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20th Century Warmest In 1200 Years

gcranston writes "Research from the University of East Anglia in Norwich, U.K. shows that the 20th century was the warmest for the northern hemisphere since approximately 800AD. Historical climate data were calculated from weather 'proxies' such as tree rings, ice cores, and seashells from Europe, Asia, and North America, and attempted to address the shortcomings of earlier studies. The findings support the argument for global warming as a result of human interference rather than natural climate change."

30 of 608 comments (clear)

  1. Interesting... by Seoulstriker · · Score: 3, Insightful

    If this is the warmest in so many years, then back then it was hotter that what we have now.

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    1. Re:Interesting... by Dashing+Leech · · Score: 4, Insightful
      "a) it's not very probable we happen to be in the warm part of a cycle"

      Not that I disagree with the overall belief that it is humans causing the warming trend, but your arguments are not valid. Pick any part of a cycle and you can say the same thing as above. Replace "warm" with "cold". If you believe the models we are on the way upward too, so it's not even a distinct point like a peak high or low. If the cycle is 1000 years of normal temps, 10 years of high temps, and 1000 years of normal temps, then I can see your argument (a 1/100 chance of being in the warm spot when we happen to figure out the cycle). But not something that could cycle over hundreds to thousands of years that we don't have sufficient data to get full cycles for. (Or even not a cycle, just a natural trend with or without us.)

      The second argument (b) says nothing about the validity of a cycle argument. Newton's models of motion accurately portray what happens if I drop a hammar. That doesn't make them "right" and rule out other explanations such as relativity. (Fine, pick on the analogy, but the point is that 1 model working in some cases does not invalidate other possible models.)

      I do think that we play a part in global climate change. But that's just a belief on enough circumstantial evidence. The data is not conclusive and no model (natural or human-caused) explains some of the major observations.

    2. Re:Interesting... by JWW · · Score: 2, Insightful

      What is always debated is if Man is at fault for climate change or not. Clearly the climate is changing.

      The question that is interesting to see never asked is: "Even if climate change is not mankinds fault, would we still be interested in trying to keep the climate from changing."

      I postulate that we would want to keep the climate from changing, because of its impact on our society and economy. But, if the change is not mankinds fault, then coming up with the fix is going to be harder. I think also, that we're emotionally wired to believe that we actually can and are having an impact. On the small scale that is definately so, but on the large scale, I'm not so sure.

      I know its difficult, but it would be nice to find a way to quantitatively measure climate change with regards to mankinds actions. If we make the changes some proposals require, we really must be vigilant at trying to observe change in the other direction. Otherwise we are just emotionally telling ourselves that we're making a difference when we may not be.

      There is a lot of study needed here. This study is a start in seeing the bigger picture.

    3. Re:Interesting... by nwbvt · · Score: 2, Insightful

      Also, this is just a BS statistic. Wouldn't it have been more consistent to say "20th Century Warmest in past 12 centuries"? By using a much smaller interval in the comparision, you get something that sounds much more extreme than it really is. 1200 years really isn't that long, especially considering half of that was during the little ice age.

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  2. OK lets stop before it starts by OverlordQ · · Score: 2, Insightful

    Historical climate data were calculated from weather 'proxies' such as tree rings, ice cores, and seashells from Europe, Asia, and North America, and attempted to address the shortcomings of earlier studies.

    And we all know how accurate and exact historical measurements are.

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  3. Cue the misunderstandings by Anonymous Coward · · Score: 5, Insightful

    Let's take a pool on exactly how many posts this story will receive from partisans claiming that because the earth has been this warm in the past (the 800s) through natural causes, the earth either is not unusually warm now, or if it is warm now it must be because of natural causes--

    not realizing that (1) the thing that makes manmade global climate change distinguishable from natural global climate fluctuations is not how warm the earth has become, but how quickly and consistently the earth has warmed since the industrial revolution;

    and (2) the problem with manmade global climate change is not how warm the earth is now, but how warm it will become if this consistent, quick rise continues...

    What's your guess? 10? 40? 100?

    1. Re:Cue the misunderstandings by Dixie_Flatline · · Score: 2, Insightful

      Mod parent up. The single most important thing to remember about the Earth, and geology and climatology in general is that things happen very slowly. Certainly, there are fast, catastrophic events like Volcanos erupting and Earthquakes changing the landscape, but even those take enormous amounts of time to set up.

      Generally speaking, 500 years is an extremely short time frame for major change to happen on the planet. To see climate change in under 100 years is distressingly fast.

    2. Re:Cue the misunderstandings by electroniceric · · Score: 2, Insightful

      Mod parent up. This is exactly the point.

      Look, if you combine the two unassailable points that
      1) injecting vast amounts of carbon into the atmosphere poses a substantial risk of climate change
      (any "scientist" here care to deny the greenhouse effect?)
      and
      2) we are nearly certain to run out of oil in the next 20-100 years

      it makes absolutely no sense to sit on our thumbs and wait until we're really fscked to work on changing our energy infrastructure. It takes a *little while* to replace every single petroleum-fueled combustion engine car on the planet, so why would we want to do it when our backs are against the wall instead of taking steps now to deal with it?

      OK, now cue the standard whining about how Kyoto will "destroy" the economy (as if the GOP's liared goons like George Deutsch haven't done enough bludgeoning of our scientific competitiveness)... except the American economy has done quite nicely during periods of much heavier taxation, thank you very much. By way of comparison to a true command economy, nobody's seriously proposing that the government outlaw gasoline cars, or even restrict the sale of any of them, or produce its own vehicles. All we're talking about here are a) some taxes on carbon emissions and b) serious investment in alternate energy (order of billions, not 10M somebody sneezed onto the budget and couldn't be bothered to wipe off).

      You know you're living in dark days when common-sense statements like "we should take some steps to fix this real risk" are shouted down by cries of "No! Let's do nothing instead and wait until the problem is really a crisis!"

  4. What happened in 800 AD? by krgallagher · · Score: 2, Insightful
    "Research from the University of East Anglia in Norwich, U.K. shows that the 20th century was the warmest for the northern hemisphere since approximately 800AD. ... The findings support the argument for global warming as a result of human interference rather than natural climate change"

    Help me out here. If it was warmer in 800 AD, what 'human interferance' caused the global warming in the 9th century?

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  5. Snapshot by AnonymousJackass · · Score: 3, Insightful
    The findings support the argument for global warming as a result of human interference rather than natural climate change.
    No they don't. What about the Little Ice-Age? That was a major gloabl climate change that was certainly not induced by man.
    Fact is, we're looking at a ~2000 year snapshot of an incredibly comlex system that's a few billion years old.
    I'm not saying that there isn't claimte change -- of course there is. I'm also not saying that man doesn't affect it -- of course we do. But what I'm saying is that we don't know how we are affecting it. Maybe the "Little Ice-Age" ended because of man. Perhaps we saved ourselves from freezing to death by creating a cozy CO2 blanket?
    My 2c...
    1. Re:Snapshot by lgw · · Score: 3, Insightful

      A stable climate is a myth. There's no evidence of such a thing.

      It's true that human CO2 emissions are pushing climate change in some direction, but no one has a clue whther the results of that change will be more or less pleasant then the climate change that would have happene without human intervention.

      So we don't know which way we're driving, all we know is we're driving quickly. That's reason for concern, to be sure, but not for despair.

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    2. Re:Snapshot by Random+Utinni · · Score: 2, Insightful

      I don't know why people keep getting into arguments over whether climate-change/global-warming is caused by humanity or not. Does it really matter? When the house is burning down, does it matter at that moment if it's arson or just an accident? No... the thing that's important is: put out the damn fire.

      Right now, I don't care if we're the ones responsible for climate-change. I just don't want to deal with the consequences of it. Let's cut back on CO2 emissions... not because they may or may not have caused this climate change, but because by cutting back we can compensate for the changes that are happening.

      I don't think anyone is really disputing that the changes are happening... they're disputing whether we're responsible or not. And that's just ridiculous. Fix the problem first. Then figure out who to blame... not the other way around.

  6. Re:If only it felt like it by OwnedByTwoCats · · Score: 4, Insightful

    And, in a few years, when melting arctic and Greenland ice has disrupted the Atlantic Conveyor, northern europe, including Great Britain and Scandanavia, will be much, much colder.

  7. Re:Global warming is a myth because we say it is. by pete-classic · · Score: 5, Insightful
    You said:

    It's stating the facts, not going to extreme left positions and saying humans are causing the earth to heat up.


    The article said:

    The researchers think their work bolsters the case that global warming due to human activity has created a change in climate unlike anything seen in more than a millennium.


    What the fuck?

    -Peter
  8. Re:If only it felt like it by Daniel_Staal · · Score: 4, Insightful

    The warming of the globe as a whole will cause some locations to actually cool down, as air and water currents re-route.

    This does not change the fact that the globe as a whole is warming.

    (And frankly it is irrelevent whether humans are to blame or not. It is warming, which is going to cause climate change. Are we ready for it? If not, we may want to try to stop it (or at least slow it down).

    I doubt we are.)

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  9. Right on by Anonymous Coward · · Score: 2, Insightful

    We're looking at a ~2000 year snapshot of an incredibly complex system that's a few billion years old and that our immediate livelihood and wellbeing depend on. And we keep pushing it like it has never been pushed before - all the while claiming that because we don't understand the system, it's ok to continue current behavior. How is that smart?

  10. I feel like I'm taking Crazy Pills! by jamesdps · · Score: 3, Insightful

    I'm going insane here -- everyone is saying "how does this prove anything if it was warmer in 800AD?" THAT'S NOT WHAT THE ARTICLE SAYS! "Warmest in 1200 years" does NOT implicitly mean it was warmer 1200 years ago, people -- read the article, we CAN ONLY TEST BACK 1200 years using ice cores, trees, etc.... it was COLDER 1200 years ago, that's what the article says... and as for the folks who mentioned the Little Ice Age, etc. -- yes, they mention that too (and the Medieval Warm Period from 890 to 1170), but both eras were not CONTINUOUSLY warm or cool, but were PUNCTUATED by hot and cold SPELLS... The concern of global warming is that the CONTINUOUS temperature is changing. I will concede that without data before 800AD, the study is looking at a pretty small sample of time, and that there are so many factors in such a hugely complex weather system to take into consideration, so I have no problem at all with those arguments, just with the fact that the majority of people here seem to be good at quickly sorting through text looking for keywords (such as "since 800AD") without actually COMPREHENDING what they are reading.... /rant.

  11. Re:Food for thought by Anonymous Coward · · Score: 3, Insightful
    Yet, in spite of all this, the climate is still cooler than it was in 800 AD.

    No, TFA doesn't say this at all. Rather, their reconstruction only goes back to 800 AD; apparently they felt like the quality of their data wasn't sufficient to support a hemispheric temperature reconstruction prior to this -- not too surprising if they're relying heavily upon tree rings, though others (e.g. Mann et al.) have taken this sort of reconstruction back at least 2000 years (with essentially the same results).

  12. The headline of this story should read... by Artifex33 · · Score: 2, Insightful

    "7th century A.D. found to be warmer than 20th."

    Reads a bit differently, doesn't it?

    How many cars were belching so-called greenhouse gases across North America in 800 A.D.? Were the theories of man-caused global warming correct, then shouldn't the 20th century be BY FAR the warmest century ever, thanks to car emissions and CFC's?

    Perhaps, before they were thinned out, the environment was being catastrophically altered by all the buffalo flatulence.

  13. Re:If only it felt like it by spun · · Score: 5, Insightful

    That's an important point. Calling the phenomenon Global Warming is perhaps misleading. Some places will get warmer, others colder. Some will be wetter, some dryer. Dumping more energy into a chaotic system like the climate means more extreme climates, not necessarily warmer ones.

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  14. Re:Global warming is a myth because we say it is. by drdewm · · Score: 2, Insightful

    I walk around now in the "Winter" without a jacket on year after year and as a kid I couldn't do that. The hopelessly corrupt and biased arguments not withstanding my experience tells me something is different.

  15. exactly by chinadrum · · Score: 2, Insightful

    When we can get a reliable weekly weather forcast I'll start putting more faith in their predictions and understanding of a few billion years of changes.

  16. Duh....its the end of an ice age stupid by katorga · · Score: 2, Insightful

    The last ice age started melting roughly 10,000 years ago. The climate has been on a warming trend since that time. The average temperature for the earth over the historical period since complex life developed is much warmer than it is now. Logically, our current mean temperatures are abnormally cold compared to the mean temperatures over the last 35 million years.

    The high probability is that "global warming" is simply the globe resetting from the "global cooling" of the last 100,000 years. That may not be good for us, since we evolved to live in a cooler climate, but its normal for the planet.

    At the end of the day, the argument is not how to prevent global warming since that cannot be done. The argument is how to adapt to the new conditions.

  17. Implications by Peter+Mork · · Score: 4, Insightful

    Not necessarily:

    Assume we are looking at n time intervals numbered 1, 2, ..., n. If the maximum observed temperature was in interval n, we can assert that this interval was the warmest of the last n intervals.

    Now consider interval 0. If this interval is warmer than n, the strongest assertion we can make is that the recent interval is the warmest of the last n. If the recent interval is warmer than 0, we could make a stronger assertion. However, the validity of 'warmest of the last n remains.

    In effect, you are assuming that the researchers made the strongest possible assertion. Another alternative is that they were only able to measure a certain number of intervals.

  18. Re:Logic clew-by-four by qw(name) · · Score: 2, Insightful


    A very distinct possibility is that their data collection methodologies are flawed.

  19. Re:Global warming is a myth because we say it is. by greginnj · · Score: 4, Insightful
    Now what doesn't amke sense to me is that they say "yes, it has been this warm (and warmer) before.... BUT this somehow proves that it's human activity making it warm this time."
    Huh? Where in TFA do they say that it's been that warm (and warmer) before? They say:
    the 20th century has been the most widespread and longest period of unusual climate experienced at any time during at least the past 1,200 years
    Note well the 'at least', meaning they only looked at tree rings going back that far; it doesn't show that anything was necessarily warmer (or colder). This study has no info on pre-800AD.

    Now let's look at the other hot-button sentence:
    The researchers think their work bolsters the case that global warming due to human activity has created a change in climate unlike anything seen in more than a millennium.
    The key word here is 'bolsters', not 'makes' the case. How could it bolster? Because we know CO2 is going up, and climate models show CO2 leads to heating. Also note that there are two things to prove -- first, is global warming occurring (whatever the cause), and second, what caused it? This study makes a strong case for proving the first. The fact that the tree-ring data agrees with the CO2 models must be explained somehow -- it could be a coincidence, it could be there are errors with the models or with the tree-ring study, or it could be CO2 heating. I'd accept your criticism if they said 'conclusively proves', but 'bolsters' is acceptable.
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  20. Get Together For Warmth by Doc+Ruby · · Score: 2, Insightful

    Everyone stop fighting over whether humans have caused the current climate change. Those saying "NO" aren't going to change their minds, even as incremental new evidence adds to the substantial body already accepted by climatologists - or maybe they're right. It's not worth arguing about, because it's an abstract blame game.

    What is worth arguing about is how to slow, stop or reverse the change obviously now underway. The same science used to fight the blame game is much better used to learn how reducing emissions and sinking carbon can mitigate the serious risk of climate change destroying our civilization. Past civilizations, like the Anasazi in the American Southwest and whatever you want to call the civilization that desertified the Sahara across to the Gobi in China, might not have had our advantage of science and engineering. So their change happened slower, but was more inevitable. Let's harness our climate science to create new climate engineering to cope with this climate change, whether it's manmade or as natural as the arrival of Winter.

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  21. Re:Food for thought by IWannaBeAnAC · · Score: 2, Insightful

    The problem is, for every isolated instance of cooling that you dig up, someone else can dig up a (or, more likely, a whole bunch) of isolated instances of warming. This kind of argument doesn't get us anywhere.

  22. People who argue GW are funny.... by duffstone · · Score: 2, Insightful

    Even if the human race and all trace of our existence were to be wiped off the face of the planet, Do you really think things will return to normal now? And if you can answer that question, maybe you can explain just exactly what normal is anyway.

    I think most people get so caught up in the argument that they don't realize how stupid they sound. You do realize that even if everyone in the world got a soft heart and green conscious, we'd still be burning fuels, we'd still be pumping out WV and Co2, We'd still need fires or some type of heat to keep us warm, still need livestock or something to eat, and still need some way to get around.

    Even tree-hugging green freaks won't give up their modes of transportation or winter heat, or processed / clean foods. If they did, they'd be living the hermit life in the back woods competing with the wildlife for food. Which would be a fantastic TV show, but I digress.

    What really makes me laugh are the people who are fully clothed with picket signs walking around telling industry to stop killing the world. As if the clothes on their back were completely made industry free. As if their food were industry free. Tofu is processed... Common folks... Hybrid cars contain plastics, yes they are derived from petroleum products. Most "Necessary" chemicals and vaccinations are either based on petroleum, or produced in "Industry" that uses petroleum.

    Paper signs are produced in factories, guess what, they use petro to power the factory.

    The world cannot be saved by us. You can preach, picket, and protest all you want, but some moron somewhere is going to burn something, releasing heat, Co2 and WV into the atmosphere and 'WHAM' we're back to square one. But we might as well argue the what if on /. Anyway cause it's Friday and we're obviously all bored and ready to go home and fire up the "Green" computer and play WoW....

    Right?

    -Duff

  23. Change by Mark_MF-WN · · Score: 2, Insightful

    What a lame criticism. I use CE/BCE because that's how I was taught throughout high school and university. You should try to deal with the fact that terminology changes. Or do you still refer to the sky as "the heavens", refer to the number 20 as "a score", and your car as an "automobile"? Do you use Roman Numerals? For that matter, AD itself is a relatively new term; people used to refer to "the 2006th year of our lord". Why not just revert to that, while you marvel at the miracle of fire and ponder the concept of using round wooden structures to accelerate travel. Seriously, grow up and try to live in the real world.