The Jotunheimen mountains showing Lake Gjende. Changes in temperature and precipitation influence ice formation and the depth and duration of snow cover. 

The Jotunheimen mountains showing Lake Gjende. Changes in temperature and precipitation influence ice formation and the depth and duration of snow cover. Snow cover is very important for animals and plants in the mountains. Photo: Lars Fuglevaag

Climate change despite steps to prevent it

There is now sound documentation that climate change is taking place and that current trends will continue for many years, for example in the assessment reports from the Intergovernmental Panel on Climate Change (IPCC) and the 2004 Arctic Climate Impact Assessment (ACIA). Climate change will continue despite the measures being implemented to limit greenhouse gas emissions. Recently developed scenarios of climate change in Norway suggest that in the next 110 years, the temperature will rise by 2.5–4 degrees, precipitation will rise by 10–15 per cent, and the growing season will become 3–6 weeks longer. 

Changes already apparent in Norway

In Norway, many effects of the rising temperatures have already been observed both on land and in water. Migratory species of birds are arriving earlier in spring; animals are reaching sexual maturity more quickly; production and reproduction rates are higher; trees are coming into leaf earlier; salmonids leaving rivers for the sea are younger; and the spawning areas used by fish in the sea are changing.
 
Changes in precipitation patterns affect the runoff of water, particulate matter and nutrients, and this in turn can have a major impact, especially on coastal and freshwater ecosystems. Changes in snow- and rainfall together with temperature influence ice formation and the depth and duration of snow cover. Deep snow has been shown to have a negative effect on population growth for some animals. The duration of snow cover influences the length of the growing season, and the formation of thicker ice crusts results in poorer grazing conditions for species such as reindeer. On the other hand, ice cover on rivers has been shown to provide protection for salmon smolt before migration to the sea.
 
The RegClim project has produced regional and local climate scenarios for Norway. These indicate that we must expect changes in all habitat types as a result of future climate change. The precise effects will be determined by complex ecological interactions. The climate interacts with other factors such as overgrowing of open habitats, construction and development, and pollution. 

Northerly shifts in species distribution expected

As the climate warms up, both terrestrial and aquatic species will shift northwards, and new species will therefore reach Norway. In the warmer conditions, some alien species that were not able to survive Norway’s cold climate will probably also become established in marine, fresh-water and terrestrial habitats. However, some species that are adapted to today’s climate may find it more difficult to survive. Climate change is therefore expected to result in certain changes in species diversity in Norway.
 
Given the increase in the number of species moving northwards, the number of species in Norway is expected to rise rather than fall. This may have adverse effects on species-poor ecosystems such as the oligotrophic fresh-water ecosystems that are typical of Norway.

Overgrowing of open habitats will speed up

Climate change is expected to speed up overgrowing of open habitats, which is already having very marked effects in habitats such as coastal heaths and former pastures at summer farms in the mountains. This will reduce the diversity of habitat types and landscapes in Norway, which is very high in European terms at present, and also restrict opportunities to enjoy different types of countryside and affect other ecosystem services. This will have a substantial impact on the tourism industry in Norway, which uses nature and the landscape as its most important “product”. Views are lost and landscapes become less accessible as they become overgrown. This also obliterates evidence of the landscape’s history and the special characteristics of certain types of landscapes and habitats.  

Great changes for outdoor recreation

The effects of climate change that are likely to be most important for outdoor recreation are higher summer temperatures in Southern Norway, higher snowfall in the mountains in the short term (50 years) and higher precipitation, which will entail a risk of flooding and erosion. These changes will have consequences for access to the countryside and opportunities for people to take part in various activities.

A warmer climate will offer less opportunity for playing in the snow and skiing.

A warmer climate will offer less opportunity for playing in the snow and skiing. Photo: Djaka Dwiputra

Adaptation to climate change

The process of climate change would continue even if we could halt current anthropogenic greenhouse gas emissions immediately, because these gases have a long lifetime in the atmosphere. We must therefore find ways of adapting to climate change at the same time as seeking to reduce emissions. Climate change will affect most sectors of society.
 
In the field of nature management, adaptation to climate change means attempting to reinforce its benefits while reducing the negative impacts on biodiversity and outdoor recreation. Possible measures include steps to minimise other environmental pressures, the protection of large areas of natural habitat, safeguarding habitat corridors to allow the spread of species, and adapting the way various sectors operate.
 
The nature management authorities must also ensure that other sectors adapt their activities to avoid negative effects on biodiversity as the climate changes.