Saturday
May292010
by 
Bishop Hill
Bishop Hill The Holocene optimum
May 29, 2010 Climate: MWP Current temperatures are unprecedented? Not so says Matt Ridley:
A study of sea sediment cores in the Chukchi Sea shelf in the Arctic Ocean concluded that `during the middle Holocene the August sea surface temperature fluctuated by 5°C and was 3-7°C warmer than it is today.
Yes, you read that right: up to SEVEN DEGREES CENTIGRADE.
Reader Comments (4)
Amazing! I took a quick look at the MacDonald et al paper that forms the foundation for Matt Ridley's post. The next step is for someone to go searching for research documenting the contemporaneous CO2 levels. I am willing to wager a decent bottle of wine that the CO2 levels were at least equal to the current levels if not higher and that nothing "tipped." Of course, the winner will have to come to the San Francisco Bay Area to collect. btw, I found it amusing that some of the MacDonald et al data came from the Yamal Peninsula
Matt Ridley's remarks about how the Sahara dried up about 5,300 years ago, at about the same time as Greenland cooled, reminded me of a BBC Horizon programme perhaps ten years ago.
At the time, Egyptian civilisation was under what was known as the Old Kingdom. This was prior to the Pharonic system which built the Pyramids.
The Old Kingdom did build and appears to have thrived. Until 5,300 years ago. Then it died amid great distress - it was clear that at the end, they ate their children.
Other readers can probably correct me on the details, but the lesson remains: cold kills, and can destroy civilisations.
Yeah. And the National Geographic for June has an article entitled "Viking weather", and the subtitle is "As Greenland returns to the warm climate that allowed Vikings to colonize it in the Middle ages, its isolated and dependent people dream of greener fields and pastures and also of oil from ice-free winters" On page 56 we read "The Vikings settled Greenland during a period of exceptional warmth, the same warm period that saw expanded agriculture and the construction of great cathedrals in Europe". That's the MWP. Eat your heart out Michael Mann.
I wonder when this uneducated riffraff of North America and Britain are going to stop calling the Icelandic settlers "Vikings"?