The Rise Of Empires As Seen By Trees
    By Hank Campbell | January 14th 2011 11:40 AM | 4 comments | Print | E-mail | Track Comments
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    In ancient times, when things went wrong in battle or the economy, people blamed leaders (if they didn't like them) or the Gods (if they liked the leaders) but maybe they should have blamed global warming.   Errr, and cooling.

    A new study in Science uses the same techniques as dendrochronology to map the rise and fall of empires and cultures as it was recorded in tree rings - and then to weather conditions.

    Obviously this requires some calibration, which is as much art as science.    They took weather records from the past 200 years (I know, I know, sketchy for all but the last 40 years, but that is why I say it is tricky) and then mapped those temperatures to still-living trees and examined how temperature and moisture affected tree-ring growth.

    Then, armed with that sort of decoder ring they went back in time, looking at wood in old buildings or otherwise preserved.    They call the results 'precise' and that is not accurate but it sure is interesting - and the results are precise assuming the baselines they created are accurate, but there is no way to prove that.

    The results, they tell Andew Curry at Science, show results like warm, wet summers ideal for agriculture mapping to prosperity and long-term droughts that match the timing of barbarian invasions while colder, wetter weather coincided with the plague that devastated Europe in 1347.

    More accurately than trying to blame weather for the fall of Rome, though, is that it gave them a rough measure of human activity.  During good times, more trees were cut down for building and fuel, leaving behind more samples, while during bad times the wood samples are few.   

    So even the absence of data can tell us something about the conditions of the time.

    Citation: Ulf Büntgen, Willy Tegel, Kurt Nicolussi, Michael McCormick, David Frank, Valerie Trouet, Jed O. Kaplan, Franz Herzig, Karl-Uwe Heussner, Heinz Wanner, Jürg Luterbacher and Jan Esper, '2500 Years of European Climate Variability and Human Susceptibility', Science DOI: 10.1126/science.1197175


    Is that a little bit simplistic. I f you want to talk about Rome there are several reasons who pulled down the Roman Empire. I don't have time tonight, but just for the barbarians, they rushed into the vast roman Empire, because they were scared to death by the Mongolians and the Huns...

    Absolutely, I am writing about a study done by someone else, not advocating the truthiness of climate change leading to the fall of the Roman Empire or global cooling causing the Plague!
    And I submit you the Europe invasion by Vickings and Normands during IX century. In those years, the Scandinavia crossed a period of warming, but they made raids over Europe with a single goal : Looting into cities and isolated and unarmed monasteries. $$$

    The same phenomenon happened about in the same period of time. The muslim Sarrazins made the conquest of Sicilia, and become pirates who terrorised the Mediterranean sea. Taking slaves and welth

    Another group who rode over Europe was the Turco-mongolian barbarians who came from Hungary for simply steel, kill .and destroy...

    Brieve, it is true that the article is interesting, but the main reason who could incite a group of warriors to attack another kingdom or another country, is that the leaders have the conviction that they can win with benefits.

    Climate change is correlation/causation du jour for a lot of things.   We may not agree it had the impact these fellows do, but they got me to write about it.   So I guess they did what they set out to do.