15.3.2.8. Arctic Border
A case study of the regional impacts of climate change scenarios has been completed
in the Mackenzie basin, a watershed that extends from the mid-latitudes to the
subarctic in northwest Canada. A lengthy description of this case study, known
as the Mackenzie Basin Impact Study, is available in Cohen (1994, 1996, 1997a,b,c).
A sketch of the MBIS integrating framework is shown in Figure
15-10. Within this process, several types of integration exercises were
used, including models, stakeholder consultation, and thematic discussions.
As a high-latitude watershed, the Mackenzie basin has been regarded as an area
that might benefit in certain ways from a warmer climate. Taken individually,
economic impacts could be quantified, and these impacts might show substantial
benefits for the region. Other factors must be considered, however, and some
of these factors may constrain the potential benefits:
- The current system of land transportation, much of which is based on a stable
ice and snow cover for winter roads
- Current ranges and habitats of wildlife, which underpin conservation plans
and native land claims
- Scientific uncertainty, which hampers anticipatory responses to projected
beneficial conditions.
Potential negative impacts of climate warming also must be considered because
they may offset possible benefits. An example is the implication of hydrological
and landscape changes on water management agreements. Initial projections of
runoff and lake levels are for declines below observed minima (Soulis et
al., 1994; Kerr, 1997). Peace River ice cover will be affected by temperature
changes and changes in outflow from the Bennett Dam in northeast British Columbia
(Andres, 1994). There continue to be uncertainties in projections of hydrological
impacts; the Global Energy and Water Cycle Experiment (GEWEX) is addressing
these uncertainties (see Chapter 16). There has been a
strong warming trend in the region during the past 40 years, and Great Slave
Lake experienced new record minimum lake levels in 1995.
It would appear that the other main threats to the Mackenzie landscape are
accelerated erosion and landslides caused by permafrost thaw and extreme events
(fire, storm surges), especially in sloping terrain and the Beaufort Sea coastal
zone (Aylsworth and Egginton, 1994; Solomon, 1994; Aylsworth and Duk-Rodkin,
1997; Dyke et al., 1997); increased fire hazard (Hartley and Marshall,
1997; Kadonaga, 1997); changes in climate conditions that influence the development
of peatlands (Nicholson et al., 1996, 1997; Gignac et al., 1998);
and invasion of new pests and diseases from warmer regions (Sieben et al.,
1997).
Impacts on fisheries and wildlife are difficult to project, as a result of
lack of long-term data, complexity of life cycles, and incomplete information
on responses to previous environmental changes (Brotton and Wall, 1997; Gratto-Trevor,
1997; Latour and MacLean, 1997; Maarouf and Boyd, 1997; Melville, 1997). Outside
of MBIS, there have been few impact studies on North American boreal and Arctic
freshwater fisheries (Weatherhead and Morseth, 1998). Some information is available
on terrestrial wildlife and Arctic marine fisheries (see Chapter
16). Others have outlined the potential for freshwater ecosystem impacts,
including loss or reduction of deltaic lakes, increased pondwater temperatures,
side effects of permafrost thaw (including sedimentation of rivers), and changes
in primary productivity depending on nutrient levels (Rouse et al., 1997;
Schindler et al., 1997; Meyer et al., 1999).
First-order and second-order impacts eventually lead to others that are considerably
more difficult to address. Will land claims or water resources agreements be
affected? Would it be appropriate to artificially maintain historic water levels
in the Peace-Athabasca delta within this scenario of climate change (see Chapter
16)? Could there be new conflicts over land use, especially if agriculture
expands northward to take advantage of improved soil capability to support crop
production (Brklacich et al., 1996, 1997b)? What might be the effects
on parks and other protected areas (Pollard and Benton, 1994) and tourism (Staple
and Wall, 1996; Brotton and Wall, 1997; Brotton et al., 1997; Wall, 1998a,b)?
Could climate change affect the economics of commercial forestry (Rothman and
Herbert, 1997) or oil and gas production in the Beaufort Sea (Anderson and DiFrancesco,
1997)?
Two exercises dealt with individual perceptions of aboriginal responses to
future scenarios. The first asked for a listing of physical and biological impacts,
as well as how aboriginal people would be affected if they continued to pursue
a traditional aboriginal lifestyle or if they became more active in the formal
wage economy (similar to the dual-economy situation described by Shukla, 1997).
Results showed that perceptions of impact and vulnerability were influenced
by visions of future lifestyles (Aharonian, 1994). The second exercise used
input-output modeling and a community survey to look at responses to a potential
benefit of warming—an opportunity for expanded activity in the formal wage
economy (because of the longer summer) that would force people to relocate from
their traditional community if they wanted the employment. Results showed a
willingness to accept the opportunity, but there were concerns about social
impacts on the community of relocation or creation of commuter workers who would
be absent for extended periods (Lonergan and Kavanagh, 1997).
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