Lay summary
Current climate research is challenged by questions on (i) the characteristics of natural climate variability, (ii) the discrimination from anthropogenic forcing, and (iii) ecological, societal and economic risks. Insight into regional climate change is critically important: Instrumental data and high resolution climate reconstructions show that regional climatic trends and extremes strongly exceed changes reported at hemispheric or global scales.
Seasonal to annual, quantitative, regional multi-proxy climate reconstructions are fundamental to assess natural (i.e. pre-anthropogenic), forced and stochastic climate variability. Accurate reconstruction with quantified uncertainties of the “baseline climate” is the precondition for evaluating the sensitivity of the Earth System to different forcing factors, and validating the results of global and regional, past and future climate modelling. In consequence, one of the hotspots of the international research agenda is to assess natural climate variability of the last 1000 years which encompass the ‘Medieval Warm Period’ and the ‘Little Ice Age’.
Among the most fundamental conclusions of recent work is the finding that the structure of past climate change in Europe is very different for each of the four seasons of the year. Most significant are deviations during fall, winter and spring, precisely during the seasons that are poorly or not recorded in natural climate archives. Thus new cold-season proxies are critically important and need to be explored.
This is where our project and the new equipment come in. The innovation and novelty of our research is that, besides the classic lake-sediment proxies, Chrysophyte stomatocysts (microfossils produced by ‘golden algae’) are used for quantitative temperature reconstruction. Recent pioneering work has shown that stomatocysts in Alpine lakes are among the very few proxies and the only ‘terrestrial’ microfossils that allow quantitative winter/spring temperature reconstructions. This information is unique and has a great potential to evolve into the key parameter for cold-season climate reconstructions. Primary target archive for our research is Lake Silvaplana, a lake with 3500 years of varved sediments.
High-quality analysis of stomatocysts requires scanning electron microscopy (acquisition of equipment subject to this proposal). International cutting-edge research calls for continuous, high resolution (annual) sampling. Consequently our research plan has two goals: (i) to optimize the efficiency of data collection with automated image acquisition and off-line image analysis, and (ii) to produce annual winter/spring temperature series for the last 1000 years.