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  2516  2517  2518  2519  2520  2521  2522  2523  2524  2525  2526  2527  2528  2529  2530  2531  Next

Comments 126151 to 126200:

  1. Can you make a hockey stick without tree rings?
    Good post. I was hoping you could clarify this point though: "Of course, these examples only go back as far as 500 years - this doesn't even cover the Medieval Warm Period. When you combine all the various proxies, including ice cores, coral, lake sediments, glaciers, boreholes & stalagmites, it's possible to reconstruct Northern Hemisphere temperatures without tree-ring proxies going back 1,300 years" I'm assuming that the 1,300 figure comes from ice cores, coral, and lake sediment, which aren't depicted as separate graphs in the post. Is that accurate? Do you have separate graphs of those proxies?
    Response: Plotting separate graphs from each proxy was my initial intention for this post. I scratched around for global reconstructions from other proxies, found it difficult to find (I probably could've kept looking but I only have so many hours in the day). My impression is that some of the other proxies are sparse enough to make global averages from that individual proxy problematic. It's when all the proxies are combined that a more global spatial pattern is possible.
  2. What do the hacked CRU emails tell us?
    Let's be clear as to exactly what the "trick" was. Steve McIntyre lays out the various steps as follows: Jones deleted the post-1960 values of the Briffa reconstruction, replaced them with instrumental values, smoothed the spliced series (see posts by both Jean S and myself proving this) and ended up with a reconstruction that looked like an accurate reconstruction of late 20th century temperatures. He didn’t merely show a temperature series alongside a proxy reconstruction, which is what the NAS panel did. The NAS panel had a different approach to the “problem” of the Briffa reconstruction. They simply didn’t show it. Many of these steps were not evident and were not adequately disclosed. Thus, the "trick" was much more than simply "plotting recent instrumental data along with the reconstructed data" as John Cook states above.
  3. Measuring Earth's energy imbalance
    For all of the above, there are still deep uncertainties in the models, which climate scientists are willing to admit privately if not publicly. For instance: From: Kevin Trenberth To: Michael Mann Subject: Re: BBC U-turn on climate Date: Mon, 12 Oct 2009 08:57:37 -0600 Cc: Stephen H Schneider , Myles Allen , peter stott , "Philip D. Jones" , Benjamin Santer , Tom Wigley , Thomas R Karl , Gavin Schmidt , James Hansen , Michael Oppenheimer Hi all Well I have my own article on where the heck is global warming? We are asking that here in Boulder where we have broken records the past two days for the coldest days on record. We had 4 inches of snow. The high the last 2 days was below 30F and the normal is 69F, and it smashed the previous records for these days by 10F. The low was about 18F and also a record low, well below the previous record low. This is January weather (see the Rockies baseball playoff game was canceled on saturday and then played last night in below freezing weather). Trenberth, K. E., 2009: An imperative for climate change planning: tracking Earth's global energy. Current Opinion in Environmental Sustainability, 1, 19-27, doi:10.1016/j.cosust.2009.06.001. [1][PDF] (A PDF of the published version can be obtained from the author.) The fact is that we can't account for the lack of warming at the moment and it is a travesty that we can't. The CERES data published in the August BAMS 09 supplement on 2008 shows there should be even more warming: but the data are surely wrong. Our observing system is inadequate. *** Kevin Respectfully, if our leading scientists "can't account for lack of warming", then the science isn't "settled" on this matter. To be clear, I (and most other fair-minded skeptics) concede that the earth has warmed, but we are much less certain that the "consensus" as to: 1) How much it has warmed; 2) How much of that warming is man-made; 3) How sensitive the climate is to additional CO2 forcing; 4) How many liberties we should all be prepared to sacrifice to counter the threat. On these points, there are great uncertainties and the science most certainly isn't settled. This is especially true with regard to the issue of climate sensitivity. And regrettably, I find little on this website that seeks to resolve these uncertainties. Instead, the site seems to be primarily designed to attack the straw man argument that "skeptics" deny warming altogether.
  4. How do we know CO2 is causing warming?
    Riccardo, I agree and disagree. An overall TAO energy balance would mean that incoming solar would be equal to outgoing long wave plus outgoing short wave. An increase in OLR should be a combination of an increase due to a high temperature (obviously) modified by any changes in cloud or other OLR factors. If Golovko is correct (this is only one paper!), the increase in long wave anomaly is greater than the decrease in short wave anomaly (see figure 3): http://www.isprs.org/publications/related/ISRSE/html/papers/332.pdf Assuming that the incoming solar is constant, this would imply that the Earth is losing more heat over time. I agree that the Earth has been warming over the period Golovko analyzed, but this does not preclude it from moving back toward a TOA radiative balance. Based on the article above "How do we know CO2 is causing warming?" I would have expected increasing CO2 concentration to cause an overall (integrated over the whole spectrum) decrease in OLR, which results in radiative inbalance at TOA the thus warming. Am I misinterpreting the mechanism of how CO2 affects the radiative balance?
  5. Can you make a hockey stick without tree rings?
    John, How can this type of reasoning be broadly disseminated out to the general public, as a counter to the viral spreading of "climategate". In general those who read this blog need no convincing but the information serves to deepen our conviction, thanks for all you do. There is a desperate need to reach out beyond the bounds of this site and others that support the science, beyond a preaching to the choir, as public understanding and support for mitigation declines.
    Response: The best way to get the science out there, as Auriam says, is to actively discuss climate science on other websites, blogs, forums, etc. I provide a webpage that generates quick links to all the various pages on Skeptical Science so you can point people to where they can find out more info.

    I do recommend if you do post links to Skeptical Science that you take the time to read the page you're linking to and describe the page you're linking to in your own words. One of my pet peeves is comments that merely post a link without any explanation - a lazy way to discuss climate science. You show more respect for the people you're discussing with and provide more useful, enlightening discussion if you can at least give a brief description of the science you're linking to.
  6. Can you make a hockey stick without tree rings?
    What can I say? Well done!
  7. Empirical evidence that humans are causing global warming
    Regarding CO2 saturation in our atmosphere (post#1), isn't it also true that over-saturation would cause MORE heat to be trapped at lower and lower altitudes in our atmosphere, where the effect actually matters (since surfaces are where H2O is evaporated, ocean temps are affected, and much of what constitutes 'weather' is determined)? I mean, who cares if the stratosphere is hot or not?
  8. Climategate CRU emails suggest conspiracy
    As i see it, there are two parts in this story. One is the behaviour of the few scientists involved in the stolen emails, the other is the broad impact on climate science. Starting from the latter, which i think is the topic of this post, i can see no impact whatsoever. Luckly, science is not a matter of a few guys or a few experiments. So even if some fake science could have made it's way through the selection of the scientific community, it does not affect climate science as a whole. And even admitting (i do not) scientific misconduct by those CRU scientists, are we allowed to doubt of hundreds of other? Not for sure, each of us is responsible of its own actions and there is nothing in the emails pointing to a much broader involvement of the whole community. Here is the link to the first part of the problem. What did they actually do? I mean, actions, not words. At the very least, from the emails we can't deduce anything and there are no facts elsewhere confirming any action. There is some not appropiate wording, but nothing regarding arbitrary data manipulation. While I can understand that they might be "condemned" for their personal attitudes i strongly disagree to involve the science. Finally, a political consideration. Before a couple of decades ago, global warming was not a political issue. But then, when the "risk" of concrete actions became too high, it switched to a political issue. The explicit interest was to confuse the two planes, politics and science. This is not new, indeed, we've seen this happen before (mainly in the USA i admit). Who is responsible? Not scientists for sure, they kept doing their work while were being involved in the arena. Some of them even started to be advocate, which is definitely a right for anyone. Should we conclude that AGW is now politics and not science? Not at all. The solution of the problem is politics, indeed; its assessment is science.
  9. The hockey stick divergence problem
    HumanityRules, as you correctly say, we all need a full explanation of the divergence problem and this is exactly what scientists are researching actively. In the meanwhile we are forced to stick to possibility #2 "devaluing" (i'd say put on hold) part of the data, which is all but the most desirable solution. I hope there's no #3, throw away all the data. This would really be giving data no value at all.
  10. Climategate CRU emails suggest conspiracy
    As stated above: "However, the crucial question is whether these emails reveal that climate data has been falsified." It's your website, but, for what it's worth, I disagree with your line of reasoning here. I think the crucial question is: was this scientist attempting to mislead? And if so, what was his motivation? Also, could this same motivation broadly exist in the climate science community. If we are intellectually honest, we have to address this question. I think reasonable people could agree that the climate issue has been so politicized over the last decade that it is often extremely difficult to discern the truth. I appreciate the efforts of this site to attempt to coherently dispute the disputers. I do, however think that the recently publicized e-mails by a "ranking" member of the non-skeptic climate community are harmful to the cause of discerning the truth, at least for those people who have not drawn a final conclusion about the evidence, which apparently concludes that anthropogenic CO2 + feedbacks = catastrophy, and that climate sensitivity is a solved problem.
  11. The hockey stick divergence problem
    The "hide the decline" storm in a teacup is very pertinent to this discussion. The 'divergence problem' is essentially a question on how much value you put on the data. The divergence means that the correlation between the temp record and tree ring data is lowered. The data data becomes a less valuble tool. There are several ways to get around this. 1)Fully explain the divergence and do the appropriate compensation to the data. This would maintain the high correlation and high value to the data. 2)Remove the divergent period, another way to put this is "hide the decline". Many would see this as intrinsically devaluing the data. I would struggle with doing this to my own data. With a failure to fully explain 1) then it appears there is a move toward 2) John the value of data is an important aspect of science I hope you don't think this is off topic!!
  12. There's no empirical evidence
    Sorry if I seem dense. Allow me to make an analogy to evolutionary theory. It is observed that species change over time (evolution). Natural selection is a theory that explains how that happens. The fact of evolution doesn’t prove natural selection. Natural selection explains evolution. If evolution did not happen (species did not change over time) then natural selection would be in trouble, but that doesn’t mean that a scientist can say, “Look at how these species have changed. Natural selection is therefore proven!” Evolution is consistent with natural selection, but evolution doesn’t prove that the natural selection hypothesis is correct. Instead, we accept that evolution happens (based on considerable evidence) and compare different explanations for what causes it (natural selection vs. Lamarckism, for example). Natural selection makes many correct predictions, while Lamarckism makes many incorrect predictions. Therefore, natural selection is accepted as true (as true as anything in science). In the same manner, once we accept global warming, it does nothing to support AGW vs. any other explanation for increased global temperatures. What testable predictions does AGW make? What testable predictions do alternative theories (such as increased solar activity) make? How do those predictions hold up when compared with facts? That’s really the case that needs to be made here, I think.
    Response: I had hoped that I had made a clear case above not only for global warming, but more importantly, that humans are causing global warming. If humans are causing global warming, we expect to see an enhanced greenhouse effect. More specifically, we expect to see the enhanced greenhouse effect at the wavelengths that CO2 absorb energy. This has been observed both by satellite measurements observing less infrared radiation escaping to space and surface measurements observing more infrared radiation returning back to the Earth's surface.
  13. Was there a Medieval Warm Period?
    @TruthSeeker: If you are really seeking the truth, how come you over and over again present judgments and 'facts' that are clearly contradicted by lots of information many consider as facts? "Firing their editorial staff"? Could you please check out better? It _is_ a big problem in science when flawed papers get through, and journals with too bad quality control _should_ be questioned. It is not about whether someone is factually correct, it is the quality of data, data processing, reporting and discussion. Soon/Baliunas may well be right, but that does not make the paper more worthy of publishing. One particularly important point, is to discuss alternative hypotheses, conflicting results and possible interpretation issues. In this regard, I think a lot of work should be improved. This is one of the reasons why the 'skeptics' often experience problems with the peer review process: They very often fail to discuss evidence contradicting their own views, and it does not help them that the mainstream guys also do a lot of the same. When you represent consensus, you normally don't have to discuss everything yourself, because so much of the stuff under discussion has already been handled by others. And the weight of consensus is mainly the weight of the evidence, not the weight of the 'authorities'. If we have 7 studies indicating no MWP in an area, and 2 indicating it, all studies equally reliable, the best estimate would probably be that there wasn't any, but we can't say for sure. It is always a mistake to neglect conflicting evidence, but it is a greater mistake to neglect 7 studies than to neglect 2. Such things must be kept in mind, otherwise it's too easy to become a conspiration theorist instead of a truth seeker. Remember, too, that shortcomings don't necessarily render a work worthless, nor do errors by themselves 'prove' fraud.
  14. The physical realities of global warming
    TrueSeeker, adding to what chris just said, it's not even true that there has been no warming in the last 10 years. The decade 1999-2008 (annual GISS data) gives a trend of 0.19+-0.09 °C/decade. Would you call this "no increase"? But I know, you (or someone else), will come out with a different and accurately choosen range to show that there has been no warming ... In any case, eyeballing is not enough in science because the eyes can be easily fooled. So please, stick to science; it might not be the "Truth" (it surely isn't) but it definitely is the best that we can do.
  15. 1934 - hottest year on record
    This post needs updating. USHCN v2 makes a slight adjustment upward in U.S. mean temperature over the last decade, which puts 2006 and 1998 above 1934. Almost nil implication as far as global warming goes, just like the previous adjustment, although one wonders what the spin from the global warming denial crowd will be this time...something like "NASA fabricates data to support hoax! Erases fact that 1934 was the warmest year on record!" "Nov. 14, 2009: USHCN_V2 is now used rather than the older version 1. The only visible effect is a slight increase of the US trend after year 2000 due to the fact that NOAA extended the TOBS and other adjustment to those years. " http://data.giss.nasa.gov/gistemp/graphs/ Revised U.S. data: http://data.giss.nasa.gov/gistemp/graphs/Fig.D.txt
  16. Was there a Medieval Warm Period?
    Here's the EOS article that helped further convince the Climate Research editors that publishing Soon/Baliunas was a failure of the peer review process of that journal. http://www.geo.umass.edu/faculty/bradley/mann2003a.pdf It was also a clear attempt from Soon/Baliunas to game the peer review system by sending political junk to an editor they knew wouldn't give it critical evaluation. All of this context is lost when viewing only stolen personal emails on the topic. Mann and colleagues should be applauded for standing up for science.
  17. The physical realities of global warming
    That's an odd interpretation TS. It looks like the maximum temperature is 2005. Obviously we aren't so ill-informed that we don't understand that 1998 was lifted around 0.2 oC above the long term trend by the strongest El Nino of the last century! Come December, every year of the "noughties" will be warmer than every year of the 90's bar the well understood anomalous 1998. So yes the earth's surface temperature hasn't warmed since 2005. That's probably not surprising given that the solar output has decreased a tad during the last 20 years and the glaringly obvious fact that we're smack at the bottom of the solar cycle. We expect all the greenhouse warming of the last 5 years to be (temporarily) opposed by the solar cyle, since we all know rather well that the solar cycle has an effect on the surface temperature near 0.1 oC max-min (and min to max!). That's pretty straightforward, wouldn't you say?
  18. Was there a Medieval Warm Period?
    Today's Nature has an insightful editorial on the CRU nonsense (apols for posting this on the wrong thread): http://www.nature.com/nature/journal/v462/n7273/full/462545a.html (not sure if this is freely accessible)...
  19. Was there a Medieval Warm Period?
    You missed the truth "Truth"seeker. Your "understanding" is something other than "understanding". If you "read the whole story" you didn't comprehend it...or perhaps you read the wrong story??? The editorial staff weren't fired; they resigned. The publisher issued a statement that that the paper shouldn't have been published in the form that it was. http://www.sgr.org.uk/climate/StormyTimes_NL28.htm The paper was rubbish. The conclusions weren't supported by the data presented (there was no significant evidence for spatially-distributed contemporaneous warming on a worldwide scale in the hodge-podge of data presented, let alone that this constituted a global scale warming that was as significant as late 20th century and contemporary global warming). It's not a big deal. If we want to understand the science we don't "create" our "understanding" from one obviously dodgy analysis. That flawed paper (like all obviously flawed analysis) simply doesn't impact the insight of informed science, even if it is used for propaganda/misinformation purposes. There are dozens of papers that address paleoclimate/paleotemperature over the past millenium or two, and that body of work is what informs our understanding. It really depends whether one is or isn't interested in the truth....
  20. Why is Greenland's ice loss accelerating?
    Ok! I think I realize now that we are just interested in how much ice is being lost, and this is just the trend, not the absolute values. The paper itself is even clearer: "GRACE values are not absolute numbers, and the curve has been vertically shifted for clarity". The correlation coefficient is 0.99! So it really is a strong independent confirmation of the GRACE-derived estimates (that had recently been questioned). *Now I see that your nickname seems Italian, so I guess we may be able to understand each other in any of our mother languages (I'm Spanish ;-) ) (though it would be very bad-mannered in an English forum, of course ;-) ) Thanks again for your answers. Cheers!
  21. There's no empirical evidence
    David Rourke, the first point is not simply that CO2 is rising. The point instead is that humans are causing the rise of CO2. Since that rise of CO2 increases heat retention, it does indeed follow that humans are causing a rise of heat retention via the mechanism of increasing CO2.
  22. The physical realities of global warming
    Tom, Look at the last 10 years. There is no increase.
  23. Was there a Medieval Warm Period?
    I think I read the whole story. My understanding is that the paper challenged the Mann's work, Mann and Phil coordinated on a response / rejoinder (completely acceptable). They weren't satisfied, and felt the need to coerce and the publication into firing their editorial staff by threatening to coordinate a mass with holding of publications by them and their buddies. The publication fired their editorial staff. did I miss anything?
  24. The hockey stick divergence problem
    Riccardo, I skimed through your document, and I am not sure what that was supposed to show me. I guess, I would like to see evidence that there is a correlation between some other climate data (other than temp) that would suggest that Tree Ring data is valid.
  25. There's no empirical evidence
    Thanks for the thoughtful presentation of evidence in favor of AGW. I'm concerned with the logic of how you put your argument together on this page, however. Your first point is that CO2 is increasing. The second is that CO2 traps heat. OK so far. The third point is that the earth is warming. You lose me there. The reason we know that humans are causing the earth to warm is that the earth is warming? I just don't see how that logically follows. I'd really like to see a clear argument for the AGW hypothesis that separates evidence of warming from evidence for the cause of that warming. That's what I was hoping to find here, but did not.
    Response: The cause of global warming is outlined above in point 2: the enhanced greenhouse effect from increasing CO2. Point 3 (warming is happening) is the logical consequence of Points 1 (we're raising CO2) and 2 (CO2 traps heat). To accept the first two points, that human CO2 emissions are causing heat to be trapped, is to accept that humans are causing the planet to accumulate heat. With more heat in our climate, temperatures will rise.
  26. Why is Greenland's ice loss accelerating?
    PeterPan, my mother language is not english, so i might be wrong as well ;) If a have that bit of knowledge, I'm always happy to answer questions from people willing to understand. You are right, it is the reference period that must be the same. But then you are left with just the linear trend. In other words, the fact that the GRACE anomaly is lower would indicate just a different reference period with no other physics involved. This is the reason why people usually do not bother to specify it and just shift one curve for visual clarity.
  27. Water vapor is the most powerful greenhouse gas
    villar, you can demonstrate non-runaway positive feedback in a spreadsheet: Cell A1: 0 Cell A2: 10 Cell A3: =A2+0.5*(A2-A1) Cell A4: =A3+0.5*(A3-A2) Now copy and paste cell A4 into cell A5 and on down the column for about 15 cells. The formula should automatically adjust to each cell, so each cell's value is the previous cell's value plus 50% of the increase that the previous cell had experienced over its predecessor. The feedback is an increase of each increase, not of the total resulting amount.
  28. Why is Greenland's ice loss accelerating?
    Thanks, Riccardo. Yes, I was referring to fig. 1 in this post. It seems that my English is worse than I thought :) I had read that sentence, but that sounds merely descriptive to me, kind of "there is a vertical difference compared to GRACE"... I'll check my dictionary when I'm back home this evening ;-) "If you look at anomalies the offset does not matter", unless those anomalies refer to the same reference period, isn't it? (eg. mass annomaly with reference to the 1980-1990 average) I realize I lack some education on the matter and this is just a small non-important bit in the whole post, so there's no problem if you don't feel like addressing this ;-). Thanks!
  29. Why is Greenland's ice loss accelerating?
    PeterPan, if you are referring to fig.1 in this post, it is stated in the caption "GRACE data is offset vertically". But anyway, if you look at anomalies the offset does not matter.
  30. The hockey stick divergence problem
    Thanks. This puts the "hide the decline" storm in a teacup into context, but isn’t it also relevant to the recent Yamal controversy that was whipped up by McIntyre? Was McIntyre simply unaware of or ignored the divergence problem? Seems to me that he did.
  31. Why is Greenland's ice loss accelerating?
    Why is there an offset of about 500 Gt between GRACE and van den Broeke et al 2009? To my unskilled view it would suggest that van den Broeke 2009 confirms the GRACE trend but not the amount of ice loss(?). Or is it shown this way just for clarity? Thanks! John, your great site is improving one post to the other. I think this is currently the best online resource on climate change for the lay public. Congrats and thank you!
  32. The hockey stick divergence problem
    I think the point here is that we should treat the data with appropriate caution but not throw it out altogether. If the pre-1880 data turns out to be consistent with proxies from other, completely independent methods (sediments / ice cores / whatever) then that should increase our confidence in the data (it would be unlikely that different proxies are wrong in the same way, at the same time, to the same degree). I think some people would like to just reject all proxy data and say we can't ever know anything about past climate, and therefore can't infer anything about the significance of current changes. The way to deal with such data is not to reject it out of hand but to publish it and make it open to challenge in the scientific literature.
  33. The hockey stick divergence problem
    Tree rings wouldn't be the first proxy thermometer doing something else than being the instrument we thought it was.
  34. Was there a Medieval Warm Period?
    Those of you interested in temperature reconstructions might want to take a look at this recent review I happened to notice.
  35. Water vapor is the most powerful greenhouse gas
    I really don'y buy the positive feedback model of water vapor. All positive feedback loops are unstable. The planet should have gone wildly hot millions of years ago in a positive feedback model. We have to conclude that water is in a negative feedback loop, either alone, as from the reflection of clouds alone, or in concert with other elements.
  36. The hockey stick divergence problem
    You would think drought conditions just might have accompanied warming periods in the past, (whether anthropogenic or not). Maybe all that is happening here is the discovery that the interpretation of tree ring data is not as simple as previously believed.
  37. The hockey stick divergence problem
    WAG I'm not sure what has been killed. Couple of quotes from Briffa 1998 "It seems clear that a major, wide-scale change has occurred in the ecology of Northern Hemisphere tree-growth and temperature. As yet, the cause is not understood, but a number of factors such as increasing atmospheric CO2, higher levels of pollutant (i.e. nitrates or phosphates) transport, other changes in soil chemistry or increased UV-B levels might be involved. There is also evidence that increasing atmospheric opacity has resulted in a notable reduction in the amount of solar radiation reaching the earth's surface since the middle of this century (Bradley & Jones 1992). Several factors could be acting together, and possibly interacting with changes in climate itself." And from the Q+A session at the end "K. R. BRIFFA. At this time, we do not know why maximum late-wood density declines in relation to large-scale changes (recent warming) in temperature." There are many possible explanations/suggestions put forward to explain the "divergence problem" but there appears no nailed explanation for it. In most cases the sorts of work that is required plant physiology, field ecology (as well as climatology) is not done by dendrochronologists. Until this sort of work is done it can only ever be speculation. In fact Briffa 1998 lists many possible factor this appears to be speculation (I count nine if you include ones in the first quote). "potential factors such as changing CO2, O3, and UV-B levels, and widely experienced alterations in the other atmospheric and soil balances, must be considered" "higher nitrate levels or perhaps tropospheric ozone"
  38. Was there a Medieval Warm Period?
    Truthseeker, re #50. You are being sarcastic, right?
  39. What do the hacked CRU emails tell us?
    Imo the use of the word skeptic in this context is misplaced. "skeptic" is a word that I find ambiguous. Skeptic toward science is not the same as being skeptic with in science, in where we associate skepticism with being rational as contrasted to a meaning of irrationality or ignornace. In the rational meaning all scientist are skeptics, even to their own ideas. What you describe/define I would not call skeptic, but dogmatic denial or irrational thinking.
    Response: We could get in the whole argument about whether global warming skeptics should be labelled skeptic, denier, denialist, etc. But that just gets us off the science. So I'll concede the term 'skeptic' if it allows us to discuss real issues and not get in an argument on what we should be calling each other (never a constructive topic).
  40. The hockey stick divergence problem
    Once again, John Cook kills it. If only every skeptic read Skeptical Science.
  41. Was there a Medieval Warm Period?
    Why do you post Mann and not Baliunas and Soon were authors of excellent work confirming the existence of the Medieval Warm Period (MWP) from a multitude of sources?
  42. The hockey stick divergence problem
    As I read it, John Cook did not conclude that the origin of divergence is anthropogenic. It's one possible explanation, as reported in the litterature. For the same reason you can not conclude that "tree ring proxies are not reliable during warmer periods". Here you're assuming that the problem is temperature; again, it's just a possible explanation. Also, you should consider that not all the trees in all locations show divergence, so you should have specified (like D'Arrigo did) tree rings affected by divergence. But whatever the reason of divergence is, if the reconstruction of MWP gives a temperature lower than the '60 of last century (or whenever divergence starts), there's no reason of concern.
  43. What do the hacked CRU emails tell us?
    I think this is the "divergence problem" John is refering to (hint: it's not a divergence problem): http://www.climateaudit.org/?p=7844
  44. The hockey stick divergence problem
    Just to add to my comments above, here is a quote from the D'Arrigo 2008 paper: "For example, reconstructions based on northern tree-ring data impacted by divergence cannot be used to directly compare past natural warm periods (notably, the MWP) with recent 20th century warming, making it more difficult to state unequivocally that the recent warming is unprecedented."
  45. The physical realities of global warming
    Or maybe CRU got their data from NOAA; I can't remember. Anyway, the organization from which CRU got their data still has those data, and anybody wanting those data need to ask those originators. You'd think skeptics would want to go to the original sources anyway, since apparently they don't trust CRU.
  46. The hockey stick divergence problem
    The only thing one can conclude from the verifiable, recent tree ring record is that tree ring proxies are not reliable during warmer periods, including possibly the MWP. This means that graps like Mann et al 1998 are not reliable indicators of T in eg the MWP. You can't conclude the cause of the decline is anthropogenic, either from Briffka 1998, or Cook 2004, as there is not enough reliable data to make a comparison prior to 1200 AD (most of the MWP) in Cook 2004 with the post 1960 records, and none in Briffka 1998 prior to 1880 to make a comparison with post 1960 records. Your inferance that the cause is anthropogenic does not come from tree ring science.
  47. The physical realities of global warming
    TruthSeeker, the raw data are safe and sound, and available, from the UK Meteorological Office that compiled the data set in the first place. CRU is merely one consumer of those data, and is prohibited by the Met Office from distributing the raw data anyway. That's the restriction that the Met Office places on all people/organizations to whom it gives those data. The Met Office's agreement is posted somewhere in the comments on one of the RealClimate threads, but I can't find it right now.
  48. The physical realities of global warming
    SNRatio I appreciate your suggestions, they are quality. I intend to take action on them. Along those lines, what are your thoughts that the CRU destroyed the raw data, it tends to undermine my or anyone else ability to really check into this?
  49. The hockey stick divergence problem
    Humanity, correct me if I am wrong, but are the papers to which you refer documenting the increase in NDVI over the Boreal Tundra? The Tundra has indeed greened in response to warmer temperatures and longer growing seasons, but the cores were not sourced from the tundra were they? The Nemani paper shows that growth in northern Eurasia seems to be primarily limited by energy/insolation-- so global dimming would likely have an impact there. Nemani et al's Fig 1 does show an increase in VPD which would decrease stomatal aperture (increase canopy resistance) which would reduce gross photosynthesis-- so it is perplexing that the NPP there has allegedly increased. Their Fig. 1C shows that N. Eurasia has cooled somewhat between 1982 and 1999. So this is clearly a complex problem. Fortunately, we have more reliable proxies for global temperature. Soil moisture is a limiting factor for tree growth. What is critical is whether or not the regional climate is such that water stress is an issue, certain regions are obviously more prone to frequent drought than others. In fact, you probably know that scientists also use dendrology data as a proxy for drought. That said, how do we know that historical regional droughts did not affect the tree growth in the past? Anyhow, I'm clearly not an expert, but perhaps someone in the know or John could address these issues. Thanks.
  50. CO2 is not the only driver of climate
    "The electrical power (Sun) heats the Microprocessor (Earth) just like the Sun heats the Earth." Gord, have you ever been wondering of the purpose of cooling paste put between a heat sink and the object which is to be cooled?

Prev  2516  2517  2518  2519  2520  2521  2522  2523  2524  2525  2526  2527  2528  2529  2530  2531  Next


The Consensus Project Website

THE ESCALATOR

(free to republish)


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