Climate lessons from the past 2....

This follows on from the first lesson about the people living in Fezzan, Libya.



This week I thought I would discuss about what happened in Greenland about 750 years ago. This time period in Britain was called the Medieval. It was was also significantly warmer during this period as much as 1 degrees Celsuis and thus in climate circles is known as the Medieval Warm Period. In this period wine and olive oil was grown in South East England. It is also believed that the plague spread more quickly due to the heat.

How does this link to Greenland?

Well, because of the higher temperatures the sea-ice had melted and retreated opening up ocean passages to Greenland. On Greenland itself the ice had melted and revealed lush green meadows. People from Scandinavia and Iceland undertook the epic journey by boat to Greenland. They set up towns and villages and farmed the surrounding areas. They also fished the rich Arctic seas around Greenland including Whales!

What went wrong?

Roughly about 600 years ago the climate changed and got significantly colder; as much as 2.5 degrees Celsuis. The ice spread back over Greenland meaning the people could no longer grow crops and rear sheep. Also the sea-ice was spreading and people could not set sail from Greenland back to Scandinavia, so the people starved.

What is the evidence?

Evidence has come from a variety of sources. One of the most obvious is written records e.g. letters being sent from Greenland to Scandinavia and the UK detailing how the ice was growing and food was becoming harder to grow. Another peice of evidence are dead flies. Flies are very sensitive to changes in temperatures. For example warm species will die as the temperature rises and cold weather species will start to grow in number. Scientists found that fly species changed when the ice started to grow.

What drove the climate change?

Scientists are not sure and have linked both the Medieval Warm Period and Little Ice Age to changes in ocean circulation and sunspot cycles.

Useful links:

http://en.wikipedia.org/wiki/Sunspot

http://www.atmosphere.mpg.de/enid/1vc.html

The video is about climate change over the last 120,000 years!!








Enjoy!!