Sønderborg 17/6/2003 Modelling future climate in the Baltic region Ole Bøssing Christensen DMI

Sønderborg 17/6/2003 Ændring i global middeltemperatur (CRU 2002)

Sønderborg 17/6/2003 Change in radiative forcing since pre-industrial time NET: ~1,46 W/m 2 Radiative Forcing

Sønderborg 17/6/2003 Scenarios  A1 represents aworld in rapid economic growth, but with a population reaching its maximum in about 50 years. Relatively rapid introduction of energy-efficient technologies.  A2 represents a world in varying rates of economic development and a continuous population growth. Initially the economic growth is smaller than A1.  B1 is a world where environmental technologies are introduced worldwide. Population growth will culminate in about 50 years.  B2 is a world with regional introduction of environmental technologies. There will be a continued but moderate population growth.. IPCC: Intergovernmental Panel on Climate Change.

Sønderborg 17/6/2003 CO 2 emissions in the IPCC SRES scenarios. Emission scenarios

Sønderborg 17/6/2003 IPCC’s SRES scenarios (concentrations) ppmv CO 2 (kuldioxid) Scenarios : CH 4 (methan) ppbv Scenarios : N 2 O (lattergas) ppbv Scenarios :

Sønderborg 17/6/2003 Climate forcing

Sønderborg 17/6/2003 Feedbacks of the Climate System Positive: –Water vapor –Ice-snow albedo effect –CO 2 og CH 4 uptake by oceans and land surfaces Negative: –Infrared heat loss (  T 4 ) increasing with temperature Uncertain: –Clouds

Sønderborg 17/6/2003 What is a climate model? A numerical model based on the fundamental laws of physics. The flow of atmosphere and oceans are described globally or regionally. A typical global model: ECHAM4/OPYC3. Atmospheric component consists of 128x64 horisontal boxes in 19 vertical layers. Time step around 20 minutes. The ocean model has 11 vertical layers and a variable horisontal resolution, about 55 km near the Equator. Also land surface and sea ice are described. A typical regional model: HIRHAM 110x104 lattice boxes of about 50 km distance, 19 vertical layers. Time step around 5 minutes. Ocean, sea ice and atmopspheric boundary conditions from a ”driving” model.

Sønderborg 17/6/2003 Resolution issues GCM 250 kmHIRHAM 0.44°

Sønderborg 17/6/2003 Reconstruction of climate variations

Sønderborg 17/6/2003 Span of model results A2, winter B2, winter Change in 9 different models

Sønderborg 17/6/2003 Summary of expected changes Temperature

Sønderborg 17/6/2003 Summary of expected changes Precipitation

Sønderborg 17/6/2003 RCM 2-meter Temperature Summer (C) GCM

Sønderborg 17/6/2003 RCM 2-meter Temperature Winter (C)

Sønderborg 17/6/2003 d GCM RCM Precipitation Summer (mm/d)

Sønderborg 17/6/2003 RCM Precipitation Winter (mm/d)

Sønderborg 17/6/2003 GC Climate change Temperature Summer Climate change Precipitation Summer

Sønderborg 17/6/2003 Climate change Temperature Winter Climate change Precipitation Winter

Sønderborg 17/6/2003 ECHAMHIRHAM Change in mean temperature Summer

Sønderborg 17/6/2003 ECHAMHIRHAM Change in mean precipitation (%) July-August-September

Sønderborg 17/6/2003 Precipitation events and resolution From Christensen et al. (2002) JJA

Sønderborg 17/6/2003 Change in summer precipitation JAS

Sønderborg 17/6/2003 n=1, f=95%, 99%, 99.9% (4.5/y – 1/y – 1/10y)

Sønderborg 17/6/2003 n=1, f=95%, 99%, 99.9% (4.5/y – 1/y – 1/10y)

Sønderborg 17/6/2003 f=99%, n=1, 5, 11

Sønderborg 17/6/2003 MeanHIRHAM Change in precipitation (%) > 99% percentile for n = 5 July-August-September

Sønderborg 17/6/2003 Ebro Rhone Kemi Donau Elbe Po Ångerman Daugava Garonne Göta Guadalquivir Indalsälven Loire Luleå Neman Oder Rhein Seine Torneälven Vistula Vuoksi 400 m contour River catchments Hagemann personal communication

Sønderborg 17/6/2003 Mean precipitation mean exceeding the 95%, 99%, and 99.9% percentile IPCC A2 (full line) and B2 (dotted line) scenarios.

Sønderborg 17/6/2003 Wind change Winter 10-m wind change Summer 10-m wind change

Sønderborg 17/6/2003 Further information DOWNLOADS: IPCC’s home page ( ) contains many reports for free downloadwww.ipcc.ch The DMI’s home page ( ), contains several papers, reports and translations regarding climate change and variations. Three European projects are concerned with changes in extreme events. See the common web portal BOOKS: IPCC 2001: Climate Change The Scientific Basis (edited by J. T. Houghton et al.). Cambridge University Press, Cambridge, 881p. Jørgensen m.fl. 2001: Climate Change Research, Danish Contributions. Gads Forlag, 408p. Jørgensen, Halsnæs og Fenger 2002: Den Globale Opvarmning –bekæmpelse og tilpasning Gads Forlag ISBN: Dansgaard, 1987: Klima, Vejr og Menneske, Geografforlaget, ISBN