RealClimate logo

Unforced Variations: March 2012

Filed under: — group @ 1 March 2012

This month’s open thread – for appetizers we have: William Nordhaus’s extremely impressive debunking in the NY Review of Books of the WSJ 16 letter and public polling on the issue of climate change. Over to you…

617 Responses to “Unforced Variations: March 2012”

  1. 201
    MARodger says:

    Dan H @198
    That’s a strange “citation” you link to. Zero authorship, zero references, zero date & a graphic that is off-topic, it looks to me very much like an academic prospectus for a MIT CGCS research programme. And as a prospectus, it’s a pretty vague account. That makes it little more than somebody’s wish list.
    Perhaps if you examine the publications that CGCS so helpfully list out, you might be able to find a proper “citation.”

  2. 202
    Rattus Norvegicus says:

    And Hank, one must remember that the group being cited is Lindzen’s group. Maybe not the best source. I also question the statement about observations — I was under the impression that we currently are unable to diagnose the sign of the cloud feedback from the observations.

  3. 203
    Ray Ladbury says:

    Simon Abingdon: “You can’t keep a corpse warm with a blanket.”

    Well, then I guess all your zombee arguments will have to resign themselves to the cold.

    Oh, and Simon. You’re wrong. It all depends on the relative temperature of the corpse and the environment.

  4. 204
    R. W. Gort says:

    At least in the USA the record of science denial is very grim. The Gallup poll has numbers online that show how consistently, for decades, a large chunk of the American public has said that they don’t believe in evolution and that another large chunk believe evolution is guided by God to make sure humans are the top animal (my sarcastic wording).

  5. 205
    t_p_hamilton says:

    Dan H:”Yes, clouds help keep nights warmer. They also help to keep days cooler. These are separate from the albedo effect.”

    Clouds have albedo!

    And no, the change in clouds and the resulting forcing is not known.

  6. 206
    dbostrom says:

    Simon Abingdon: “You can’t keep a corpse warm with a blanket.”

    But you can fool the coroner.

  7. 207
    David B. Benson says:

    vukcevic @186 — Granger causality runs from global temperature to the AMO.

  8. 208

    #197 Dan H.

    That’s why scientists measure these things including physics and observations.

    It’s not a guessing game, as you might think.

  9. 209
    Hank Roberts says:

    > the group being cited is Lindzen’s group.

    D’oh. Missed that. Dan H. is a very clever guy at what he does, isn’t he?

    I did search for publications for that area of research.
    None were listed at their website. I wonder what their results were?

  10. 210
    Dan H. says:

    Exactly! However, there are those who would prefer to “guess” as to what the outcomes will be without actually doing any measuring. The same people then try to rationalize why the observations and measurements are not matching their “guesses.”

  11. 211
    Dan H. says:

    Since you did not like my previous citation, here is a link to journal article which measures (local) increases in both water vapor and clouds during warming.

  12. 212

    #210 Dan H.

    Who are you talking about? Who is guessing? Certainly you can’t mean the climate science community?

    Do you know that there is a difference between what the data indicates, and a guess?

    And my all accounts, you are married to guessing. You have ignored the science in context at so many turns it is difficult to count.

    Why you are obsessed with obfuscation is a much more pertinent question.

  13. 213

    Dan, not a matter of ‘liking’ your citation or not. The question is, what did it say? The closest to a statement about cloud trends I could find–and I read the thing twice–was this:

    “In existing climate models about one third of the predicted warming due to increasing CO2 arises because of the predicted cloud changes.”

    Never says what they are, or how the warming ‘arises!’

    The second link is interesting. I don’t see that it really supports your idea that global cloud will ‘almost certainly’ increase in a warming world. The Arctic–which is what the study is about–is rather a special case due to the comings and goings of sea ice; so its applicability is questionable. Still an interesting (if tough) read, though, so thanks.

    “The major trends over time are a wintertime WVP
    and LWP increase south and southwest of Greenland also
    seen in precipitation, consistent with modification of continental
    air flowing out over increasingly warmer waters. The
    Barents and surrounding seas, site of much of the recent
    winter sea ice loss, have experienced some WVP increases
    during all four seasons and a recent winter LWP increase
    (Figures 8 and 13), despite the relaxation of the NAO index
    to more neutral values in recent years. Much of the recent
    sea ice loss is attributed to warmer sea surface temperatures
    with southerly wind anomalies a contributing cause [Francis
    and Hunter, 2007; Sorteberg and Kvingedal, 2006], with
    thermodynamic coupling leading to associated increases in
    atmospheric moisture.”

    So the sea-ice goes, the south wind blows, and you get clouds! Makes sense.

  14. 214

    Oh, I should, in quoting from the Zuidema paper, have noted that “LWP” is the term to watch: it denotes “Liquid water path,” and refers to the sensor “path.” Basically, cloud. “WVP” is, correspondingly, “water vapor path.” (Or ‘vapour,’ if you prefer.)

    [And Captcha says “path ivacywor.” Cryptic, but fortuitously apt.]

  15. 215
    simon abingdon says:

    #195 Kevin McKinney. I would like to get this straight. As I understand it the issue of whether the feedback of clouds is positive or negative has nothing whatsoever to do with the contribution clouds make to the earth’s albedo. If this is so, let me ask this simple question: what is the more dominant contributor to the earth’s albedo, the 60-70% cloud cover or the various areas of snow/ice?

  16. 216
    Mitch says:

    I am interested in comments or corrections from the readers of this blog to a talk I have written on the physics of climate change. My presentation is designed to give a lay audience a good understanding of how greenhouse gasses work, and why we know the value of climate sensitivity. My impression is that most of the explanations for the lay audience skip over a bit too much the physical arguments, leaving the audience less persuaded than they might be.

    If any of you have the time to view the video and comment I would much appreciate it. (You can leave comments at youtube.)


  17. 217
    Hank Roberts says:

    > As I understand it … If this is so …

    Whoah, there, you leaped from a misunderstanding to an assumption to an argument. That’s a debataing ploy.

    I refute it thus:

    Don’t just look for what you wish were true.

  18. 218
    t_p_hamilton says:

    Simon said:”As I understand it the issue of whether the feedback of clouds is positive or negative has nothing whatsoever to do with the contribution clouds make to the earth’s albedo.”

    It has everything to do with it. But there are other things to consider –
    greenhouse effect from cloud vapor, type of cloud, and location (height and latitude).

    ” If this is so, let me ask this simple question: what is the more dominant contributor to the earth’s albedo, the 60-70% cloud cover or the various areas of snow/ice?”

    Albedo is the fraction of incoming (visible) light reflected back upwards. The key concept is how much light gets reflected, not its fraction. The latitude affects the intensity coming in, which also affects the amount reflected.

    I suppose one could do back of the envelope calculations. The average albedo is 0.3 and the snow albedo is 0.8. The average ice area is 18 million sq km. The total surface area of the earth is 510 million sq km.
    Assume equal distribution of light (this favors ice since polar regions actually receive less light per unit area). Total reflected is 510*0.3*constants. This is equal to ice reflected 18*0.8*constants + cloud reflected. Clouds are way more important for total light reflected.

  19. 219
    simon abingdon says:

    #217, #218.

    Hank, thanks for the (intended) link. I had wrongly assumed that the term “cloud feedback” was generally used to refer exclusively to the greenhouse effect.

    tph, thanks for correcting me. I think I now have my terms right.

    Notwithstanding my confusion, tph has answered the question I asked, the bottom line being:

    “Clouds are way more important [than snow/ice] for total light reflected”.

    I find the overwhelming importance of clouds and our far from complete understanding of their consequences disquieting.

  20. 220
    MARodger says:

    Dan H @211
    You really are struggling with this one. You talk of “…(local)…” and well you might, although it is not a parethesised term I would have sneaked in so casually here. I think most would agree that the peculiarities of the (local) Arctic atmosphere are not much applicable to the vast majority of the planet mainly due to the presence of sea ice!
    Further, your talk of “increases in both water vapor and clouds during warming” is wholly misplaced. The inter-annual trends discussed are primarily due to loss of sea ice etc, not due to ‘warming’ as you assert.

    Through your inability to locate a citation to suit your needs, you are beginning to dispprove your own assertion quite convincingly.

  21. 221
    Tony Weddle says:

    I noted the WSJ response by Kevin Trenberth and others was titled, “Check With Climate Scientists for Views on Climate”. It was great up until they started to offer views on the economy: “the transition to a low-carbon economy will not only allow the world to avoid the worst risks of climate change, but could also drive decades of economic growth”. I think it’s time that climate scientists don’t offer views on the economy. This was clearly an off the cuff, unresearched, remark. Economic growth is pretty much in its death throes, for many reasons. Switching from a high quality set of energy sources to a much lower quality set is unlikely to drive economic growth for decades. We are hitting all sorts of “limits to growth” and switching energy sources isn’t going to suddenly make it all better.

    This isn’t to say that we shouldn’t decarbonise; we should. But it’s a bit more complicated that their off the cuff remark implies.

  22. 222

    #215, 218–tp hamilton I think provided a useful answer to your ‘simple question,’ Simon. But let me expand a bit on the larger point, about the relationship between albedo and cloud feedback.

    Put plainly, the albedo effect of clouds is a major component of cloud feedback. As you know, it’s a negative component–the albedo effect tends to cool. Opposing that effect is the greenhouse effect of clouds–they radiate to the surface quite a bit more powerfully than you might think–a fact first entering the scientific literature back in 1814. (I’m working on an Skeptical Science piece about that last.)

    Moreover, the net greenhouse effect of clouds can vary a lot, depending upon altitude and other factors–high, cold cloud radiates upwards less efficiently, while still intercepting radiation from below, and so tends to warm more than lower cloud. So, clouds both warm and cool, and their overall effect upon climate depends upon the balance between albedo cooling and greenhouse warming.

    It’s even tougher to figure because not only are the results affected by cloud characteristics, they are affected by insolation–most obviously, as has been pointed out above, cloud tends to warm at night, since the albedo effect isn’t in play. In the Arctic, to take an important sub-case, it’s very possible that heavy low-level cloud in June will cool, while the same cloud in early September will warm.

    So you can see that this cloud puzzle is a big, tough one. But people are gnawing away at it.

  23. 223
    Brian Dodge says:

    In Relationships between Water Vapor Path and Precipitation over the Tropical Oceans, Bretherton et al showed that although the Western Pacific warmer surface waters increased the water in the atmosphere compared to the Eastern Pacific, rainfall was lower in the Western Pacific compared to the Eastern Pacific for equal amounts of water vapor in the atmospheric column – e.g., about 10mm/day in the Western Pacific, versus ~20mm/day in the Eastern Pacific at 55mm water vapor, the peak of the distribution of water vapor amounts.

    When they compared rainfall to relative humidity, the differences between the warmer Western Pacific and cooler Eastern Pacific were much less.

    By analogy, a warmer world wouldn’t be rainier (or cloudier); it’s an imperfect analogy, because rain isn’t absolutely correlated with cloudiness, and lateral transport of energy by ocean, air, and latent heat currents in and out of the E & W Pacific Ocean areas won’t scale to global warming

    In Relative humidity changes in a warmer climate, Sherwood et al teach us that:

    “Finally, subtropical drying trends predicted from the warming alone fall well short of those observed in recent decades. While this discrepancy supports previous reports of GCMs underestimating Hadley cell expansion, our results imply that shifts alone are not a sufficient interpretation of changes.”

    “It is now widely known that the water vapor feedback in general circulation models (GCMs) is close to that which would result from a climate‐invariant distribution of relative humidity [Soden and Held, 2006], as long anticipated before the advent of such models [e.g., Arrhenius, 1896; Manabe and Wetherald, 1967].” What’s that I hear about climatology being a “young science”?-BD.

    “Thus changes in the pattern of R could directly influence that of precipitation, regardless of any impact on the global mean radiation budget.”

    “The observed drying well exceeds that predicted in any of the GCMs as a consequence of warming, even though we have not accounted for the impact of UT/LS moistening on the UTH signal. Either most of the actual drying was not caused by warming per se, or the models are all significantly underestimating a key aspect of climate change (see section 7) even though many of them are getting the spatial gradients in today’s climate about right.”

    GCM’s have underestimated (misunderestimated?) subtropical drying and Hadley Cell expansion, in addition to Arctic Sea Ice loss – take that, Texas drought!

    If you download 1998-2009 cloud cover here, and sea surface temperatures here, you can see that, except for a cloud band from ~0 to 10 degrees N, cloudiness is generally less where SST is warmer, though there are lots of details and spatial variation that lessen the correlation. Large patches N & S from the equatorial band haw lower cloudiness, and the SST falls and clouds increase as you move towards the poles. Also, cooler SST’s on the South American coast have higher cloudiness than the warm patch of SST along the Mexican coast.
    If you download cloudiness and SST from the cooler period 1950-1962 here and here, the spatial patterns are the same, but the overall cloudiness is more in the cooler period.

    Is this statistically significant? Right now, we’re in the same position as Phil Jones when he said that the warming wasn’t statistically significant. However, the data shows that cloud feedback may be positive, and is unlikely to be negative enough to keep from frying our bacon.

    The Republican denialist approach to this problem? From the ICOADS home page – “Public Notice: Termination of ICOADS Development Due to NOAA Budget Cuts”

  24. 224

    Got a question for model experts about winter near surface inversions. Do they always show them?
    Is there a variance in lapse rates incorporated or do they tend to be fairly standard?

    I have observed greater variations in Arctic Inversions lately, the tendency is towards less steep inversions,
    this is expected when the Arctic lower atmosphere warms during winter, if the models maintain a stronger inversion while its observed weakening this may explain why sea ice models fail, strong boundary layers appear to be collapsing. This is seen 2 ways, by larger high elevation sun disks during cold weather and lesser refraction diurnal variations causing sun disks to shrink less near the horizon.

    If the models capture this phenomena, I ‘ll go back to chalk board, ie the sky!

  25. 225
    Dan H. says:

    Let me ask you this: Since you think that an increase in water vapor will lead to decreased cloud cover, can you point to a citation to support your view?

    To show that this relationship is not confined to the Arctic, similar results have been found in the Amazon.

    To quote from the results, “CF [cloud fraction] and CWV [column water vapor] are understandably highly positively correlated, as water vapor is one of the principal [misspelled] components required for cloud formation.”

  26. 226

    #225–Only had time for the abstract, but will return to the paper.

    (NB–“principal”–ie., “main,” or “major”–is correct. “Principle” means something quite different–eg., “The first principle of climate modeling is. . .”)

  27. 227
    Hank Roberts says:

    Dan H. — MA didn’t say what you claim.
    He pointed out you couldn’t cite your claim.

    You assert that he argued the exact opposite of your claim.
    He didn’t do that.
    It’s not a debate.
    He pointed out your overly broad simple claim isn’t supported.
    That doesn’t mean an opposite, equally overbroad claim _is_ supported.

    You pretend he’s arguing the opposite of what you’ve been saying.
    You’re just playing with this site like it’s a video game.

  28. 228

    No comments on the YD impact thing yet? I guess that’s too hot to handle right now, better to just let that thing cool off for a while.

  29. 229
    Gordon Cutler says:

    Hank, you are one of the many here with the patience of saints. I have profited greatly through the years from your comments and explanations as well as from those of our intrepid climate scientists and all the other regulars.

    I am not nearly as mature.

    Dan H, I stopped allowing you to waste my time weeks ago and look forward to the day when I shall only find your comments in the Bore Hole; not that I’ll be checking…

  30. 230
    simon abingdon says:

    #221 Kevin McKinney. Thank you for your helpful response. However I can’t help feeling rather surprised when you finish by saying “So you can see that this cloud puzzle is a big, tough one”. I read that as saying that we don’t yet know whether the resultant feedback is going to turn out positive or negative.

    Your earlier #182 was equally disconcerting where you quoted Norris and Slingo (2009) saying “At present, it is not known whether changes in cloudiness will exacerbate, mitigate, or have little effect on the increasing global surface temperature caused by anthropogenic greenhouse radiative forcing.”

    I think that Joe Public would be quite shocked that there is still so much apparent uncertainty in such a fundamental aspect of climate science, given the huge disruption already being caused by what may turn out to be premature attempts at mitigation.

  31. 231
    t_p_hamilton says:

    Simon may or may not be seeing the problem with uncertainty:”I find the overwhelming importance of clouds and our far from complete understanding of their consequences disquieting.”

    Yes, overall change in clouds may be a positive feedback, rather than a negative feedback assumed from simple ideas like more water -> more clouds -> cooling. The “more water” is clearly seen, and the sensitivity from water vapor plus greenhouse gases is about 3 degrees C per doubling. Cloud changes have the potential to increase or decrease that number.

  32. 232
    MARodger says:

    Dan H @225
    It is as Hank Roberts @227 says, I solely criticise here the imbalance between your assertiveness and your scholarship.
    ‘Temperature/cloud albedo’ – “That is the main unanswered question in the entire debate,” is your comment @186. Of course somewhere in the process, discussion of ‘temperature/cloud albedo’ turned into discussion of the narrower ‘water vapour/cloud formation,’ which may not have been your intention. I think you now are trying to prove something that (as Ten Hoeve et al say) is quite ‘understandable’ and something that at a basic level nobody would disagree with (certainly while relative/specific humidity remains outwith the discussion).

    So we’ve nailed the Arctic after a fashion & Rondonia for three months of the year, both instances with quite extreme increases in water vapour. So where next? The Indian subcontinent in June? Or how about the tropics between 0600hrs & 1400hrs?

  33. 233
    t_p_hamilton says:

    Simon as a member of Joe Public?:”I think that Joe Public would be quite shocked that there is still so much apparent uncertainty in such a fundamental aspect of climate science, given the huge disruption already being caused by what may turn out to be premature attempts at mitigation.”

    Joe Public can’t tell good arguments from bad, good information from bad, good sources from bad. PR experts take advantage of poor Joe Public, misleading him with arguments such as science is uncertain, therefore the only risk to think of is risk of “huge disruption”. What are you doing to help Joe Public see that this argument is deceptive?

  34. 234
    dbostrom says:

    Hmm. Stepping back and looking at the big picture, observations so far seem to indicate that clouds are not kicking in to protect us to the degree necessary for us to feel entirely happy. Those of us keen on confirmation by observation should fit that into their mental models.

  35. 235
    SecularAnimist says:

    simon abingdon wrote: “given the huge disruption already being caused by what may turn out to be premature attempts at mitigation”

    What in the world are you talking about? What “huge disruption” is “already being caused”? What “premature attempts at mitigation”?

    “Joe Public” has experienced NO “disruptions” whatsoever from any “attempts” to mitigate anthropogenic global warming.

  36. 236
    SecularAnimist says:

    Tony Weddle wrote: “Switching from a high quality set of energy sources to a much lower quality set is unlikely to drive economic growth for decades.”

    What on Earth are you talking about?

    Solar and wind are a MUCH “higher quality set” of energy sources than fossil fuels. Not to mention a vastly greater set of energy sources — indeed, a limitless set of energy sources on any time scale that’s meaningful to human civilization.

  37. 237
    dbostrom says:

    Electronic Arts to bring SimCity back in 2013

    The game franchise that first defined the city-building genre in 1989 will be re-released next year as a multi-player online computer game, developed by Maxis and published by Electronic Arts Inc.

    This time, however, SimCity has an environmental theme, a la “An Inconvenient Truth,” the 2006 documentary about Al Gore’s campaign to educate the public about global warming. In SimCity, a fetish for coal burning plants in one city can spread smog and sickness in adjacent cities run by other players, for example.

    “For the first time in SimCity, players’ decisions will have consequences that will extend beyond their city limits,” said Lucy Bradshaw, senior vice president of Maxis. “It’s up to the players to decide whether to compete or collaborate to shape the world of tomorrow — for better or for worse.”

  38. 238
    Craig Nazor says:

    Dan H. has long held (in classic denier fashion) that the climate feedbacks are too uncertain to accurately constrain the climate sensitivity to the values that the IPCC has determined are the consensus opinion. He sometimes fills the conversation with minutiae and vague jargon. He posts links of varying degrees of quality that frequently don’t say what he claims that they say (but which one has to read to figure that out). He sometimes claims that his opponent has said something that they didn’t actually say, which must then be refuted, wasting time and energy. The result is confusion and delay, and that’s the point.

    Dan has yet to acknowledged is that the fossil record clearly shows that the best value of the known feedbacks, whatever their “exact” values may be, are included in the IPCC’s approximate estimate of the climate sensitivity, and that this is strongly supported by the GCMs. A very simple and straightforward explanation can be seen here:

    So Dan – with what about this lecture do you disagree? Can you state your disagreement without misquoting the source and by referencing peer-reviewed studies that actually support your opinion? Go ahead – give it a shot! But remember: at this web site, there are lots of people who can see through any BS.

  39. 239

    Well, I hope “Joe Public” wouldn’t take it amiss that difficulties (such as measuring cloud feedbacks) are honestly stated, as they have been all along. Likewise, I would also hope that Joe wouldn’t jump to the conclusion that that means we don’t have good reason to think that warming will a) continue, and b) become quite problematic for our health, wealth, and well-being in the future.

    For one, paleo-climate proxies for the present situation shed some light on the question of what might happen in the near future. They help provide a useful constraint on climate sensitivity.

  40. 240
    Martin Smith says:

    This solar storm that’s about to reach earth, it took two days for it to get here. That means the particles are traveling at much less than the speed of light. Are these particles still referred to as cosmic rays? Or, is there a speed below which a particle is just a particle?

  41. 241
    MARodger says:

    Craig Nazor @238
    …values that the IPCC has determined are the consensus opinion.” You could have strengthened this sentence by adding “.., a consensus branded “alarmist” by Dan H who considers the IPCC as being unrepresentitive of most scientists.

  42. 242
    Martin Vermeer says:

    Simon says #230

    > … what may turn out to be premature attempts at mitigation

    My link. They’ll never forgive the scientists for being right

  43. 243
    Ray Ladbury says:

    Martin Smith,
    We generally refer to the particles from the Sun as “solar particles,” or solar-event particles, while the flux of extremely high-energy particles from outsde the solar system are referred to as “galactic cosmic rays” (GCR). Solar event particles tend to be much lower in energy, and both particle type and energy of the particles varies considerably from one event to another.

  44. 244
    Dan H. says:

    I tend to dismiss those who people call alarmists or deniers, because their views tend to be outside the views of most scientists; however I did listen to the entire video.

    There was little presentation on climate sensitivity, except to mention that weak solar changes can result in a large CO2 feedback loop that can enhance temperature increases. We have already mentioned recent paleo work which estimates long term climate sensitivity to be ~2.3, with a range from 1.6 – 3.0. This was discussed at length last fall, referencing other studies which calculated both higher and lower ranges.

    The only specific with which I would disagree is his claim of accelerating sea level rise, which could reach 5m this century. The current rate of SLR would yield less than 0.3m of rise by 2100, and has shown a slight deceleration recently.

    Hansen talks repeatedly about “deniers” who would dismiss the fact that CO2 is a greenhouse gas, which causes planetary warming. His implications is that there are two groups of people; those that think the climate sensitivity is near zero, and those who think it is 3+! He appears to neglect an entire group of scientists in between. I tend to agree most closely with the APS statement of 1-3C / doubling, although I fell that this is too constraining. With the uncertainty in clouds and surface albedo, I would add another 0.5 to each end.

    You must remember that the IPCC values are only the consensus opinion of the IPCC, and not the greater scientific community.

    A recent survey by the AMS found that 52% of respondents thought that human activity was mostly to blame for global warming. While 15% though it was all natural or equally manmade and natural, 25% were uncertain about the cause or if warming has occurred.

  45. 245
  46. 246
    flxible says:

    “You must remember that the IPCC values are only the consensus opinion of the IPCC, and not the greater scientific community.”
    HUH?? Please explain the difference between the IPCC and “the greater scientific community”.

  47. 247
    SecularAnimist says:

    Dan H wrote: “… the IPCC values are only the consensus opinion of the IPCC …”

    Can your clumsy lies about the IPCC have any purpose except to amuse yourself with your ability to annoy people?

  48. 248

    A recent survey by the AMS found

    Scientific insight doesn’t come from surveys, and consensus is meaningless to people who have already made up their minds, and are never going to change it.

  49. 249
    Hank Roberts says:

    Guys, you’re asking Dan H. to keep posting stuff now.
    He’s succeeded, when he has an audience asking for more.
    He’s posted a 2nd order polynomial trend
    — without linking to the source
    — without attaching any explanation;

    it’s more bait for responses, quite typical of him.

    The caption suggests it’s a fairly old file from here:

    Their explanations might be worth a look.

    If you ask him for more, he’ll give you more.
    Of the same.

  50. 250
    Hank Roberts says:

    Ack, Dan H. is doing a Wegman/Lindzen now, the stuff he’s posting isn’t even his own work and he hides the source he took it from — because it’s bad info.
    Looks like he got it from a tricky chart somebody posted in a comment thread

    Next mole, please.