The coupled ocean-atmosphere-cryosphere system is fundamental for understanding a dynamic climate. This holds true in the North Atlantic region, and Europe in particular, where theory suggests that future increases in melt water flux from the Greenland Ice Sheet may have enormous ramifications for climate. The mechanism, via freshening and cooling of the North Atlantic (NA), should reduce the strength of the Meridional Overturning Circulation (MOC) or force it to migrate southwards. Either scenario results in reduced heat energy delivery to Europe. An ideal approach to model the earth system response to future climate change is by using analogues from the past.
A similar freshening event occurred during the Younger Dryas (YD), between 12900 and 11700 years before present. It was a period of very rapid climate change, which was triggered by the rapid release of melt water from the Laurentide Ice Sheet. The melt water input freshened the NA causing reorganisation of the MOC and a rapid cooling of Europe and possibly beyond. However, a key open question regarding the YD and an essential one for future climate predictions is the timing and magnitude of the climate response to the change in the MOC.
This project aims to address this question by analysing palaeo-glaciers. Present-day retreating glaciers mark on-going changes in climate.
Likewise palaeo-glacier geometries and distributions provide key information regarding the state of the climate during the YD. For example the Fennoscandian Ice Sheet covered much of Norway, Sweden and Finland and glaciers in the Alps were advanced well beyond their cirques, sometimes coalescing to form small ice caps. Importantly however, many ice masses existed in the lesser mountain regions, areas which are currently unglaciated (eg the Scottish Highlands). On the other hand impact of Younger Dryas in glaciers and, therefore, in climate, seemed much less dramatic across Eastern Europe.
Key objectives will be to establish the synchronicity of advances and the magnitude of change across the region, by using a well-supported methodology. This will tell us about weather patterns during that period.
Outputs from this project will be:
1. Development of a benchmark methodology and workflow model (including tools e.g. spreadsheets/ArcGIS scripts) which will be made publically available for palaeo-glacier-climate reconstructions thus promoting greater coherency in subsequent research.
2. Development of an extended and internally-consistent chronology of YD glacier advance(s) across Europe.
3. Improved understanding of climate across Europe during the YD, the synchroneity of response to the perturbation and the location of the Polar Front