Oh dear. Scientists have discovered the Vikings enjoyed a warm Greenland. Archaeology has been telling us that for quite some time as Viking farms have been revealed by melting ice. At https://www.eurekalert.org/pub_releases/2019-02/nu-sst020519.php … were medieval Vikings baking in 50 degrees summer weather? Presumably this is fahrenheit rather than celsius – and let's face it, 50 degrees F is not very warm. Then it is Greenland – just down the road from the pole. The press release doesn't allow us to see the broader picture, parking their bus at the medieval period. The press release also tells us the medieval warm period is local – rather than a global phenomenon (even though there is now multiple investigations that actually do show the medieval period was as warm if not warmer than modern temperatures – all around the world). One suspects the local bit has been inserted either because the writer of the press release was pro-AGW, or because the study authors don't wish to tread on too many toes. Unless we have access to the full article one can only surmise.
We are told the climate record for Greenland has been constructed over the last 3000 years – which would include the RFoman Warm Period. This is not mentioned in the press release. It was, they say. much warmer between AD986 until AD1450 (compared to previous and later temperatures). AD 1450 is a bit late but the climate in the 13th and 14th centuries did include warm periods (and lots of rain in NW Europe). Normally, it is considered to be a relatively cool phase of climate. Not as cold as the so called Little Ice Age in the 17th and 18th centuries but cooler than the medieval period AD950-1300. Hence, it is a pity no graph is included in the press release. What emerges is that in the Viking era on Greenland temperatures were not dissimilar to modern ones – and yet we are supposed to be in a phase of global warming as a result of burning fossil fuel. Someone might be telling us porkies.
We also learn that the North Atlantic Oscillation could not explain the warming/It was probably not in a dominant phase for multiple medieval centuries. When in position phase it brings cold air over Greenland. This appears to contradict the idea the NAO plays a signficant role in long term climate change. The authors think it was down to warmer ocean currents – which is interesting. However, as they used the remains of dead flies in lake sediments, and their exo skeletons (for oxygen isoptopes) one can only say, it is amazing what dead flies can tell scientists about the weather. Lovely piece of research and laboratory analysis.