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  1584  1585  1586  1587  1588  1589  1590  1591  1592  1593  1594  1595  1596  1597  1598  1599  Next

Comments 79551 to 79600:

  1. The Medieval Warm(ish) Period In Pictures
    Sphaerica @20, Good points. And let us not forget this: Comparison of temperature reconstructions, re-centered to match CRUTEM NH land record (based on each reconstruction's period of overlap). [Source]
  2. Rob Painting at 07:28 AM on 12 July 2011
    The Medieval Warm(ish) Period In Pictures
    Eric Red - "The MWP has been acknowledged as the last period of globally warm temperatures (not just NH as claimed above). The global temperature anomalies are similar to today" So you comment without actually reading the post? How can global temperature anomalies be similar to modern-day when North American glaciers were growing in the MWP?, and when the central and eastern tropical Pacific was much cooler than the 1961-1990 reference period?
  3. Ocean acidification: Coming soon
    Camburn: Since we have not heard otherwise, we trust you have found the explanations thus far to be sufficiently robust to satisfy your expectations.
  4. Bob Lacatena at 07:16 AM on 12 July 2011
    The Medieval Warm(ish) Period In Pictures
    18, Eric the Red, First, did you actually look at the papers you linked to? The last, Kellerhals et al, shows current temps substantially higher than the MWP. The first, Cook, shows the MWP to be a fractionally present bump not much greater than other temps in the period, and also much lower than current temps. So what exactly are you trying to prove? And even if you found 3 proxy studies that show what you want, you're missing both points. The first is that that is mere cherry picking. A careful analysis of the data shows that warming that is supposedly the MWP is not contemporaneous... one study shows a peak in 1100, another 1300, another 950. It's also not nearly uniform around the globe. While one study shows a warm period here, another location at that same time shows cooling. There is no doubt that there was a MCA, but there is no evidence that it was global, substantial evidence that it was not, and substantial evidence (as you have so kindly provided yourself) that temperatures even regionally did not match those of modern times. Beyond this, you missed the other main points, which are first that whether there was a MWP or not, it does not change the radiative physics which clearly show we are causing greenhouse gas warming now, and if there was a MWP, and it was as warm as temperatures are now, then climate sensitivity is high and your constant admonishment that you are sure that climate sensitivity is likely to be below 2C goes out the window.
  5. Trenberth on Tracking Earth’s energy: A key to climate variability and change
    Hansen claims to have resolved the issue with the "missing heat"(e.g. fig 19) in a draft paper. Does any expert here have a simple summary of the difference between Hansen's and Trenberth's approaches?
  6. 2010 - 2011: Earth's most extreme weather since 1816?
    EricRed @327, You, like Norman, seem intent on missing the point entirely-- I even bolded the text @326 and reproduced the figure from Trapp et al. (2007). You somehow missed this from my post @ 326: "You are conflating the more subtle changes by month or by seasons with the quite drastic changes observe during the course of the spring and summer (March-August). This is similar to stating that most locations experience marked temperature changes between winter and summer each year, so a few degrees of AGW is nothing to be concerned about. The studies I am referring (see Trapp et al. 2007 kindly provided by Tom Curtis here) to look at the changes between the mean MAM (March, April, May) conditions for 1962-1989 and how mean MAM conditions might look in the future, 2072–2099." They are comparing apples with apples, you are not. You and Norman are in fact hopelessly confused on this. Also, it is obvious that you have either not read Trapp et al. (2007, 2009), or you did read it but are incapable of following the science (and there is no shame in that, we can't all be experts at everything or even most things). I'll give you the same advice that I gave Norman: "I urge you to read Trapp et al. (2007) and Trapp et al. (2009)in their entirety." Otherwise it is very clear that you are pontificating and talking through your hat, and I have no intention of wasting any more of my time arguing in circles with you either. You both keep repeating the same incorrect notions, sadly that doesn't make them any more correct or real. PS: In retrospect asking you to read the paper when you are not an expert in the field and have preconceived ideas may not help. then again, Tom Curtis is not an expert in this field, yet he managed to correctly interpret the science in the papers. PPS: The point of me quoting Schaefer and Edwards was to demonstrate that Norman had not accurately reflected their findings.
  7. 2010 - 2011: Earth's most extreme weather since 1816?
    Norman at 16:03 PM on 9 July, 2011 You say "I am reading the articles you link to (mostly abstracts). They are predictions based upon their models about what will take place. They seem to assume the lapse rate will stay the same and the warmer wetter air will have more energy to generate more intense storms. I do not understand the logic they used to arrive at that conclusion. That is part of what I am questioning." Actually, Tom Curtis provided you links to two of the seminal papers, not just abstracts. This glib dismissal of the science based on your incorrect and incomplete understanding of the science left me speechless. They did not "assume the lapse rate will stay the same", your claim in this regard is demonstrably false (see below), yet it seems to be your reason for dismissing their findings as you then go on to argue the strawman that you created. This is nonsense Norman. In fact, your whole premise for creating your argument about lapse rates just shows how out of your depth you are and how little you understand the science-- in fact, so confuse dis your reasoning that I had a hard time figuring out what you were trying to say. You also seem to be confusing meridional gradients with vertical temperature gradients (i.e., lapse rates), are far too focused on the role of differential temperature advection in creating steep lapse rates (forgetting the role of the Mexican plateau and strong diabatic heating in generating steep lapse rates over the southern Great Plains, for example) and under the misconception that Arctic air is somehow stored in the upper-levels of the troposphere. Yet, you seem to feel compelled to argue the experts in this field and dismiss their findings equipped only with your preconceived and misguided notions and Google. From Trapp et al. (2007): "The two quantitative measures of CAPE and S06 were computed at each model grid point, for each day during the RF and A2 periods, using the RegCM3 output at 00 UTC." To calculate CAPE they used the vertical profiles of temperature (the RegCM3 model has 18 levels in the vertical), which would by default include information about the vertical lapse rates. The profiles were not constant, nor were the lapse rates. From Marsh et al. (2009): "The atmospheric portion of the CCSM3, the Community Atmospheric Model 3 (CAM3), is a spectral model with 85- wavenumber triangular truncation (approximately 1.4° at the equator) in the horizontal with 26 terrain-following hybrid levels in the vertical. The numerical scheme used in the CAM3 is an Eulerian spectral transform with semi-Langrangian tracer transport and semi-implicit leapfrog time stepping (Collins et al., 2006). CAM3's vertical resolution contains 4 levels below 850 hPa and 13 levels above 200 hPa (topmost being 2.2 hPa)." Again, the temperature profiles were not constant/specified. Again, any changes in the lapse rates would be reflected in the CAPE values. Please do not respond to me Norman, I and others have wasted hours of our lives drafting these posts and trying to explain the science to you, all to no avail it seems. I'm done here. PS: I have no idea what compels people to think that climate science and complex issue such as severe storms are an open house to speculation and 'debunking'; that equipped with Google and their misguided and shallow understanding that the science and physics can be dimissed or overthrown. It is infuriating to say the least. I am pretty well educated, yet have no intent or drive to argue with an engineer or oncologist that they have gotten something wrong because I happen to think differently, or because a result is not intuitive to me (nor should it be, I am not an expert in that field) and have access to Google. So it blows my mind to see self-professed 'skeptics' on the internet passionately arguing the physics and science on all aspects on climate science (oceanography, radiative transfer, physics, modelling etc.). Worse yet, when presented with the physics and facts, they then contort all kinds of excuses to dismiss them rather than using it as an opportunity to learn.
  8. Climate Solutions by Rob Painting
    Trueofvoice - central heating and double glazing are rare. Insulation levels are low (estimated that 600,000 home are uninsulated period in a country of 4m). Talking to visitors, we do indeed live differently, wearing warmer clothes. However, except in Central Otago and mid North Island, it doesnt get that cold. Winter frosts except in upper quarter yes, but seldom below zero. Normally people heat one or two rooms (wood burners often, but heat pumps are making a big impact).
  9. Trenberth on Tracking Earth’s energy: A key to climate variability and change
    Muoncounter #3: If there is an increase in the net energy budget, then either more energy is coming in or less is going out. If it's not the sun, then doesn't that leave either albedo (changing the absorption of incoming radiation) or greenhouse effect (changing the outgoing radiation)? What else is there? The change in figure 4a is not small: The difference in net energy flux from 2000 to 2009 in figure 4a is nearly 1W/m^2, and half of that in the last 2 years. That's equivalent to adding ~80ppm of CO2! Can weather cause fluctuations that big, or is it change in natural or anthropogenic forcing?
  10. Eric the Red at 06:05 AM on 12 July 2011
    2010 - 2011: Earth's most extreme weather since 1816?
    Albatross, Your last two paragraphs above seem to be saying the same thing, rather than being contrasting. In fact, if you eliminate April from the first paragraph and wind from the second, they are the same. If May becomes similar to July, then severe storms should diminish in May and June, with July and August diminishing further.
  11. SkS Weekly Digest #6
    EDITORS ATTENTION NEEDED! The link in your "News Bites" section that says "Climate Change May Pose Biggest Security Threat" does not go to the correct URL. Instead of linking to the intended article, it links to a Skeptical Science blog-editing page which needs an administrative password.
    Response:

    [dana1981] Thanks to you and Byron Smith for the correction.  Link fixed.

  12. 2010 - 2011: Earth's most extreme weather since 1816?
    #314 Norman at 14:59 PM on 9 July, 2011 You ask "The question to you would be why do severe storms diminish in July and August even though that air is the warmest and contains the most amount of water vapor (fuel for storms)?" Norman, you may not realize it but your question is quite ridiculous in the context of what the research shows and int he context of what I said-- your question makes no sense in relation to what I said. You are conflating the more subtle changes by month or by seasons with the quite drastic changes observe during the course of the spring and summer (March-August). This is similar to stating that most locations experience marked temperature changes between winter and summer each year, so a few degrees of AGW is nothing to be concerned about. The studies I am referring (see Trapp et al. 2007 kindly provided by Tom Curtis here) to look at the changes between the mean MAM (March, April, May) conditions for 1962-1989 and how mean MAM conditions might look in the future, 2072–2099. I urge you to read Trapp et al. (2007) and Trapp et al. (2009) in their entirety. They are not talking about the "new May" becoming similar to the present July, for example. One has to compare apples with apples. This is a very important point, and one that you repeatedly keep on missing. I do not know whether this is intentional on your part, or simply because you are so far out of your depth on this complex issue. Marsh et al. (2009) made similar findings for Europe concerning the potential for an increase in severe thunderstorm episodes over Europe. They found that: "Preliminary comparisons of the CCSM3's 21st century simulation under the IPCC's A2 emissions scenario to the 20th century simulation indicated a slight increase in mean CAPE in the cool season and a slight decrease in the warm season and little change in mean wind shear. However, there was a small increase in favorable severe environments for most locations resulting from an increase in the joint occurrence of high CAPE and high deep layer shear." They add that: "At best, one can say that the CCSM3 predicts the number of favorable severe environments will increase in a future characterized by anthropogenic warming." You say "In the United States the most severe storms occur April, May, June and diminish in July and August (tornadoes, hail, rain, lightning)" Funny how we can look at the same graphs and arrive at different conclusions. According to the database compiled by Schaefer and Edwards, they say "May and June are the peak months for the occurrence of tornadoes and large hail. In contrast, July and June are the top months for wind storms." April and July are the next highest for all tornadoes, respectively.
  13. A Detailed Look at Renewable Baseload Energy
    CBDunkerson #264
    Thus, a 20% efficient panel would indeed generate an average of about 200 W/m^2 (more nearer the equator / less nearer the poles)... when the Sun was shining.
    Well, it's average performance that counts. So what concerns us is this: 20% x 250 = 50W/m2 Slighly less idealised: 15% x 200 = 30W/m2 MacKay gives a real-world estimate for CSP of 15W/m2. I think he's right, as efficiency will no doubt rise over time. However, current real-world plant power density is even lower than assumed above. There are a number of reasons for this. Here are some real-world numbers:
    Europe’s first commercial solar tower, PS (Planta Solar) 10, completed by Abengoa Solar in Sanlúcar la Mayor in 2007, is rated at 11 MWp. With annual generation of 24.3 GWh (87.5 TJ, 2.77 MW), its capacity factor is 25%. Its heliostats occupy 74,880 m2 (624 x 120 m2), and the entire site claims about 65ha; the facility’s power density is thus about 37 W/m2 factoring in the area taken up by the heliostats alone, and a bit more than 4 W/m2 if the entire area is considered. PS20 (completed in 2009) is nearly twice the size (20 MWp; 48.6 GWh or 175 TJ/year at average power of 5.55 MW and capacity factor of nearly 28%). Its mirrors occupy 150,600 m2 and hence the project’s heliostat power density is, at 36.85 W/m2, identical to that of PS10 but, with its entire site covering about 90 ha, its overall power density is higher at about 6 W/m2. Bright Source Energy’s proposed Ivanpah CSP in San Bernardino, CA should have an eventual rating of 1.3 GWp and it is expected to generate 1.08 TWh (3.88 PJ) a year and deliver on the average 123.3 MW with a capacity factor of just 9.5%. Heliostat area should be 229.6 ha and the entire site claim is 1645 ha. This implies power densities of 53.75 W/m2 for the heliostats and 7.5 W/m2 for the entire site. Again, no stunning improvements of these rates are expected any time soon and hence it is safe to conclude that optimally located CSP plants will operate with power densities of 35-55 W/m2 of their large heliostat fields and with rates no higher than 10 W/m2 of their entire site area.
    So, again but with 10W/m*2: 10,000km2 = 100GW 100,000km2 = 1TW 2,300,000km2 = 23TW Smil's examination of the impact of packing factor on installation footprint finds the following energy densities for SPV plant: Olmedilla 85 GWh/year = 9.7 MW 9.7 MW/108 ha = 9 W/m2 Moura 88 GWh/year = 10 MW 10 MW/130 ha = 7.7 W/m2 Waldpolenz 40 GWh/year = 4.56 MW 4.56 MW/110 ha = 4.1 W/m2
  14. actually thoughtful at 03:47 AM on 12 July 2011
    Climate Solutions by Rob Painting
    John Russell - awesome list. Where do you live? _________________________ In the discussion so far regarding personal vs political, I haven't seen any explicit statement that we all are, personally, political. When elections roll around and a politician puts forward a pro-PV plan; my neighbor the extreme right winger (with the PV panels) is going to be able to give the politician a serious look - afterall - PV CAN'T be crazy if my right wing neighbor ALREADY has it, right? Personal action changes each of us, in small to large ways (I think John Russell and Ranyl said as much in their posts of relatively major changes in how the power their lives). Change people = a changed electorate. Which changes policies. I would enjoy living in a world where rational policies are chosen for rational reasons. But I am stuck on this one. The strategy of "do the science and policy makers will grasp the severity of the situation and act pro-actively to save humanity from the very dire outcomes currently anticipated" has FAILED. It is not happening (I am somewhat US centric, but the US is still the worst offender on a per capita basis, so it is hopefully an OK centricsm). What is the next plan? Gorilla action. Because personal action also changes those around you. A rudimentary understanding of the Operating System of humanity is necessary here - we are sheeple. We DO look to see what so-and-so is doing. The strategy is to dramatically increase the percentage of so-and-sos who have taken action (preferably visible action that you brag about endlessly). As near as I can tell, this is the best/fastest path to changing the current ruinous path that we are on. Also, there is much talk about achieving grid parity for PV and wind. And it is well known that PV efficiency increases as a function of installed capacity (not that the installation increases the efficiency mind you). So those that are taking action now are literally priming the pump for the zero carbon economy (and it is necessary to overcome the chorus of naysayers (some of whom are relatively well-meaning)). Sheeple - its not a bug, its a feature.
  15. CO2 has a short residence time
    The theoretical estimation of adjustment time (vs. residence time) is being done by measuring or estimating the various rates in the carbon cycle box models. The derived growth rates are quite small, compared to the measured (or estimated) flows into and out of many of the boxes. This means that the derived adjustment time depends on accurately knowing a small difference between large numbers. As a result, the adjustment (or relaxation) time is known (from box models) with a much greater uncertainty than the larger flows are known. It is easy to do some numerical experiments with a calculator to convince yourself of this, if you haven't already been exposed to it via measurement statistics. A much better solution is to actually measure the relaxation time of CO2 in the atmosphere. Conveniently, this has been done by several of the peer-reviewed studies in the [snip] link given by poster #1, Tom Dayton. The studies I’m referring to used radioactive carbon-14 as a tracer. Prior to WWII, C14 was essentially in equilibrium with C12 in the environment, in all those ‘boxes’ that have significant in and out flows. (This is why carbon14 dating works – when something dies, the exchange stops and the C14 slowly decays radioactively with a 5000 year half life. The resulting drop in C14 concentration is therefore an indication of the date of death.) Between 1945 and 1964, the human race injected a relatively large amount of C14 into the atmosphere via the atmospheric explosion of atomic bombs. The Atmospheric Test Ban treaty of 1964 put an abrupt stop to this injection. The decay of atmospheric C14 concentration since then is a direct measurement of the relaxation (e.g., adjustment) time for CO2 in the atmosphere. (Since most bomb tests were in the Northern Hemisphere, it also gives us a measurement of the mixing time between hemispheres -- about 2-3 years.) The results, which can be seen on Wikipedia’s Carbon-14 page, is that the CO2 adjustment time in the atmosphere is ~10-12 years (stated as a half-life). Compare the plot shown on this page with the theoretical plots (from box models) posted by Dikran Marsupial @ 93. If you want to dispute this, you shouldn’t argue with me about it, but rather the thousands of scientists and engineers (and published papers) that use the well known and tested method of tracer measurement. (Google "tracer" and "measurement" for a huge list -- start anywhere you like.)
    Moderator Response: [Dikran Marsupial] minor edit (as discussed with author)
  16. 2010 - 2011: Earth's most extreme weather since 1816?
    Norman @313, Regarding the myths--well myth may be too strong a word, perhaps misconception is more appropriate. You say "Ice is not deposited on hailstones to make them grow." While hail growth from the accretion (interception) of supercooled droplets is very important, the hail growth equations also allow for the growth of hail by intercepting ice crystals. This is especially effective during wet growth when collection efficiencies of ice onto the wet surface is quite high, but is less effective during dry growth when the collection efficiency for ice is very low. Anyhow, the first common misconception that I was referring to are that hailstones grow to large sized by "clumping together". While this may happen on rare occasions, it is certainly not the norm. This misunderstanding probably arises because of images like this (of the largest hailstone on record in the USA): Those nodes/knobs can be simulated without having to allow for hailstones "clumping together" (e.g., Lozowski et al. 1991"). They can also form when a gyrating hailstone undergoes melting (e.g., Lesins and List 1986) . The second misconception that I was referring to was that the layer son a hailstone form because the stone grows by undertaking repeated cycling through the updraft. Research has shown that this, while again is certainly possible, is not the norm. According to a meta analysis of Knight and Knight (2001)[Chpt. 6 in "Severe Convective Storms"]: "The trajectories themselves, however, are usually quite simple, given embryos to start with: single, up-and-down paths though and around the main updraft. Recycling paths are found, but not very often, and when recycling trajectories are found the decision of what part belongs to the embryo stage can be quite arbitrary" And "...they [hailstone layers] do not carry a message of drastic, repeated vertical excursions, but if anything the opposite: of relatively simple growth trajectories, often with most of the growth within a fairly narrow altitude and temperature ranges.
  17. A Detailed Look at Renewable Baseload Energy
    CBDunkerson "PS: 200 * 20% = 40. Not 20. " Whoops. Thank you.
  18. A Detailed Look at Renewable Baseload Energy
    Two different surface insolation values are being cited in the 'discussion' above. The 'correct' values are: 1000 W/m^2 is the global average insolation under full sunlight 250 W/m^2 is the global average 24 hour insolation... including morning, afternoon, night, cloud cover, et cetera. Thus, a 20% efficient panel would indeed generate an average of about 200 W/m^2 (more nearer the equator / less nearer the poles)... when the Sun was shining. The lower values (50 W/m^2 in this case) come from averaging that power generation over a 24 hour day... even night, when the generation is obviously near 0%. PS: 200 * 20% = 40. Not 20.
  19. A Detailed Look at Renewable Baseload Energy
    Tom I appeal for clarity and reason:
    So, and most emphatically, the 0.2 KW was not simply drawn from nowhere. It was calculated by multiplying the expected insolation by an efficiency factor. You may want to argue that 20% efficiency is to high, but it is not 100% efficiency. LAGI do not use a 200 Watt insolation value (which they give as 1000 W/m^2), and they do not omitting the panel conversion efficiency (which they give as 20%).
    - Of course the 200W/m2 (0.2kW/m2) was not 'drawn from nowhere'. I have repeatedly said that it is a fair estimate for average surface insolation for low latitude desert locations. - Here (again) is a table which shows why I would say this. Look at the values for average sunshine in W/m2. - Now, please show me where LAGI uses the necessary additional technology conversion factor - At the same time it will be trivial to show me that LAGI did not use 200W/m2 as the basis for the rest of its calculation, which would of course invalidate its estimate No more insulting language, no more straying away to other matters. I want your point-for-point response to this with full workings for any additional calculations you use.
  20. A Detailed Look at Renewable Baseload Energy
    BBD @257: From LAGI:
    "Using 70% as the average sunshine days per year (large parts of the world like upper Africa and the Arabian peninsula see 90-95% – so this number is more than fair), we can say that there will be 250 sun days per year at 8 hours of daylight on average. That’s 2,000 hours per year of direct sunlight."
    2000 hours times 1000 Watts/m^2 equals 2,000,000 * 60 * 60 = 7.2 billion Joules/m^2 per annum of insolation. 7.2 billion Joules over one year = 7,200,000,000 / (365.25 * 24 * 60 * 60) = 228 W/m^2 averaged over the year. So LAGI plainly take into account the average rate of insolation, but they do so by direct calculation rather than taking an initially averaged value for insolation. Of course, we already knew this because we had a direct comparison between the LAGI figures for insolation and those for Andasol from 247 above:
    "4) LAGI quote a thousand Watts of direct sunlight for 2,000 hours (23%) of the year for a total of 2,000 kWh/m^2 of direct sunlight per annum. For comparison, the Andersol plants experience per annum from 2,136 kWh/m^2 per annum in the south of Spain, so again the LAGI figures are conservative with areas in North Africa likely to experience much more both because of higher solar intensity and fewer cloud days."
    That's right, LAGI's figures for direct insolation are 6% less than those achieved at Andasol in the South of Spain, even though many of the LAGI sites are located in regions achieving 16% or more greater annual insolation than the south of Spain. Of course, when I say "we knew this" I am excluding those who are unable to comprehend more than one paragraph at a time of a viewpoint they disagree with, and who continuously quote out of context to try and give substance to arguments that are, in the end nothing but dogmatism. ( -Snip- )
    Response:

    [DB] Everyone, please take a deep breath and try to keep the emotions out of the discussion.  I know that's hard, as that's why I moderate instead of engaging as participant (I often end up deleting my own comments on those occasions I get caught into a discussion). 

    Letting others knock us off our "A" game only detracts from the quality of the dialogue.

  21. Trenberth on Tracking Earth’s energy: A key to climate variability and change
    #2 Kevin C: "I presume the difference is either a change in albedo and/or a reduction in OLR." Why do you presume? If there is evidence for either, what is it?
  22. A Detailed Look at Renewable Baseload Energy
    KR ( -Snip-):
    Now - taking a look at PV power plants, which can attain fill factors approaching 100%, we're looking at 150 W/m^2 for a 15% efficient PV system. So - your 15 W/m^2 is low to start with, by almost an order of magnitude.
    If surface insolation at the site is 200W/m2, and we use the 20% efficiency you claim for Andasol (which I do not necessarily accept btw), we get 20W/m2 Please explain here, with your workings shown, how you get from a 200W/m2 insolation (or 150W/m2 if you prefer) to an efficiency of '150W/m2' applying a 15% conversion efficiency. I'm struggling to remain polite now. I will say this: you appear to have become confused between packing factor and conversion efficiency. It sounds to me as if you don't really understand what is being discussed here.
    Response:

    [DB] As CBD has pointed out, 200W/m2*(0.20)=40W/m2.

    Before complaining about the splinters in other's maths, one would do well to first remove the planks in one's own.  In maths and rhetoric.

    Everyone, please focus on keeping civility in this discussion.  The moderation level has just been toggled up a notch.

  23. Trenberth on Tracking Earth’s energy: A key to climate variability and change
    Very helpful article. You show the net radiation increasing significantly after 2005. This is based on satellite measurements, right? What is changing? The increase seems to early to me to be solar cycle 24, so I presume the difference is either a change in albedo and/or a reduction in OLR. Are there numbers for each of these? Are they in accord with changes in e.g. atmospheric composition? Thanks!
  24. OA not OK part 4: The f-word: pH
    Thanks Doug. :-) Seriously, I really do appreciate this series. I have little to offer on the conceptual science, as my own formal chemistry education ceased when I was 18, but had actually been looking for a more in-depth explanation of ocean acidification to offer on the countless threads with chemistry-illiterate (and yet predictably vociferous) deniers.
  25. A Detailed Look at Renewable Baseload Energy
    Tom You just do not see it yet. Look at the average sunshine in W/m2. 200W/m2 is a fair estimate for average ground level insolation in a low latitude arid/semi-arid location. Let's say we apply a 20% technology conversion efficiency to this. We get 20W/m2. This is obvious and elementary reasoning. But LAGI uses the whole 200W/m2. There is no conversion efficiency step. I literally cannot understand why you don't see this. It's trivial. This is why LAGI comes up with a nonsense result of 500,000 km2 = 23TW and MacKay (and other numerates) come up with 1,500,000 km2 = 23TW. When are you going to concede that you've got this wrong? LAGI is missing a vital step and I have shown you exactly where it happens.
  26. Venus doesn't have a runaway greenhouse effect
    Hello, this a really nice article, I want to give a thanks for it.
  27. Humanracesurvival at 01:38 AM on 12 July 2011
    Trenberth on Tracking Earth’s energy: A key to climate variability and change
    Great article, i will study the details in the coming days! Here a topic i currently working on... Pedology – Erosion & Weathering during the PETM In 1998 Karl and Knight reported that from 1910 to 1996 total precipitation over the contiguous U.S. increased, and that 53% of the increase came from the upper 10% of precipitation events (the most intense precipitation). The percent of precipitation coming from days of precipitation in excess of 50 mm has also increased significantly. Studies by Pruski and Nearing indicated that, other factors such as land use not considered, we can expect approximately a 1.7% change in soil erosion for each 1% change in total precipitation under climate change. The removal by erosion of large amounts of rock from a particular region, and its deposition elsewhere, can result in a lightening of the load on the lower crust and mantle. This can cause tectonic or isostatic uplift in the region. Research undertaken since the early 1990s suggests that the spatial distribution of erosion at the surface of an orogen can exert a key influence on its growth and its final internal structure (see erosion and tectonics).
    Moderator Response: [muoncounter] Hot-linked; however, this has nothing to do with the topic of this thread. Please stay on topic.
  28. A Detailed Look at Renewable Baseload Energy
    Tom You are going to have to stop doing this sort of thing and re-engage, with a clear head:
    Ignoring the irrelevance given that LAGI calculate an area of approx 500,000 km^2, not 10,000 km^2 (100*100), we now know that when Mackay writes "allowing no space for anything else" he actually means "using just one quarter of that space for the solar field". We also know that he arbitrarily and with no justification given excludes any possibility of dual land use, at least in that calculation. (At another point in the book he points out that wind and solar power can occupy the same land footprint with very little loss of efficiency for either, then brushes it of. Clearly offshore wind and wave power can also take advantage of shared location with no efficiency loss in generation, and efficiency gains for transmission.)
    - What 'irrelevance'? It's an argument about scale and capacity. You are trying to delegitimise MacKay - When MacKay writes 'allowing no space for anything else' that's exactly what he means. Go back, and read it again. Where on earth do you get 'using just one quarter of that space for the solar field'? Seriously? Where? (See below before replying) - We are discussing the incorrect LAGI claim that 500,000 km2 of solar plant (with no spacing; 100% packing factor is assumed) can generate 23TW - But anyway, hot deserts are not windy enough for efficient wind generation The rest is a descent into further irrelevance. Until we get to this:
    However, I do admit that my 232 was in error, partly because I did not note Mackay's mistaken figure of 1/3rd land used when he meant 1/2, but mostly because I made an error due to tiredness (at 3:41 am).
    Your 232 is wrong because using MacKay's numbers you need ca 1,500,000 km2 to generate 23TW. That's because his calculation includes a conversion efficiency step and works from 15W/m2. Unlike LAGI, which mistakenly omits this step and runs on 200W/m2. Which is how it gets a seriously wrong result. MacKay is working with 100% coverage - the irrelevance of the erratum on p181 is irrelevant. You misunderstand this because you haven't read the caption. Do so now. See the numbers: 65 x 1500 km2 areas of 50% plant footprint, 10GW generation per area. Which yield just 16kWh/d/p for 1bn people. As compared to the 125kWh/d/p average European usage. Not only is this result consistent with MacKay's 100% coverage estimate, it is further confirmation of the scale of the error in LAGI. Errors happen. Nobody minds. It is willful refusal to acknowledge the exact nature of an error that is a problem.
  29. A Detailed Look at Renewable Baseload Energy
    BBD - "MacKay uses 15W/m2 energy density for desert sited CSP" That's low even by CSP standards - the Spanish AndaSol facility will have (due to only a small percentage of fill area) a gross efficiency of 2.6%, or >20 W/m^2. CSP has a conversion efficiency of 18-30% of collection area, depending on design, with some of the linear trough and Fresnel layouts having considerably higher fill factors than basic tower geometries. Fully filled a CSP would have a 200 W/m^2 output, although I don't expect that to get over ~100 given current designs. They do seem to be less expensive to build than PV systems on a per/Watt basis, though, and thermal storage is very attractive. Now - taking a look at PV power plants, which can attain fill factors approaching 100%, we're looking at 150 W/m^2 for a 15% efficient PV system. So - your 15 W/m^2 is low to start with, by almost an order of magnitude.
  30. A Detailed Look at Renewable Baseload Energy
    Tom, why you bother? It looks to me like just some game of power is played here, with (non)-renewable energies as the party theme. Be sure of not being driven where you don't want to be. You can't address the arguments of an innumerate using his own 10, 15, 20, 30, 50 and 70s and multiplying or dividing by 2 like they do. Get your figures reusable. Never do them just for these creatures: they don't want them, they don't allow them, and most importantly, they can't understand them as independent of wishing conclusions generated in advance. Also, let them to abuse of adjectives and other 'rhetoricalities'. Moderators: Please, consider if it is not time of flushing a lot of comments that are just spam.
  31. SkS Weekly Digest #6
    Check out UAH channel 5: http://discover.itsc.uah.edu/amsutemps/execute.csh?amsutemps Lower troposphere temperatures just matched the record (for the date) set in 2010. This despite us coming out of a major La Nina. I thought we were headed for a GCR induced Svensmark Ice Age. Didn't he claim that global warming stopped in 2009? Looks like he was wrong and James Hansen right about 2012 as the next record year. What a surprise.
  32. A Detailed Look at Renewable Baseload Energy
    BBD @244 (again): 1) The efficiency is unitless. It is kW/m^2 of electricity produced divided by kW/m^2 of insolation. 2) LAGI write:
    We can figure a capacity of .2KW per SM of land (an efficiency of 20% of the 1000 watts that strikes the surface in each SM of land). So now we know the capacity of each square meter and what our goal is. We have our capacity in KW so in order to figure out how much area we’ll need, we have to multiply it by the number of hours that we can expect each of those square meters of photovoltaic panel to be outputting the .2KW capacity (kilowatts x hours = kW•h)."
    (my emphasis. Bolded section is the context BBD elided in his quotation.) So, and most emphatically, the 0.2 KW was not simply drawn from nowhere. It was calculated by multiplying the expected insolation by an efficiency factor. You may want to argue that 20% efficiency is to high, but it is not 100% efficiency. LAGI do not use a 200 Watt insolation value (which they give as 1000 W/m^2), and they do not omitting the panel conversion efficiency (which they give as 20%). What is more, LAGI explicitly stated this. Indeed, they did so in the sentence immediately before the paragraph you chose to quote. To quote, in fact, in order to prove that they used an insolation value one fifth of that which they had just stated they had used, and that they did not use the efficiency factor they explicitly stated they used. In my world, what you have done is called "quotation out of context" and your example ranks well up their with some of the more egregious examples I have seen from creationists. Now I will once give you the benefit of the doubt and simply assume that you are not practised in reading for comprehension. But you had better come down of your high horse and pretence that we are not reading your words of wisdom when you are plainly not reading our simple statements of fact.
  33. A Detailed Look at Renewable Baseload Energy
    More good grief:
    3) LAGI quotes a 20% efficiency of collection. For comparison , the Andasol 1, 2 and 3 plants have a 28% peak efficiency and an annual average of 15%, so 20% is reasonable.
    The words 'annual average' mean 'annual average'. So an 'annual average' of 15% is and annual average of 15%. Not 20% or half a green cheese. This is not the stuff of rational debate.
  34. The Medieval Warm(ish) Period In Pictures
    @#15 Rob, why somebody would analyse "the Medieval Warming Period" and "the Litle Ice Age" if not for comparison with actual developments? If the adjectives "Western European" or "Northern Atlantic" were added, that would be a horse of a different colour. Why a warming period in human history has no paired higher global temperature to show? So, there must be some preconceptions the researchers are trying to address, for instance, that the actual warming period can't be compared with the so-called MWP. Then, baselines are important, otherwise, why they use anomalies instead of instrumental temperatures? If we have to be sensitive to change, be sure we are sensitized using a proper base. In a post that is addressing general publics that is no minor an issue. On the other hands, when a thing is an important subject for analysis and not a bit of a stretch, one should easily find other works with other base temperatures. Summarizing: MWP, LIA and actual AGW could be "easily" shown in contrast against a "normal" base, showing some misleading local warming and cooling for the first two what has clearly nothing to do with actual developments. Don't we have it? Well, such things happen when one allows [-snipped inflammatory comment] to dictate one's syllabus.
  35. Eric the Red at 00:52 AM on 12 July 2011
    The Medieval Warm(ish) Period In Pictures
    True, Am I misreading Figure 1. It looks as if Mann was saying that the two Russian areas were cooling by 1+C rather than warmer by 1+C. If Mann is stating that they were warming, then I agree. Sphaerica, Some evidence, in addition to those precedented in my previous post, showing a global MWP. http://ruby.fgcu.edu/courses/twimberley/EnviroPhilo/CookPalmer.pdf http://www.clas.ufl.edu/users/rrusso/gly6932/Oppo_etal_Nature09.pdf http://www.leif.org/EOS/2009JD012603.pdf
  36. A Detailed Look at Renewable Baseload Energy
    Tom MacKay is Mr Renewables. He's a big fan. Why would he do this?
    It is a rather underhanded way to deflate the actual efficiencies of solar plants.
    Why? He's also a professor of physics at Cambridge. And the chief scientific advisor to the UK Department of Energy and Climate Change (DECC). But, yes, of course he's talking through his hat and you are entirely correct. Go back, and read #236 and #244 again. Carefully. And read Mackay's chapter 25 thoroughly including end notes. Your work here is sloppy.
  37. A Detailed Look at Renewable Baseload Energy
    Tom I'm getting fed up with this:
    2) Mackay also quotes an average annual capacity of 15 Watts/m^2 for concentrated solar in North African deserts. You have provided no explanation for this discrepancy.
    See #244, third from last paragraph. Follow the link at "it doesn't matter if it's CSP or SVP". Read, and inwardly digest.
    3) LAGI quotes a 20% efficiency of collection. For comparison , the Andasol 1, 2 and 3 plants have a 28% peak efficiency and an annual average of 15%, so 20% is reasonable.
    How do you do it? How can you read a crystal-clear explanation of how LAGI gets it wrong and still come back with this? It is clear that you are not reading my comments. You have one of the most relentlessly closed minds I have encountered for a while. You need to open up a bit. you will not take me in with a shell game.. Good grief. The only person deceiving you is yourself. Stop muddling. Start thinking. Go back and read #236 and #244. It's all there.
  38. A Detailed Look at Renewable Baseload Energy
    BBD @244, quotes Mackay as saying:
    ""All the world’s power could be provided by a square 100 km by 100 km in the Sahara.” Is this true? Concentrating solar power in deserts delivers an average power per unit land area of roughly 15 W/m2. So, allowing no space for anything else in such a square, the power delivered would be 150 GW. This is not the same as current world power consumption. It’s not even near current world electricity consumption, which is 2000 GW. "
    (my emphasis) Ignoring the irrelevance given that LAGI calculate an area of approx 500,000 km^2, not 10,000 km^2 (100*100), we now know that when Mackay writes "allowing no space for anything else" he actually means "using just one quarter of that space for the solar field". We also know that he arbitrarily and with no justification given excludes any possibility of dual land use, at least in that calculation. (At another point in the book he points out that wind and solar power can occupy the same land footprint with very little loss of efficiency for either, then brushes it of. Clearly offshore wind and wave power can also take advantage of shared location with no efficiency loss in generation, and efficiency gains for transmission.) However, I do admit that my 232 was in error, partly because I did not note Mackay's mistaken figure of 1/3rd land used when he meant 1/2, but mostly because I made an error due to tiredness (at 3:41 am).
  39. A Detailed Look at Renewable Baseload Energy
    BBD, KR and I have both read 236. What is more, I adressed your arguments in 236 directly and found them to be without foundation. Disagreeing with you is not the same thing as not having read your comments or understood them. If anything, it is rather the opposite, a sign of both having read and understood what you say. To review: 1) Mackay quotes an average annual insolation rate in England of 100 Watts/m^2 after allowing for the effects of latitude and weather. A 15% efficient collector in England will therefore collect 15 Watts/m^2 even if laid flat on the ground. 2) Mackay also quotes an average annual capacity of 15 Watts/m^2 for concentrated solar in North African deserts. You have provided no explanation for this discrepancy. 3) LAGI quotes a 20% efficiency of collection. For comparison , the Andasol 1, 2 and 3 plants have a 28% peak efficiency and an annual average of 15%, so 20% is reasonable. 4) LAGI quote a thousand Watts of direct sunlight for 2,000 hours (23%) of the year for a total of 2,000 kWh/m^2 of direct sunlight per annum. For comparison, the Andersol plants experience per annum from 2,136 kWh/m^2 per annum in the south of Spain, so again the LAGI figures are conservative with areas in North Africa likely to experience much more both because of higher solar intensity and fewer cloud days. 5) From this LAGI calculate an electricity production of 400 kWh/m^2 per annum. For comparison, the Andasol plants achieve 350 kWh/m^2 per annum, so again the LAGI calculated value is reasonable. Indeed, with much of North Africa experiencing 17% more annual insolation than the south of Spain, that alone would lift an Andasol style plant in North Africa to 400kWh/m^2. I have to admit to being perplexed by Mackay's insistence on using a power generation factor of 15 W/m^2 in desert, until I stumbled on his description of the efficiency of the Andasol plant, which he gives as 10 W/m^2. In fact the Andersol plants achieve 41 W/m^2 of solar field averaged over the year, four times the amount Mackay quotes. The reason is evident, the solar field of the Andersol plants occupy just one quarter the site area. Mackay is calculating the efficiency relative to the site area rather than to the solar field. It is a rather underhanded way to deflate the actual efficiencies of solar plants. It is underhanded because, unlike in the south of England, in the south of Spain, and certainly in North Africa, the cost of land is so little as to be an almost negligible component of the overall cost. If it were not, it would be trivially easy to inflate the efficiency of power production per unit site area at a cost to the efficiency of power production per unit of solar field area. One obvious mechanism is to have adjacent troughs, with every second trough going to a neutral, non-shadow generating position when the sun is low in the sky, thus making the solar field almost equal in area to the site area most of the day, while halving efficiency relative to solar field area for a few hours on either side of dawn and dusk. Another method would be to have a continuous field of fixed shallow parabolic troughs with the collector moved during the day to remain in the focal point. In fact, if land area (rather than solar field area) where a real concern, it would probably be better to space the troughs further apart to allow more sunlight to the ground. The area between and under the troughs could then be used to grow fast growing grasses either for pasture or biofuel, thus gaining dual use of the land. None of these measures is considered worthwhile for the simple reason that the land itself is too small a cost to make such measures worthwhile. Mackay, in other words, is inflating a trivial cost as an artificial impediment to solar power. So, I'm happy to dump all preconceptions and start with an open mind, but you will not take me in with a shell game.
  40. Rob Honeycutt at 00:21 AM on 12 July 2011
    The Medieval Warm(ish) Period In Pictures
    Sphaerica... Spot on. In fact, the whole challenge of the MWP is getting an accurate read on what the actual global temperature was then, rather than just local temps. What climate deniers continually do is locate the one (or a few) proxies that support their position and claim that everything beyond that is a big conspiracy without ever bothering to look at the full body of evidence.
  41. Eric (skeptic) at 00:18 AM on 12 July 2011
    The Medieval Warm(ish) Period In Pictures
    I can imagine one source for warming in the MWP: a small forcing and a high sensitivity. I can also imagine that sensitivity is not a constant, in fact I propose that in various threads e.g. and never get an answer except "weather won't save us". It may well be that weather won't save us and that amplification of CO2 will be high. But that doesn't mean that weather didn't help cook the MWP.
    Moderator Response: (DB) You again make unsupported assertions (both here and on the other threads you reference) that fly in the face of known physics; that type of statement is referred to as "climastrology" and may fly in endeavors such as automotive research in the US, but is simply not credible in a climate science forum.
  42. Rob Honeycutt at 00:14 AM on 12 July 2011
    The Medieval Warm(ish) Period In Pictures
    Alec... I'm not sure why you're stuck on baseline periods. Pick a baseline of your own, it doesn't really matter. Choose a random baseline period if you like, it doesn't change the result of any of the data. The only thing a baseline period does is establish a zero axis.
  43. A Detailed Look at Renewable Baseload Energy
    @BBD #236 How do you get all your numbers so round, even in your errata? It sounds pretty much like 100 scientist found 1000 reasons for temperature not raising 1 degree (Celsius/Kelvin, Fahrenheit, Réaumur, who cares?) in the next 100 years. With such figures, does anyone need to point what is wrong? I think not. 30 Helens would agree.
  44. Bob Lacatena at 23:49 PM on 11 July 2011
    The Medieval Warm(ish) Period In Pictures
    11, Eric the Red,
    The MWP has been acknowledged as the last period of globally warm temperatures (not just NH as claimed above).
    Completely untrue. Citation, please.
    The global temperature anomalies are similar to today...
    Untrue. Citation please. It was not as warm, and temperatures in many, many areas were cooler. The warming was far from global, or equally distributed in either space or time. Hence, your statement is only remotely close to true if you use a running 200 year average to compute temperatures, and even then temperatures were still markedly lower than those of the last ten years in particular.
    Whether that period was warmer than today is still open to debate...
    Not remotely true. Look at the literature instead of just making stuff up.
    In order to show that today's warming is unprecedented...
    There is no need to show that today's warming is unprecedented. That it will inevitably be unprecedented, whether or not it is now, is the second important point, but the main point is that the cause of today's warming is unprecedented. It is being caused by the understandable and predicted effect of CO2, and it will be close to irreversible in human time frames if we take things too far. What is most entertaining about you, of all people, clinging to the MWP as yet another excuse to deny the physics behind climate science is the fact that there is no known or imaginable major source for warming in the MWP. This implies that such a cause was relatively small. This in turn points to a very, very high climate sensitivity as opposed to the foolishly low values to which you are so dearly wedded. That is the only way that the MWP could have been "as warm as today." If you believe in the MWP, then you must refute your need to cling to climate sensitivity predictions below 3˚C per doubling.
  45. The Medieval Warm(ish) Period In Pictures
    @#10 Rob, I'm downloading the article by Mann, Zhang, Rutherford et al, and the supporting online material and I'm finding -correct me if I'm wrong- that a few proxies were used, that grey masks indicates regions were 1961-1990 data is insufficient to draw climatic normals -not insufficient proxy data, what didn't mean there were aplenty-, regions without hatching didn't pass validation, and the whole set was got using computer modeling. I suppose that when I read and analyze the article and dataset -at the best of my capacity- I'll be able to find what role played the proxies other than getting low-frequency components of the signals to reconstruct. I know it's nice to look at a world map and confirm happy Vikings in Iceland and Greenland and turbulent Mongols and Tartars in the seek of better pastures. It looks like reassurance. It's not so nice that the reconstruction for the Little Ice Age in the same work is showing also not cooling Iceland and southern Greenland. In my opinion variability in times of slow changing technologies is what makes your living impossible. Then, what's the use of a 12-generation anomaly? What I've seen so far makes me think that not much more imprecision would have come from using 1941-1970 normals. What would have let us comparing MCA, LIA and nowadays AGW. There'll always be the layman approach to the driven conclusions. That shouldn't drive anybody to choose inappropriate base periods.
  46. Climate Solutions by Rob Painting
    @Ed Davies, New Zealanders don't heat their homes? Planning on moving to NZ from South Carolina early next year. Should I stock up on really warm clothing?
  47. A Detailed Look at Renewable Baseload Energy
    KR
    You keep returning to UK, and UK only - that's less than 0.2% the land area of the Earth - you are focusing on local issues rather than global.
    I have always been clear to distinguish between UK and global issues (eg in discussion of wind power above). This is a misrepresentation. Your reading of the discussion above is similarly careless. Time to sharpen up.
  48. A Detailed Look at Renewable Baseload Energy
    Tom You are making a hash of this. I think you should take deep breath and slow down a little.
    BBD @236 read 230 (and David Mackay) again. David Mackay quotes 100 Watt insolation per meter squared laid flat in England. 100*0.15 efficiency times 1 million meters squared per km squared = 15 million Watts collected [etc]
    No. See here. Please read and re-read this until you have absorbed its meaning completely.
    "All the world’s power could be provided by a square 100 km by 100 km in the Sahara.” Is this true? Concentrating solar power in deserts delivers an average power per unit land area of roughly 15 W/m2. So, allowing no space for anything else in such a square, the power delivered would be 150 GW. This is not the same as current world power consumption. It’s not even near current world electricity consumption, which is 2000 GW. World power consumption today is 15 000 GW. So the correct statement about power from the Sahara is that today’s consumption could be provided by a 1000 km by 1000 km square in the desert, completely filled with concentrating solar power. That’s four times the area of the UK. And if we are interested in living in an equitable world, we should presumably aim to supply more than today’s consumption. To supply every person in the world with an average European’s power consumption (125 kWh/d), the area required would be two 1000 km by 1000 km squares in the desert.
    Let's be absolutely clear: - MacKay uses 15W/m2 energy density for desert sited CSP - Based on this assumption, the area of desert sited CSP required to provide 23TW is 1,533,333 km2. Unless you can show that there is an error here, you must concede this point.
    LAGI gives the conversion efficiency (2) as 0.2
    [Please state units in further discussion.] No. LAGI does not use a conversion efficiency. It uses 0.2kW (insolation) and omits the panel conversion efficiency entirely. Once again, here is where they make the mistake:
    We have our capacity in KW so in order to figure out how much area we’ll need, we have to multiply it by the number of hours that we can expect each of those square meters of photovoltaic panel to be outputting the .2KW capacity (kilowatts x hours = kW•h).
    Look: "the .2kW capacity". See? That's 200W/m2. Based on real-world installations, you're doing well to get 15% and it doesn't matter if it's SPV or CSP (well, actually it does - CSP is the better choice. What matters is that the conversion efficiency has not been factored into the LAGI analysis. That's why they think you can get 23TW out of 500,000 km2 and MacKay knows it will take ca 1.5 million km2 of desert sited CSP I repeat: you are rushing and being careless. Read this again. Then go back and read #236.
  49. The Medieval Warm(ish) Period In Pictures
    @ Eric, #11 Your link to Baikal Science confirms Mann's analysis. The areas it identifies as having significantly warmd during the MWP (Taymir and Putoran, are also labelled in Figure 1 above as having warmed. The area of the Ural Mountains discussed in your link to Demezhko are also represented as having warmed in figure 1. As you're currently 0-2 I'm not going to bother with your link to Solomina.
  50. A Detailed Look at Renewable Baseload Energy
    Dump all preconceptions. Clear the mind and start afresh: #236

Prev  1584  1585  1586  1587  1588  1589  1590  1591  1592  1593  1594  1595  1596  1597  1598  1599  Next



The Consensus Project Website

THE ESCALATOR

(free to republish)


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