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Changes to the Arctic Environment
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limate change is altering the basic characteristics of
the arctic environment. It is melting the snow, ice
and permafrost that make it unique; altering its ocean
temperature, chemistry and currents that regulate
1979
2005
shows that the annual amount of summer sea ice cover in
September has shrunk by 11.7 percent per decade since
1979. In 2007, the area of summer sea ice was 39 percent
below the 1979 to 2000 average, and in 2008, it was
2007
The annual amount of summer Arctic sea ice cover in September has shrunk by 11.7 percent per decade since 1979. In 2007, the
area of summer sea ice was 39 percent below the 1979 to 2000 average, and in 2008, it was 35 percent below this average. NASA
temperature; changing weather patterns; and raising
sea levels.These changes are moving the Arctic toward
tipping points that, once crossed, will cause rapid global
climate change.
Melting Surface Ice and Snow
35 percent below this average. Prior to these past two years,
the Intergovernmental Panel on Climate Change (IPCC) had
predicted the Arctic would be free of ice for part of the
summer by 2100. Following these record years
of rapid sea ice melt, some scientists are now predicting that
the Arctic could be ice free for part of the summer sometime
between 2013 and 2018.
Contributing to sea ice melt is the fact that young ice
formed over open ocean is thinner and melts more rapidly
than ice that has built up on other ice for two or more years.
The amount of sea and land ice and snow cover in the
Arctic is shrinking. Because light surfaces reflect much
more sunlight than dark, the melting of ice and snow
leaves dark water and land surfaces behind that
absorb sunlight and contribute to a warming
Earth. Snow loss and each type of ice loss also
have other consequences for the environment.
Shrinking Sea Ice. Since the late 1970s,
when satellite images of the Arctic first
became available, the area covered in sea ice
has been shrinking. Decreasing sea ice causes
the ocean to absorb more heat, increasing the
rate of global warming.
The amount of sea ice cover varies
somewhat annually, depending on a suite of
weather and climate conditions as well as
the amount of sea ice formed in past years.
However, this sea ice typically expands from
fall through the winter until it reaches its
maximum area in March. It then begins to
From 1985 to 2000, a significant portion of the Arctic’s sea ice was
contract in the summer months until September, greater than three years old and more than eight feet thick. As of 2008,
when it covers the least area. Satellite imagery
the majority is less than a year old and less than five feet thick.
2: Changes to the Arctic Environment
In the last two decades, thicker, multi-year ice is down
from covering 50 to 60 percent of the Arctic Ocean to 30
percent, while very old ice (greater than 6 years old) has
dropped to just 6 percent. Overall, sea ice thickness has
decreased more than 42 percent since the mid-1970s.
This loss of sea ice has several effects. Sea ice
loss is altering arctic ecosystems and threatening the
survival of some ice-dependent arctic species. In
addition, because ice reflects up to 90 percent of
sunlight that hits it whereas dark ocean waters absorb
heat, the ocean will warm as ice cover is reduced.
This can speed up the melting of sea ice and increase
ocean temperatures overall. This increase in ocean
temperatures can be compounded because sea ice does
not contain salt, so melting sea ice adds fresh water to
the Arctic. This changes the water’s salinity, which can
alter the major ocean current that regulates the Earth’s
temperatures, the thermohaline circulation.This global
current carries warm equatorial waters in the Atlantic
poleward along the surface and brings cold water south
along the seafloor. In the Arctic, once ocean water is
cooled, it becomes very dense and sinks. Salty marine
water is also heavier than fresh, so the sinking of dense
water helps to drive the current like a conveyor belt.
The many impacts that sea ice loss will have on
the physical and biological systems in the Arctic are
profound, including decreasing habitat and feeding
areas for ice-dependent species. They will also
influence global climate, such as accelerating warming
in the tropics. At some unknown point, the loss of sea
ice will become less of a result of and more of a driver
of global climate change.
The Jakobshavn Glacier is Greenland’s fastest moving and
largest glacier. Starting in late 2000, it has nearly doubled its
discharge of ice from land into the ocean and it now drains
6.5 percent of Greenland’s ice sheet area. Such deposits of
ice into the ocean will contribute to sea level rise. NASA
2: Changes to the Arctic Environment
Melting Land Ice. The ice that covers Arctic
land is sufficient to raise global sea levels 26.4 feet
(8 meters). Most of this is found in the Greenland ice
sheet, which holds about 700 percent more water than
the rest of Arctic ice sheets. The rate of ice melt on
Greenland is speeding up. Between 1998 and 2003,
it melted more than twice as fast as it did from 1993
to 1998. In 2007, 60 percent more surface area on
Greenland was melting than during its next highest
year of 1998, and it had an average of 20 more days of
melting than it did from 1973 to 2000.
Conservative estimates of sea level rise from
melting of the Greenland ice sheet are about 0.05 inch
(1.3 millimeters) per decade. Most of this is from rapid
melting on the surface and iceberg calving on the
coasts. If this sheet were to melt entirely, it would raise
global sea levels by about 23.1 feet (7 meters).
Other arctic glaciers are also melting, with their
rate of loss varying depending on the region. As ice
sheets melt, they can accelerate global climate change
in the same ways that melting sea ice can. Their melting
increases dark surfaces that absorb heat. And melting
glaciers also deposit fresh water into the ocean, altering
ocean salinity, which could influence ocean circulation
and interrupt the cooling of ocean waters. But melting
land ice will also raise sea levels, which erodes coastlines
and damages infrastructure and coastal habitat.
Reduced Snow Cover. The amount of snow on
the ground is the most rapidly varying aspect of the
Arctic and the Northern Hemisphere as a whole. It
ranges from less than 387,000 square miles (1 million
square kilometers) in August to more than 19 million
square miles (50 million square kilometers) in February.
Snow reflects sunlight from land and insulates the
ground.This moderates soil temperatures for plants and
burrowing mammals.
From the early 1970s to 2003, the area of Arctic land
covered by snow in winter decreased by 10 percent.
Spring melt occurred almost two weeks earlier in 2000
compared to in 1972. The reduced snow cover and early
melting have led to an earlier onset of spring. This alters
biological processes and phenomena like migrations, egg
laying and food availability. Increased melting in winter
and autumn also increases the amount of fresh water
that is flowing to the ocean in these seasons, altering
marine habitats and ocean currents.
Melting Lakes and Rivers. For much of the
year, Arctic lakes and rivers are frozen and covered
in snow. The frozen waterways help reflect sunlight
and provide a hard surface upon which animals and
people can travel safely.
The time period during which lakes and rivers are
frozen and safe to cross has shortened considerably.
They freeze more than a week later and the ice breaks
up 1.5 weeks sooner on average than in 1846. While
this means that boats can travel for longer periods,
animals and people have less time. Fewer ice roads
will affect land mammal migrations and the delivery of
supplies to remote outposts.
a tipping point for the climate system. Such a release
would drive rapid climate change, regardless of efforts
to control carbon emissions.
Altered Waters
Disappearing Permafrost
Loss of ice below the surface, or permafrost, is also
altering the artic environment. Permafrost is soil, rocks
and sediments that have remained frozen for two years
or more, either on land or on the seafloor. These frozen
layers stabilize the land and stores vast quantities of
carbon. As it thaws, the land above it can collapse,
hampering land travel and damaging infrastructure.
This can also release large amounts of carbon dioxide
and methane trapped in the frozen permafrost into the
atmosphere, increasing the rate of climate change.
Thawing of permafrost is causing uneven
topography called thermokarst, land subsidence and
the draining of wetlands.Thermokarst formation has
led to what are called “drunken forests,” trees that
lean at odd angles as permafrost melts.These trees are
weakened and therefore more prone to disease and
infestation, increasing the risk of fire. Land subsidence
and thermokarst formation also damages infrastructure
like buildings and roads and makes traversing such land
more dangerous.
Potentially even more detrimental will be
the release of methane and carbon dioxide from
permafrost thawing in coastal and undersea areas.
These areas are believed to contain large amounts of
frozen methane, which is 20 times more capable of
trapping heat radiated from the Earth’s surface than
carbon dioxide. A 2008 research cruise along the
Russian Arctic coast documented levels of dissolved
methane in the east Siberian Sea up to 10,000 times
higher than normal and an area that had “chimneys” of
methane bubbling to the surface. If large quantities of
methane are released from the seafloor, this could be
The increase in global temperatures and atmospheric
carbon dioxide levels are changing marine waters.
These changes will affect not only ocean currents, and
therefore temperature regulation, but also the survival
of certain organisms.
Climate change is producing three phenomena
that are now adversely affecting the ability of the
thermohaline circulation, or the conveyor belt that
circulates water north to the Arctic and then south to
help cool the Earth. First, the Arctic Ocean is warming,
reducing the difference in temperature between northern
and southern waters, which is potentially slowing this
current and its ability to bring warm waters north to the
poles. Secondly, glaciers full of fresh water are melting
into the ocean, reducing the salinity of oceanic surface
waters. Thirdly, increased river flow from increased land
ice melt and precipitation is also adding to the freshening
of the Arctic Ocean.Warming and freshening of Arctic
waters could disrupt the power of the conveyor belt to
circulate ocean waters and cool the planet. One result
could be that the northward transport of warm water in
the Atlantic could slow, increasing the rate of warming in
the tropics.
The ocean absorbs large quantities of carbon dioxide
from the atmosphere. Since the Industrial Revolution,
about 50 percent of anthropogenic carbon dioxide has
been stored in the ocean. Once in the ocean, carbon
dioxide reacts with water to form carbonic acid. As the
ocean absorbs more and more carbon dioxide, levels
of carbonic acid increase, causing the ocean’s pH level
to drop. The current pH level is about 8.1, or about 30
percent more acidic than pre-Industrial level of about 8.2.
During the next century, this level is projected to fall by
another 0.3 to 0.4 units, making the ocean 150 percent
more acidic. As the pH drops, oceanic concentrations of
calcium carbonate will also decrease, impairing the ability
of many marine organisms to use this mineral to make
their supporting and protective structures.
Changes in Arctic Weather
Sections of soil are collapsing into the voids left as permafrost
melts throughout the Arctic, as did this section of Alaskan
tundra in which this scientist now stands. Peter Thomson
As air and water temperatures rise, weather patterns
are predicted to shift significantly. These shifts will
vary regionally, some places becoming wetter with
increased participation and others, drier, perhaps
experiencing prolonged heat waves. More intense or
frequent storms are also possible in some areas.
The Arctic is not immune to these changes.
From 1903 to 2004, average Arctic precipitation has
increased about 8 percent, especially in the autumn
and winter. Much of the increase has come in the form
of rain, especially in winter, further melting snow and
ice. Changing amounts of precipitation causes flooding
2: Changes to the Arctic Environment
in some areas and droughts in others. As elsewhere,
however, such changes vary from region to region. For
example, western Russia has had a 50 percent increase
in winter rain events in the last 50 years, yet eastern
Russia has had large decreases.
Storms have been moving further north and
their frequency has grown in the Arctic from 1950 to
2006. Storms increase wave strength and frequency,
endangering ships in open water, eroding coastlines
and destabilizing coastal infrastructure. Storms also
cause sea ice to drift faster, moving surrounding water
as they travel.This changes the mix of surface and
deep waters, and therefore water temperatures and the
amounts of nutrients in areas of the Arctic Ocean—all
of which will alter marine ecosystems.
Sea Level Fluctuations
Not only is the temperature and composition of the
ocean changing, so is its amount. Global sea levels
are determined by both ocean temperature and how
much water runs into the ocean from land. Raising the
temperature of ocean water causes its volume to increase,
just as heating air in a balloon causes the balloon to
inflate even though the number of air molecules has
not changed. As marine water warms, it increases in
volume and raises sea levels. This volume increase due
to increasing higher ocean temperatures is estimated to
account for more than half of current sea level rise. The
other contribution comes from the melting of ice on land.
(Ice that is floating in the sea does not raise sea levels as it
melts, however, just as ice floating in a cup of water does
not cause the glass to overflow when it melts.)
Global sea levels have risen more than 7.5 inches (20
centimeters) in the last 100 years.The rate of increase has
grown from 0.078 inches (2 millimeters) per year during
1880 to 1993 to 0.13 inches (3.4 millimeters) per year
from 1993 until today. The IPCC predicts that sea levels
will rise up to 23 inches (59 centimeters) by the end of
the 21st century from thermal expansion alone.
While a 19.7-inch (50-centimeter) rise in sea levels
does not seem like much, it will inundate up to 164
feet (50 meters) inland in relatively flat coastal plains.
Rising sea levels will increase coastal erosion and storm
surges will penetrate further inland. This will impact not
only the Arctic environment but also settlements and
infrastructure such as oil production and storage facilities.
Crossing Arctic Tipping Points
The Arctic environment is changing significantly—and
most evidence indicates this is occurring at an increasing
rate. Some of these changes, such as loss of sea ice and
the release of methane from the seafloor, indicates that
Draft. Not for attribution.
we are about to or already have crossed tipping points
that may lead to abrupt climate changes exceeding
current IPCC predictions. These potentially catastrophic
changes could have devastating impacts on global
ecosystems.
Governance Mechanisms
and Governing Bodies
Controlling Carbon Emissions
Kyoto Protocol, United Nations Framework Convention
on Climate Change (Global)
Sea Level Rise
Convention on Biological Diversity, Conference of
Parties, United Nations (Global)
Impacts on Arctic Marine Mammals and
Endangered Species
Convention on the Protection of the Marine
Environment of the Northeast Atlantic (Global)
Convention on Biological Diversity,
United Nations (Global)
Convention on International Trade in Endangered
Species of Flora and Fauna (Global)
International Convention on the Regulation of Whaling,
International Whaling Commission (Global)
Jakarta Mandate on Marine and Coastal
Biological Diversity (Global)
Ramsar Convention on Wetlands (Global)
Beluga whale management, Canada and United States
(Regional)
Beluga whale management, North Atlantic Marine
Mammal Commission, Iceland, Norway and
Greenland (Regional)
Migratory narwhal and beluga whale management,
Canada and Greenland (Regional)
Indigenous hunting of polar bears, Russia and United
States (Regional)
International Agreement for the Conservation of Polar
Bears, Arctic States (Regional)
Working Group on the Conservation of Arctic Flora and
Fauna, Arctic Council (Regional)
National Invasive Species Act of 1996, United States
Nonindigenous Aquatic Nuisance and Prevention and
Control Act of 1990, United States
U.S. Endangered Species Act, United States
U.S. Marine Mammal Protection Act, United States
Additional information available in Appendix 1:
Governing a Warming Arctic