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Climategate?

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Comments

  • #602
    coletti
    Closed Accounts Posts: 79 ✭✭coletti


    By calling it an "error", that suggests that it was something which the IPCC did inadvertently and by mistake.

    For me, I find it hard to believe the IPCC thought they had explored the available evidence from some, or the majority, of qualified scientists, evaluated the evidence and come up with a reasonable and logical conclusion, rather that what they did which was to lift a journalists story from a magazine, consult no one, and make a claim which was entirely based on a magazine article, for which there is, and was, no evidence whatsoever.

    To me, that is more than an "error".

    I wasn't aware there was a review carried out of the claims of the IPCC claiming they had evidence that the Himalayan glaciers will have melted by 2035 as a result of global warming/climate change. Are you confusing the review into the leaked emails with the claim by the IPCC re the Himalayan glaciers will have melted by 2035 as a result of global warming/climate change? I am talking about the latter. Are you talking about the former?


  • #603
    Macha
    Moderators, Science, Health & Environment Moderators Posts: 6,385 Mod ✭✭✭✭Macha


    coletti wrote: »
    By calling it an "error", that suggests that it was something which the IPCC did inadvertently and by mistake.

    For me, I find it hard to believe the IPCC thought they had explored the available evidence from some, or the majority, of qualified scientists, evaluated the evidence and come up with a reasonable and logical conclusion, rather that what they did which was to lift a journalists story from a magazine, consult no one, and make a claim which was entirely based on a magazine article, for which there is, and was, no evidence whatsoever.
    This is an inaccurate account. What actually happened is the reference was taken from a WWF report, which in turn based the figure on an interview with a scientist. The WWF report was not peer-reviewed and as such, the inclusion of the report did not follow proper IPCC procedure.

    Ultimately, it would appear that the original year was 2350, not 2035. I might also add that this claim did not make it into the report for policy makers or into the overall synthesis report.

    If you want to read up on the details, I'd suggest you go here:

    http://www.chron.com/commons/readerblogs/atmosphere.html?plckController=Blog&plckBlogPage=BlogViewPost&newspaperUserId=54e0b21f-aaba-475d-87ab-1df5075ce621&plckPostId=Blog:54e0b21f-aaba-475d-87ab-1df5075ce621Post:a2b394cc-5b5f-47ad-8bb5-c1aec91409ad&plckScript=blogScript&plckElementId=blogDest
    coletti wrote: »
    To me, that is more than an "error".
    It's only more than an error if something like the above story is true, which you haven't proven.
    coletti wrote: »
    I wasn't aware there was a review carried out of the claims of the IPCC claiming they had evidence that the Himalayan glaciers will have melted by 2035 as a result of global warming/climate change. Are you confusing the review into the leaked emails with the claim by the IPCC re the Himalayan glaciers will have melted by 2035 as a result of global warming/climate change? I am talking about the latter. Are you talking about the former?
    I am talking about the review by the Dutch government that was released earlier this month.


  • #604
    coletti
    Closed Accounts Posts: 79 ✭✭coletti


    The claim that Himalayan glaciers were set to disappear by 2035 rests on two 1999 magazine interviews with a glaciologist, Syed Hasnain, which were then recycled without any further investigation in a 2005 report by the environmental campaign group WWF.

    I conclude from the evidence that the IPCC is not reliable and that its reputation as a scientific body basing its conclusions on evidence is damaged by this example. You may come to a different conclusion and its not up to me to "prove" it to you any more than it's up to you to "prove" it to anyone else.

    It would be unusual if everyone came to the same conclusion on every matter, and we should respect each others different conclusions.


  • #605
    Macha
    Moderators, Science, Health & Environment Moderators Posts: 6,385 Mod ✭✭✭✭Macha


    coletti wrote: »
    The claim that Himalayan glaciers were set to disappear by 2035 rests on two 1999 magazine interviews with a glaciologist, Syed Hasnain, which were then recycled without any further investigation in a 2005 report by the environmental campaign group WWF.
    I conclude from the evidence that the IPCC is not reliable and that its reputation as a scientific body basing its conclusions on evidence is damaged by this example. You may come to a different conclusion and its not up to me to "prove" it to you any more than it's up to you to "prove" it to anyone else.
    Well then don't ask me to respect your conclusion if you don't want to "prove it". I'm not in the business of just accepting people's opinions or versions of facts at face value.
    coletti wrote: »
    It would be unusual if everyone came to the same conclusion on every matter, and we should respect each others different conclusions.
    Not really. I would respect a differing conclusion to that of the inquiry if it were based on fact and logic. So far I have seen none of that.


  • #606
    edanto
    Registered Users, Registered Users 2 Posts: 2,809 ✭✭✭edanto


    coletti wrote: »
    I conclude from the evidence that the IPCC is not reliable and that its reputation as a scientific body basing its conclusions on evidence is damaged by this example.

    (emphasis mine)

    I'm afraid one example does not evidence make. Methinks you have been confused by climate sceptologists.

    Though to apply your logic to all stakeholders, we would be forced to conclude that by virtue of making any error in the past, a source could not be relied up.

    Have the climate sceptologists admitted to any errors recently? If so, what were they? If not, then would you say that they have never made any errors and are unimpeachable?


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  • #607
    coletti
    Closed Accounts Posts: 79 ✭✭coletti


    taconnol wrote: »
    Well then don't ask me to respect your conclusion if you don't want to "prove it". I'm not in the business of just accepting people's opinions or versions of facts at face value.


    I don't ask you to and have not asked you to.


  • #608
    coletti
    Closed Accounts Posts: 79 ✭✭coletti


    edanto wrote: »
    (emphasis mine)

    I'm afraid one example does not evidence make. Methinks you have been confused by climate sceptologists.

    Though to apply your logic to all stakeholders, we would be forced to conclude that by virtue of making any error in the past, a source could not be relied up.

    Have the climate sceptologists admitted to any errors recently? If so, what were they? If not, then would you say that they have never made any errors and are unimpeachable?

    I'm not sure I agree that we can't learn anything from one example. Evidence is evidence, and doesn't become evidence only when it is becomes apparent 10 times.

    For my money, if a person or organisation is prepared to be less than honest once, then that indicates that they are probably prepared to be less than honest more than once. You may disagree, but to me the evidence shown of the IPCC shows a mindset or agenda.

    How many similar examples would you consider makes evidence? And why do you consider one example is not evidence?


  • #609
    Macha
    Moderators, Science, Health & Environment Moderators Posts: 6,385 Mod ✭✭✭✭Macha


    coletti wrote: »
    I'm not sure I agree that we can't learn anything from one example. Evidence is evidence, and doesn't become evidence only when it is becomes apparent 10 times.

    For my money, if a person or organisation is prepared to be less than honest once, then that indicates that they are probably prepared to be less than honest more than once. You may disagree, but to me the evidence shown of the IPCC shows a mindset or agenda.

    How many similar examples would you consider makes evidence? And why do you consider one example is not evidence?
    So because one individual did not follow proper IPCC procedure, the entire organisation is fit for the bin? By this logic, only the data from flawless research work should be considered, which is itself an impossibility since research is carried out by humans.

    Is that a reason to discount the work of the IPCC? No says each of the three independent reviews.


  • #610
    coletti
    Closed Accounts Posts: 79 ✭✭coletti


    taconnol wrote: »
    So because one individual did not follow proper IPCC procedure, the entire organisation is fit for the bin? By this logic, only the data from flawless research work should be considered, which is itself an impossibility since research is carried out by humans.

    Is that a reason to discount the work of the IPCC? No says each of the three independent reviews.

    I wasn't aware that it was one individual, and its great to learn that. Are you able to provide evidence to prove it was one individual? :D Who was it and what disciplinary action has been taken against the one individual?

    Was it the same individual who included, in the 2007 report "“up to 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation”.

    This time based not on any scientific evidence, and again not peer reviewed, but appearing to be based on a paper discussing, incredibly, the effect of logging and forest fires on the Amazon.

    This seems very similar to the previous story about the claim that Himalayan glaciers were set to disappear by 2035. Both claims are untrue, and both show that the IPCC repeated claims without checking them, without peer review, and without seeming to do even rudimentary checks as to their veracity.


  • #611
    Macha
    Moderators, Science, Health & Environment Moderators Posts: 6,385 Mod ✭✭✭✭Macha


    coletti wrote: »
    I wasn't aware that it was one individual, and its great to learn that. Are you able to provide evidence to prove it was one individual? :D Who was it and what disciplinary action has been taken against the one individual?
    I've already posted to quite a comprehensive description of what happened. You might try reading it.
    coletti wrote: »
    Was it the same individual who included, in the 2007 report "“up to 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation”.

    This time based not on any scientific evidence, and again not peer reviewed, but appearing to be based on a paper discussing, incredibly, the effect of logging and forest fires on the Amazon.
    Um, you might want to keep up with the latest news...
    In fact, as the paper now concedes, the IPCC's Amazon statement was supported by peer-reviewed scientific evidence. In the case of the WWF report, the figure had, in error, not been referenced, but was based on research by the respected Amazon Environmental Research Institute (IPAM) which did relate to the impact of climate change.

    The "correction" added: "We also understand and accept that Mr Rowell is an experienced environmental journalist and that Dr Moore is an expert in forest management, and apologise for any suggestion to the contrary."

    But there was more humble pie to eat, because the article also quoted criticism of the IPCC's use of the WWF report by Dr Simon Lewis, a Royal Society research fellow at the University of Leeds and a leading specialist in tropical forest ecology. He made no such criticism.

    So the paper had to retract its remarks about him too. "We accept that, in his quoted remarks, Dr Lewis was making the general point that both the IPCC and WWF should have cited the appropriate peer-reviewed scientific research literature.

    http://www.guardian.co.uk/media/greenslade/2010/jun/21/sundaytimes-scienceofclimatechange
    coletti wrote: »
    This seems very similar to the previous story about the claim that Himalayan glaciers were set to disappear by 2035. Both claims are untrue, and both show that the IPCC repeated claims without checking them, without peer review, and without seeming to do even rudimentary checks as to their veracity.
    Actually, it's nothing of the sort.


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  • #612
    coletti
    Closed Accounts Posts: 79 ✭✭coletti


    taconnol wrote: »
    I've already posted to quite a comprehensive description of what happened. You might try reading it.


    Um, you might want to keep up with the latest news...



    http://www.guardian.co.uk/media/greenslade/2010/jun/21/sundaytimes-scienceofclimatechange


    Actually, it's nothing of the sort.

    Are you saying that you believe what is written in a newspaper article as evidence?

    I can show you countless of newspaper articles which disagree with your analysis. Are you saying you agree that newspaper articles are evidence, or are you saying they are only evidence when they agree with you?

    Are you further saying that the statement "...up to 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation”, did not, in fact appear in the 2007 report?

    Or are you saying that it did appear in the 2007 report and that it is, in fact, correct and backed up by peer review proof and that it is accurate and based on sound science?


  • #613
    djpbarry
    Registered Users, Registered Users 2 Posts: 13,104 ✭✭✭✭djpbarry


    coletti wrote: »
    Are you further saying that the statement "...up to 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation”, did not, in fact appear in the 2007 report?

    Or are you saying that it did appear in the 2007 report and that it is, in fact, correct and backed up by peer review proof and that it is accurate and based on sound science?
    Yes, it is.


  • #614
    coletti
    Closed Accounts Posts: 79 ✭✭coletti


    A link was to an article entitled "Large-scale impoverishment of Amazonian forests by logging and fire" does not, at face value, constitute either sound science or peer review, quite apart from the fact that it is about logging and fire.

    Even if the article says or concludes "...up to 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation...” (maybe you'd be so kind as to point out where the article says this as I can't find it,), the evidence to support this would be the really interesting material to examine.

    I'm looking forward to you pointing out where the article says that, and, if it does say that, further looking forward here to examining the evidence to support the claims.

    I am very excited at the prospect of being proved wrong here, as science is all about being proved wrong, learning, and progressing.


  • #615
    Macha
    Moderators, Science, Health & Environment Moderators Posts: 6,385 Mod ✭✭✭✭Macha


    coletti wrote: »
    A link was to an article entitled "Large-scale impoverishment of Amazonian forests by logging and fire" does not, at face value, constitute either sound science or peer review, quite apart from the fact that it is about logging and fire.
    Maybe you shouldn't take it at face value. Even the most brief of glances would tell you:
    -the article appeared in the highly-respected Nature science journal
    - the lead author of the article comes from Woods Hole Research Centre in the US
    -the article was peer-reviewed

    So your attempts to portray it as not "sound science or peer reviewed" simply, it would appear, by describing it as so, fall flat.
    coletti wrote: »
    Even if the article says or concludes "...up to 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation...” (maybe you'd be so kind as to point out where the article says this as I can't find it,), the evidence to support this would be the really interesting material to examine.
    The article itself requires subscription. You're welcome to subscribe and read the article yourself. After all, it is you that is making the claim that the IPCC made a mistake and therefore it's up to you to provide the evidence to back up your claim.
    coletti wrote: »
    I am very excited at the prospect of being proved wrong here, as science is all about being proved wrong, learning, and progressing.
    You appear more excited at the prospect of misrepresenting facts to suit your argument, which is what most of your efforts on here consist of.


  • #616
    djpbarry
    Registered Users, Registered Users 2 Posts: 13,104 ✭✭✭✭djpbarry


    coletti wrote: »
    A link was to an article entitled "Large-scale impoverishment of Amazonian forests by logging and fire"...
    A link was also provided to a letter from Dr. Daniel Nepstad, which explains the basis for the IPCC statement. You seem to have conveniently overlooked this, so I'll link to it again - he's even provided an email address so you can contact him personally if you're still not satisfied.
    coletti wrote: »
    Even if the article says or concludes "...up to 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation...” (maybe you'd be so kind as to point out where the article says this as I can't find it,), the evidence to support this would be the really interesting material to examine.
    If you want to pick apart the methodology used in scientific papers, go right ahead. But critiquing peer-reviewed publications goes somewhat beyond the scope of an internet discussion forum - apart from anything else, most posters cannot access them. Any shortcomings in said paper (or any other) should really be brought to the attention of the publishers.
    coletti wrote: »
    I am very excited at the prospect of being proved wrong here...
    Oh please...


  • #617
    bonkey
    Registered Users, Registered Users 2 Posts: 15,443 ✭✭✭✭bonkey


    At this stage in the debate, its perhaps worth reminding ourselves (or learning) about what, exactly the IPCC "report" is.

    There are, in fact, four volumes to the report, three from seperate working groups, and a fourth which is a "synthesis" report.

    The three working group reports are :

    WG1 : The Physical Science Basis
    WG2 : Impacts, Adaptation and Vulnerability
    WG3 : Mitigation of Climate Change


    Concentrating on the first 2 of these for a moment, the following can be seen in teh Technical Summary sections of each:

    WG1 wrote:
    The key findings of the IPCC Working Group I assessment are presented in the Summary for Policymakers. This Technical Summary provides a more detailed overview of the scientific basis for those findings...
    ...
    Each paragraph in the Technical Summary reporting substantive results is followed by a reference in curly brackets to the corresponding chapter section(s) of the underlying report where the detailed assessment of the scientific literature and additional information can be found.

    So...WG1's report as its title suggests, is looking at the science.
    WG2 wrote:
    Each chapter presents a balanced assessment of the literature which has appeared since the Third Assessment Report[1] (TAR), including non-English language and, where appropriate, ‘grey’ literature.

    WG2, by its own admission, did not limit itself to looking at nothing but the science. It allowed other sources. It didn't hide this, but rather admitted it straight up. It did, however, state that the assessment reflects "the understanding based onm peer-reviewed literature".

    So...its saying that while non-peer-reviewed material might be included, the understanding - the actual conclusions - are formed from peer-review material.


    Now consider the nature of these errors which have been so contentious. They are all from "grey" literature covered in WG2....they're all from information which was stated up front not to have been key in terms of the conclusions reached. The information which was said to be key? It still stands.


  • #618
    bonkey
    Registered Users, Registered Users 2 Posts: 15,443 ✭✭✭✭bonkey


    coletti wrote: »
    Indeed. It's interesting to note the error was to state, as fact, indeed as scientifically proven fact, that the Himalayan glaciers will have melted by 2035 as a result of global warming/climate change.

    I think you'll find that they didn't claim scientifically proven fact. They didn't even claim fact.

    Don't believe me?

    Here is the exact text, from section 10.6.2 of the WG2 report:

    Glaciers in the Himalaya are receding faster than in any other part of the world (see Table 10.9) and, if the present rate continues, the likelihood of them disappearing by the year 2035 and perhaps sooner is very high if the Earth keeps warming at the current rate. Its total area will likely shrink from the present 500,000 to 100,000 km2 by the year 2035


  • #619
    coletti
    Closed Accounts Posts: 79 ✭✭coletti


    taconnol wrote: »
    Maybe you shouldn't take it at face value. Even the most brief of glances would tell you:
    -the article appeared in the highly-respected Nature science journal
    - the lead author of the article comes from Woods Hole Research Centre in the US
    -the article was peer-reviewed

    So your attempts to portray it as not "sound science or peer reviewed" simply, it would appear, by describing it as so, fall flat.


    Fire in the Amazon was published by a group called Instituto de Pesquiza Ambiental da Amazonia, which is headed by Dr. Daniel Nepstad. It concerns logging and fires in Brazil and has nothing to do with climate change. This article is the basis for the IPCC to claim that 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation. The IPCC made this claim from a document about fire and logging!

    If this is incorrect then feel free to quote from the article and correct me, with the scientific sources and methodology. I’ll bet you won’t as the article doesn’t contain this claim.

    I’m afraid, where I come from, simply saying the author of an article is well respected doesn’t cut the mustard. We need evidence.

    You claim this article was peer reviewed? Who peer reviewed it and where can I check the documents they peer reviewed, their methodology, and their results?

    It may well be that you are entirely happy with the two claims made by the IPCC, the first that Himalayan glaciers were set to disappear by 2035 and, the second that up to 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation, are you may well even believe sincerely that the science is well founded and documented.

    If so I find it hard to agree.


  • #620
    djpbarry
    Registered Users, Registered Users 2 Posts: 13,104 ✭✭✭✭djpbarry


    coletti wrote: »
    Fire in the Amazon was published by a group called Instituto de Pesquiza Ambiental da Amazonia, which is headed by Dr. Daniel Nepstad. It concerns logging and fires in Brazil and has nothing to do with climate change.
    Doesn't it? Forest fires are in no way influenced by, say, precipitation?
    coletti wrote: »
    This article is the basis for the IPCC to claim that 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation. The IPCC made this claim from a document about fire and logging!
    No, "they" didn't. The claim was apparently based on "Global Review of Forest Fires", published by the WWF and available here. While the validity of this source is questionable, the claim itself is supported by evidence in the scientific literature, as explained here. So what we have here is little more than a poorly-referenced statement.
    coletti wrote: »
    I’m afraid, where I come from, simply saying the author of an article is well respected doesn’t cut the mustard. We need evidence.
    The letter from Nepstad above contains several references that you are free to examine at your leisure.
    coletti wrote: »
    You claim this article was peer reviewed? Who peer reviewed it and where can I check the documents they peer reviewed, their methodology, and their results?
    As I’m sure you are only too aware, the peer-review process is (obviously) anonymous. You can however read about Nature’s peer-review process here.
    coletti wrote: »
    It may well be that you are entirely happy with the two claims made by the IPCC, the first that Himalayan glaciers were set to disappear by 2035...
    How many times need it be stated that this has been recognised as an error?


  • #621
    bonkey
    Registered Users, Registered Users 2 Posts: 15,443 ✭✭✭✭bonkey


    coletti wrote: »
    It may well be that you are entirely happy with the two claims made by the IPCC, the first that Himalayan glaciers were set to disappear by 2035 and, the second that up to 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation, are you may well even believe sincerely that the science is well founded and documented.

    If so I find it hard to agree.

    As I've already pointed out, the science isn't founded on these claims. The IPCC report which summarises the science isn't founded on these claims. The science in the IPCC report which utilised "grey" sources is not founded on these claims. The IPCC report clearly laid this out, long before the errors were discovered.

    I'm not sure how you conclude that this is a basis on which to question the foundation on which the science is laid.


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  • #622
    coletti
    Closed Accounts Posts: 79 ✭✭coletti


    I completely agree that the the science isn't founded on these claims. My point is simply that the IPCC made a claim that "...up to 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation...” which was not based on any science.


  • #623
    djpbarry
    Registered Users, Registered Users 2 Posts: 13,104 ✭✭✭✭djpbarry


    coletti wrote: »
    My point is simply that the IPCC made a claim that "...up to 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation...” which was not based on any science.
    Once again, yes, this statement does have scientific evidence to support it:
    http://www.whrc.org/resources/essays/pdf/2010-02-Nepstad_Amazon.pdf


  • #624
    edanto
    Registered Users, Registered Users 2 Posts: 2,809 ✭✭✭edanto


    Well, I guess that puts that claim to rest then. Cheers.


  • #625
    bonkey
    Registered Users, Registered Users 2 Posts: 15,443 ✭✭✭✭bonkey


    coletti wrote: »
    I completely agree that the the science isn't founded on these claims. My point is simply that the IPCC made a claim that "...up to 40 per cent of the Amazonian forests could react drastically to even a slight reduction in precipitation...” which was not based on any science.

    Not too many posts ago, you claimed that you "conclude from the evidence that the IPCC is not reliable and that its reputation as a scientific body basing its conclusions on evidence is damaged by this example".

    You now completely agree that the science isn't based on this example.

    Should we then take it that this means you no longer believe that this example tarnishes the reputation of the IPCC - that you now believe your earlier conclusions were wrong?

    If not, then perhaps you could explain how this example tarnishes something you accept it has nothing to do with.


  • #626
    BluePlanet
    Registered Users, Registered Users 2 Posts: 2,444 ✭✭✭BluePlanet


    Just letting people know there are now photos showing Himalayan glaciers receding.

    http://www.france24.com/en/20100716-photos-show-himalayan-glaciers-receding
    When British climbing legend George Mallory took his iconic 1921 photo of Mount Everest's north face, the mighty, river-shaped glacier snaking under his feet seemed eternal.

    Decades of pollution and global warming later, modern mountaineer David Breashears has reshot the picture at the same spot -- and proved an alarming reality.

    Or was the argument about WHEN the glaciers would disappear, not IF they were receding?


  • #627
    coletti
    Closed Accounts Posts: 79 ✭✭coletti


    BluePlanet wrote: »
    Just letting people know there are now photos showing Himalayan glaciers receding.

    http://www.france24.com/en/20100716-photos-show-himalayan-glaciers-receding



    Or was the argument about WHEN the glaciers would disappear, not IF they were receding?

    Perhaps someone could be so kind as to post photographs of the areas in Greenland which used to be farmed by the Vikings. They are now covered on, oh yes, ice! Whereas when the Vikings farmed there they were covered in....no ice.

    I'm afraid photographs can be misleading as ice advances and retreats all the time. I can show you photographs of ice in 2010 where it hasn't been for years before, but it wouldn't prove anything either as Europe has a particularly cold winter and ice was pretty much everywhere in early 2010 in Europe.

    Photographs aren't mush use as evidence unless, perhaps, they are taken at the same spot on the same date every year for a large number of years to see if we can spot a pattern


  • #628
    djpbarry
    Registered Users, Registered Users 2 Posts: 13,104 ✭✭✭✭djpbarry


    coletti wrote: »
    Perhaps someone could be so kind as to post photographs of the areas in Greenland which used to be farmed by the Vikings. They are now covered on, oh yes, ice!
    Looks pretty ice-free to me.


  • #629
    [Deleted User]
    Posts: 31,118 ✭✭✭✭ [Deleted User]


    djpbarry wrote: »
    Looks pretty ice-free to me.

    A classic example of past climate change, Greenland has been both colder and milder (warmer) than today.

    During the medieval warm period it was mild enough to support mixed farming and a "modern" farming community, then it froze over and now it's ice free again.

    In a couple of centuries time it will again be different.


  • #630
    djpbarry
    Registered Users, Registered Users 2 Posts: 13,104 ✭✭✭✭djpbarry


    Deleted User wrote: »
    A classic example of past climate change, Greenland has been both colder and milder (warmer) than today.
    Maybe, but we do not have a reliable (relative to modern standards) means of estimating Medieval temperatures in Greenland. Furthermore, regional climactic variation in Greenland obviously does not equate to global variation, so all-in-all, discussion of what the Vikings did or did not do in Greenland is somewhat meaningless.


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  • #631
    [Deleted User]
    Posts: 31,118 ✭✭✭✭ [Deleted User]


    djpbarry wrote: »
    Furthermore, regional climactic variation in Greenland obviously does not equate to global variation.

    That's true, but there is evidence of climatic changes in other parts of the world at similar times, some places in the US that had reliable rains became dry for example. Northern Europe had the "Mini Iceage" etc.

    The cold winter (in Ireland) just past was occurring at the same time as parts of North America had their warmest winter for years.

    With weather patterns, if one part of the globe gets an unusually warm period, it's often accompanied by somewhere else getting a colder one.

    The same could be said for the climate.


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