebook YouTube Pinterest MeWe

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

New temperature reconstruction vindicates ...

Posted on 28 September 2010 by Ned

Guest post by Ned

A new temperature reconstruction has been published in the Swedish journal Geografiska Annaler: Series A, Physical Geography.  The reconstruction (hereafter Ljungqvist 2010) covers the past 2000 years for the middle and high latitudes of the Northern Hemisphere.

This reconstruction includes a number of new proxies that have not been included in previous hemispherical or global temperature reconstructions, and avoids many of the proxies that have been the subject of contention in the past. The results are shown in Figure 1:

Figure 1.  Extratropical (30-90 N) northern hemisphere temperature reconstruction by Ljungqvist (2010).  Northern hemisphere instrumental temperature records shown for comparison (CRUTEM land only, and HADCRUT land/ocean).

Ljungqvist notes that this reconstruction shows a Roman Warm Period prior to AD 300, followed by a Dark Ages Cold Period (AD 300 to 800), a Medieval Warm Period (AD 800 to 1300), the Little Ice Age (AD 1300 to 1900), and modern warming in the 20th century.  While there has been debate about how "globally consistent" these various warm and cold periods have been, they have long been recognized as prominent features of the extratropical Northern Hemisphere temperature record, so their appearance in Ljungqvist 2010 is not surprising.

Readers may wonder how this new reconstruction compares to previous hemispherical and global temperature reconstructions.  In his conclusion, Ljungqvist (2010) reports that:

"Although partly different data and methods have been used in our reconstruction than in Moberg et al. (2005) and Mann et al. (2008), the result is surprisingly similar. The inclusion of additional records would probably not substantially change the overall picture of the temperature variability."

On the other hand, Craig Loehle claims that Ljungqvist's work vindicates his own previous "global" reconstruction (Loehle and McCulloch 2008, previously discussed elsewhere on this site). Writing on the website Watts Up With That, Loehle claims:

"In this post I demonstrate perhaps a little vindication [...] There is excellent agreement over the past 1100 years [...] My peak temperature occurs about 100 years earlier, but I agree with the new reconstruction [....]  The MWP looks real."

So who's right?  Does Ljungqvist confirm the results of Mann (2008) and Moberg (2005)?  Or do his results agree with Loehle and McCulloch (2008)?  Figure 2 provides a comparison of them all, starting in AD 500 (the earliest date in Mann 2008's global reconstruction), with the northern hemisphere instrumental record shown for comparison.

 

Figure 2.  Comparison of northern hemisphere and global temperature reconstructions.  Northern hemisphere instrumental temperature records shown for comparison (CRUTEM land only, and HADCRUT land/ocean).

It's worth noting that all the reconstructions show the Medieval Warm Period, the Little Ice Age, and 20th-century warming (though Loehle 2008 only runs through 1935).  

Loehle's Medieval Warm Period is both warmer and earlier than the rest (and, as noted above, Loehle recognizes that his early peak circa AD 850 is probably incorrect).  Loehle also shows a much colder Little Ice Age.  All of the reconstructions diverge more in the period before AD 800, with Moberg being the coolest, Loehle the warmest, and Mann and Ljungqvist being in the middle of the pack.

When comparing Ljungqvist 2010 to Loehle 2008, it's important to remember that Ljungqvist's reconstruction is for the mid- and high-latitude Northern Hemisphere only, while Loehle's was supposed to be global.  In this light, the presence of relatively extreme temperatures in Loehle's reconstruction during both the Medieval Warm Period and the Little Ice Age ought to be viewed somewhat skeptically.  Whether or not these episodes were truly "global", they were certainly strongest in the Northern Hemisphere, particularly in the North Atlantic region. Ljungqvist 2010 suggests that his own reconstruction may have underestimated the magnitude of Northern Hemisphere cooling during the Little Ice Age, but Loehle's still appears to be an outlier if it is considered as a global reconstruction.

Finally, it's worth noting that comparison to the instrumental record suggests that modern temperatures are significantly warmer than those during the height of the Medieval Warm Period.  Additional projected 21st Century warming will produce a climate unlike anything experienced in the history of human civilization.

Update (29 Sep 2010)

Several people have expressed interest in seeing how the various reconstructions compare to current temperatures (from the instrumental record).  In order to do this, it's important to carefully "center" each reconstruction such that it matches the instrumental record as closely as possible during the period of overlap.

I've taken the three Northern Hemisphere reconstructions (Mann, Moberg, and Ljungqvist) plus Loehle's "global" reconstruction, and carefully matched each one to the same instrumental temperature record (CRUTEM Northern Hemisphere land temperatures).  The results are in Fig. 3:

 

Figure 3.  Comparison of temperature reconstructions, re-centered to match CRUTEM NH land record (based on each reconstruction's period of overlap).

Bit of a mess, eh?  To focus on just the Medieval Warm Period and the Little Ice Age, I've pulled out the three warmest decades and three coolest decades in each reconstruction (during the period from AD 500 to 1900).

Figure 4.  Warmest decades of the Medieval Warm Period, and coolest decades of the Little Ice Age, after re-centering each reconstruction to match the instrumental temperature record during the period of overlap.

Moberg is a bit on the cool side overall -- which might just mean it was anomalously warm during the calibration period used for centering.  Mann and Ljungqvist agree very closely on the Medieval Warm Period, though Mann's Little Ice Age is not as cold. 

Loehle manages to be both too warm and too early on the Medieval Warm Period and on the cool side during the Little Ice Age.  This difference would not be all that noteworthy, except for the fact that Loehle 2008 is supposed to be a global reconstruction ... and the magnitude of the MWP-LIA difference should almost certainly be smaller for a global reconstruction than for a Northern Hemisphere one.

The other obvious point is that when we compare these to the current instrumental temperature record, the Medieval Warm Period seems to be about 0.7 degrees C cooler than the 2000-2010 mean temperature.  

0 0

Printable Version  |  Link to this page

Comments

Prev  1  2  3  Next

Comments 51 to 100 out of 104:

  1. fydijkstra @ 39... "The red curves in the reconstruction graphs should be omitted, because the instrumental data are not comparable to the proxy records" Wouldn't that be a case of "hiding the incline?" The whole purpose, as I understand it, to looking at these reconstructions is to compare them to current warming.
    0 0
  2. Rob Honeycutt at 05:40 AM, on the other hand, unless the reconstructions track the instrumental data, then the assumptions made to enable the reconstruction have not been validated. The whole purpose I believe is that recent data should validate the proxy data.
    0 0
  3. KL #43: Oh, and all the temp charts in this thread seem to stop at year 2000 - missing the last 10 years of flattening at a time when claimed AGW forcing is 'the highest decade in history'. In a sense I can't believe that you're still peddling this misinformation. Can you explain how the fact that the decade 2000-2010 is the warmest decade on record is consistent with your assertion please? In fact, I think I've asked you that question before; you've never provided a satisfactory answer (you may have repeatedly ignored the question), and yet still wheel out the same old poorly thought out repetitive rubbish without justification.
    0 0
  4. kdkd@54, Maybe this will help KL out (and these data only go till 2009). I have posted before, but some people seem to choose to ignore the facts: An updated figure (Fig. 21a), can be found here (pg. 48).
    0 0
  5. johnd... Are you suggesting the reconstructions don't track the instrumental record?
    0 0
  6. Could someone direct me to an image that shows temps from 0-2100 i.e reconstruction plus IPCC estimates.
    0 0
  7. Rob @56, I think he may be trying to make a straw man argument about the divergence problem in some of the dendro chronologies from 1960 onwards.
    0 0
  8. Rob Honeycutt at 06:49 AM, yes, those based on tree ring proxies being a prime example. Perhaps you can identify those reconstructions that are tracking recent instrumental records to date.
    0 0
  9. johnd... I think I'm going to leave this one alone. It would be off topic for this thread and an issue that has long been put to rest as well. If you wish to rehash this one I would suggest this thread.
    0 0
  10. Michael @57, you must be telepathic. John Cook just posted this:
    0 0
  11. Based on the second graph that shows the warmest part of the Med-evil warm period being near .3c above "0" or avg to todays global .8c above normal. So we're half a agree oC above the med-evil warm period. Also I was reading that we're very close to the Holocene climatic optimum of 5,000-7,000 years ago->"The Holocene Climate Optimum warm event consisted of increases of up to 4 °C near the North Pole (in one study, winter warming of 3 to 9 °C and summer of 2 to 6 °C in northern central Siberia)[1]. Northwestern Europe experienced warming, while there was cooling in the south.[2] The average temperature change appears to have declined rapidly with latitude so that essentially no change in mean temperature is reported at low and mid latitudes. Tropical reefs tend to show temperature increases of less than 1 °C; the tropical ocean surface at the Great Barrier Reef ~5350 years ago was 1°C warmer and enriched in 18O by 0.5 per mil relative to modern seawater.[3] In terms of the global average, temperatures were probably colder than present day (depending on estimates of latitude dependence and seasonality in response patterns). While temperatures in the Northern Hemisphere were warmer than average during the summers, the tropics and areas of the Southern Hemisphere were colder than average which comprised an average global temperature still overall lower than present day temperatures.[4" http://upload.wikimedia.org/wikipedia/commons/c/ca/Holocene_Temperature_Variations.png If we're now warmer then the midevil warm period and possibly the climatic optimum then we have to go back to the at least 115 thousand years to find possibly warmer temperatures then today. 3-4c would put us back to where we where 15+ million years ago?
    0 0
  12. Rob Honeycutt at 07:04 AM, the tree rings was just a mere example to illustrate a point. I was asking specifically about which of those reconstructions that are the subject of this thread, thus the question was very much ON topic.
    0 0
  13. Johnd @63, please read the thread (i.e., Ned's comment).
    0 0
  14. Albatross at 07:56 AM, I have and unless I overlooked it, there is no mention that the higher temperatures of the last two decades ARE NOT reflected in the Ljungqvist 2010 reconstruction itself. Perhaps others missed the omission as well? That then brings us back to the point of whether reconstructions are being validated by recent instrumental data, and if not, why not?
    0 0
  15. Johnd I think that we are getting our wires crossed. The authors are quoted @4 saying: "The proxy reconstruction itself does not show such an unprecedented warming but we must consider that only a few records used in the reconstruction extend into the 1990s." So the reconstruction (base don limited proxies) goes into the 90s. From the figures shown here, their reconstruction seems to compare very well with the thermometers over the remainder of the instrumented record before the 90s.. I do not know what calibration/training period they used (the paper is behind a pay wall). Maybe Ned can help?
    0 0
  16. Albatross at 08:19 AM, thanks I missed that early comment and only had the abstract to go on. However I am still not clear where the reconstruction ends and left wondering what proxies could provide data for all but the last couple of decades. Surely for the sake on continuity and validation of the proxies themselves, the same data should be continued to be progressively collected as time moves forward.
    0 0
  17. Johnd, helps to remember that researchers in the topic are not primarily invested in policy outcomes, obsessive scrutiny of 12 year old papers, etc. Life moves on, there are new things to investigate. There's also the matter of money. Who's going to pay for repeating the research? The iconic Keeling lost his Antarctic sample continuity due to funding cuts.
    0 0
  18. Johnd @67, OK, downloaded the paper. The Ljungqvist reconstruction runs from 1 AD through 1999 AD, and the calibration period was 1850-1989.
    0 0
  19. Albatross at 08:58 AM, thanks once again. I assume therefore that the note in the abstract "The temperature of the last two decades, however, is possibly higher than during any previous time in the past two millennia, although this is only seen in the instrumental temperature data and not in the multi-proxy reconstruction itself." is referring to the last two decades of the reconstructed time span. The calibration period therefore covers periods of lower temperatures whereas it is the periods of higher temperatures that are of most interest. doug_bostrom at 08:50 AM, I understand the need for funding, however given the importance of the matter whether or not current temperatures or past temperatures are greater, it becomes vitally important to calibrate any reconstructions against current temperatures levels in order to ensure apples are being compared with apples. As with any calibration, say of instrumentation, the calibration should be such that it is most accurate within the working range, not at the extremities. As a sideline, that temperature sensor that failed at high temperatures made me wonder whether it had an appropriate range or not, and how accurate it would have been as it approached the failure point.
    0 0
  20. Loehle's piece shows, with a quick eyeball, that (using his figures) the difference between the absolute hottest peak of the MWP (greater than the Roman period and the coldest trough of the "Little Ice Age" is about 1.15 deg C tops. The difference between grapes growing all over the place, such as Singer would say, and iron hard frozen English rivers is not that much. Small changes make a dramatic difference. Few or no credible sceptic scientists (that minority who believe sensitivity is low) dispute that the forcing from the extra CO2 we have dug up and put back into the atmosphere will increase the average global temperature by less than 1 deg C. Unless I'm mistaken, this looks like all credible scientists, sceptical or "IPCC", should be united that what's already in the pipeline will cause dramatic differences that will last a very long time even if the sensitivity is low. If the sensitivity is as the IPCC say it'll be worse. If there are "unknown unknowns" about sensitivity to catch us out, then "Hell and High Water" could be optimistic. Thoughts?
    0 0
  21. Nick Palmer writes: Thoughts? Yes, that's a really good point. Loehle is the skeptics' own reconstruction, and there's certainly reason to believe that it exaggerates the MWP-LIA difference. But even if you ignore that, the range itself is still small compared to current and projected future warming. If you're a skeptic who believes that past natural climate changes had a significant impact on human societies (Greenland, the Anasazi, ...) then you should be really concerned about the future.
    0 0
  22. @Nick Palmer #71 the forcing from the extra CO2 we have dug up and put back into the atmosphere Gaah. I didn't mean we dug it up in the form of CO2! (greater than the Roman period Forgot to close the bracket too...
    0 0
  23. kdkd #54 Its a wonder that Moderator John Cook has not moderated your language kdkd. Your accusations about my 'peddling misinformation' and 'repetive rubbish', I usually ignore because it has no place in this blog. Put up a scientific argument supported by numbers or shut up.
    0 0
  24. Ned #44 This thread is about temperature. Temperature is a measure of energy applied to or removed from the mass involved. The mass involved is the Earth system - land ice, atmosphere and ocean. Temperature does not distinguish the origin of the energy applied. The proportions of energy contributed by forcing from CO2GHG and Solar are critical to the AGW hypothesis. If there is a storage reservoir in the system (the oceans), and heat is erupting or about to erupt from this storage, then quantifying a long term Solar imbalance is as much a part of the story as 30-35 years of official AGW by CO2GHG forcing; and given the lack of evidence for short term (decadal) sequestration of heat in the oceans over the last 30-35 years might be the obvious place to look.
    0 0
  25. Nick, I'm not so sure that that's such a bad formulation. What we dig up is the result of long ago sequestration of CO2. To me at least, it emphasises that we're releasing in a couple of dozen decades what was sequestered over many 10s of millions of years.
    0 0
  26. Ken, that's just handwaving. A climate forcing (solar, greenhouse gases, whatever) is defined based on a departure from some base period. The Earth does not have to be in some imaginary "equilibrium" at that base period. It is perfectly straightforward to say that since 1750 (or whenever), the forcing from greenhouse gases is X and the forcing from increasing solar irradiance is Y, and X > Y or vice versa. This does not depend on anything being in "equilibrium" at 1750. I am literally unaware of anybody anywhere (other than you) who makes that claim. If there is some controversy over this point in the scientific literature that I've somehow missed, please enlighten me with a link.
    0 0
  27. @adelady #76 Over many hundreds of millions of years volcanoes have been releasing CO2 from non-biological subterranean sources of carbon. Without life sequestering the carbon back down underground again, CO2 would continue to build up. Life as a whole acts as a negative feedback to prevent CO2 buildup thus stabilising temperatures to its benefit. One element of life (Homo Sapiens Fatuus) has recently been acting as a positive feedback. As you say, we are digging up in a few decades what took millions of years to get down there.
    0 0
  28. KL #74. We've been through the scientific argument many many times. You seem to claim that the ocean heat content data is capable of falsifying the remaining evidence for anthropogenic global warming. You do not seem to have any other 'evidence' to support this position. A large and important part of your position is the need to maintain the pretence that the existing measures of ocean heat content are accurate enough to draw strong conclusions. It has been demonstrated to you many many times that it is not. As you have no other argument to support your position, you maintain the position regardless of the evidence presented to you (like the 'flattening of temperature post 1998' claim that you cling to as well), I think that repetitive rubbish is a fair comment which summarises your argument well.
    0 0
  29. Kdkd 2000-2009 warmed about .15c, which is below the 1990's. Is that true?
    0 0
  30. Nick Palmer at 03:20 AM, regarding your comment of digging up CO2 that took millions of years to sequester. If we look at the carbon cycle where the the natural sources and sinks exceed anthropogenic emissions by a factor of 30, and those natural sinks each year sequester approximately half of the man made emissions, then one could make a case showing that in fact man is only releasing carbon in one year that took two years to get down there.
    0 0
  31. johnd - Actually, much of the anthropogenic emissions are going right into acidifying the oceans. It takes quite some time for that absorbed CO2 to move deeper. The rate required to be absorbed by the environment and not change ocean pH would be much much smaller than 50% of current emissions.
    0 0
  32. KR at 07:14 AM, the CO2 sequestration of the oceans and the plants and soil are divided roughly equal. The drop in CO2 levels that coincide with the seasonal growing periods in each hemisphere show that the plants and soil are a significant destination for CO2 with a capacity that is only partly utilised for a portion of each annual cycle.
    0 0
  33. johnd - Seasonal variation is cyclic; what goes in comes out. Actual long-term sequestration of CO2 occurs through rock weathering, subduction in ocean zones, and the formation of those hydrocarbons we're so rapidly burning. The long term trend is what's important, currently +2ppm/year, not seasonal variations. The only long term sequestration of CO2 involves plants that are not then burnt, eaten, or rotted away. That's a pretty small portion.
    0 0
  34. Matthew #80. "Kdkd 2000-2009 warmed about .15c, which is below the 1990's. Is that true? Nope. Firstly you can't really assess trends properly over such a short time period in isolation due to a lack of statistical power. The difference in trend is almost certainly not statistically significant even before correcting for autocorrelation. The calculation for actual statistical significance is fiddly so I'm not going to do it, but with 10 paired data points it would require quite a large difference in correlations to be significant (probably greater than r=0.6 from memory) - the observed difference in correlation is only 0.15 which is definitely not statistically significant for 10 paired observations. Looking at the satellite data for 1990-1999 and comparing it to the satellite data for 2000-2009, the mean anomaly for the 2000s is 0.25 deg C greater for the 2000s period than for the 1990s period (95% confidence interval: 0.095-0.40).
    0 0
  35. Matthew @80, I concur with kdkd, or rather Hansen does ;) "Contrary to a popular misconception, the rate of warming has not declined. Global temperature is rising as fast in the past decade as in the prior two decades, despite year-to-year fluctuations associated with the El Nino-La Nina cycle of tropical ocean temperature. Record high global 12-month running-mean temperature for the period with instrumental data was reached in 2010." From: Hansen, J., R. Ruedy, Mki. Sato, and K. Lo, 2010: Global surface temperature change. Rev. Geophys., in press, doi:10.1029/2010RG000345.
    0 0
  36. KR at 08:09 AM, the rate at which CO2 is being moved deeper in the oceans will be tied to the rate at which the heat also absorbed at the surface is redistributed and moved deeper, and that, whilst subject to great discussion, is more reflective of shorter rather than longer term circulation.
    0 0
  37. johnd - My point was that seasonal CO2 variations due to the growing season are very definitely not the trend - and that you cannot count on large seasonal variations to take care of a multi-decade CO2 increase.
    0 0
  38. #81 johnd at 06:47 AM on 1 October, 2010 wrote: "If we look at the carbon cycle where the the natural sources and sinks exceed anthropogenic emissions by a factor of 30, and those natural sinks each year sequester approximately half of the man made emissions" Perhaps you might like to consider the difference between short and long term sequestration. I was referring to the digging up of (semi-)permanently sequestrated carbon.
    0 0
  39. Follow up from #85 Of course there's an easy way of assessing the significance of the difference between the trends - correlate the difference between the 1990s and the 2000s against the position in the series. This gives a correlation coefficient of -0.07, 95% confidence interval of -0.67 to +0.58. As this confidence interval intersects zero (and as I indicated previously is a very wide interval) there's clearly no significant difference between trends in the 1990s and the 2000s as measured by the annualised satellite data. For this analysis to be statistically significant the correlation would have to be (0.58 - 0.67)-1 = 0.91 which would be very difficult to achieve with this system, even if we were seeing clear evidence of runaway global warming (or cooling) over such a short time frame.
    0 0
  40. KR: ...long term sequestration of CO2 involves plants that are not then burnt, eaten, or rotted away. Also foraminifera, coccolithophores, diatoms. C in C02 ends up in hydrocarbons, carbonates. Of course we're short on enormous shallow seas these days.
    0 0
  41. @80 Mathew and 85 kdkd Regarding the trend for 1990-2000 vs. 2000-present: I made a plot showing the trend for the last period August 2000-August 2010 and for the period August 1990- August 2000, with confidence intervals (with and witout AR1 correction) for the trendlines: It shows that the trends are not different from each other in a statistical signicant manner. Correcting for AR1-noise, they are not statistical significant on their own.
    0 0
  42. SRJ #92 "Correcting for AR1-noise, they are not statistical significant on their own." What does that mean SRJ?? Does it mean no statistically significant warming at all in either time period?? No different from a random walk perhaps??
    0 0
  43. Getting excited there, Ken? Guess what? The warming in the 1980s is not statistically significant on its own. The warming in the 1990s is not statistically significant on its own. The warming in the 2000s is not statistically significant on its own. But the warming from 1980-2009 is very highly significant. Can you explain what that means, Ken?
    0 0
  44. It might be helpful for Ken to consider the following set of questions: Is the temperature trend during the first week of spring significant? Is the temperature trend during the second week of spring significant? ... Is the temperature trend during the last week of spring significant? If your answer to each of the above questions happened to be "No", would that mean that there's no temperature change between winter and summer?
    0 0
  45. KL #93 "No different from a random walk perhaps??" Another piece of so-called sceptic misanalysis of the instrumental record you've latched onto. Yes, quite different from a "random walk" when the analysis is done properly, according to the respectable analysis I've read in the past. But with abuse of the assumptions, as ever it's possible to "prove" anything using statistics - the trick is knowing when the assumptions have been abused. In the case of the WUWT crowd (where I think the 'random walk' idea came from) this seems to be pretty much any time they do statistical 'analysis'.
    0 0
  46. Even more than the point that a long time frame with statistically significant warming will likely not show that warming at the same confidence level when carved up into smaller sub-durations, I think the telling part of this analysis is that the supposed 'extreme warming' of the 90s and 'cooling' of the 00s are not statistically different from each other. In short, people are assigning different perceptual significance to things which are mathematically NOT different. The reality is that both decades show apparent warming, but it falls short of 95% confidence until the longer combined period is considered.
    0 0
  47. Ned #77 "Ken, that's just handwaving." Handwaving - a new scientific or engineering term Ned? Forcing is an unscientific term for energy flux or power with the units W/sq.m. These values are instantaneous at any point in time. Total energy transferred is the time integral of the forcing - and temperature change beween times T1 and T2 is a measure of the total energy transferred to or removed from the mass in that period. By definition all the AG forcings were zero in pre-industrial times (set at AD1750 by IPCC AR4). If you plot the AG forcings (heating and cooling) in W/sq.m on the vertical axis and time on the horizontal axis, you will start at (0,0) in AD1750. Integrate the Forcings WRT time and you will get the area under these curves (positive or negative) and the sum of these areas will give the total energy balance in Joules added or removed from the Earth system due to AG forcings. CO2GHG should be positive and Aerosol albedo should be negative. Throw in volcanic aerosol cooling as well if you like. Now do the same chart with 'natural' Solar forcing with W/sq.m on the vertical axis and time on the horizontal axis and plot the curve. Do you start at (0,0) in AD1750? To do that you must assume that Solar forcing was zero in AD1750. To do that you must assume that the Earth was in equilibrium -no heating or cooling from Solar forcing and of course no AG forcings exist. With me?? Now we have already seen that the areas under all the AG curves when summed give the total energy applied to the Earth system since AD1750, so similarly the area under the Solar forcing curve will give the Solar energy applied to same. If the Solar forcing curve were to start not at (0,0) but say (0.1W/sq.m, 0) - a slight positive forcing, then the extra area under the curve would be offset positively by 0.1W/sq.m x 260 years x 365 days x 24 hours x 3600 seconds x surface area of Earth; which equals approx 4190E20 Joules. At Dr Trenberth's current 145E20 Joules/year imbalance -that equals 29 years warming at todays full rate and 56 years warming at half rate, which alone would account for a big chunk of 20th century temperature increase by energy imbalance, without the rest of the curve which we know is also positive. Now do you see the importance of a non-zero Solar forcing in AD1750?? Maybe all those 'scientists' out there who are working on their complex specialties miss the simpler minded basics.
    0 0
  48. Ken Lambert wrote : "Maybe all those 'scientists' out there who are working on their complex specialties miss the simpler minded basics." Of course ! That must be it. Not only are none of them proper scientists (they are 'scientists') but they are probably not reading these threads (especially the ones you are posting on) and thereby missing all the basic stuff that they have obviously forgotten about. I think we should all make it our duties to contact as many of them as possible and pass on your details so they can be made aware of what they are stupidly missing. They are SO going to kick themselves...;-)
    0 0
  49. JMurphy #99 Happy for you to point out the parts of my post #98 which are wrong JMurphy. Where do you want to start?
    0 0
  50. KL #98 "Do you start at (0,0) in AD1750? To do that you must assume that Solar forcing was zero in AD1750. To do that you must assume that the Earth was in equilibrium -no heating or cooling from Solar forcing and of course no AG forcings exist." Thanks for demonstrating another fundamental flaw with your analysis which has been pointed out to you previously. There is no assumption of equilibrium here - the figure of 0 is merely a baseline, which has nothing to do with equilibrium at all. The logic underlying one of your fundamental assumptions is wrong, and there's absolutely no getting around that. Although you could continue to ignore the problems with your argument and continue with the same old repetitive rubbish.
    0 0

Prev  1  2  3  Next

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.



The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2020 John Cook
Home | Links | Translations | About Us | Privacy | Contact Us