Tree Rings Suggest Roman World was Warmer than Thought

Michael Mann

By Fred Pearce

How did the Romans manage to grow grapes in northern England when most climate studies suggest the weather was much cooler then? We may now have an answer: it wasn’t that cold at all.

Long-term temperature reconstructions often rely on the width of tree rings: they assume that warmer summers make for wider rings. Using this measure, it seems that global temperatures changed very little over the past two millennia. Such studies are behind the famous “hockey stick” graph, created by Michael Mann of Pennsylvania State University in University Park, which shows stable temperatures for a millennium before the 20th century.

Jan Esper of Johannes Gutenberg University in Mainz, Germany, thinks that at least some of those tree rings actually show something else: a long-term cooling trend that lasted right up until the Industrial Revolution.

Read the rest at NewScientist

3 Responses to Tree Rings Suggest Roman World was Warmer than Thought

  1. Joe July 25, 2012 at 10:19 pm #

    Neilio, Nice read.

  2. Rob N. Hood August 1, 2012 at 8:57 am #

    This just in: All tree rings found to reveal the Bible Code, at least the ones looked at so far. Unfortunately no one has been able to crack the Bible Code, yet.

  3. Joe August 3, 2012 at 11:59 pm #

    Nor will they until they pass.

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