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What is the context of this research?

Viking settlers went to Greenland sometime during the Middle Ages. There are various theories about why they went there, but the most controversial is that they took advantage of climatic conditions in the North Atlantic that were much warmer than today. If that was the case, it begs the question—why was it so much warmer? It could not have been due to fossil fuel consumption, so some have suggested that solar activity may have been stronger at that time. We propose to try and answer the question by collecting lake sediment cores from near the Viking settlements in southern Greenland, then applying new analytical techniques to the sediments, to reconstruct what the temperatures were actually like in Medieval time. This will complement research we are already doing on the other side of the Atlantic, in Svalbard and in northern Norway, so we should be able to obtain a broad regional picture of Medieval temperatures in those areas that the Vikings explored. We will look at specific organic molecules in the sediments (biomarkers) that can tell us about past temperatures, and also what kinds of impacts the Vikings had on the landscape itself during the period of colonization, such as soil erosion and water pollution due to agriculture and animal grazing.

What is the significance of this project?

We know that temperatures have risen a lot in the last 150 years, but before that, the picture is more uncertain. There were no instruments to measure temperatures in Medieval time, so we have to rely on other “proxies” of past climate—natural phenomena that in some way recorded how temperatures changed. Often tree rings are used to do this, but there are no trees in the Arctic, so the next best thing is to use lake sediments that have accumulated in close proximity to the Viking settlements. New techniques have been developed over the last few years that give us ways to extract a temperature record from the organic compounds in lake sediments. And new instruments give us the capability of sampling the sediments in great detail, so we should be able to build up a detailed picture of how the environment changed in southern Greenland from the present day right back into Medieval time. Fortunately, we have these new instruments in our research lab, and we are refining the new techniques to reconstruct past changes in the environment. This will help to answer questions about how different the climate was when the Vikings arrived in southern Greenland, and how much the climate changed after they settled there, leading to their eventual demise. These questions are also very relevant to today, as we ponder whether a further rise in temperatures in Greenland will lead to recession of the Greenland Ice Sheet and a rise in sea-level around the globe.

What are the goals of the project?

60% of the funds would be used for 2-3 people to travel to Southern Greenland to collect sediment cores and transport them back to UMass (Amherst), where I am working on my Ph.D (specializing in Arctic sediment analysis). The remaining funds would be used to pay for radiocarbon dates, and for biomarker sample analysis. Because we are able to run samples in-house at relatively low cost, the analyses will be carried out at high-resolution, producing a detailed record of past climate and landscape changes associated with the Vikings in Southern Greenland!