Climate variations, climate- and Earth-system modelling

The interactions of the cryosphere with other components of the Earth system involve the atmosphere, the oceans and the biosphere, as well as the solid Earth. Modelling of variations of the cryosphere through the ice-age cycles and other climate oscillations requires adequate representation of all these components in order to understand the rapid changes that have taken place in the past. Similarly, future climate development can only be assessed with models that represent the complex interactions and feedbacks that are activated by the anthropogenic increase of greenhouse gasses in the atmosphere. Earth system models (ESM) are designed to simulate all relevant aspects of the Earth system, including physical, chemical and biological processes. In addition to the classical climate model components (atmosphere, soil, ocean, and sea ice), Earth System models may add model representations of atmospheric chemistry and aerosols, ocean bio-geo-chemistry, dynamic vegetation, ice sheets, glaciers, permafrost and crustal deformation due to ice loading. The flow of CO2 and other greenhouse gasses through the atmosphere, biosphere, soil and the oceans, the melting of ice shelves and calving ice fronts in Antarctica and Greenland by the sea, the release of greenhouse gasses from permafrost on land and in shallow seas, and the effect of aerosols on the albedo of sea ice and snow cover are among the processes that can be analysed by Earth system models.

Presentations in this session may deal with, but are not limited to, the following topics:

• The paleoclimate of glacial and interglacial periods (including the Eem-interglacial and the rapid changes during the last glacial period), can the main characteristics of past climates be reproduced by the models?
• The cryosphere as a trigger of rapid climate change;
• Arctic amplification of future warming, simulations of Arctic sea ice and ice sheet retreat in the future.

Image credit: Þorvarður Árnason