Open Climate 101 Online

Almost 3000 non-science major undergraduates at the University of Chicago have taken PHSC13400, Global Warming: Understanding the Forecast, since Ray Pierrehumbert and I (David Archer) first developed it back in 1995. Since the publication of the textbook for the class in 2005 (and a much-cleaned-up 2nd edition now shipping), enrollment has gone through the roof, it’s all I’ve been able to teach the last few years, trying to keep up with demand. I hear it is the largest class on campus, with 4-500 students a year out of an annual class of only around 1400. Now the content of this class is being served to the internet world at large: Open Climate 101.

You can watch video lectures followed by quizzes to challenge and hopefully stimulate your understanding, and work your way through tutorials with interactive models and simple mathematical ideas. Actually all that stuff has been available for a long time, online or in the textbook, but now it’s packaged into an interactive assessing system, which admittedly lacks the personality and finesse of our graduate student teaching assistants, but I hope it’ll get the job done. You can work at your own pace, on your own time. You don’t get University of Chicago credit, but it’s free, and if you get to the end of it you can download a certificate of accomplishment with your name and a verification code, signed by me. I hope people find it useful.

99 comments on this post.
  1. John P. Reisman (OSS Foundation):

    Thanks David, this is a wonderful gift. I was about to start my first quiz to see what I knew and then realized I need to the road soon. Does it have a save in place feature so one does not blow ones first attempt if interrupted? Otherwise, I will hold off until I have enough time.

    [Response:I’m just getting to learn “moodle” myself, but, yes, it does seem to remember where you are in a quiz from last time. On weird thing I’ve found is that if you blow the first attempt and then pass the second, the system knows you passed and will give you the certificate, but the gradebook doesn’t show the updated score. David]

  2. Edward Greisch:

    Not exactly free. The book is $51.06, not a download.

    [Response:Apologies for that sticker shock, that’s what they do to textbooks. But you can get the same information for free from the video lectures. David]

  3. Hengist McStone:

    OK I’m game sign me up. Ive already watched a couple of Dr Archer’s videos on Peter Sinclair’s climate crocks site. It’d be useful if you could give us some idea of how long the whole course is supposed to take(or even better each module).

    [Response:A few people have signed on already, but I don’t see your name. There’s a link “Create a new account” under the login prompt, let me know if you have problems. The class is a non-trivial amount of work to get through. The students here do it in 10 weeks, coming to three lectures (some of them) and on 90 minute “lab session” a week. They take maybe four classes at a time. They’re non-science majors but they still go through some pretty technical stuff. David]

  4. Barton Paul Levenson:

    For what it’s worth, I just self-published (through a short nonfiction book: The Greenhouse Effect: What It Is, How It Works. $2.99 from, Kobo, Google Editions, and I think a couple of others as well. It’s about 40 pages, an e-book.

  5. Tom Mellis:

    Many thanks, David. I am definitely looking forward to taking your on-line class.

    And thanks to all of you at RC for the time you devote to keeping the general public (e.g., me) informed on this very serious issue.

    You are the perfect antidote to much of the nonsense we see, hear and read on a regular basis from the so-called experts who know very little but are quite loud in their opinions. To them I have only this to say: Show me your evidence!

    Keep up the good work! You have more friends “out there” than you will ever know. I am one.

  6. Harry Kal:

    Another scaremongering scenario I guess?

    [Response:The class discusses the Ultraviolet Catastrophe and the Collapse of the Wave Function, scary stuff. Actually the scary stuff is in the lecture about Lynas’ book Six Degrees, the stuff also known as “impacts” and “working group II” in IPCC-speak. David]

  7. Snapple:

    Could I copy this post on my blog with attribution so I can find it later? I think I will give this a try.

  8. Paul Gee:

    Harry Kal
    Why guess?
    Sign up, do the course and find out for yourself

  9. Radge Havers:

    Harry Kal @ 6

    If what you mean by ‘scare mongering scenario’ is histrionic predictions of economic apocalypse following any attempt to deal with AGW, then no, you’re probably guessing wrong. Do you do a lot of guessing?

  10. Jim Eager:

    Why guess, Harry? Why not take the curse and watch the lectures for yourself so you’ll know for sure?

    Having read David’s book and watched the lectures I can assure you it’s just basic physics and chemistry, but then perhaps you found high school science ‘scary.’

    Come on, what do you have to lose, other than your own ignorance, that is?

  11. Jan Galkowski:

    Love to get the book, but my shelves are bending under the weight of my statistical textbooks. Happy to pay for it, but I’d far prefer it on my Kindle.

    I am definitely checking out and recommending the course.

    [Response:Just found out the textbook has a kindle edition, available here. David]

  12. Frank Grober:

    I think the science should be something that most voters can understand well enough to to make intelligent choices and I applaud anyone who is trying to spread the word. It just won’t be easy. I’m assuming that most readers will have had experiences like mine watching as the numbers in my Halliday and Resnick physics class declined as students who wanted to be scientists and did well in high school math and science found it tough going. Good luck getting the majority of Americans who didn’t even take high school chemistry to grasp all the details of many important arguments. Now I think a lot of people won’t even try to understand the science because they acccept arguments like the scientists are saying it to get grant money or it’s all a plot to make money for Al Gore or “Climategate” proves it was all a fraud. I think there would be a lot to be said for producing a complimentary package that for starters explains where money for science comes from and how many scientists work for fossil fuel and smokestack industries whereas a paid climatologist of any description is a rare bird indeed. I will spare you all of my arguments I use against deniers based on social science analysis, but I’m sure most readers will have their own largely overlapping set of comebacks. I personally happen to like this stuff at least as much as “real science” and I think they’re both essential to avoiding a planetary catastrophe. I will confess to having grown up in a family that loved to talk politics and enjoying high school debate so this sort of thing may come easier to me than it would to much better scientists, but when the mob is trying to burn down your lab trying to talk them out of it can be an important skill for scientists.

  13. Sphaerica (Bob):

    When I click the introductory lecture on a Mac (OS X Lion, Firefox) I get nothing. I could get to the lecture by instead by following the Video Lectures link at the top of the page, that worked fine, although the first link is to a php page while the one that worked right away was a link directly to the mp4 file.

    I look forward to the course, however. Thanks for it.

    [Response:I just figured out how to enable a multimedia plugin which brings the videos up embedded in the pages, except for the intro lecture, and I also figured out that the intro lecture link wasn’t working. Fixed now, tested and works in Safari, Chrome, and Firefox (which seems to be bizarrely slow). David]

  14. Spencer:

    Great service. But did you test it in Google’s Chrome browser? I can’t download a lecture (although I can in Firefox).

  15. Salamano:

    What is the method of assessment of mastery for such a class..? That sounds like an exceedingly large class size for an individual to reliably assess using what modern pedagogy reaches for in terms of ‘authentic’ methods. I can’t muster more than 25 per class without going into the fetal position correcting the writing work, etc. ;)

    [Response:The enrolled students at UC do get individual attention from graduate student TA’s in lab sections of 20. I use scantron forms to give quizzes and exams; actually the questions for the on-line class came from compiling old exams for the last couple of years. Most students do well on the labs if they care enough to work at it, which pulls their grades up some from the exams, which do differentiate between students. Yeah, grading written answers is really hard and time consuming, we used to do that. I’d divide up the exam questions, one per TA, and everyone had to sit and read hundreds of answers. Scantron rules. David]

  16. Dave Rado:

    I’ve tried creating a new account but whenever I click “Create my new account”, it just reloads the page. Although I suspect the problem is reCAPTCHA, there is no error message whatsoever, the page just reloads, so I don’t know whether that’s actually the problem or not. I’ve tried 10 times, 5 with the image CAPTCHA and 5 with the audio one, and have now given up. Is there any way you could sign me up for the course?

    [Response:Tried to set up an account for you. Send me an email. David]

  17. Richard Pauli:

    Ummm…”You can work at your own pace, on your own time.” But please hurry.

    Because destabilizing climate change unfolds according to physical laws that seems to be an increasing pace…. and whether our goals are adaptation or mitigation – too many people going at their own pace and time is one of the reasons we are in this mess.

  18. Isotopious:

    Here is the youtube version:

    Uploaded by UChicago on Apr 6, 2010

  19. Lynn Vincentnathan:

    This is great (as were your previous course materials). We just now got an Environmental Studies Minor approved to start next year, and I’ve been working on the science faculty to offer courses the non-science major students can take (without 8 science course as prereqs, as required for their Env Science courses in their Env Sci major).

    We had an expert, Shirley Vincent, Director of Educational Research at the National Council for Science and the Environment, come and give a faculty teaching workshop last spring, and she said that the trend in environmental studies and sciences education is for truly interdisciplinary studies that include the sciences, social sciences and humanities, etc.

  20. Wanda Ballentine:

    Hopefully! But – look,0,2808837.story

    Climate change skepticism seeps into science classrooms
    Some states have introduced education standards requiring teachers to defend the denial of man-made global warming. A national watchdog group says it will start monitoring classrooms.

  21. Chris McGrath:

    Thanks so much David, this is a wonderful resource.

    I teach environmental law in Australia and when talking about climate change law and policy I recommend to my students, if they aren’t up to speed with climate change science, to read:

    1. Spencer Weart’s book, ‘The Discovery of Global Warming’; and

    2. your book for a more technical understanding without being overwhelmed by lots of complex maths and physics.

    Spencer’s book reads like a detective novel and gives a good background to the history and development of ideas. It’s a great introduction for the lay-person. Your book gives a more technical understanding of the physics involved.

    I haven’t looked at the new edition of your book yet but I look forward to reading it.

    Thank you for the work you do and the new online course.

    Dr Chris McGrath
    Senior Lecturer (Environmental Regulation)
    The University of Queensland, Brisbane, Australia

    [Response:I remember thinking, as I read Weart’s book, how could he know all that stuff? It was like he was there. The magic of the historian. I agree, a great book. David]

  22. Bill:

    In the last six months I have made two copies of Archer’s lectures and sent them off to friends who were non-science majors a decade or three ago and they both have really enjoyed them. Maybe they will take the quizzes?
    Thank you for doing this.

  23. Ernst K:

    I watched your videos when you linked them back in 2009 (“an offering”). It definitely helped fill some gaps in my knowledge (particularly the geologic regulation and the reason why CO2 is a GHG and O2 and N2 are not). Together with continued reading of Stephen Weart, it really helped organize the many lines of evidence underlie climate change science.

    By coincidence, I was asked a year later to teach an undergraduate course that included a major unit on climate change. So, to the extent that your lectures helped improve my lectures, you can add 150+ future civil engineers to your running total.

    And I concur with Chris McGrath that between you and Weart, your “offerings” lay an excellent groundwork for understanding the science of climate change.

  24. danny bloom:

    This is fantastic! Bravo. Some good, positive news. Go go go.

    In related news, in the distant
    future — some say the near future — North America, northern Asia and
    Europe will see millions of climate refugees from southern lands
    trekking northward, as you know, and our descendants in 2121 or 2222 might all might be under threat from the
    devastating impacts of ”climate chaos” — from rising sea levels to a
    scary scarcity of food, fuel and shelter.

    So please read “Polar City Red,” sci fi writer Jim Laughter’s cli-fi fiction novel set in an imagined
    Alaska in the year 2080. Forget NASA’s missions to Mars, says Laughter, and start thinking
    about mass migrations of ”climate refugees” north to Alaska. (By the
    way, the term “climate refugees” was coined by Robin Bronen, a woman
    professor in Anchorage.)

  25. Thomas Bleakney:

    Good show. I have read your “Understanding the Forecast,” the “Long Thaw,”” Weart’s “Discovery of GW” as well “6 degrees.” I have tried my best to spread the word, and I find receptive people part of the time. So many people are stuck at denial stage 2, asking how we are so sure GW is anthropogenic. I point to the ISOTOPIC SIGNATURE of the rising CO2 that shows it originates mostly from fossil fuel (no C14) and deforestation (surface organic). Do you get good response from your students on this point ?

  26. Edward Greisch:

    6 Degrees is a good book and I read it a long time ago. Why did you prescribe a book by Friedman? I have read the first chapter, and so far it lives up to my expectation of Thomas Friedman: not interesting, mostly sideshow issues.

    [Response:Seems to me interesting ideas about how energy issues fit with other global sociopolitical trends. Maybe the first chapter wasn’t the best, it’s been a while. David]

  27. Trent1492:


    I went looking for your book at Amazon through a title and author search and your book is not popping up.

  28. CM:


    Registration and enrollment: check. Oddly, “Course completion status” still says “You are not enrolled in this course”. “Course administration” offers the option of unenrolling, though.

    [Response:That’s weird. I don’t get that in my student account. You do show up as enrolled. Can you take a quiz etc? David]

    Textbook: check, ordered. I may just have snatched Amazon’s last copy in stock this side of the Atlantic — sorry, folks.

    Video lectures: working in Firefox.

    Projected pace: glacial, regulated by the mounting in-tray homeostat.

    Captcha, sensing my new academic ambitions, is trying to get me to typeset set theory.

  29. Alexandre:

    I second Ernst K above.

    I watched the videos back then, and it really helped me filling the gaps of my internet-based self-teaching. Playing around with the online models also helped. Highly recommended.

    Thanks David!

  30. Warren Hendricks:

    Thank you for putting this course on line! I will spread the word. Also, for those interested, used copies of the textbook are available from Amazon for about $10. And for those who use Itunes on your portable devices, you can get the video lectures in ITunes U.

  31. John Atkeison:

    I’m interested in hearing about the response to your announcement– I posted on facebook and got a bigger response than I expected, both in “Likes” and “shares.”
    John ClimateHawk Atkeison

    [Response:Currently 340 students enrolled, about 26 hours after I posted the announcement on realclimate. My largest class, evah! David]

  32. Christoph Rose:

    This is very nice, but the interface is slightly confusing, as you have to register, enroll in the system, and then enroll for the course in order to be able to start it.

    One extremely slight complaint: During my second attempt at the exam for the first lecture, I got a question about blackbody radiation, which hadn’t been addressed during the filmed lecture.

  33. CM:

    David, re #28,

    After logging out and in again, everything looks right – sorry about the noise.

  34. Jeff Rubinoff:

    @BPL, just bought your book on my Kindle. Not to be confused with Big, Blooming & Wild! Greenhouse Effect, which also popped up in my search.

  35. BillC:

    looking forward to it. many thanks.

  36. Chris Colose:


    Thanks for this. This is a tremendous resource. My graduate advisor is using your text for his undergrad Climate Change classes, so hopefully some of his students gain from this online supplement. The quiz’s certainly help reinforce some of the concepts very well. A couple comments:

    – it might help to expose answers that the student was unable to get, especially since a lot of questions (for example in Lab 1 on units) require using previous answers for several later questions; if one were unable to get an answer to a question, it might prevent them from answering three or four more after that.

    – I also think some of the answers are wrong, for example the question on converting kW hr to joules for the PV cell (600 kW hr *(3600000 J/KW hr) doesn’t work), or need re-wording (like “what is the ratio of the Hoover dam to the solar farm”, what does that mean?) In another case, you ask “FM radio operates at a frequency of about 100 MHz. What is its wavelength?” but you don’t specify what units the answer should be in.

    – I continue to get an Internal server error when trying to use the NCAR radiation code module, which for example prevents me from answering the first question in Lab 3 or 6.

  37. Peter Bellin:

    I would like to use some of this material in my class on Air Pollution. the last third is climate change. I have seen your lectures on youtube, and thank you for your sharing this online.

    I only have to decide how to utilize it. I will take some time to start viewing the material in the next few days.

  38. Edward Greisch:

    26 David: Sciopolitical trends: How about books on wars started by GW effects? Those big new rich populations won’t be rich long. China is loosing a Rhode Island sized chunk of farmland to desert annually. A new green revolution is not going to happen. India and China could have a nuclear war over water from Tibet.

    72 billion people’s worth of consumption? Sorry, I just don’t believe it can happen. Sciopolitical trends can be interrupted by Mother Nature so easily that I don’t believe in the sciopolitical trends. It finally snowed this winter in January. Did the winter wheat survive?

    I guess if I just leave my computer on a lecture it will eventually download so I can watch a whole lecture. It won’t save, so I have to watch the lecture after waiting for the download.

  39. Edward Greisch:

    So where do I register?

  40. Barton Paul Levenson:


    Sorry about that. I posted a day before it actually went on sale. It’s up now and the URL is


  41. Barton Paul Levenson:

    Thanks, Jeff! I appreciate it.
    Realclimate hosts: Thanks for revising the reCaptcha thingy. It’s a heck of a lot easier to use now.

  42. Tony:

    signed up last night!

  43. Septic Matthew:

    I think that making this available online is a great idea.

  44. Septic Matthew:

    Edward Greisch: A new green revolution is not going to happen.

    FWIW, the old green revolution was predicted not to happen as well. You might just as usefully predict that electricity from solar power will never be as cheap as electricity from coal.

  45. Daniel C Goodwin:

    This online course is a wonderful gift for aspiring climate geeks. I’m signed up and raring to go after the Introductory Lecture video. Thanks so much!

    One question for the cheapskates: the first edition of your textbook can be had (from a used-book site like at a fraction of the price of the second edition. For folks who like to follow along with a textbook, would the first edition work out okay with the video lectures?

    [Response:Yes, either will be fine. The layout etc are the same. The 1st edition makes me cringe a bit, but it’ll do. David]

  46. CM:

    Hi, BPL,

    Got your booklet, so now I can crib from my Kindle should anyone put a gun to my head and make me write down the equation of radiative transfer. I don’t know why anyone would do that, really, but I remember you raising the hypothetical a couple of times. :-) Typo alert: density should be in kg per cubic meter, not square.

  47. Lee Norton:

    I downloaded your course last year and have viewed it with my wife. I’ve also re-visited several sections that my slow brain needed to review. I also sent your website to Audrey at Canada’s Climate Reality Project who in turn made it available to all presenters. From emails, I know she has looked at it. In summary thanks for putting out such a great learning resource.

  48. John E. Pearson:

    I just had my copy of Barton’s little book delivered to my kindle. You can get it here:

  49. Barton Paul Levenson:

    CM, John, thanks. CM, you’re absolutely right about the density. Don’t know how I missed that. Oh, well, if there’s ever another edition…

  50. Barton Paul Levenson:

    CM, John, thanks!

    CM, thanks for pointing out the typo–you’re right, of course. If there’s ever another edition…

  51. Barton Paul Levenson:

    Okay, that’s 3 attempts to post the same damn message, all with “That reCAPTCHA response was incorrect.” Did you guys step it up as soon as I said it was okay, on the theory that if I can get past, it’s not tight enough? RealClimate maintains its record as the hardest climate blog to post on, and once again, I am out of here. CM, John, thanks for buying the book, and CM, you’re right about the typo.

    [Response:We have nothing to do with that thing.–Jim]

  52. Daniela:

    Thank you for the class. Can you please explain why “Choose the approximate time scale for the CO2 weathering thermostat” gives as wrong the answer > 1000 years which I believe to be the correct one? From time to time I encountered a few bugs or at least so it seemed. Thank you.

    [Response:I think it’s longer than that. But do alert me if you think there are other errors. David]

  53. Daniela:

    Thank you a lot for your kind answer, I got (twice) the following choice of options (select one or more):
    a. one year
    b. 1000 years
    c. 100 years
    d. > 1000 years
    e. ten years
    There is no option in the timescale of some hundreds of thousand years or so, and the automated grading system did not give a correct answer after I finished.

    Unfortunately it does not allow me to review the labs I have already done. There were a few answers obtained by the models webapps that were marked as wrong, and it puzzled me. I will post if I find any in the future.

    I appreciate very much the class which is giving me an insight into a field which is very distant from my professionality and expertise and which I wished to learn more about, as it concerns all of us and our future.

    Thanks again

    [Response:You are correct, I missed the “>” sign in your question, and the question in the system was wrong, fixed now. Apologies for not reading your query more closely. David]

  54. Sarah:

    In the question Daniela mentioned, “>1000 years” was the largest option available.

  55. Sarah:

    Some of the issues I’ve come across are below. There were others but I don’t remember which questions, and I don’t know if it’s an error in the marking script or an error in my thinking. (Some at the end of lab 3, and a question on ears of corn in an earlier lab.)
    From the link in Lab 4: The Lapse Rate and the Skin Altitude, NCAR Radiation Code starts up from the “Run me” but when the “Do it!” button is pressed, I get “Internal Server Error”.

    Running it from the “On-line Models” tab works, but then the answer given by the program 16.0C (with no settings changed) is not the one required in Lab 4 question 1. Maybe I misunderstood what the lab wanted.

    On the next question, setting the lapse rate to 0, I got the right answer but some mess in the output:

    qneg! 1 1 8 qneg! 1 1 9 qneg! 1 1 10 qneg! 1 1 11 qneg! 1 1 12 qneg! 1 1 13 qneg! 1 1 14 qneg! 1 1 15 qneg! 1 1 16 qneg! 1 1 17 qneg! 1 1 18 qneg! 1 1 19 qneg! 1 1 20 qneg! 1 1 21 qneg! 1 1 22 qneg! 1 1 23 qneg! 1 1 24 qneg! 1 1 25 Equilibrium near-surface air temperature is -11.1 degC (262.0 K)

    The= next question says to set the lapse rate to 10. I tried both -10 (and got “A problem occurred in a Python script. Here is the sequence of function calls leading up to the error, in the order they occurred.” and so on) and +10 and I got “qneg! 1 1 10 qneg! 1 1 11 qneg! 1 1 12 qneg! 1 1 13 qneg! 1 1 14 qneg! 1 1 15 qneg! 1 1 16 qneg! 1 1 17 qneg! 1 1 18 qneg! 1 1 19 qneg! 1 1 20 qneg! 1 1 21 qneg! 1 1 22 qneg! 1 1 23 qneg! 1 1 24 qneg! 1 1 25 qneg! 1 1 26
    Equilibrium surface temperature less than -100 oC.”
    Lab 5 has the same problem with the link to the program in question 1.

    [Response:Yikes. I got the links from the labs fixed, but it sounds like there is some code problem, I’ll get it fixed. Appreciate the feedback. David]

  56. Sarah:

    For a long time, I’ve been aware of my ignorance in this field but my efforts to correct that ignorance have failed since the material I’ve seen has assumed more than I’ve known. This course is filling an important gap in my knowledge, at a level I can understand, and giving me quite a few “Aha!” moments as things suddenly become clear. Having exercises and labs, as opposed to just watching videos, is helpful in showing me where I haven’t quite understood. Thank you for the opportunity to study this, and the effort you’ve put in to bring this course to us.

  57. Hank Roberts:

    > The 1st edition makes me cringe a bit, but it’ll do. David]

    David, do you have an errata list for the 1st ed., so those of us with more time than money can buy cheap and mark up an old first edition with corrections?

    [Response:My document of shame, yes, I’ll email it to you. David]

  58. J Althauser:

    Thanks for reminding everyone of this resource David. But none of the video links to individual lectures work for me – Mac OS X 10.4.11, Safari v 4.3.1. Nor did they work in 2009, only show scrambled characters.

    The Youtube lecture are nice, via #18. Thanks for linking them Isotopious.

    I am currently reading Ruddiman’s Earth’s Climate: Past and Future ca 2001. An overview with emphasis on geologic processes, a narrative of the search for the causes of climate change.

    J Althauser

    [Response:There are multiple options. The embedded links in the quizzes come from youtube edu, which you can also go to directly (search for my name and a lecture name or number). They are also served as mp4 files from a server at UChicago with links from here. Or iTunes University is probably the easiest way to download and watch off-line, from a tablet or phone or laptop. David]

  59. Rob:

    Does the learning material state what the rate of warming will be as a result of the Greenhouse effect in the real world? Does it state what the impact of the warming will be on other factors such as rainfall?

  60. Hank Roberts:

    For Rob — projections and details vary; here,for example:
    “the best estimate (solid bar) and likely range (grey bar) for six SRES scenarios, based on both the model results in the left part of the figure and expert judgment derived from a variety of additional information. Note that this figure illustrates the uncertainties arising from different greenhouse gas scenarios and climate models, but almost certainly underestimates the uncertainty associated with carbon-cycle feedbacks.”

  61. Sarah:

    Further to my comment on Lab 5, question 1 links the wrong program. I believe it should link to

    [Response:fixed, thanks, d]

    I answered question 1, got no feedback as I have in previous questions, and it went immediately to question 2. From my score I now see that means it was correct. I actually prefer no feedback when the answer is correct as it speeds up the process.

    [Response:I agree, found the option in the setup, and set all of the labs to work that way. d]

    Question 2 links to the correct program but again I get the internal server error.

    Questions 3 and 4 I get wrong. On question 3, the only figure I changed from question 2 was the TOA radiative imbalance until I got exactly 30.0. This was obtained at -65.4 W/m^2. I continued to question 4, changed insolation and suface albedo as indicated (just like in question 2, which was marked right), and set TOA radiative inbalance back to 0. I got -53.1 W/m^2 which was again wrong. I have no idea what I might be doing wrong as it seems a simple task.

    [Response:Yep, you’re right again, I had the question set up wrong. Fixed now. Your comments are extremely helpful, thank you for documenting so clearly. David]

  62. John E. Pearson:

    J Althauser says:
    20 Jan 2012 at 11:14 AM
    Thanks for reminding everyone of this resource David. But none of the video links to individual lectures work for me – Mac OS X 10.4.11, Safari v 4.3.1.

    I watch them on a Mac running 10.6.7 and version 5.0.4 of Safari

  63. Hank Roberts:

    Safari 5.1.2 and OSX 10.7.2, opens the videos OK in Safari for me
    Firefox downloads them as .mp4s for Quicktime to open.

  64. Sharon Black Hawkins-Fauster:

    Thanks, David, for offering the online course for non-science majors. I had given books to friends and family on global warming and they said they were unable to understand the technical language. This course has really been needed — I’ll pass on the info that this is available.

  65. Sarah:

    It seems that a lot of the questions which involve multiple tick boxes do not give a correct answer after a wrong answer.

    Furthermore, in ‘The Present in the Bosom of the Past’ both of the answers in the following question are marked wrong.

    Which of these is an example of climate change mitgation
    Select one or more:
    a. switching from air conditioning to fans
    b. adding air conditioning

  66. Daniela:

    Is it possible to check “Oil and Methane” questions? I got 0 correct and it does not give me the correct answers. Thank you again!

    [Response:Yes, it looks like those questions didn’t import correctly, any of them, how frustrating for the student. My apologies and thanks, fixed now. David]

  67. Daniela:

    There may be a bug with the “Oil and Methane” questions: I got 0 correct and it does not give me the correct solutions after submitting. Thank you again!

  68. Daniela:

    David thank you a lot and no problem at all. I am writing to remark that the set of questions “Six Degrees” tell me the following message. Thank you again!

    Attempts allowed: 2

    Grading method: Highest grade

    No questions have been added yet

    [Response:Oops. Fixed now. Thanks! David]

  69. Daniela:

    Thank you a lot! Can you please check, in “Six degrees” the question that asks to explain the faint young sun paradox? It gave me wrong answers to what I clicked, and it did not gave me the correct answers after submission. I really appreciate.

  70. Daniela:

    Thank you again and apologize for pestering :) I retried “Six degrees” and I got wrong my answer for the following question, with no correct answer given.

    The air at the top of the troposphere is colder than the air at the ground because of
    a. water vapor
    b. expansion of gas
    c. light energy
    d. ozone

    Also, even though I completed everything and have 85% or something, the homepage says:
    Open Climate 101 Certificate of Completion
    Not available until you achieve a required score in Course total.

    Thank you so very much. Daniela

    [Response:You’re absolutely not pestering, you’re helping me out, and I appreciate it. I reviewed all the questions and rooted out this error and the last one you found. I’m less sure about the certificate issue. I made a tweak, can you have another try and let me know? Thanks again David]

  71. Daniela:

    More precisely this is the message I get, if I check the status on the webpage (everything else has a “Yes”)

    Course grade Passing grade 65% 85.83537% No 21 January

  72. Chris Colose:


    I also have a problem with a pair of questions in Lab 3 on greenhouse gases, that contrasts the constant vapor mixing ratio and constant relative humidity MODTRAN cases. One question is “Now repeat the calculation but at constant relative humidity. (Starting from a base case, record the total outgoing IR flux. Now increase pCO2 by 30 ppm. The IR flux goes down. Increase the Temperature Offset until you get the original IR flux back again.) How much temperature change do you need this time?”

    Starting from the base case, the IR flux is 287.844 W/m2, which decreases to 287.498 W/m2 at 405 ppm CO2. I only need to make the Ground T offset 0.09 degrees for constant mixing ratio (or 0.16 C for const. relative humidity, consistent with an enhanced sensitivity). Neither of those answers appear correct. That seems hard to screw up, but I could have missed something.

    [Response:Yep, I’m not sure where the numbers I had in there came from. Thanks, fixed now. David]

  73. Daniela:

    Thank you a lot for your overwhelming kindness. I still get the same error messages as above in msgs 70 and 71, both on the main page and on the status page, where, however, it marks the course as “Complete”, yet gives me the error message I posted in 71. Thank you again. Daniela

    [Response:Congratulations, you and Sarah (who has also been great about posting feedback) are the first students to complete the class. I had to move the certificate link into the class site, beneath all the lectures and labs. I think it will work now. Congrats again, and thanks. David]

  74. Sarah:

    Thank you so much for the course, David, and for your rapid responses to all the issues. It’s been a pleasure doing the course. Are there any more planned?

    The certificate link is now working.

  75. Daniela:

    I confirm the certificate works, and if I may add, it is very nice. I hope the info about this class gets around and many people take advantage of it, as it is really an awesome course and fruitfully enjoyable by a very diverse audience. One thing (and already difficult enough) is teaching Physics 2 to students all of whom have just followed Physics 1 and all of whom are interested in the skill to tackle Physics 3 coming up next; but to teach a subject from the very basic foundations and to be appealing to people with all sorts of professionalities and backgrounds, has all of my admiration. Thanks again. Daniela

  76. Daniela:

    I second the comment 74 by Sarah. It has been a pleasure and please if possible, consider offering more classes in the future. I know time is never enough, but the subject, which is crucial to our future, is all too often discussed without knowledge, holding on to prejudices and unscientific ideas. Please consider offering more. Thanks again.

  77. Matt Bequette:

    I highly recommend David’s course. The Linus and Friedman books are worth the read too. Thanks David!

  78. Daniela:

    @Matt and other fellow students who already completed the class (I don’t have anyone’s email except for Sarah’s): the previous Lab 1 has been broken in three parts. Feel free to take again the ones that appear not-yet-taken, especially if you found bugs the first time around. Enjoy!
    And again a big thank you to David for this improvement.

    [Response:There were so many questions in the lab before, without any notice of how many there were, that it seemed daunting, and it was a problem because the system isn’t very good at remembering a student’s progress, if they make it part way through a lab, stop, and come back. So I broke it up into nicer-sized chunks. David]

  79. Alastair MDonald:

    Hi David,

    I am enjoying your course but I am having a problem with Lab 4. When I set the lapse rate to -10 as required in Exercise 3 I get the messages appended below.

    When I set the lapse rate to -9 I get the answer 16.4 C, but -9.1 and -9.9 give similar results as -10.

    [Response:This does seem weird, I’ll alert the guy who supports this particular model. For now I “dropped 10 and punted” and just deleted the question. When all else fails, lower your expectations. David]

    There is a second problem because when I enter 16.4 as the answer it corectly says I am wrong but when I select “No, I just want to go to the next question” it takes me back to try again, as it does if I select “Yes, I’d like to try again”. That means I am stuck at that exercise and cannot move on to the others. Would it be possible to fix that problem as well which I think applies to all the other exercises?

    [Response:Yeah, actually, that is weird, not how moodle is supposed to work. I’ve tried changing the options, to allowing the user to re-try, or not, and either way it seems impossible to get through a lab if you can’t get one of the questions. I’ll keep chewing on it, this isn’t right. Thanks much for the detailed feedback, very helpful. David]

    Cheers, Alastair.

    Python 2.5.5: /usr/bin/python2.5
    Sat Jan 28 10:30:01 2012

    A problem occurred in a Python script. Here is the sequence of function calls leading up to the error, in the order they occurred.
    /var/www/forecast/cgi-bin/ in ()
    517 try:
    519 Teq = climt.mathutil.ridder_root(TOAFlux, (173.15,403.15), accuracy=0.1)
    521 except climt.mathutil.BracketingException, err:
    Teq undefined, climt = , climt.mathutil = , climt.mathutil.ridder_root = , TOAFlux = , accuracy undefined
    /home/mcguire/lib/python2.5/site-packages/climt/ in ridder_root(f=, bracket=(173.15000000000001, 403.14999999999998), fnvals=None, accuracy=0.10000000000000001, max_iterations=50)
    94 if min(abs(x1-x2),abs(x4-x4old))<accuracy or temp==0:
    95 return x4
    96 raise RootFindingException("too many iterations")
    98 def root(f, interval=(0.,1.), accuracy=1e-4, max_iterations=50):
    global RootFindingException =

    : too many iterations
    args = (‘too many iterations’,)
    message = ‘too many iterations’

  80. Edward Greisch:

    I have watched all but the last 2 lectures. I still don’t see any labs or quizzes or homework assignments or exams. Are those only for paying students?

  81. Alastair McDonald:

    Re #80

    Hi Edward,

    I did not pay but I did register which is free.

    Cheers, Alastair.

  82. Hank Roberts:

    I would suggest creating a separate forum — entry upon passing the course — for climate discussions.

    It might help the noise level.

    [Response:That’s a great idea, so I’ve set up so that when a user passes the 10% mark (like a down payment) they see a link to a discussion forum. It’s up in the “syllabus” box, up at the top. David]

  83. Alastair mcDonald:

    Re #80 again


    I now reckon that you must be using the ITunes library here but to get to the exercises and get a certificate you have to register and go in through here

    For others who have registered then the ITunes link gets you to other goodies such as stuff from Cambridge University.


    Cheers, Alastair.

  84. Alastair mcDonald:

    Hi again Edward,

    You register here:

    Cheers, Alastair.

  85. Sarah:

    I’m not sure what you mean about noise levels, Hank, but it would be nice to have somewhere to have discussions. I’ve certainly got questions that I’d like to ask/discuss but don’t know where to ask them.

  86. Edward Greisch:

    83 Alastair mcDonald: I did the register thing.

  87. Alastair mcDonald:

    Hi Edward,

    But are you logging in to see the videos?

    Cheers, Alastair.

  88. Alastair mcDonald:

    Hi again Edward,

    I think I now know where you are going wrong :-) When you log in there is a page headed “Open Climate Science 101”. On the menu bar for that page one item is “Video Lectures”, but that is NOT what you should use. Instead click below where it says “My Courses” on the “Open Climate 101” hyper link. That will take you to a list of the videos and exercises.

    Hoping I have got it right this time,

    Cheers, Alastair.

  89. Hank Roberts:

    > questions that I’d like to ask/discuss but don’t know where to ask them.

    For Gavin and Dave Archer — offering a discussion area — limiting access to those who _pass_ the class — might be helpful to all concerned.

  90. Daniela:

    Thank you for the discussion area and please restore the question about high and low clouds! In regards to the labs, I have had the impression that, if a student gets wrong an answer for the first time, we will be forced to redo the question (and if correct, it’s marked correctly). After two incorrect tries, one may proceed to the next by clicking “No thanks”. Sort of wierd but has a logic. Just my hypotesis as I don’t have any experience with moodle. Thank you again for the continuing improvements. Daniela

    [Response:I’m having the same trouble as Alastair, in particular on the questions in the lessons that require a numerical answer. So lab 1a starts out with one of these, and the lab which he was working on. What kind of questions are you getting the “No thanks” button on? David]

  91. Edward Greisch:

    Alastair mcDonald: It says “all courses” not “my courses.” That doesn’t work either. Mac OS 10.6.8 with Safari 5.1 and Firefox 9.0.1

  92. Alastair McDonald:

    Re #90


    I have put my question on clouds back again. I had deleted it temporarily while I checked what the models did. They give a surface temperature of >100C for 100% Cirrus cloud which I can’t believe is what would occur in real life.


    Although I had that problem with Lab 4 I managed to get through Lab 6 with mistakes. I did not report this earlier as I am not sure it will be any help.

    [Response:I think I fixed the issue with numerical questions not allowing the user to pass until they got it right. In case anyone cares, the numerical question type (Moodle 2.1) had to be told that a numerical answer outside the “correct” range (#1) was wrong, by setting a range #2 of -1E18:1E18, and giving that a score of 0 but moving to the next page. Let me know if any more weirdness ensues. With the NCAR model, that is one of the few on the site that I don’t deal with. Hopefully we’ll get it right soon. David]


    I see now that all the pages are entitled “Open Climate Science 101″ so that was not much help :-(

    The page I was referring to has a heading on the left column saying “My courses” (not “All courses”), and below that two hyperlinks “Open Climate 101” and “All courses”. Below that is another heading saying “Settings” below which is a hyperlink to “My profile settings”.

    The URL for that webpage is .

    But the page you want to get to is:

    But to get to it you may have to log in first, or it may force you to log in if you haven’t already.

    I am using Firefox and Windows XP. I would have thought that Moodle would have worked with Firefox on a Mac.

    Hope that helps this time :-)

    Cheers, Alastair.

  93. Daniela:

    Sorry for the delay in answering. I am not sure if now it is changed, when I first did the labs, they sent me back to the same question (whatever I answered) after the first mistake; but the second time had different statement (something like “Not quite”) and it was possible for me to click continue if I wanted to, and move on to the next question. I also noticed that some answers, which I had gotten right at attempt 2, were counted as correct.
    Now is much nicer, with automatical transition to next question if the previous one was correct.
    Please let me know if debugging is useful, I’ll surely find a few minutes. The class was very helpful to me and I again express my thanks.

    @Alastair: thank you for restoring the Q. It has been puzzling me as well.


  94. Edward Greisch:

    92 Alastair McDonald: Thanks! Now I see something labeled “lab.”

  95. Edward Greisch:

    Use the “back” button on your browser to do the question over.

  96. Alastair McDonald:

    Hi David,

    Thanks for fixing that. I have completed Lab 4 now with 100%, but…

    I think it is now accepting wrong numerical answers as correct, and allowing second and third attempts at multiple choice questions to be treated as first attempts and the mark being counted.

    With the multiple choice questions, one can find out what the correct answer is by trying all the choices, but with numerical questions that is not true. It would be better if the question following a numerical contained the answer to the previous question. Then if one is not able to find the correct answer, there would be a clue to where one had gone wrong. It would also be nice if each question included a line saying “Question x of y” so we had some idea of how far we had got through the Lab, and it would also help us to report problems with which we are having difficulty.

    That seems a lot of work so maybe you could get a student to help you with it.

    Thanks again for providing it. I am finding it very useful.

    Cheers, Alastair.

  97. Alastair McDonald:

    Hi Edward,

    Glad to hear to have found the labs, but there are also quizzes associated with the lectures. You won’t have to watch the lectures again, just do the quizzes to get more marks.

    My problem was not that I wanted to do the question over. It was that I didn’t want to do it over! But that’s been fixed now :-)

    Cheers, Alastair.

  98. Edward Greisch:

    It won’t let me take the quizzes. It says I’m not registered. I did the chapter 1 labs.

    [Response:The site lists you as a use, but you’re right, it doesn’t have you “enroled” in the class (the weird spelling of “enrol” is apparently British). You need to click on a link that says “enrol me in this class”. My recollection is that it’s on the left side once you enter the class. David]

  99. Klaus Flemløse:

    Dear David,
    I am following your video lectures on global warming and I have bought the text book. It has been a great pleasure for me.

    However, I have found one case where I do not think you are right, and where a corrections may be needed.

    In you lecture dealing with Chapter 9, after 21 minutes, you are talking about Danish wind energy. You mention that “50% of the wind power is exported …”. This figure is not correct.

    The information you are referring to originates from misinformation published by oil funded groups in USA via the Danish 3rd party organization CEPOS with links to Bjørn Lomborg.

    It is not possible to determine the share of exported wind in the way CEPOS does, simply because it is not possible to separate electricity produced by wind from electricity produced by coal. If one should give a figure using pro rata production it is around 20%.

    The CEPOS report can be found here:

    A reply from a group of scientists from University of Aalborg can be found here:

    The controversy is also discussed on Wikipedia:

    The present Danish government wants to increase the share of electricity produced by wind from 20% today to 50% in 2020.

    [Response:I am getting lots of great feedback on the class, your comment among many. Thanks, David]