2,000 Years of Climate Change

I was playing around with Moberg’s 2005 paleoclimate reconstruction and found something “funny”. Moberg’s reconstruction runs from 1 AD to 1979 AD. I calculated an average annual anomaly for the UAH Lower Trop., normalized it to Moberg and tacked it onto the end (not quite “apples to apples”; but it gets us 2008 years of temperature data).

I then applied a couple of moving averages (31-yr and 101-yr) and a linear trend-line… The funniest thing happened: The linear trend-line is flat as a pancake (with just a hint of negative slope)…

The Modern Warming that began in the late 19th century is remarkably similar to the Medieval Warm Period (~800 AD – 1300 AD). The most anomalous climate feature of the last two millennia is the Little Ice Age (~1300 AD – 1880 AD); which was considerably colder than the cool period preceding the Medieval Warm Period (the Dark Ages).

The only anomalous feature during the Modern Warming is the year 1998… Although it’s difficult to assess how anomalous it is because the proxy data used by Moberg don’t have anywhere near the resolution of the modern satellite temperature data.

I plotted the Hadley Northern Hemisphere temperature anomalies from 1840-2009 against the Moberg’s reconstruction of the early Medieval Warm Period.  The two curves exhibit remarkably similar frequencies and amplitudes…

Moberg's Medieval Warm Period Reconstruction bears an uncanny resemblance to the Modern Warming Period.

So much for unprecedented climate change!