Arctic Climate Change: ACIA Report Summary

08 Nov 2006 - Special Reports, Logistics, Atmosphere & Space, Water & Oceans, Land & Geology, Ice & Snow, Flora & Fauna, Human Dimension, Arctic

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Our climate is already changing, particularly in the Arctic where the permafrost is melting, glaciers are receding, and sea ice is disappearing. Changes in the Arctic not only affect local people and ecosystems but also the rest of the world, because the Arctic plays a special role in global climate.

Artic Council recognised needed to be addressed in commissioning the landmark 2004 ACIA report. In addressing them, the report put the worsening plight of the Arctic firmly in the spotlight of the world's attention.

The International Polar Foundation, through SciencePoles, has contributed to a GreenFacts summary of this major scientific report. Alain Hubert, polar explorer and co-founder of the IPF has said that

"due to the vulnerability of its ecosystems, Arctic climate change is a bellwether for global climate change. The implications and consequences of Arctic climate change stretch far beyond the limits of this region and affect the world as a whole. Thus, climate change in the Arctic requires urgent public attention."

According to the report, the current increase in temperatures goes beyond natural climate variability. In the Arctic, average temperatures have risen almost twice as fast as in the rest of the world, and are projected to rise by 3 to 7°C between 2000 and 2100. The melting of Arctic glaciers is also expected increasingly to contribute to global sea-level rise.

Moreover, three major Arctic climate mechanisms directly feed back into further global warming:

as snow and ice melt, the amount of the sun's energy that is reflected back to space decreases - since darker surfaces absorb more heat - which in turn leads to more melting;
with the melting of Arctic ice, and increased fresh water run-off from continental rivers, the circulation of water in the oceans can change and affect currents such as the Gulf Stream;
as global warming progresses, there are changes in the net amount of greenhouse gases released into the atmosphere, including methane from melting permafrost.

Due to the complexity of the Earth's climatic system, major surprises are possible if climate change evolves more abruptly than the gradual scenarios assumed in the ACIA report. Records indicate that very large shifts in Arctic climate patterns have occurred very quickly in the past. The implications are particularly significant for future generations that will face the consequences of current action or inaction.

This SciencePoles feature includes summary text addressing the ACIA report's key findings. You can also find more detail on the Greenfacts website

Global climate change and the Arctic region

The world's climate is changing. On average, the temperature on the Earth's surface has increased by 0.6°C (1°F) over the last two centuries. Most of the warming observed in the past 50 years is attributed to human activities and particularly to the burning of fossil fuels.

Information on past climatic conditions obtained from ice cores and other sources show that the current increase in global temperatures goes beyond natural climate variability. In the Arctic, average temperatures have risen almost twice as fast as in the rest of the world and climate changes are particularly intense. Changes in the Arctic climate will also affect the rest of the world through increased global warming and rising sea levels.

The Arctic region is the area around the North Pole, essentially an ocean surrounded by land. In the far north, the Arctic is mostly covered by snow and ice, whereas the southernmost part is covered by boreal forests. In between, there is a wide expanse of tundra. The Arctic is home to an array of plants, animals, and people that survive in some of the most extreme conditions on the planet and that are uniquely adapted to such conditions. Climate change, pollution, and growing resource use are factors that put an increasing pressure on fragile Arctic populations and ecosystems.

The Arctic region is home to almost four million people, including an increasing majority of non-indigenous settlers. The Arctic includes Greenland, Iceland, and the northern parts of Norway, Sweden, Finland, Canada, Russia, and the United States. Economically, the region depends largely on natural resources, ranging from oil, gas, and metal ores to fish, reindeer and birds. Recently, the tourism sector has also grown in many parts of the Arctic.

How is the climate changing in the Arctic?

Evidence of the recent warming of the Arctic is provided by: records of increasing temperatures, melting glaciers / sea ice / permafrost and rising sea levels

The Earth is expected to warm more than twice as much between 2000 and 2100 as it did during the last century. Climate models indicate that the warming in the Arctic will be substantially greater than global average warming.

Over the course of this century the following changes are projected to take place in the Arctic:

The average annual temperatures are projected to rise by 3 to 7 °C (5.4 to 12.6°F)
Precipitation is projected to increase by roughly 20%.
Sea ice -that has already decreased in area and thickness considerably since 1950- is expected to decline significantly. Reductions in sea ice will increase regional and global warming, because solar radiation that was previously reflected by the ice will be more readily absorbed by the darker sea surface.
The area of Arctic land covered by snow, which has decreased by about 10% over the past 30 years, is expected to decrease by a further 10 to 20%.

While most analyses of climate impacts focus on scenarios of steady gradual warming of the climate, abrupt changes in climate triggered by the warming could also be possible). Such potential abrupt changes are not adequately taken into account in current climate models, meaning that surprises are possible. Records indicate that very large shifts in Arctic climate patterns have occurred very quickly in the past.

How will Arctic warming affect the rest of the planet?

Arctic warming and its consequences have worldwide implications. Changes that occur in the Arctic can influence global climate through three major mechanisms that are all likely to be affected by global warming.

The amount of the sun's energy reflected back to space by the ground and seas changes as snow and ice melt and vegetation changes, creating a feedback loop in which, for example, darker open seas absorb more heat, which in turn leads to more melt, and so on.
The circulation of water in the oceans can change as Arctic ice melts, adding freshwater to the oceans. This can potentially affect ocean currents, such as the Gulf Stream, that transport warm water from tropical regions to higher latitudes.
The net amount of greenhouse gases released into the atmosphere may change as warming progresses. On the one hand, the thawing of now permanently frozen soil can lead to the release of methane. On the other hand a warming can increase the biological growth in the oceans and on land, and thus the absorption of CO2.

Projections from global climate models suggest that the melting of Arctic glaciers will increasingly contribute to the global sea-level rise during the next 100 years. By 2100, these glaciers alone will contribute to a sea level rise of roughly 4-6 cm (1.6-2.4 inches) possibly more. Sea-level rise is projected to have serious implications for coastal communities and industries, islands, river deltas, and harbors.

Arctic resources include both wildlife, such as whales, seals, birds, and fish sold on world markets, and significant oil, gas and mineral reserves. Access to those resources by land or by sea is likely to be affected by climate change.

The many links between the Arctic and the rest of the planet mean that changes to Arctic ecosystems will have an impact on a global scale. For instance, many species from around the world, particularly birds, depend on summer breeding and feeding grounds in the Arctic, and these habitats will be affected by climate change.

How will the vegetation be affected by Arctic warming?

Arctic vegetation zones are likely to shift, causing wide-ranging impacts.

The main types of vegetation found in the Arctic are polar deserts in the north, boreal forests in the south, and a wide expanse of tundra inbetween. Polar deserts are characterized by sparse vegetation, open patches of bare ground and an absence of shrubs, which are characteristic of the tundra.

During this century, rising temperatures are expected to favor taller and denser vegetation and thus to cause, a northward expansion of boreal forests into the Arctic tundra, as well as an extension of tundra into the polar deserts.

The projected expansion of forest will amplify global warming, because the newly forested areas are darker and will absorb more of the sun's energy than the lighter, smoother tundra. This is expected to outweigh the fact that the taller and denser vegetation will be taking up more carbon from the atmosphere.

Due to the warming, insect outbreaks are increasingly likely to disturb large areas of forest. The types of weather that cause extreme fire danger could also affect a greater area of forest according to projected changes in climate. Fires are expected to be more frequent and of higher intensity in all ecosystems. However, some scenarios suggest that fire could possibly become more frequent in some regions and less frequent in others, greatly affecting individual areas but amounting to only a small overall change in the total amount of forest fires.

Climate change is expected to increase the range of crops that can be grown in the Arctic. Not only could varieties with a higher yield be grown, but the growing season would also be longer, increasing the potential number of harvests per year. However, problems caused by insects, diseases, and weeds are also likely to increase throughout the Arctic with increasing temperatures.

How will animals be affected by Arctic warming?

Animal species' diversity, ranges, and distribution will change.

Many Arctic life forms rely on the sea's biological productivity and on the presence of sea ice, both of which are highly dependent on climatic conditions.

Polar bears, seals, walruses, and seabirds often depend on the presence of sea ice which they use as a place to rest or hunt. Moreover, the food web of the Arctic Ocean relies in part on microscopic algae that grow in sea ice, which is why the melt of sea ice could disrupt the whole food web.

Arctic marine fish stocks are an important food source for the world and play a vital role in the economy of the region. Climate change could result in radical changes in species composition, with unknown consequences.
Aquaculture of salmon and trout is a major industry in the Arctic. Fish might be expected to grow more quickly in slightly warmer water, but if water temperatures increase significantly, growth rates and the general health of farmed fish may suffer. The extension or relocation of infrastructure for aquaculture towards cooler waters would be a costly operation.
On land, climate-related changes are also likely to cause a series of disruptions involving many species of plants and animals. Arctic animals living on land include small plant-eaters such as lemmings, large plant-eaters such as caribou/reindeer, and meat-eaters such as foxes and birds of prey. If certain types of vegetation decline in a given area as a result of climate change, it will have deep implications for the animals that feed on them, as well as on the predators or human communities that depend on those animals.
Freshwater ecosystems in the Arctic, such as rivers, lakes, and wetlands, are home to a variety of animals including fish, mammals, waterfowl, and fish-eating birds. Increases in water temperature, thawing of permanently frozen ground, and ice cover break-up earlier in spring are examples of climate-related disruptions that would have significant impacts on freshwater ecosystems.

How will settlements and infrastructures be affected by Arctic warming?

Many coastal communities and facilities face increasing exposure to storms.

Rising temperatures are modifying the Arctic coastline and are expected to change it even more in the future. Indeed, reduced sea ice allows stronger waves to form, increasing shore erosion. This problem is worsened by the thawing of coastal permafrost. Moreover, sea level rise is likely to cause flooding of marshes and coastal plains accelerate beach erosion, and force salt water into bays, rivers, and groundwater. Some towns and industrial facilities are already suffering severe damage as a result and are now facing the prospect of relocation.

Reduced sea ice is very likely to increase marine transport and access to resources.

Over the past 50 years, a decline in the area of Arctic sea-ice has been observed. Recent studies have shown that the ice becomes thinner and thinner. This trend will allow better accessibility by ship around the Arctic Basin and will probably open new shipping routes and extend the period during which shipping is feasible, with potential growing issues regarding access to natural resources, as well as safety, security, and sovereignty.

Thawing ground will disrupt transportation, buildings, and other infrastructure

Arctic land is generally more accessible in winter, when the tundra is frozen and roads can be built on the ice . The availability of these transportation routes is likely to be affected by changing climatic conditions. Increases in the temperatures affect the permafrost layer and pose significant engineering challenges to existing infrastructure such as roads, buildings, and industrial facilities. New constructions will require deeper foundations, thicker insulation, and other preventive measures likely to increase construction costs.

Climate-induced changes in permafrost interact in many ways with ecosystems, and its thawing will, for instance, affect the water balance in streams, ponds and peatlands.

How will people and their environment be affected by Arctic warming?

Indigenous communities are facing major economic and cultural impacts.

The Arctic is home to many indigenous populations whose cultures and activities are shaped by the Arctic environment. The rapid climate change of recent decades together with current social, economic and political conditions impose new challenges on these populations. To the indigenous people, the weather seems less stable and predictable, due to changing seasonal weather patterns. They also observe that snow characteristics are changing, that there is more freezing rain, and that the timing and quality of sea ice is less reliable, with important consequences for marine hunters.

Elevated ultraviolet radiation levels will affect people, plants, and animals.

The increase of ultraviolet radiation (UV) reaching the Earth's surface as a result of the thinning of the ozone layer causes increasing concern in the Arctic. Ozone depletion over the Arctic has been severe and is greatest in the spring when living organisms are most vulnerable. Humans, animals and plants are all adversely affected by an increase in UV radiation. Because ozone depletion is likely to persist over the Arctic for several more decades, episodes of very low spring ozone levels are likely to continue.

Multiple influences interact to cause impacts to people and ecosystems.

Climate change in the Arctic is taking place within the context of many other changes. Some of these changes are environmental, such as chemical pollution or increased ultraviolet radiation, while others are societal, such as growing populations, urbanization, or self-determination movements. The ability of the Arctic populations to cope with the impacts of climate change will thus be greatly affected by political, legal, economic, social, and other factors.

What changes are expected in specific areas of the Arctic?

In a region as large as the Arctic, there are significant sub-regional variations in climate. Recent warming has been more dramatic in some regions than in others. Moreover, local features of the natural world and societies create differences in what impacts will occur and which will be most significant locally.

The Arctic Climate Impact Assessment (ACIA) focuses on four sub-regions and considers a series of key impacts:

impacts on the environment, such as changes in habitats and in the geographic spread of plant and animal species,
impacts on the economy, such as changes in access to resources, and
impacts on people's lives, such as effects on traditional lifestyles or damage to infrastructure.

How can future assessments be improved?

The Arctic Climate Impact Assessment (ACIA) represents the first effort to comprehensively examine climate change and its impacts in the Arctic region. As such, it represents the beginning of a process. The assessment brought together the findings of hundreds of scientists and the insights of Indigenous Peoples. This linking of scientific and indigenous perspectives is still in its early stages and can potentially improve our understanding of climate change and its impacts.

Important gaps in knowledge remain that need to be addressed, specifically in order to understand sub-regional impacts, socioeconomic impacts, and the vulnerabilities to multiple stresses. To address these gaps will require improved long-term monitoring, studies of ecosystem processes, climate modeling, as well as analysis of impacts on Society.

The ACIA has built on the substance and conclusions of the assessments prepared by the Intergovernmental Panel on Climate Change (IPCC). In turn, the next IPCC report, in 2007, will build on ACIA's findings with regard to the Arctic, doing so in a way that adds more global context. Other national and international efforts such as the upcoming International Polar Year (in 2007-2009) offer opportunities to improve our understanding of the impacts of climate change and ultraviolet radiation.

Conclusion

Climate change presents a major and growing challenge to the Arctic and the world as a whole. Implications are particularly great for future generations that will face the consequences of the current actions or inaction. The findings of this first Arctic Climate Impact Assessment provide a scientific basis upon which decision makers can consider, craft, and implement appropriate actions to respond to this important and far-reaching challenge.

Climate change is very likely to result in major environmental changes that will present risks as well as opportunities across the Arctic. For example, the large reduction in summer sea ice threatens the future of several ice-dependent species but will also increase marine access to resources and population centers.

Due to the complexity of the Earth's climatic system, major surprises are possible if climate change evolves differently than the scenarios assumed in this assessment in which changes are gradual. For example, ocean currents that are in part influenced by key processes taking place in the Arctic might undergo major changes with wide-ranging consequences on climate. Although such changes could cause severe impacts (as they have in the Earth's past), little information is currently available to assess how such possibilities might unfold.

Changes in climate and their impacts in the Arctic are already being widely observed and felt. They provide an early indication for the rest of the world of the significance of climate change. The changes will also reach far beyond the Arctic, affecting global climate, sea level, biodiversity, and many aspects of human social and economic systems. Climate change in the Arctic thus deserves and requires urgent attention by decision makers and the public worldwide.

The 10 key findings

Arctic climate is now warming rapidly and much larger changes are projected.
Arctic warming and its consequences have worldwide implications.
Arctic vegetation zones are likely to shift, causing wide-ranging impacts.
Animal species' diversity, ranges, and distribution will change.
Many coastal communities and facilities face increasing exposure to storms.
Reduced sea ice is very likely to increase marine transport and access to resources.
Thawing ground will disrupt transportation, buildings and other infrastructure.
Indigenous communities are facing major economic and cultural impacts.
Elevated ultraviolet radiation levels will affect people, plants, and animals.
Multiple influences interact to cause impacts to people and ecosystems.

By: Gauthier Chapelle