Climate Variability and Change—Hydrological Impacts (Proceedings of the Fifth FRIEND World
Conference held at Havana, Cuba, November 2006), IAHS Publ. 308, 2006, 502–507.
Past and future changes in flood and drought in
the Nordic countries
HEGE HISDAL, LARS A. ROALD & STEIN BELDRING
Norwegian Water Resources and Energy Directorate (NVE), PO Box 5091 Majorstua, N-0301 Oslo, Norway
hege.hisdal@nve.no
Abstract Based on a data set of 46
daily streamflow records from the Nordic region for the period 1920–2002 the
natural variability in trends and estimated return levels of flood and drought
has been studied. In addition, for a subset of series, return level estimates
based on historical records were compared to extreme estimates for a control period,
1961–1990, and a scenario period, 2071–2100. It was shown that detected trends
and return levels strongly depend on the time period studied because the
natural variability in the extremes is large. The scenarios indicated reduced
annual floods in eastern Norway, increased annual floods in the western part
and varying results for the basins in central and northern Norway. Droughts in
general tended to become more severe in the scenarios. The expected changes in
floods in the scenarios were only larger than the differences found due to
natural variability for one AOGCM-Regional climate model combination.
Key words Scandinavia, flood, drought, trend, climate variability and change, scenarios