Taupo District Flood Hazard Study - Whareroa Stream June 2012

Taupo District Flood Hazard Study - Whareroa Stream
Given how little exotic forest there is within the catchment, any conversion to pasture would
have little effect on the risk of flooding. If anything, a conversion from pasture to forestry
appears a more likely scenario. Such a conversion would cause a reduction in the flood
peak rather than any increase.
3.8 Potential effects of climate change
If predicted global warming eventuates, it could cause more than just a rise in the world’s
temperature. Warmer temperatures mean that more water vapour will enter the atmosphere.
Higher temperatures will also increase the ability of the air to hold moisture. Therefore, apart
from higher temperatures, the greatest effect of climate change is likely to be on water
resources. Furthermore, sensitivity analysis has indicated that changes in rainfall are always
amplified in runoff, and this effect is greater in drier catchments. A detailed discussion of the
potential effects of climate change within the Lake Taupo catchment is provided in
McConchie et al. (2008).
A methodology has been developed for determining the projected increase in rainfall as a
result of climate change in New Zealand (Ministry for the Environment, 2008). The mean
annual temperature for the Lake Taupo catchment is predicted to increase by between 0.2
and 2.4°C by the 2040s and 0.6 and 5.6°C by the 2090s (Figures 3.14). These changes are
data are summarised in Table 3.6.
Figure 3.14:
Projections for increases in mean annual temperature by 2040 and 2090 relative
to 1990; average of 12 climate models for A1B emission scenario (Figure 2.3,
Ministry for the Environment, 2010a).
350855.00
June 2012 20