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The source document for this Digest states:
Global Climate Change
Ice cores and other evidence of climate conditions in the distant past provide evidence that rising atmospheric carbon dioxide levels are associated with rising global temperatures. Human activities, primarily the burning of fossil fuels (coal, oil, and natural gas), and secondarily the clearing of land, have increased the concentration of carbon dioxide, methane, and other heat-trapping (“greenhouse”) gases in the atmosphere. Since the start of the industrial revolution, the atmospheric carbon dioxide concentration has increased by about 35% and the global average temperature has risen by about 0.6˚C. There is an international scientific consensus that most of the warming observed over the last 50 years is attributable to human activities.
Continuing to add carbon dioxide and other greenhouse gases to the atmosphere is projected to lead to significant and persistent changes in climate, including an increase in average global temperature of 1.4 to 5.8˚C (according to the IPCC) over the course of this century. Climatic changes are projected to include shifts in atmospheric and oceanic circulation patterns, an accelerating rate of sea-level rise, and wider variations in precipitation. Together, these changes are projected to lead to wide-ranging consequences including significant impacts on coastal communities, animal and plant species, water resources, and human health and well-being.
About 80% of the world's energy is currently derived from burning fossil fuels, and carbon dioxide emissions from these sources are growing rapidly. Because excess carbon dioxide persists in the atmosphere for centuries, it will take at least a few decades for concentrations to peak and then begin to decline even if concerted efforts to reduce emissions are begun immediately. Altering the warming trend will thus be a long-term process, and the world will face some degree of climate change and its impacts for centuries.
The science suggests that responding to this challenge will require two sets of actions: one, called mitigation, to slow the speed and amount of future climate change by reducing greenhouse gas emissions; and the other, called adaptation, to attempt to limit adverse impacts by becoming more resilient to the climate changes that will occur while society pursues the first set of actions. The scope of this assessment did not include an evaluation of either of these sets of actions. These are being addressed by efforts under the auspices of the United Nations Framework Convention on Climate Change and other bodies.
Stratospheric Ozone Depletion is Another Issue
Depletion of the stratospheric ozone layer due to chlorofluorocarbons and other manmade chemicals is a different problem, although there are important connections between ozone depletion and climate change. For example, climate change is projected to delay recovery of stratospheric ozone over the Arctic. This assessment, in addition to its principal focus on climate change impacts, also examined changes in stratospheric ozone, subsequent changes in ultraviolet radiation, and related impacts in the Arctic. A summary of these findings can be found on pages 98-105 of this report
Source & ©: ACIA Impacts of a Warming Arctic: Arctic Climate Impact Assessment
The source document for this Digest states:
The Arctic Region
Polaris, the North Star, is located almost directly above the North Pole. Around it are the stars that form the constellation known as Ursa Major, the Great Bear. The term Arctic comes from the ancient Greek word Arktikós, the country of the Great Bear.
Earth’s northern polar region consists of a vast ocean surrounded by land, in contrast to the southern polar region in which an ice-covered continent is surrounded by ocean. Perhaps the most striking features are the snow and ice that cover much of the arctic land and sea surface, particularly in the high Arctic. And draped like a pair of great green shawls over the shoulders of the two facing continents are the boreal (meaning northern) forests. A wide expanse of tundra – treeless plains over frozen ground – lies between the icy high north and the forested sub-arctic.
One line often used to define the region is the Arctic Circle, drawn at the latitude north of which the sun does not rise above the horizon at winter solstice and does not set below it at summer solstice – “the land of the midnight sun”. Other boundaries used to define the Arctic include treeline, climatic boundaries, and permafrost extent on land and sea-ice extent on the ocean. For the purposes of this assessment, the boundary will be more flexible, also encompassing sub-arctic areas integral to the functioning of the arctic system.
High arctic lands and seas are home to an array of plants, animals, and people that survive in some of the most extreme conditions on the planet. From the algae that live on the underside of sea ice, to the polar bears that hunt on top of the ice, to the indigenous human societies that have developed in close connection with their environment, these communities are uniquely adapted to what many outside the region would view as a very severe climate.
Life in the Arctic has historically been both vulnerable and resilient. Factors that contribute to the Arctic’s vulnerability include its relatively short growing season and smaller variety of living things compared to temperate regions. In addition, arctic climate is highly variable, and a sudden summer storm or freeze can wipe out an entire generation of young birds, thousands of seal pups, or hundreds of caribou calves. Yet some arctic species have also displayed remarkable resilience to historic extremes, as evidenced by the recovery of populations that have occasionally been decimated by climatic variations.
The increasingly rapid rate of recent climate change poses new challenges to the resilience of arctic life. In addition to the impacts of climate change, many other stresses brought about by human activities are simultaneously affecting life in the Arctic, including air and water contamination, overfishing, increasing levels of ultraviolet radiation due to ozone depletion, habitat alteration and pollution due to resource extraction, and increasing pressure on land and resources related to the growing human population in the region. The sum of these factors threatens to overwhelm the adaptive capacity of some arctic populations and ecosystems.
Source & ©: ACIA Impacts of a Warming Arctic: Arctic Climate Impact Assessment
The source document for this Digest states:
People of the Arctic
Almost four million people live in the Arctic today, with the precise number depending on where the boundary is drawn. They include indigenous people and recent arrivals, hunters and herders living on the land, and city dwellers. Many distinct indigenous groups are found only in the Arctic, where they continue traditional activities and adapt to the modern world at the same time. Humans have long been part of the arctic system, shaping and being shaped by the local and regional environment. In the past few centuries, the influx of new arrivals has increased pressure on the arctic environment through rising fish and wildlife harvests and industrial development.
The Arctic includes part or all of the territories of eight nations: Norway, Sweden, Finland, Denmark, Iceland, Canada, Russia, and the United States, as well as the homelands of dozens of indigenous groups that encompass distinct sub-groups and communities. Indigenous people currently make up roughly 10% of the total arctic population, though in Canada, they represent about half the nation’s arctic population, and in Greenland they are the majority. Non-indigenous residents also include many different peoples with distinct identities and ways of life.
People have occupied parts of the Arctic since at least the peak of the last ice age, about 20 000 years ago, and recent studies suggest a human presence up to 30 000 years ago. In North America, humans are believed to have spread across the Arctic in several waves, reaching Greenland as many as 4500 years ago before abandoning the island for a millennium or more. Innovations such as the harpoon enabled people to hunt large marine mammals, making it possible to inhabit remote coastal areas in which the land offered scant resources. The development of reindeer husbandry in Eurasia allowed human populations to increase dramatically owing to a reliable food source. In Eurasia and across the North Atlantic, new groups of people moved northward over the past thousand years, colonizing new lands such as the Faroe Islands and Iceland, and encountering indigenous populations already present in West Greenland, and northern Norway, Sweden, Finland, and Russia.
In the 20th century, immigration to the Arctic increased dramatically, to the point where the non-indigenous population currently outnumbers the indigenous population in most regions. Many immigrants have been drawn by the prospect of new opportunities such as developing natural resources. Conflicts over land and resource ownership and access have been exacerbated by the rise in population and the incompatibility of some aspects of traditional and modern ways of life. In North America, the indigenous struggle to re-establish rights to land and resources has been addressed to some extent in land claims agreements, the creation of largely self-governed regions within nation-states, and other political and economic actions. In some areas, conflicts remain, particularly concerning the right to use living and mineral resources. In Eurasia, by contrast, indigenous claims and rights have only begun to be addressed as matters of national policy in recent years.
Populations are changing and northern regions are becoming more tightly related economically, politically, and socially to national mainstreams. Life expectancy has increased greatly across most of the Arctic in recent decades. The prevalence of indigenous language use, however, has decreased in most areas, with several languages in danger of disappearing in coming decades. In some respects, the disparities between northern and southern arctic communities in terms of living standards, income, and education are decreasing, although the gaps remain large in most cases.
The economy of the region is based largely on natural resources, from oil, gas, and metal ores to fish, reindeer, caribou, whales, seals, and birds. In recent decades, tourism has added a growing sector to the economies of many communities and regions of the Arctic. Government services including the military are also a major part of the economy in nearly all areas of the Arctic, responsible in some cases for over half of the available jobs. In addition to the cash economy, traditional subsistence and barter economies make a major contribution to the overall well-being of parts of the region, producing significant value that is not recorded in official statistics.
Source & ©: ACIA Impacts of a Warming Arctic: Arctic Climate Impact Assessment
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