Environment and climate in the Arctic

Many plants and animals in the Arctic are highly adapted to a life in this harsh environment. Some are even so specialised that they cannot survive anywhere else. Arctic ecosystems often include very few species, with very few levels between the plants at the bottom of the food chain and the predators at the top. But even if species diversity is small, each species can be represented by several million individuals. Many creatures develop more slowly, become sexually mature later and produce fewer young than related species farther south. Warm-blooded animals must expend more energy simply to maintain body heat and survive than they would in warmer climes, and less energy is left over for reproduction.

The second Norwegian government under Jens Stoltenberg made the High North its main focus for strategic development because of the region’s immense possibilities and challenges. The Barents Sea is pivotal in several contexts, particularly energy, resource management and the environment. The Fisheries Protection Zone around Svalbard is the subject of international disagreement concerning regulation of fishing. Oil and gas exploitation in the High North is being followed closely in many countries.

Climate change will have impact on life in the High North

The climate changes because systems on and outside our planet change. The Earth’s climate has always been changing, but this has previously been a result of natural alterations in the tilt of the Earth’s axis, the planet’s orbit around the sun, and variations in solar radiation. Since the Industrial Revolution, the use of fossil fuel has increased dramatically. Burning of fossil fuel raises the atmospheric content of greenhouse gases, including CO₂. Measurements show that over the past 100 years, the average temperature has increased twice as fast in the Arctic as in the world as a whole. This uneven warming is caused by interactions between atmosphere, sea and ice.

In 2004, the Arctic Council project “Arctic Climate Impact Assessment” published an analysis of the consequences of climate change in the Arctic. In 2010, the Norwegian follow-up project NorACIA (Norwegian Arctic Climate Assessment)  presented its main report.

NorACIA ends with eleven key findings:

1. The Norwegian Arctic is getting warmer and wetter, with large local variations
2. Feedback processes in the Arctic increase global climate change
3. Climate change makes the Arctic more vulnerable to environmental pollutants and ultraviolet radiation
4. Sea ice is diminishing, threatening ice-dependent species
5. The ocean is getting warmer and the ecosystems are changing
6. The acidity of the ocean is increasing and coral species may disappear
7. Forests are spreading northwards and to higher elevations
8. Freshwater ecosystems are vulnerable to climate change
9. The infrastructure in the north is vulnerable
10. Nature-based enterprises will gain new opportunities – and face new challenges
11. Society can – and must – adapt

The entire NorACIA report “Climate change in the Norwegian Arctic: Consequences for life in the north” can be ordered from the Norwegian Polar Institute or be downloaded free of charge as a PDF file from our electronic publication archive.

Changes in the oceans

Global warming can lead to changes in the systems that transport water to the Arctic. When the current of Atlantic Ocean water flowing northward grows stronger and warmer, this contributes towards a warmer Arctic Ocean. Another important factor in the warming trend is that when the white sea ice melts, the dark seawater takes up more heat from the sun and the water temperature increases. Such reinforcing feedback mechanisms contribute global climate change.

Owing to greater movement in the water molecules, a warm ocean has larger volume than a cold ocean. As water temperatures rise, sea level also rises. The oceans can store huge amounts of energy: they absorb heat slowly and retain it for a long time. Even if we stop emitting greenhouse gases immediately, the oceans will continue to warm and expand for the next 20 years. In addition, calculations show that sea level will rise when large ice caps on land melt away. As temperatures in air and seawater increase, there will be less sea ice. Dark ocean and land surfaces absorb more solar energy and they heat quickly. This heating counteracts accumulation of snow and ice. It is not just the extent of the ice that has changed: the ice has also changed character. It has grown thinner in recent years, and there is less of the thick multi-year ice. This means that the sea ice can melt even more rapidly in response to further warming. Sea ice is important for most of the organisms that live in the Arctic. Plankton productivity, which is particularly high along the edge of the ice zone, influences all life forms in the area. For the large mammals, disappearance of the ice could be devastating. The ringed seal requires ice – particularly ice attached to land – to maintain its way of life. Polar bears have ringed seals at the top of their menu, and use the ice to walk to the denning areas and feed their cubs. Polar bears follow the ice edge as it retreats northwards through the summer. There the bears find ample food to survive through the long winter. Bears that get left behind on islands when the ice retreats find little food on land and must wait until the ice forms in the autumn before they can lay on the fat reserves they need to survive through the winter

Changes on land

Glaciers are shrinking because the climate has generally grown warmer over the past 100 years. When a glacier shrinks, it loses more volume during the summer than it gains during the winter. This process is determined mainly by temperature and precipitation. Melting of the Greenland Ice Sheet and of smaller glaciers such as those in Svalbard contribute towards increased sea level.

When meltwater forms on the surface of a glacier, it will eventually penetrate to the bottom of the glacier through sinkholes in the ice. This makes the glacier slide more quickly over the underlying rocks; it will calve more frequently, producing more icebergs. Eroded material from the glacier is transported to the sea and settles to the bottom. The seabed near a glacier usually does not support much life, but if the formation of new sediment is rapid, bottom-dwelling organisms farther out in the fjord may be buried. In addition, many species of plankton are sensitive to changes in salinity.

Melting of permafrost has impact both locally and globally. The thaw leads to changes in the vegetation which in turn change conditions for the animals that live in the Arctic. Wetlands, which are important for many bird species, can dry out because the permafrost no longer serves as a barrier for surface meltwater. On the global scale, thawing permafrost will release large amounts of methane (CH₄) and carbon dioxide (CO₂) that had previously been trapped in the frozen ground. These gases enhance the greenhouse effect and contribute towards further increases in temperature.

In Svalbard, there is permafrost everywhere except under the largest glaciers (which insulate against cold and prevent the ground from freezing). The permafrost goes to about 100 m deep near the coast and can reach as far as 400-500 m depth at higher elevations. In the summer, the top layer thaws and provides sustenance for plants and animals. In Svalbard, this layer is about one metre thick. However, measurements have shown that the temperature of the permafrost has increased as far down as 40 m depth, and the thickness of the top layer that thaws every summer is continually growing.

Pollution

The Arctic is still clean, but threats are encroaching. Trash and environmental pollutants are transported to the Arctic with sea and air currents. Several of these contaminants are non-biodegradable. Instead of being broken down, they are taken up by organisms – large and small. Animals differ in their capacity to break down and eliminate environmental pollutants, many of which accumulate in fat. When the animals have little food and must mobilise their fat reserves, the pollutants are released into the body where they can harm vital organs and reduce fertility.

Arctic systems contain high levels of the heavy metals mercury and cadmium. Lead used to be a major environmental threat, but since the 1980s, the amount of lead released has been substantially reduced. Measurements show that the lead burden in plants and animals has dropped sharply over the past ten years. The concentrations of the dangerous environmental pollutant PCB (polychlorinated biphenyls) have also gone down after international political agreement was reached to ban these compounds.

Changes in air and sea temperature can lead to increased transport of pollutants to the Arctic. In addition, environmental pollutants frozen into ice will be released to land and sea when the ice melts. Plankton and fish take up pollutants directly from the water they live in. Species that live on phytoplankton have the lowest levels of pollutants, whereas those that prey on animals farther up in the food chain or scavenge for dead material have higher levels. It is the predators at the top of the food chain that have the highest levels of all. These are also the species in which deformities and disease have been registered.