Topic 4: Synthesis: The Earth System from a Polar Perspective

WP 1 "Current and Future Changes of the Earth System"

In Work Package 1 the recent past variations and expected future changes in the earth system are considered on the basis of regional and globally coupled earth system models with resolved ocean and atmospheric dynamics.  Reliable projections of the climate state in the Arctic throughout the 21st century are crucially dependent on long-term and high-quality observations and improved model systems carefully evaluated against available instrumental observations, the synthesis between them and a better understanding of the basic operation of high northern latitude climate variability modes and the interaction between high and low latitudes.

The emphasis is on main components and processes in polar regions. We will carry out explicit modelling, data analysis and inverse modelling with a special focus on the extent of Arctic sea ice under global warming and a changing thermohaline circulation, the change of atmospheric teleconnection patterns and ozone concentration in a cooling polar stratosphere on decadal time scales, the melting of permafrost, the impact of circulation and biogeochemistry in the Southern Ocean on the global carbon cycle.

WP 2 "The Earth System on Long Time Scales"

In Work Package 2, we bring together earth system modelling, data analyses, as well as conceptual work. A three-dimensional climate model will explicitly resolve the atmosphere-ocean dynamics, including climate components such as the cryosphere. The development of the huge ice sheets on long time-scales provide a major impact on the climate system in terms of, e.g., freshwater fluxes, sea level, and water mass formation which need to be considered in a thorough ESM approach. As a further innovative step, the ESM should be capable of simulating biogeochemical cycles, including the carbon cycle and marine sediments, as well as isotopes in the climate and biosphere components. Large-scale teleconnections and climate modes have to be identified on decadal to multi-millennial time-scales, including the Atlantic multidecadal mode linked to the oceanic meridional overturning circulation.

WP 3 "Assessment of existing knowledge about coastal climate change in Laptev Sea / Lena Delta and North Sea"

Work Package 3 will provide an "Assessment of existing knowledge about coastal climate change in Laptev Sea / Lena Delta and North Sea". The knowledge about climate change (not only) in coastal regions is fragmented over different disciplines, in particular oceanography, meteorology and ecology. In public claims, the borders between lay knowledge, journalistic metamorphoses and scientific facts are blurred. In order to overcome this confusing mix, the international community has established the Intergovernmental Panel on Climate Change (IPCC); following the example, also regional assessments have been prepared, among others the BALTEX Assessment of Climate Change in the Baltic Sea region (BACC).