Annual report 2008
Nature and climate

Identifying processes leading to the current climate and environment situation in Denmark and the North Atlantic in particular

Renewable energy from the ice sheet
Since 1993, renewable energy from hydro power has been part of energy supply in Greenland. In that year, Greenland's first hydropower plant near Buksefjorden came online to supply Nuuk, and since then another two plants have come into operation to supply the towns of Tasiilaq, Narsaq and Qaqortoq. A fourth plant is being built near Sisimiut, and Nukissiorfiit (Greenland's energy utility) is planning yet another plant at Paakitsoq to supply the town of Ilulissat. The majority of the water flowing into the Paakitsoq basin is meltwater from the ice sheet, and during 2008 GEUS, on behalf of Nukissiorfiit, carried out an assessment of the hydropower potential of the basin. The work has included calculations of the drainage patterns of the meltwater and the movement of the ice under selected climate scenarios calculated by the Danish Meteorological Institute. The work concludes that undesirable changes are unlikely to occur in the drainage routes of the meltwater and in the location of the ice margin in the period up to 2080, and that the amount of meltwater for power generation will be stable up to 2035, slightly increasing in the subsequent years up to 2080.

Glacier-induced earthquakes reveal the dynamics of the ice
Since 2003, it has been well known that occasionally a special type of earthquake occurs close to several large glaciers which calve icebergs into the sea from the ice covers in the Antarctica, Alaska and Greenland. The tremors do not resemble ordinary earthquakes, but they can be measured on seismographs throughout the world. The large glaciers originating from the ice sheet in East Greenland have caused many of these glacial earthquakes in recent years. After three years of surveying the Helheim glacier in East Greenland, in 2008 it was possible for an international group of researchers, including researchers from GEUS, to solve the riddle behind these quakes. The tremors arise when large icebergs hit the seabed after breaking free from the glacier. The results have aroused great interest, and researchers now have an extra and cheap tool to monitor the dynamics of the ice in often remote areas. Using seismographs it is possible to measure the tremors from the icebergs breaking off, and thereby monitor whether the large glaciers are suddenly starting to calve ice at a higher rate than previously.

Reconstruction of the state of the aquatic environment
Lakes and bogs are nature's own archives of the changes in nature and the environment. Studies of lake sediments and their contents of plants and animals provide us with a clear picture of how the environment has changed thousands of years back in time. Danish nature has been heavily impacted by human activity everywhere, and studies of old lake sediments are a good tool to illustrate how far we now are from the natural state. This is important for implementation of the EU Water Framework Directive, for example, which requires a description and definition of the natural background state of the aquatic environment. In recent years, GEUS has examined sediment cores from the lake Sarup Sø in south-western Funen, which covers a period of more than ten thousand years. The results show that the budding agricultural society in the Stone Age was already causing great changes in the landscape and the environment as early as 6,000 years ago. Surprisingly, studies of kisel algae and algae pigments in the lake sediments show that Stone Age agriculture was already causing increased concentrations of phosphorus in the lake. The environmental effects of nutrients have increased significantly since then, and the studies show that the lake was already heavily impacted by nutrients 1,000 years ago. The research project at Sarup Sø is being partly funded by Forskningsrådet for Kultur og Kommunikation.

Monitoring earthquakes
GEUS monitors earthquakes in Danish areas. This is done at four permanent seismograph stations in Denmark and at four permanent stations in Greenland as well as a number of temporary stations. Seismologists register large earthquakes around the world and smaller local earthquakes as well as tremors from explosions, traffic and other human disruptions close to the instruments. Fortunately, Denmark and Greenland are not greatly affected by large earthquakes, but on 16 Decem ber 2008 at 6:20 a.m. many Danes were awoken by tremors from an earthquake with its epicentre in Skåne, just 50 km east of Copenhagen. Interest in the earthquake, with a strength of 4.8 on the Richter scale, was overwhelming, and in a very short time GEUS received more than 4,000 eye-witness accounts via its website from Danes and Swedes who had experienced the quake. This is important data for seismologists, who use the descriptions to judge the intensity of the earthquake. Measurements from Denmark and Greenland are incorporated in a large international network of stations monitoring earthquakes around the world. These stations are part of an international network of seismographs and other geophysical stations which monitor for violations of the UN Nuclear Test Ban Treaty. Finally, seismologists advise authorities and enterprises in Denmark on the risk of earthquakes in connection with large construction projects such as the bridges over the Great Belt and Øresund.

Monitoring the Greenland ice sheet
The rate of ice melting and icebergs calving from the Greenland ice sheet has increased significantly in recent years and the loss of ice from the large ice sheet has doubled over the past 10 years. This has caused the sea level to rise, arousing concerns around the world in places where many people live in low-lying coastal areas. The Ministry of Climate and Energy has therefore launched a programme to monitor the ice sheet. The new monitoring programme is being headed by GEUS and focuses on what is happening along the margin of the ice sheet where mass loss from melting and calving of icebergs occur. Monitoring is being carried out at fully automatic measuring stations which measure melting, the climate and movements of the ice. Ten stations are already operational and sending data back to GEUS in Copenhagen via satellite. In 2009 the entire measurement network will have been completed with a total of 14 stations, representing seven different climate regions on the ice sheet. Glaciologists are supplementing the measurements on the surface with measurements from aircraft and satellites. In cooperation with the Technical University of Denmark, the edge of the ice is being measured from aircraft all the way around Greenland, and the movement of the ice is being monitored by satellite. Measurements are also being made along 20 of the largest outflow glaciers from the ice sheet from which the majority of icebergs come. Danish monitoring is being supplemented by several foreign stations on the ice. In future, the overall international efforts will provide a more accurate picture of how much ice is melting. The project is called PROMICE – Programme for Monitoring of the Greenland Ice Sheet, and it is being funded by the Danish Cooperation for Environment in the Arctic programme(DANCEA) under the Ministry of Climate and Energy.