Geoscience Reference
In-Depth Information
Chapter 12
Cryosols in a Changing Climate
12.1
Introduction
The high-latitude and high-elevation regions are undergoing more rapid and greater
changes in climate than anywhere else on Earth. Annual air temperatures in alpine
areas around the world have increased from 0.3 to 1.0 °C per decade for the past
several decades (Table
12.1
). According to CRUTEM, the arctic-wide increase in
air temperature is 0.6, which is comparable to the 0.7 °C per decade value reported
by Turner et al. (
2009
) for the western Antarctic Peninsula over the past several
decades. To put these numbers in perspective, the world annual air temperature has
increased 0.06 °C per decade since 1880 (IPCC
2013
).
The reasons for the rapid increase in air temperature at the high latitudes and
elevations pertain to the effect of atmospheric warming on snow cover and albedo.
Let us now look at the impacts of this warming on the properties and distribution
of cryosols.
12.2
Active-Layer Depths
Since the active-layer depth (ALD) is dependent on such factors as snow cover and
air temperature, warming should result in an increase in ALD, especially in areas of
sporadic or isolated permafrost but also along the southern boundary of discontinu-
ous permafrost. There should be no change in ALD in the area of continuous perma-
frost because of the universally cold air and permafrost temperatures. This indeed
appears to be the case. Based on data from CALM sites (Chap.
2
), the active-layer
has decreased 1.3 cm/year on the Qinghai-Tibet Plateau (QTP) and 1.4 cm/year
in northern Sweden, areas of sporadic and discontinuous permafrost (Table
12.1
).
In contrast, there has been no statistically signifi cant change in ALD in areas of
continuous permafrost, such as northeast Greenland, European Russia, Arctic Canada,
and northern Alaska.
