prone to slope failure are more likely to be exposed to should be possible to gradually adjust Arctic infrastruc-
slide activity. ture to a warmer climate. However, transportation in-
frastructure such as roads, railways and airstrips that
It is important to note that in permafrost regions the life- are on ice-rich permafrost will generally require reloca-
time of structures, during which they should function ac- tion or replacement using different construction meth-
cording to design with normal maintenance costs, is typi- ods. The predicted warming may have a serious effect
cally 30 to 50 years. Total renovation, or demolition and on infrastructure in warmer, discontinuous permafrost
replacement, of old structures should be expected and is zones, where permafrost is already close to thawing
56
.
part of responsible infrastructure planning. For this rea- These areas, together with coastal areas where the thaw-
son the effect of climate change on northern infrastruc- ing of ice-rich permafrost is combined with the prob-
ture is difficult to quantify. However, damage to structures lem of sea-level rise, present the greatest challenges in
is often blamed on climate changes while in reality it is a changing climate (Figure 7.6). However, many engi-
due to human error, poor construction, or simply old age. neering approaches have already been developed over
the last century to prevent and to cope with effects of
It is nevertheless necessary to prepare for and adapt permafrost warming. Such approaches are common
to the effects of permafrost changes on infrastructure. practice in North America and Scandinavia
57–59
(Figure
In colder, continuous permafrost the predicted climate 7.7). These techniques can be adapted to handle the
changes do not pose an immediate threat to infrastruc- permafrost changes predicted in the future (see box on
ture. Maintenance costs will probably increase, but it building on permafrost in northern Canada).
(a) (b)
Figure 7.7: Examples of good engineering practices which prevent permafrost thawing.
(a) A house built on concrete blocks to allow cold air under the house during the winter, north of Fairbanks, Alaska.
(b) The Trans-Alaskan Oil Pipeline is built on pile-refrigerators to prevent thawing of permafrost underneath.
Photos: (a) V. Romanovsky; (b) Roger Asbury/iStockphoto.com
CHAPTER 7 FROZEN GROUND 191