In the last decades tremendous advances have been achieved in reconstructing past climate variability on different time scales by exploiting various types of geological archives (e.g. ice cores, ocean and lake sediments, speleothems, tree-rings). However, most of the obtained proxy records of past climate variability mainly reflect regional climate signals and a compilation of all existing information into a global or at least hemispheric synthesis is still lacking, remaining a major challenge for the palaeoclimate community. Nevertheless, a global proxy synthesis from such a variety of different palaeoclimate archives is not trivial because of fundamentally different types of chronologies for the individual archives (e.g. annual layer counting in ice cores and lake sediments, radiometric dating, astronomical tuning) and a broad variety of different proxy data, which reflect different climatic parameters (e.g. temperature, precipitation) and have different sensitivities toward climate change.

The goal of work package WP 3.2, which is coordinated by GFZ Section 4.3, is the compilation and synthesis of existing high-resolution palaeoclimate records from ice cores, marine and lacustrine/terrestrial sediments as well as speleothems. The work of GFZ Section 4.3 thereby focusses on the compilation of proxy data from varved (annually laminated) lake sediments. Other working groups within WP 3.2 from AWI, MARUM and the Memorial University of Newfoundland will work on the complementary palaeoclimate archives. Schemes for quality control of palaoeclimate datasets will be developed within the work package and existing proxy records will be classified and harmonized. On this basis publicly available data bank systems will be provided and further developed that can used for validating climate model simulations carried out within the project.

In the first project phase, Section 4.3. generated the first version of the global VArved sediments DAtabase (VARDA) (Ramisch et al., 2020). VARDA offers rapid and open access to paleoclimate information from varved lakes worldwide. Version 1.0 permits to explore annually resolved sediment proxy data on uniform age models for advanced palaeoclimatic reconstruction. VARDA will be cotinuously further developed, for example, by including additional paleoclimate proxy data in forthcoming updates.

WP 3.2 Partners:
Johannes Gutenberg University Mainz
Alfred-Wegener-Institut Bremerhaven and Potsdam (AWI)
Centre for Marine Environmental Sciences (MARUM)

Links:
PalMod project website

Funding:
Federal Ministry of Education and Research (BMBF), 01LP15-[10][A]