Geology Reference
In-Depth Information
Figure 15.5.
Diagram to illustrate the probable change in carbon balance in cryosols due to
climate warming. From Tarnocai (2004a). Reproduced by permission of John Wiley & Sons Ltd.
15.3. OTHER RESPONSES
We can summarize the other potential changes which might occur in the periglacial
environment under a number of headings.
15.3.1. Seasonal-Snow Cover
The variability of periglacial climates makes it diffi cult to generalize about seasonal-snow
amounts and temporal distribution. For example, in environments of deep seasonal
frost or marginal (discontinuous) permafrost, an increase in spring temperatures and
rain events will decrease snow-cover duration and enhance summer thaw-penetration. But
if warming occurs in colder regions of continuous permafrost where temperatures are
projected to remain below or at freezing, winters would become warmer and the
snow pack would increase in depth and longevity. For example, the latter scenario is prob-
ably the explanation for the warming of permafrost reported for the Mayo area, central
Yukon Territory (Burn, 2002). In general, this is probably the most likely case for the
majority of periglacial environments that currently experience continuous permafrost. By
contrast, environments of deep seasonal frost, relict permafrost, and/or scattered or dis-
continuous permafrost may experience the former scenario, in which a decrease in
the duration of snow cover will increase the period of time in which summer thaw
can occur.
There is also a feedback mechanism associated with seasonal-snow cover. Any decrease
in snow cover will lower the surface albedo and increase net radiation, thereby enhancing
