Belgian global change research 1990 2002 Climate change

Belgian global change research 1990 -2002 Climate change Pr. J. P. van Ypersele, Université catholique de Louvain With support from: Ph. Van Haver, S. Van Homwegen, E. Vanvyve, V. Coulon, and Ph. Marbaix

Global change research 1990 -2002 : Climate change vanyp@astr. ucl. ac. be Questions 1 -5 1. How is the earth’s climate changing now? 2. Is present climate change different from past climate change? 3. Why has the climate changed in the past? 4. Why is climate changing now? 5. How will climate likely change during the 21 st century?

Global change research 1990 -2002 : Climate change vanyp@astr. ucl. ac. be Questions 6 -10 • 6. Are unexpected climate events possible in the longer term? • 7. Will climate change affect atmospheric ozone? • 8. Will the Kyoto Protocol save the climate? • 9. Where has Belgian research made a difference in the international effort? • 10. Key uncertainties to be adressed 12 years of researches can not be summarized in 10 minutes, only limited snapshots will be shown.

Global change research 1990 -2002 : Climate change vanyp@astr. ucl. ac. be How is the climate changing now ? 1833 2002 Annually-averaged surface air temperature at Brussels. Uccle, 1833 > 2002 (IRM) (fig 2. 5, p 67)

Global change research 1990 -2002 : Climate change vanyp@astr. ucl. ac. be How is the climate changing now ? (2) Sea-ice thickness decreases as well: (b) (a) 1980 1990 2000 In the Arctic Ocean, the sea-ice surface is decreasing at an average rate of 25. 000 km 2 / year (nearly the surface of Belgium) (fig 2. 10, p 70)(Source: ULB-GLACIOL)

Global change research 1990 -2002 : Climate change vanyp@astr. ucl. ac. be How is the climate changing now ? (3) Tropical regions : Rising temperatures at Bujumbura, Tanganyika lake. Links with ENSO (El Niño), lake productivity studied by ENSO and CLIMLAKE teams (RUG, MRAC, UCL, FUNDP, ULg). (fig 2. 12, p 71)

Global change research 1990 -2002 : Climate change vanyp@astr. ucl. ac. be Is present change different from past ? +0. 4 C 0 C -0. 2 C 1000 1500 1800 Climate of the last millennium : . climate reconstructions (dark and light blue). global 3 D atmosphere-sea-ice-ocean model (grey; red=mean) (UCL-ASTR) (fig 2. 17, p 73) 2000

Global change research 1990 -2002 : Climate change vanyp@astr. ucl. ac. be Is present change different from past ? Model simulation over the last glacial cycle (VUB) ice-covered area : at the last glacial maximum, time evolution (last 120 000 Y, change connected with earth orbit)

Global change research 1990 -2002 : Climate change vanyp@astr. ucl. ac. be How will climate change during the 21 st century ? • In addition to researches seeking to better know and understand the “global picture” of the anthropogenic warming, other studies involves more detailed and regional aspects. Model results for the retreat of the Sofiyskiy Glacier (Altai Mountains, South Siberia), which may completely disappear (VUB-DG)

Global change research 1990 -2002 : Climate change vanyp@astr. ucl. ac. be How will climate change during the 21 st century ? 3 hydrological models / Gete basin Total basin discharge (mm/month) (IRM, KULeuven, FUSAGx, ULg) 0 with T and precip from model 1 (CGCM 1) with T and precip from model 2 (ECHAM 4) 0 (fig 2. 35, p 91) • The more greenhouse gases, the more warming and damages • Uncertainties are still large and relates to serious issues, e. g. flooding and/or drought severity

Global change research 1990 -2002 : Climate change vanyp@astr. ucl. ac. be Unexpected longer-term events ? (fig 2. 28, p 82) - Atmosphere-ice-ocean interactions around Antarctica involve complex processes. - The West Antarctic ice sheet is potentially unstable; its melting may contribute to a large long-term sea-level rise (ULB-GLACIOL)

Global change research 1990 -2002 : Climate change vanyp@astr. ucl. ac. be Conclusions • Belgian climate research has contributed significantly to international research efforts such as WCRP, IGBP, and to the IPCC. • It has contributed to show and quantify the sensitivity of the earth’s climate to natural and human factors • It is time for action, way beyond Kyoto, and research is needed also about solutions, and obstacles to their implementation • BUT fundamental climate research continues to be essential for providing the