Climate change and water resources in the Murray Darling Basin ...

ABARE CONFERENCE PAPER 02.11
The focus in this study is to examine how different global warming trends may affect the
hydrological cycle and agricultural production in the Murray Darling Basin. It is not specifically
concerned with the assumptions of economic, technological, demographic or other
forces that underlie a specific emissions scenario. At the same time, it is useful to contrast
a scenario that reflects an extension of the current trend in emissions to one in which there
has been a significant reduction in emissions.
Two global warming curves were selected from within the SRES envelope shown in
figure 2. The A1 scenario corresponds to a story line of high economic growth but with
limited population growth, and the rapid introduction of new and more efficient energy
technologies. The B1 scenario corresponds to low population growth coupled with the
adoption of clean and resource efficient energy technologies. Estimates of temperature
rise under both scenarios selected for this study are relatively conservative in comparison
Figure 2: SRES global warming curves
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2
1
ºC
1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100
with some of the more fossil fuel intensive scenarios, with temperature predicted to increase
by 2.95°C by 2100 under scenario A1, and 1.98°C under scenario B1. The global warming
curves selected for each scenario reflect a moderate level of sensitivity to changes in the
level of greenhouse gas emissions. The shape of the global warming curves suggests that
much of the temperature increase under scenario A1 happens in the latter half of the century
whereas under scenario B1, temperature increases steadily over the coming 100 years.
The shape of the curves, and hence the timing of the climate impacts, has important implications
for both the biophysical and economic consequences of climate change in the
Murray Darling Basin.
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A1F high
A1 mid
B1 mid
B1 low