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increase runoff into the marine system while reducing the volume of the seasonal ice cover and the
amounts of freshwater from sea-ice melt that is added to the surface of the system.
Similarly, at freeze-up the amount of brine rejected and the amount of high salinity waters convected to
the layer of deep dense water will decrease. The overall impact of such shifts in the freshwater budget on
biological productivity in the system is not well understood. While it has been recognized that the outflow
from Hudson Strait does have a positive impact on biological productivity along the Labrador Coast
(Sutcliff, Loucks, Drinkwater, & Coote, 1983; Myers, Aikenhead, & Drinkwater, 1990), it is not at all clear
what the effect of an altered freshwater budget would have on the productivity of the region, on the
Labrador current or on the formation of deep water in the Labrador Sea.
We can expect to see continuing and growing interest by companies interested in exploring and extracting
minerals and oil and gas from the region. As the open water season lengthens, we can also expect that
shipping and tourism will increase. It is virtually certain that both the aboriginal and non-aboriginal
populations in the region will continue to increase and that this will in turn lead to increased pressure on
fish and wildlife in the region, perhaps leading to allocative conflicts over the harvesting of these
resources.
Climatologists have relied on a number of sophisticated global circulation models (GCMs) to help explain
current and previous climatic conditions and, most importantly, to predict future climatic conditions
under different greenhouse gas emission scenarios. These models all predict rising global temperatures
over the next century. The Intergovernmental Panel on Climate Change (IPCC, 2007) has consistently
found that Arctic and subarctic regions are warming more rapidly than other regions of the planet and
that Arctic and subarctic regions are also likely to experience more rapid warming in the next century. The
recent dramatic warming signals from Arctic and subarctic regions reinforce the expectation that the
changes in the Arctic will be more amplified than those in temperate and tropical regions. Overland (2011)
and Serreze and Barry (2011) discuss the evidence and reasons for this Arctic amplification.
The recently completed Arctic Climate Impact Assessment (ACIA, 2005) has projected that temperatures
throughout Canada’s central and eastern Arctic region will increase in all seasons. Increases between 1991
and 2001 are predicted to be hghest in winter when temperatures are projected to be higher by 3 to 9ºC.
The greatest increases in this region are projected to occur around Baffin Island and Hudson Bay. The
projections relied on five GCMs that were used by IPCC and were made before the recent record-setting
losses of sea ice on the Arctic Ocean. The dramatic reductions over the last 15 years in the minimal
(September) ice cover on the Arctic Ocean are unprecedented. They have led many to conclude that the
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IPCC and ACIA projections are unduly conservative and that a seasonally ice-free Arctic Ocean could, as
McLaughlin et al. (2011) have suggested, occur within one or two decades.
Joly, Senneville, Caya and Saucier (2011) have recently completed a modelling exercise on the sensitivity
of Hudson Bay sea ice and ocean climate to atmospheric temperature forcing. The objective was to
investigate the impact of a warmer climate scenario on the Hudson Bay marine system using the sea-ice-
ocean model presented by Saucier et al. (2004). They generated future temperatures using global and
regional circulation models for the 2041–2070 period and then used these generated values with the sea-
ice-ocean model. They found that the warmer climate led to an increase of 7–9 weeks in the ice-free
season and a decrease of 31 per cent in ice volume. However, the extent of maximum ice cover was
relatively unchanged with only a 2.6 per cent decrease indicating that at this level of warming (about
3.9ºC, compared to the base period from August 1, 2001 to July 31, 2005) the complex would continue to
be almost completely ice covered during at least some times of the year. Some of their major findings are
shown in Table 2.
These simulations are consistent with the findings of the IPCC (2007) and provide a reasonably foreseeable
glimpse of the future. They may or may not be overly conservative. It is worth noting that the period
selected to represent the present was in reality already considerably milder than earlier times in the
period of record. It is also possible, as some experts have suggested that the Arctic is warming quicker
than forecast by the IPCC (McLaughlin et al., 2011).
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Table 2. Summary of major changes between a simulation of current conditions (August 1, 2001
to July 31, 2005) and projected future conditions (2041–2070)
Ice
break-up
and freeze-up
median dates;
ice volume:
Hudson Bay
2001–2005
(Present)
2041–2070
(Future)
Present break-up: July 8; future 24
days earlier
Present freeze-up: December 4;
future 25 days later
Sea ice season reduced by 49 days
Ice volume decreased by 31 per cent
Air temperatures increase
by 3.9 per cent; summer
increase 0.8ºC;
winter increase 10.0 ºC;
summer
sea
surface
temperatures increase 3–
5ºC
The greatest change in
sea-ice climate and heat
content projected to occur
in southeastern Hudson
Bay, James Bay and
Hudson
Strait.
The
reduced ice melt will result
in a less stratified water
column
and
brine
rejection,
and
the
downward convection of
dense water is expected to
be reduced by 50 per cent.
Ice
break-up
and freeze-up
median dates:
Foxe Basin
2001–2005
(Present)
2041–2070
(Future)
Present break-up: July 13; future 22
days earlier
Present freeze-up: November 4;
future 31 days later
Sea ice season reduced by 53 days
Ice
break-up
and freeze-up
median dates:
James Bay
2001–2005
(Present)
2041–2070
(Future)
Present break-up: June 22; future 39
days earlier
Present freeze-up: December 18;
future 26 days later
Sea ice season reduced by 65 days
Ice conditions:
Hudson Strait
2001–2005
(Present)
2041–2070
(Future)
In the present climate scenario the
north shore is partially covered with
sparse and thin ice and is ice free in
the future climate scenario.
Source: Joly et al. (2011)
Note: A high resolution regional ocean model was used for both simulations and an effective carbon
dioxide concentration of 707–950 ppmv was used in the future scenario with the Canadian Regional
Climate Model (CCRM) driven by the Global General Circulation Model 3.1/T47.
The ability to track what is happening to the ice cover provides scientists with a powerful means of
documenting the status of and changes in this most important indicator of climate change. The nature,
extent and duration of ice cover in Arctic and subarctic seas also profoundly influence the physical,
chemical, and biological characteristics of these ecosystems and the fluxes between the sea, sea ice and
atmosphere. Clearly, ice-dependant species such as polar bears and ringed seals are directly affected.
Likewise, ice algae and the ice-associated fauna that these algae support are also directly affected.