World climate and the Arctic

Climate researchers meet in Potsdam
On 2nd and 3rd of June, 2003, climate experts from Europe and
the USA will meet together at the Alfred Wegener Institute's Potsdam
centre for a workshop on comparing current computer models of the
Arctic. It is suspected that signals from the Arctic can influence the
global climate. It is the aim of the European research project GLIMPSE
(Global implications of Arctic Climate Processes and Feedbacks), as a
part of which the workshop is being held, to research these
interactions.

Computer model for the Arctic
The GLIMPSE project, lead by AWI researcher Prof. Klaus Dethloff, will
employ computer models of the Arctic which describe the atmosphere,
ocean currents and sea-ice. These components, working together, could
speed up a warming processes so fast that an abrupt change in the Arctic
climate results may occur: A closed sea-ice layer reflects sunlight very
efficiently. If the ice melts, the sunlight will no longer be reflected
so strongly and the surface water is warmed. Consequently, the
overlying atmosphere is also warmed, leading to further melting of
sea-ice.

Major influence on European climate
Such a rapid change in Arctic temperatures would not remain limited to a
small area in the Arctic. It could influence the strength of the
predominantly westerly winds in Europe, changing the weather patterns
across the entire European continent, changing our climate. This, and
similar mechanisms, make the Arctic a potential motor for rapid, global
climate change. The atmosphere reacts not only to external changes such
as an increase in the concentrations of atmospheric carbon dioxide, but
may also flip into another state as a result of internal, non-linear
processes. The aim of the project is to join the results of the Arctic
models with global models, to understand the causes and probability of
sudden alterations in the world's climate.

Joining regional and global models
Global climate models are used like dummies. They are used by
scientists to test the effects of greenhouse gas emissions on the
climate. However, global models currently in use describe the atmosphere
in the Arctic fairly coarsely. This can lead to the effect that small
changes in the Arctic climate have global consequences which the model
does not capture. "Only when the information from regional and global
models is united we will be able to reliably describe climate change",
says Dr Annette Rinke of AWI-Potsdam. "That is what we would like to
achieve during GLIMPSE."

Bremerhaven, 26.5.03