CliSAP successfully finished in 2018. Climate research continues in the Cluster of Excellence "CLICCS".

Hot Climate – Green Desert? Workshop on North Africa held at the Hamburg KlimaCampus

22.02.2011

A few thousand years ago, the climate was warmer and the Sahara significantly greener than today. Current satellite photos and meteorological data show that a few desert areas are once again becoming greener despite heavy land-use patterns. Is this already a visible sign of global warming? Can past climate changes be translated to today’s conditions?

The history and development of North Africa’s climate was the central topic of an international workshop at Hamburg’s KlimaCampus. From February 7-9, around 50 Scientists from a number of disciplines participated in discussions on the topic of “Northern Africa – Past, Present and Future Climate Changes.” “Thank you very much for the most productive dialogue yet between the marine, earth and modeling communities,” said one participant who has travelled and researched the Sahara for many years.

The researchers discussed data from Paleoclimatology and model simulations of the climate’s history, as well as possible future climate changes. How abrupt was the transition in the so-called ‘African Humid Period’ 10,500 years ago, during which tropical plants could be found in some parts of the Sahara? How quickly did the Sahara recover and expand to its current state approximately 6000 years ago? The workshop resulted in the following assessment: while the African Wet Phase presumably spread across all of North Africa simultaneously, its withdrawal followed at different paces in different regions over somewhere between 6000 and 3000 years – sometimes quickly and sometimes gradually. A variety of mechanisms were identified that could have led to abrupt changes both regionally and locally among vegetation and in hydrological conditions.

The question as to whether these historical processes could be directly equated to potential changes at this time is controversial and was heavily discussed. There was general agreement however, that our climate’s history is a critical touchstone for successful climate modeling. “Only when our models accurately portray climate processes and the dynamics of both past and present climatic changes in North Africa can we produce reliable climate scenarios for the region,” clarified the workshop’s host, Martin Claussen, speaker of the Hamburg Excellence Cluster CliSAP, Professor for Physical Meteorology at the University of Hamburg, and Director of the Max Planck Institute for Meteorology.