Arctic Climate Change
5. How will animals be affected by Arctic warming?
- 5.1 How will climate change affect the Arctic marine environment?
- 5.2 What will be the impact on marine fisheries?
- 5.3 How will climate change affect aquaculture?
- 5.4 How will animals on land be affected?
- 5.5 What will be the impacts on freshwater ecosystems?
Animal species’ diversity, ranges, and distribution will change.
5.1 How will climate change affect the Arctic marine environment?
Ocean accounts for more than half of the surface area of the
Arctic region. Many Arctic life forms rely on the sea’s
biological productivity and
on the presence of sea ice,
two factors that are highly dependant on climatic
Polar Bears depend on sea ice for their survival
Polar bears give birth and hunt on
sea ice and they need it to
travel from one region to another. Survival of mothers and cubs
in the spring depends on the mothers’ hunting success, which, in
turn, depends on the stability and extent of sea ice. Less
winter sea ice means that female polar bears have to go longer
without food, which impacts their fat stores, and, in turn,
their reproductive success.
Complete loss of summer sea-ice cover, which may occur in the
course of this century, could threaten the survival of polar
bears as a species or force
them to adopt a land-based summer lifestyle. Living on land
would not be without risks due to competition with other
predators, possible cross breeding with brown or grizzly bears,
and interactions with humans.
species that rarely come to
land, such as the harp seal, spotted seal and the ringed seal,
depend on Arctic sea ice.
Not only does sea ice provide a home for resting, giving birth
and raising pups, it is also a feeding ground for some of them.
Ice-dependent seal species are likely to have difficulty
adapting to ice-free summers. Other species that currently live
farther south, such as the harbour and grey seals, are likely to
expand their geographic spread if the Arctic has less ice
Some seabirds such as ivory gulls and little
auks are likely to be negatively affected by a decline in
sea ice. Ivory gulls nest
on rocky cliffs and fly out to the sea ice to fish through
cracks in the ice and scavenge on top of the ice. A retreat of
sea ice away from the coastal nesting sites would have serious
consequences. The number of ivory gulls in Canada has already
dropped by 90% over the last 20 years.
Walrus rely on sea ice for easier access to food
The ice edge in coastal areas is an important feeding ground
for the walrus that use the ice as diving
platforms to feed on clams on the sea floor. As the ice edge
retreats away from the continental shelves to deeper areas,
there will be no clams nearby to feed on. Walrus also travel
large distances on floating ice, which allows them to feed over
a wide area.
Ice algae grow at the porous bottom of
sea ice and form the base
of the unique
marine food web connected to sea ice.
The melting of ice can affect the availability of physical
habitats for algae, as well
as the temperature and
salinity of surface waters,
potentially disrupting the whole food web.
In addition to loss of
habitat and feeding
grounds, climate change
poses other threats to Arctic marine mammals
and some seabirds:
- Increased risk of disease.
- Increased precipitation, which will carry pollution
from the south.
- Expansion of the geographic spread of
species ranges, which
will increase competition between them.
- Increased human activity, which will increasingly
affect previously untouched areas.
Many marine communities
depend on polar bears, walrus, seals, whales, seabirds, and
other marine animals. Changes in the numbers and ranges of
Arctic animals and birds may greatly affect northern
communities’ way of life. So will changes in ice conditions
which are critical to the hunters’ mobility.
5.2 What will be the impact on marine fisheries?
provide an important food source globally, and are a vital part
of the region’s economy. In the past
climate change has induced
major ecosystem shifts in
some areas and this could happen again resulting in radical
unpredictable changes in
An example of a positive impact of
climate change is the cod
population in West
Greenland which thrived between the 1920s and 1960s, a time
period when the waters were warmer then they are now. A warming
of the climate is thus likely to have a positive effect on the
cod population allowing more fishing. An example of a negative
impact is the fishing of shrimp in Greenlandic waters which is
likely to suffer, both from the predicted changes in climatic
conditions and from the growing cod population who feed on
In the early 1950s, the Norwegian
stock was the largest in the world, and was important to Norway,
Iceland, Russia, and the Faroe Islands. In the 1960s, a sudden
and severe cooling of the waters west of the Norwegian Sea where
the herrings were feeding, combined with high intensity fishing,
contributed to the collapse of the Norwegian Herring Stock.
Since the 1970s the return of favorable climatic conditions and
international agreements on restricting the capture of herring
permitted a gradual recovery of the stock. Such international
agreements will be crucial in future as
climate change alters
fish stocks and their
A climate shift also occurred in the Bering Sea in 1977,
bringing about an abrupt warming that favored a number of
species, such as
herring, pollock and
cod, and led to record
catches of salmon in subsequent years.
In some areas, such as most of the North Atlantic, where only
a relatively slight warming is expected, the total effect of
climate change on
fish stocks is likely to be
less strong than the effects of
fisheries management, at
least for the next few decades. In the Bering Sea, however, the
impacts of rapid climate change are already apparent, with a
displacement or a decline of cold-water
species brought about by
the warming of bottom waters. While it seems unlikely that the
effects of climate change on fisheries will have long-term
social and economic impacts throughout the Arctic, particular
people and places may be strongly affected.
In the past century, certain fishing towns, such as Paamiut in
West Greenland, which concentrated on a single fishery resource,
such as cod, have been
when water temperature changes led to the decline of local fish
5.3 How will climate change affect aquaculture?
Aquaculture in the Faroe Islands
Salmon and trout are the two main aquaculture
species farmed in the
Arctic. Norway has developed a large industry over the past two
decades and is now the world's largest farmed salmon producer.
The speed at which fish grow might be expected to increase in
slightly warmer water. Greater water temperature increases,
however, may have a negative impact on growth rates and the
general health of farmed
species. Other negative
impacts of warmer waters on
aquaculture may include
increases in diseases and toxic
algal blooms. Relocating
aquaculture infrastructure further north to adjust to increasing
water temperatures would be costly.
The aquaculture industry
depends on huge supplies of wild fish (in the form of
fishmeal and oil) in order
to feed farmed salmon and trout. These wild fish are caught
elsewhere in the world, like anchovies from the South Pacific,
and can also be affected by
climate change. Many of the
species that are fished to
make fishmeal are also an important part of the diet of certain
wild species that are of high commercial
value but that are currently
not abundant due to overfishing. Reductions in the production of
might be needed in order for these
stocks to recover.
The ocean surrounding the Faroe Islands is an
important feeding ground for wild
stocks of northern European
Atlantic salmon. These islands enjoy particularly good
conditions for farming Atlantic salmon and rainbow trout.
Despite early setbacks due to disease and market fluctuations,
the Faroe Islands have become an important international player
in salmon farming. Many people are employed both in fish farming
and in related industries, and
aquaculture accounts for
25% of the total income from exported goods. Global warming will
increase fish growth rates, provided it does not exceed 5°C
(9°F). This positive impact (on fish production) would, however,
be offset by some warming-related increases in fish diseases and toxic
5.4 How will animals on land be affected?
Arctic animals on land include:
- small plant-eaters like ground squirrels, hares,
lemmings and voles;
- large plant-eaters like moose, caribou/reindeer and
musk ox; and
- meat-eaters like weasels, wolverines, wolves, foxes,
bears and birds of prey.
Climate-induced changes are likely to cause a series of
cascading effects involving many
species of plants and
animals. If grasses, mosses and
lichens no longer live in
the same areas due to a changing climate, it will have
implications for the animals that feed on them, and on the
predators or human
communities that depend on
In snow-covered areas, warming could increase the occurrence
of repeated freezing and thawing which could lead to the
formation of an ice crust thus preventing animals from eating
grasses and mosses and sometimes even killing the plants.
Lemmings, musk ox and reindeer/caribou are all affected.
Dramatic population crashes
resulting from this phenomenon have been reported increasingly
frequently over recent decades.
Mild weather and wet snow lead to collapse of spaces between
the frozen ground and the snow where lemmings and voles live and
forage. Furthermore, when the surface of the snow melts and
re-freezes the resulting ice crust reduces the insulating
properties of the snow pack that is vital to the survival of
these animals. Declines in their
populations can in turn
lead to declines in animal
population that feed on
them, such as snowy owls, skuas, weasels and ermine. When
lemming populations are low, more generalist predators, such as
the Arctic fox, switch to other prey
species such as waders and
other birds, increasing pressure on those populations.
Caribou (in North America) and
reindeer (in Eurasia) are of primary importance
to people throughout the Arctic both for food and for cultural
reasons. The herds depend on the availability of food and good
foraging conditions, especially at the time when calves are
Climate-induced changes are expected to reduce the area of
tundra and thus the feeding
area of these herds. It will also increase the occurrence of
freeze-thaw cycles and freezing rain that make it harder for
caribou and reindeer
populations to find food
and raise calves. Future
climate change could
potentially lead to a decline in caribou and reindeer
populations, threatening the way of life for some Arctic
The Porcupine Caribou Herd
The Gwich’in and the Porcupine Caribou Herd
5.5 What will be the impacts on freshwater ecosystems?
ecosystems in the Arctic
include inland waters such
as rivers, lakes, ponds, wetlands and their surroundings. They
are home to a variety of animal life including fish, mammals,
waterfowls, and fish-eating birds. These ecosystems act as
intermediaries between land and ocean ecosystems.
Increases in the temperature of
inland waters can
significantly reduce the geographic spread of some
species, such as the Arctic
char, that may not be able to adapt to warmer conditions or to
invasive species that
thrive in warmer waters.
The thawing of frozen soil can lead to the drainage of surface
waters, eventually eliminating aquatic
habitats. The thawing of
permafrost can also lead to
the collapse of the ground surface, create hollows in which
ponds and wetlands can form. The balance of these changes is not
known, but as freshwater
habitats disappear, re-form, and are modified, major shifts in
aquatic habitats are likely.
The timing of ice
break-up in spring strongly
affects supplies of
nutrients, sediments, and
water that are essential to the health of
delta and floodplain
ecosystems. Changes in ice
cover also affect water temperature, levels of oxygen in the
water and the exposure of underwater life forms to ultraviolet
rays. In some areas, as a result of later freeze-up and earlier
break-up, the ice season is now up to three weeks shorter
compared to 100 years ago, and this trend is expected to
continue. Evaporation and precipitation are expected to increase
and flood patterns are likely to change, as will levels of
sediments and nutrients carried by rivers to the Arctic Ocean.
Warming and increased precipitation are very likely to
increase the amount of
persistent organic chemicals
and mercury that are deposited on the Arctic. As temperatures
rise, snow, ice and
permafrost which contain
contaminants will melt,
leading to the release of these contaminants. The resulting
increase in the concentrations of contaminants in rivers and
ponds may have harmful effects on aquatic plants and animals and
also contaminate sea waters.
freshwater fish that live
in the southernmost part of the Arctic are expected to move
northward, competing for food and
habitat with species that
live in northern
inland waters, such as the
Arctic char and Arctic cisco.
Invasive species from the
South may introduce new parasites and diseases. As water
temperatures rise, the areas where cold-water species can lay
their eggs will also shift northward and are likely to diminish.
Inland fishing in the far north is likely to be seriously
affected by such changes as the most
vulnerable species are
often the only fishable species present. However, in some areas
of the Arctic, new arrivals from the south and increased growth
of species already present may also bring new fishing
The geographic spread of aquatic mammals and waterfowl is
likely to expand northward as
habitats change with
warming. Mammal and bird
species moving northward
could carry new diseases and parasites, and take over habitats
and resources currently used by northern species. These northern
species may be reproducing less successfully due to
temperature-induced habitat changes, while changes affecting
breeding grounds and access to food may cause seasonal
migrations to take place earlier in spring and later in