Does the Medieval Warm Period mean that climate change isn't real, dangerous and caused by humans? (No)

A frequent shibboleth of climate change denialism is that the Medieval Warm Period -- a period of apparent global climate change in medieval times -- indicates that the Earth's climate rises and falls all the time, and that therefore, human beings don't cause global warming. In this paper, scientists from the National Oceanic and Atmospheric Administration investigate the best scientific findings on the Medieval Warm Period hypothesis, with special emphasis on the massive, wide-ranging, independent UN Intergovernmental Panel on Climate Change. They conclude that "the late 20th and early 21st centuries are likely the warmest period the Earth has seen in at least 1200 years."
In summary, it appears that the late 20th and early 21st centuries are likely the warmest period the Earth has seen in at least 1200 years. For a summary of the latest available research on the nature of climate during the "Medieval Warm Period", please see Box 6.4 of the IPCC 2007 Palaeoclimate chapter. To learn more about the "Medieval Warm Period", please read this review published in Climatic Change, written by M.K. Hughes and H.F. Diaz. (Click here for complete review reference). Discussion of the last 2,000 years, including the Medieval Warm Period, and regional patterns and uncertainties, appears in the National Research Council Report titled "Surface Temperature Reconstructions for the Last 2,000 Years", available from the National Academy Press.
The "Medieval Warm Period"

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  1. Cory, I’m really pleased you’re posting about more global warming issues, but the conclusions in your write-up doesn’t actually match your headline.

    They conclude that “the late 20th and early 21st centuries are likely the warmest period the Earth has seen in at least 1200 years.”

    Well… given that the the “medieval warm period” was supposed to be around 1000-1200 years ago, saying that it’s warmer than it has been at any time since then isn’t an argument that involves the warm period.

    A better argument is the fact that the medieval warm period was never warmer than it is today, that in fact it is at minimum warmer now than at any time in the last 2000 years, so eclipsing the MWP entirely. Citations available here

  2. What all this shows is that the climate can change and can change within a short period of time.

    With all the humans on this planet, changing the vegetation and pumping huge amounts of CO2, methane etc into the atmopshere…only a total idiot would expect NOTHING TO HAPPEN!

    That climate changes is not the real issue, the issue is that our current civilisation is dependent on the current climatic conditions and any change to those could have dramatic and unforseen consequces.

  3. These paleo-climate reconstructions are on pretty shaky ground. Read The M&M Project: Replication Analysis of the Mann et al. Hockey Stick by Steve McIntyre and Ross McKitrick for some pretty thorough analysis of the science and particularly the statistics behind these ‘hockey stick’ paleo-reconstructions.

    The results are not good if you want to believe that these temperature reconstruction graphs are accurate. I would go into the whys and wherefores but it is a pretty detailed subject and you should really read the linked info in detail and draw your own conclusions. (The two links in the “Crash course” bullet point are a good place to start.

  4. I think the real problem with “Global Warming” is that its just pop environmentalism. It takes away focus from other areas that are important -things like plastics disposal, or air quality, or water quality. And speaking of pop environmentalism, whatever happened to the rain forests? Don’t they supply us oxygen? Is that not important anymore? The list goes on. Oh well, at least I drive a Prius. Its ‘green’ until I try to dispose of the battery.

  5. jmiyaku: In what way does it “take away the focus” from those other issues? I think, on the contrary, it greatly heightens those issues. People are much more conscious of recycling, pollution, rain forests and all that now.

    My conservative, blue-collar neighbors, who never used to recycle, now have four recycling bins out front. Air quality? That’s the reason everyone’s buying better cars, and pushing for (possibly dubious) “clean coal.”

    What do you mean, exactly?

  6. Samsam: Here’s a couple of examples for you. Covering the landscape in wind turbines because they are CO2 reducing – habitat, view, and bird destroying, but at least they don’t produce CO2, eh?
    Or how about compact fluorescent lights – more mercury but less CO2.
    Or how about the well-loved Prius – less CO2 but all those nasty chemicals and heavy metals in the batteries to deal with.

    That’s not to mention things like bio-fuel crops driving up the price of food for the worlds poor so we can “save the environment”. Oh and telling the developing world, we’re not going to let you have electricity generation through coal or nuclear, or petrol for your internal combustion engines, so if you want to live you’ll just have to keep going with your slash and burn of the rain-forests and grazing your goats on the grasses that should be holding back the sahara. p.s. we had all those things since before it counted so we get to keep them.

    Just how does the precautionary principle decide which risk to be most precautionary about?

  7. 8 degrees in Detroit right now….

    Honestly,
    I don’t know who to believe on anything any more so I have decided to just use plain common sense in my life whenever possible. I recycle and do whatever I can to help the environment because it makes sense to do so. I still think back to that poor Native American on those commercials from my childhood with the tear running down his cheek and try to do the right thing.

  8. Samsam: Here’s a couple of examples for you. Covering the landscape in wind turbines because they are CO2 reducing – habitat, view, and bird destroying, but at least they don’t produce CO2, eh?

    Habitat destroying: A wind turbine’s footprint, even dozens of them together, is much, much smaller than the footprint of an oil rig, coal mine or nuclear power plant.

    View destroying: you may not like the look of them, but that’s neither here nor there in the environmental question.

    Bird destroying: That’s an overblown myth. See here and here.

    The old turbine designs were estimated to kill about 2.2 birds per turbine per year. Even if 1 million turbines were erected, that would cause a total of 2.2 million bird deaths a year. Now compare that to 500 million bird deaths caused by birds flying into windows, 70 million deaths caused by cars, and 27 million caused by radio antennas. See how it pales in comparison? Consider as well that newer turbines have been designed to be “bird friendly,” with long, very slow moving blades, which will drop the bird deaths to well below the 2.2 birds per year that the older, “dangerous” turbines caused.

    Or how about compact fluorescent lights – more mercury but less CO2.

    Sorry, regular bulbs release more mercury into the atmosphere than CF bulbs.

    Or how about the well-loved Prius – less CO2 but all those nasty chemicals and heavy metals in the batteries to deal with.

    Yes, there are heavy metals in the car batteries, which is why modern hybrids are being made with smaller, more efficient batteries. But the benefits greatly outweigh the costs. Yes, they reduce CO2, a major bonus. But they also require less petrol, which I see you don’t refer to as “nasty” even though it causes even more pollution, regardless of CO2. Not to mention our dependence on foreign oil. The benefits of reducing oil consumption are multitude, not just for global warming.

  9. Climate change denialism?

    It’s a scientific issue. Scientists are supposed to ask, “What if x is true? What if x is not true?” Both things. In equal spirit of inquiry. It’s good for politicians to base policy on science, but it’s not good for scientists to base conclusions on politics.

    It is perfectly sensible to note that (1) the climate fluctuates dramatically over millennia, (2) there is evidence of substantial warming and cooling prior to the current warming period, (3) 1200 years is brief given the sort of phenomena we are talking about. It is also sensible to note that nobody can really define what a normal Earth climate is and that climate modeling is an evolving science. I understand that scientific consensus is that we are in a perilous state of anthropogenic global warming, unprecedented and with possibly dire consequences, but I also understand that the politics of climate science tend to stifle scientific questions that point the “wrong” way, and that this may make bad science. So we must be alert.

    It is sensible to pay attention to skeptics, because sometimes—not always, but sometimes—they’re onto something. Boing Boing welcomes kooks of many stripes and other convictions. Why put your hands over your ears and sing “la la la la” when people arrive with questions about climate change science?

    In other words, grow up and ask what happens if everything you believe is true is not, actually, true. If it is really true, you come out the other side intact. If it is not true, you come out the other side wiser if a little dented. Don’t use names like “denialism” when it comes to science. It makes Boing Boing a less wonderful place to read.

  10. The medievel warm period does mean it is possible that man is not THE CAUSE of global warming, but a factor in said warming. Most sensible people agree in global warming, but how much we contribute to it is not settled. What we can do about it realistically is not settled either.

  11. Unfortunately Mr Doctorow’s post does not include the relevant links. Read the above-mentioned Box 6.4 (on page 468) for more information.

    #10, pseudonym:

    The medievel warm period does mean it is possible that man is not THE CAUSE of global warming

    No, it doesn’t mean that. Read the link; the ‘Medieval Warm Period’ was not GLOBAL; it only applied to certain areas of the Northern Hemisphere (and not all of those regions experienced their temperature peaks at the same time).

    All you can conclude from it is that local climate varies over time; it has nothing to tell us about global climate.

  12. Habitat destroying: A wind turbine’s footprint, even dozens of them together, is much, much smaller than the footprint of an oil rig, coal mine or nuclear power plant.

    So then it depends how many you need to replace one of said plants with wind power, and lets also ignore that you still need backup conventional power anyway for those days the wind isn’t blowing.

    But this is straying far to close to Yet Another Wind Farm Argument so I’ll go to your second point which I think goes to something more general:

    View destroying: you may not like the look of them, but that’s neither here nor there in the environmental question.

    It kind of is important in my opinion. The question I would raise is what specific environment is the perfect one that we should try to achieve? Darwinian evolution pretty much guarantees that any environment will be colonised by life (c.f. bacteria living happily inside nuclear reactors). So who gets to vote on which environments are the perfect ones, and thus which set of species get to survive, and which will be removed? The only possible view, as the alpha species at this point in time, is the one that we want. And to me, that includes pretty views!

    Onto the bulbs question, do you happen to know if this still applies when we stop using coal for power? e.g. from an environmentalist viewpoint is
    CFL + renewables better or worse than incandescent + renewables? Will we re-introduce incandescents at that point? How does nuclear power affect the equation? I don’t know either answer but it made me think at least.

    Also, don’t forget that in many places darkness comes with a requirement for heating your home. Obviously if the heat output of my bulb is reduced by 80W then I need to replace that somehow. So I still need to run that power station, only for my electric heater not my lightbulb. So now I’ve got both the coal->mercury output and the CFL->mercury output. Still seems like a net loss increase in mercury to me. Of course this doesn’t apply in places where cooling is required at night rather than heating, so perhaps it’s not a one-size-fits-all solution?

    petrol, which I see you don’t refer to as “nasty”

    Well when I spill 5 mg of petrol I don’t have to “open the windows and let the room air out for 15 to 30 minutes” before cleaning it up while wearing disposable gloves as your link says you need to for broken CFL!

    Look, don’t get me wrong, I’m not a hard-bitten capitalist with a “consume what I want and forget the consequences” attitude – I reduce, reuse, recycle what I can. I just prefer value for effort – i.e. windfarms and CFLs are not going to be the solution to our problems, and the money could be better spent elsewhere.

    If I had control of the world’s global warming mitigation funds I would channel it all into basic education and raising the standard of living
    of developing countries. The human intellect is the most valuable and scarcest resource in the world, so that’s what we should be nurturing.

    Look at what “western” science and engineering have managed to achieve in the past 100 years. Imagine how much more we could achieve if all of Africa, India, China, etc. had the education and the opportunity that the “west” has had – how many potential Einsteins have we lost to poverty and lack of education? Those are the people who could help us through this (potential, far future) crisis, and any others we encounter before or after that.

    Sadly the current trend of enviro-activism will deny them access to that development (and particularly deny access to cheap and reliable power need for that development) which is a greater loss to humanity than any near-term global warming consequences.

  13. just so I am on record:

    1. man has irrevocably shifted the planet’s climate thorough burning etc.
    2. this might be mitigated slightly by immediate concerted effort.
    3. there will be massive population movements as people seek to survive.
    4. only as many of us as we want has to die.
    5. #4 above is all that matters.
    6. see point#5 above.

  14. the ‘Medieval Warm Period’ was not GLOBAL; it only applied to certain areas of the Northern Hemisphere (and not all of those regions experienced their temperature peaks at the same time).

    Or read the link I provided in #3. Nobody knows if, what, where, or when the MWP existed to any degree of accuracy beyond the general understanding that many historical texts mention things that lead us to believe it was warmer then that it is now (in at least some places for some unknown period). Unless you happen to know of a worldwide thermometer-based temperature record that stretches back the middle ages? If not, c.f. #3 for the accuracy or proxy-based reconstructions (or lack thereof).

  15. Tania @9: While I, in a general sense, agree with the notion that skeptics should not be blindly dismissed, that’s hardly the case regarding the climate change argument. The arguments against it are almost never science, even in the rare instances when they even bother using facts.

    Most of the stances against global warming are literally denial, and nothing more. Read NJP @11 for an excellent example of name calling and hate mongering. “The faithful,” please. Or one of my favorite, oft repeated phrases, “In my opinion, the science supporting global warming is weak.” Opinions are what you have about the flavors of ice cream you prefer. As you yourself point out, if the science is actually weak, you can demonstrate it, and you will say, “here are the facts showing why the science is weak.” The appeal to opinion is denialism.

    But when it comes to applying science, the opposition is hardly any better. You have to comprehend that simply showing holes in a theory is not a ‘scientific’ demonstration demonstrating skepticism. Even were I to show, conclusively, that all data involving the effects of green hours gasses thus far had been entirely fabricated, all I would have done was poked holes in one theory. Such evidence has done nothing to scientifically promote any argument or idea. In short, I have no scientific reason to doubt global warming at at all. I simply have reason to doubt this one, single defense of global warming.

    To actually promote skepticism scientifically, you would have to define and defend alternative theories, and that means a lot more than simply saying “its plausible that all climate change is natural and cyclical, so I’m going to lazily assume that this is the case and ignore all other ideas.” This behavior isn’t science, its long winded ignorance, embracing blind assumption over reasoned conclusions upon which to found ones beliefs. When you espouse this over rational ideas, that’s when your belief structure does, in fact, become denial.

    So no, we don’t have two equal camps of science fronting two reasoned scientific theories. We have one such camp, and then we have those who are clearly looking to ignore them via any excuse they can come up with, while presenting no coherent, stand alone, scientific defense of what they claim to believe. So we should call this second camp denialism, because its not science. Science is when you can show evidence supporting your conclusion, not merely posit it as a plausible hypothesis without any testing, reasoning, etc.

  16. I can’t believe I’m being so nit-picky…

    A “shibboleth” is a secret code word used by members of a group to let others of the group know that they are a member. It does not mean “red herring” or “straw man” or whatever exactly “shibboleth” was supposed to mean in that first sentence.

    http://en.wikipedia.org/wiki/Shibboleth

    Cory is one of my favorite living writers and I’m surprised at this…

  17. Vendorx @16
    To actually promote skepticism scientifically, you would have to define and defend alternative theories

    Uh…no. I don’t have to know what is right to prove you are wrong. “I don’t know” is a perfectly valid answer in science, sadly one that you won’t find either side of this debate using much.

    As an example, consider some of the long standing mathematical theorems like the famous “Fermat’s Last Theorem”. For many years the correct scientific answer to whether they were true or not was “I don’t know”. Many people tried to give proofs, which were shown to be incorrect and thus rejected. Not replaced by a better proof, just rejected and returning us to “I don’t know”. Finally it was solved, and (so far) no one has found a flaw in the proof, so the proof stands.

  18. What have you actually proven FARRAGO? That you don’t understand how worldwide temperatures are measured in the past such as tree rings? (Which is how they know when Jamestown was founded, this part of the country was in a severe drought, typically associated with higher temperatures).

  19. I don’t think it’s possible to influence people’s behavior in a lasting way without good data, good science, and healthy debate.

    I think the use of the term “climate change denialism” goes against that by implicitly dividing participants into two camps (“with us or against us”) and ridiculing anyone who doubts the party line.

    Furthermore the phrase “massive, wide-ranging, independent UN Intergovernmental Panel on Climate Change” is an appeal to authority, implicitly asserting that only nut cases would disagree with their findings.

    My problem with the IPCC is that it’s so difficult to drill down to the actual science that got done. The web site is crammed with press releases, syntheses, and disclaimers. Here’s a choice phrase from the 2007 synthesis report, from what’s arguably one of the most important sections (2.4 Attribution of Climate Change):

    Temperatures of the most extreme hot nights, cold nights and cold days are likely to have increased due to anthropogenic forcing. It is more likely than not that anthropogenic forcing has increased
    the risk of heat waves. Anthropogenic forcing is likely to have contributed to changes in wind patterns, affecting extra-tropical storm
    tracks and temperature patterns in both hemispheres. However, the observed changes in the Northern Hemisphere circulation are larger
    than simulated by models in response to 20th century forcing change.

    If you have the least bit of scientific curiosity, doesn’t that passage leave you unsatisfied? Doesn’t it make you want to see more data?

    I think we should be looking for bugs in the IPCC documents and discussing them openly, the same way security problems get resolved in open source software. Declaring the IPCC to be a kind of Bible and mocking nonbelievers is not going to get us anywhere.

  20. Farrago @17 :

    “I don’t know” is a perfectly valid answer in science, sadly one that you won’t find either side of this debate using much.

    Yes, this is very true, “I don’t know” is entirely valid in science, but unfortunately that is not what a skeptic is, so your response really is a meaningless cry into the darkness which passes unnoticed in the night by my entire freaking point.

    Global warming skeptics are not saying, “we don’t know, ” they are saying, “we think you are wrong and that this alternative notion is RIGHT,” but the problem is that they’re showing precious few reasons why the one idea is, in fact, wrong, and absolutely none as to why what they claim to believe is right. So they’re not saying they don’t know, they’re saying they think they do know, only not for any reason, as such.

    The reason your proof fails to provide an adequate example is because it is a legitimate case of “theorize” vs “don’t know and you’re theory can be disproven.” Global warming is, “we don’t want to believe your theory and we gleefully claim that the exact opposite is true but we can’t explain why.” Hence skeptic/denial.

  21. @ qole #16:

    Quoting the article you cited: “Shibboleth is any distinguishing practice which is indicative of one’s social or regional origin.”

    A shibboleth is usually a word or phrase which you’ll pronounce differently depending on where you came from. It’s not a code word or password, although people sometimes use one as a password.

    Cory is referring to the fact “ACG deniers” talk a lot about the medieval warm period and that “ACG exponents” (?) don’t. That’s still not exactly a shibboleth, but it’s similar.

  22. @20, VendorX
    “Global warming skeptics are not saying, “we don’t know, ” they are saying, “we think you are wrong and that this alternative notion is RIGHT,” but the problem is that they’re showing precious few reasons why the one idea is, in fact, wrong, and absolutely none as to why what they claim to believe is right. So they’re not saying they don’t know, they’re saying they think they do know, only not for any reason, as such.”

    What? No. Are you even thinking before you type here or what? Skeptics are saying “We don’t know, and we are pretty damn sure YOU don’t know either (due to lack of evidence or ways of proving anything)”
    That’s the rub here, we can’t say with any certainty one way or another, whether human contributions of CO2 are significant, or whether or not a temperature increase is a bad thing. There are no proofs here, just wild conjecturing into the thin air. That’s the _problem_. Do you start basing policy that affects the whole world on thinly veiled suppositions?

    Science has never worked like this before.. you don’t get prizes for looking at a graph of some shit and saying “I bet humans are responsible for this” at some point. At least, you shouldn’t.

  23. palindromic @22 : except that none of what you’re describing is happening. First of all, the effects of green house gasses aren’t guesswork. Science has tested and supported those notions for decades, such that they’re taught as part of general public schooling across a lot of the first world. What’s funny is that I hear a lot of people claim, like you did, that its all just wild claims, but you never show any flaw with this simple, widely distributed science.

    But again, and I can’t stress this enough, the other side is not merely saying that they don’t know. Twenty years ago they were flat out denying that the climate was warming at all, and now they’re flat out denying that humanity could be responsible. They are not merely saying ” no one knows.” If they were, then they’d also be saying, “well dammit lets get some hard science in there and test it!”

    What they’re in fact saying is, “why bother reacting to something we’re going to dishonestly and without reasoning pretend is insubstantial?” You know, rather like you just did above. And for the record, science has typically worked like this, or worse.

  24. The effect of greenhouse gasses isn’t guesswork, but it’s also not rock solid established science. Remember the ozone holes that were going to cause all of our skin to melt off in huge cancerous sloughs? The truth is we have a pretty weak model of how the atmosphere actually works to do what it does.

    The problem is, you think it’s some kind of established and well documented thing that the amount of CO2 man emits has been proven to increase temperature by X degrees. These things have been inferred, as I said, by looking at graphs. It’s non-science and it’s damaging to the world of Science with a capital S.

  25. I think that people should be approach the subject of global warming with caution. We should probably work to lower our output of carbon dioxide, but we should not rush headlong into capping emissions. I think we just need to play this issue by ear, there is some variance in the graph of 20th century temperatures. The temperatures were lowest from 1945-1975 and then began rising, in fact, many people thought in the 1960s that the earth was cooling into another ice age. If we blindly and unquestioningly accept these statements WITHOUT skepticism, or if we beat down the people who cast doubt on our thoughts, we’re not getting anywhere. For scientists to liken skeptics of their theories to Holocaust deniers is childish and unscientific. The corollary to that is that using the title of famous scientists or the UN to prove your theory or hush dissent is also childish. I’m just worried that this is going to be the next big scam, they tell us that there COULD BE CATACLYSMIC DISASTER UNLESS WE (insert profitable action here). We do (profitable action) and they make a killing and then TAH-DAH, no disaster. Y2K bug anyone?

    I think that global warming will be the next War on Terror. Something noticeable and disastrous happens, we rush towards combatting it, but we’re fighting against something that’s far beyond our poor power to stop. Some private contractors make fortunes and we end up conned out of mass amounts of money.

  26. Palindromic : no, none of what you’re saying about capital S science is true. A case in point, we understand the generals of weather patterns. We still can’t predict when a hurricane will form, or how strong it will definitely be (although we can make some good guesses.) So is it somehow your bizarre notion of an affront to capital S science? No. It IS science. And more to the point, its still science we pay attention to, despite its ability to be absolutely right about everything, or even really that right about anything. Same with global warming. Your claims that this is somehow a wild claim from the left field that jumps the track of all prior scientific behavior isn’t merely wrong, its bizarre and baseless. I wish there were a less rude way to put this, but it strongly suggests that you have no real grounding in science, its history, or its modern, practical usage. Look at the science of nutrition, physics, biology, meteorology, even computing, all of this is resting on unstable, constantly evolving ground. You’re trying to espouse this mythical notion that there is some ‘true, pure’ science out there which never gets anything wrong and has all the answers, and that’s the world of make believe, not science. Climate change is no different than our models for evolution, diet or weather, and yet you’re not saying that all meteorology is some radical breach of the capital S scientific method? Why not?

  27. VendorX:

    :(

    Don’t accuse me of not understanding how science works, please. We understand weather patterns in that we can look at cold and warm fronts with satellites, and infer what they will probably do next (based on moisture content, location, jetstreams, etc) We have satellite data and we can infer things from what we see, and have seen. Okay? It doesn’t always work.. a lot of times the weather people will say “It’s likely it will rain tomorrow” and then it doesn’t rain at all, but in fact is clear and sunny. Right?

    It doesn’t mean they are idiots or not scientists, it just means they don’t know _enough_ about how the weather actually _Works_ to make accurate _predictions_.

    Kind of like what climatologists are trying to do with man’s production of CO2. They are _predicting_ it will cause the world to warm. A completely unfair hypothesis because they aren’t trying to explain why the world warmed before, or cooled before. Ds ny f ths mk sns t y?

    D y s hw thr s crrltn btwn “cn’t prdct th wthr” nd “cn’t prdct ftr clmts” ? t ll? Myb tnsy bt? Cm nnnnn…

  28. Qole #16:
    I’ve always understood shibboleth to also mean, “any widely-held view among a certain group of people that is not based in observation, but just custom.” Or something like that. Less formally, it’s all the stuff your family and friends tell you that you never bother to question, but just accept as given.

    Some of the definitions here seem to back that up.

  29. I don’t understand why there are people who hate wind turbines. When I was a kid, people talk about visiting the Netherlands to see the windmills. They were considered nice to look at. Isn’t a wind turbine just a modern version? I wouldn’t mind having thousands of wind turbines near my house and work place. There isn’t any though, due to the lack of wind.

  30. @palindromic:

    Science has never worked like this before.. you don’t get prizes for looking at a graph of some shit and saying “I bet humans are responsible for this” at some point. At least, you shouldn’t.

    Well, this is your problem right here.

    If you believe that the evidence for AGW is a few scientists looking at a graph and spouting out of their asses “Durrr… I bet humans are responsible for this,” then you clearly have no conception of the huge volumes of work on the subject.

  31. Palindromic @ 27

    I am accusing you of not understanding because you clearly don’t seem to understand. Your accusation that scientists studying climate are making no attempt to study or explore the potential causes climate change in the Earth’s past is a perfect case in point. Samsam @ 30 makes this point as well.

    I am personally aware of dozens of various theories regarding various periods of warming and cooling, all fascinating, most with a lot of research behind them and a lot of scientists still studying them. And the results are exactly like you describe meteorology. A bunch of people piecing together a bunch of different theories, tests, effects, and observations and trying to make predictions, with limited accuracy.

    One of those things that has been extensively observed and tested is the effects of human industry on climate. Your claim that somehow hundreds of thousands of independent scientists from over a hundred different nations have ignored all other possible climate models to force the idea that current climate change is 100% man made isn’t just a grossly unrealistic description of the actual scientific environment, its patently absurd.

    So when I say that you don’t appear to understand science, I am not merely trying to be rude. (see: “What? No. Are you even thinking before you type here or what?” from your initial post.) Sometimes when you perceive a flaw in someone else’s core comprehension, you point it out, and the reasons I believe that flaw exists are detailed above.

  32. #25, homestarrunrun:

    many people thought in the 1960s that the earth was cooling into another ice age

    I think you mean the 1970s. Although the popular press did publish some articles suggesting this, this was not a widely held view in the scientific community (less than 10% of climate change papers suggesting cooling).

  33. Prius batteries are NiMH – nickel metal hydride. While nickel is not something you necessarily want to have on your cornflakes the NiMH chemistry was developed (amongst other reasons) as a way of using less Cadmium (remember NiCd batteries?) which is definitely a bad thing to have in your body.
    Prius batteries are recyclable. The Nickel is almost completely recoverable and reusable for another set of batteries or for incorporation into stainless steel, coins, whatever.
    Toyata offers a bounty on dead Prius batteries (there’s a sticker right there on the battery explaining it) in order to discourage any thought of simply throwing them in landfill. As best I can find out they haven’t had to pay out much of this bounty because the batteries are lasting quite a long time. My nearest big city (Vancouver BC) has a number of Prius taxis that have passed 200,000 km without issue.

  34. #26 palindromic

    The accelerated growth of holes in the ozon layer slowed down when we stopped using freon. This indicates that the theories where right. If the holes would have continued to grow at the same increasing speed, it would have caused “all of our skin to melt off in huge cancerous sloughs”, or at least something equally unpleasant. The ozon layer holes mainly cause trouble on the northern hemisphere, i.e. in rich and powerful countries (I live in Sweden where the frequence of developed skin cancer pretty much follows the size of the ozon holes, although delayed a couple of months). The global warming has thus far mostly befall poor and powerless countries, I think that is the reason that we ignored it for decades.

    On the note of wind turbines. They aren’t that ugly and they can be made beautiful, they have frequently been made as objects of art in Denmark. People tolerate a lot of uglier things in their living area. But the turbines do sound awful (worse then a expressway) and they can’t be placed within hearing distance to places where people are supposed to live.

  35. Medieval Warm period regional? I might be reading it wrong but it might prove someone right.

    Emphasis added
    ABSTRACT:
    Planktonic foraminiferal Mg/Ca and δ18O derived sea surface temperature and salinity records from the Makassar Strait, Indonesia, show a long- term cooling and freshening trend, as well as considerable centennial- scale variability during the last millennium. The warmest temperatures and highest salinities occurred during the Medieval Warm Period (MWP), while the coolest temperatures and lowest salinities occurred during the Little Ice Age (LIA). These changes in the western Pacific, along with observations from other high resolution records indicate a regionally coherent southern displacement of the Inter-tropical Convergence Zone during the LIA, with more arid conditions in the northern tropics and wetter conditions in the southern tropics

    From :http://www.ncdc.noaa.gov/paleo/pubs/newton2006/newton2006.html

  36. @11

    Remember that the MWP is a lot harder to quantify due to the unavailability of data and therefore it can’t be taken as conclusive that the Southern Hemisphere didn’t experience some moderate warming.

    Especially when you take into accout that most of the climate change that has occured during the last two centuries has more acutely affected the Northern Hemisphere as there is far more land in the Northern Hemisphere.

  37. the ‘Medieval Warm Period’ was not GLOBAL; it only applied to certain areas of the Northern Hemisphere (and not all of those regions experienced their temperature peaks at the same time).

    And yet, in the Southern Hemisphere, the great migration across the Pacific happened during this time. In Asia historical sources report that the margin of cultivation of citrus fruits was never as far north as in the 13th century.

    Also the global retreat of glaciers that occurred in the period between about 900 to 1300 speaks for the existence of the Medieval Warm Period. An interesting detail is that many glaciers pulling back since 1850 reveal plant remnants from the Middle Ages, which is a clear proof that the extent of the glaciers at that time was lower than today.

    Where does most life exist on earth? Near the poles or near the equator? According to the IPCC the average gloabl temperature in 2007 was 14.7 degrees C. BUT the vast majority of species (plant and animal) live in climates where the average temperature is above 14.7 degrees C (Amazon, Malaysia, Ecquador, thailand, africa) So how is an average global temp rise of more than 2 degrees going to be so disasterous????

  38. I just have a few questions for some of the posters on here- 1) I’m just curious as to where SamSam got the statistics for the 578 million bird deaths per year in the US from radio antennas and windows. It’s preferable, when making such large claims, to back them up by scientific researcher (the more, the better. 2) I would also like to ask SamSam why they think that there is mercury in conventional light bulbs. If there is (the only metals I’ve ever heard of being present in light bulbs are steel and tungsten) then it is very insignificant compared to the amounts found in fluorescent bulbs. Besides, where would they use mercury in conventional light bulbs- the metals they do use are chosen for their resistance to heat- not their low melting points!
    And 3) people use the hockey stick diagram to debunk the MWP. However, you should go to http://www.john-daly.com/hockey/hockey.htm for some more enlightening details on the diagram

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