Geoscience Reference
In-Depth Information
Fig. 17.1 Changes in
average annual runoff for
2050 using A2 IPCC
Emission scenario shown by
different GCMs. Percentage
change compared to
1961-1990. (GCMs
HadCM3, ECHAM4,
CGCM2, CSIRO, GFDL and
CCSR/NIES) (Adopted from
Arnell ( 2004 ))
Change in average annual runoff: 2050s
A2
HadCM3 (A2a)
ECHAM4/OPYC
CGCM2
CSIRO Mkll
GFDL_R30
CCSR/NIES2
% change compared to 1961- 1990
< 30
-20 to -10
0 to 10
20 to 30
> 30
-30 to -20
-10 to 0
10 to 20
Change less than one standard deviation shown in grey
for precipitation such as the convection processes and the hydrological cycle or to
account for orography ( IPCC 2007b ). With uncertainties in such climate projections,
impacts studies are difficult.
17.1.2
Hydrological Studies Based on Global Climate
Projections
Arnell ( 2004 ) conducted a study of the future climate change impact on water
resources by applying GCM outputs for estimating river flows under both present
and future climates. The results of this study are shown in Fig. 17.1 which provides
an indication of the effects of future climate change on long-term average annual
river runoff by the 2050s across the world, under the IPCC A2 emission scenario,
estimated by different climate models. It was reported that climate change is likely to
increase water resources stresses in some parts of the world where runoff decreases,
including around the Mediterranean, in parts of Europe, central and southern
America, and southern Africa. In other water-stressed parts of the world, particularly
in southern and eastern Asia, climate change was likely to increase runoff. It
was also reported by the author that there were differences in the magnitude and
direction of climate change over some parts of the world, including Asia. It was
seen that even for large river basins, climate change scenarios from different
Search WWH ::




Custom Search