Geoscience Reference
In-Depth Information
worldwide. Main cryosphere factor such as ice volume can lead to catastrophic
consequences. Upon the whole, cryosphere factors include (Allison et al. 2001):
Land/ice melt contribution to sea level.
Snow/glacier melt runoff.
Thaw of clathrates.
Loss of glaciers.
Tables
6.2
and
6.3
data illustrate some of possible effects depending on the
climate-cryosphere system dynamics. Discrepancy between some data of these
tables says about existing uncertainties in this area. It is evident that different parts
of the cryosphere play various roles in the climate change. The amount of snow and
ice that melts each summer is increasing because of global warming. Main focus is
made on the potential role of the Greenland and Antarctic ice sheets a total melting
of which can raise global sea level by 7.3 and 56.6 m, respectively. Forecasting this
process is main task of present science. Solution of this task is possible by means of
the GMNSS taking into consideration of information about time scales of the
cryosphere components.
Four overarching goals that address major concerns for the WCRP can be
identi
ed (Allison et al. 2001). These are:
1. To improve understanding of the physical processes and feedbacks through
which the cryosphere interacts within the climate system.
2. To improve the representation of cryospheric processes in models to reduce
uncertainties in simulations of climate and predictions of climate change.
3. To assess and quantify the impacts of past and future climatic variability and
change on components of the cryosphere and their consequences, particularly
for global energy and water budgets, frozen ground conditions, sea level change,
and the maintenance of polar sea-ice covers.
Table 6.3 The cryosphere components and their characteristics (
http://www.unep.org/geo/geo_
Components of the cryosphere
Area covered
(million km
2
)
Ice volume
(million km
3
)
Potential sea
level rise (cm)
Snow on land in the Northern Hemisphere
(annual minimum
-
maximum)
1.9
-
45.2
0.0005
-
0.005
0.1
-
1.0
Sea ice, Arctic and Antarctic (annual
minimum
-
maximum)
19
-
27
0.019
-
0.025
0
Ice shelves
1.5
0.7
0
Ice sheets (total)
Greenland
Antarctica
14.0
1.7
12.3
27.6
2.9
24.7
6,390
730
5,660
Glaciers and ice caps (lowest and [high-
est] estimates)
0.51 [0.54]
0.05 [0.13]
15 [37]
Permafrost (Northern Hemisphere)
22.8
4.5
*
7
Search WWH ::
Custom Search