Environmental Engineering Reference
In-Depth Information
worst, expansion in land use through much of the Third World is based on
observational records that are much shorter or even non-existent. There the
risk of unforeseen climatological extremes ultimately impacting on current
developments is potentially high and that could influence the sustainability
of these investments in the future. It is too soon to be certain. Modern
climate modelling is the only feasible way of addressing the potential of these
longer-than-experience probabilities of impacts. Up to now this technology
has been poorly utilised.
Second, there is poor utilisation of existing forecasting capabilities,
meaning that significant sectors of the community consider weather and
climate variability to be a liability they have no control over, rather than a
variable they can use when assessing risk and selecting options that mini-
mise impact and maximise economic outcomes. This is not to say that
climate variability will necessarily be a major driver of business performance
in many cases, but that incorporating such risk into total business risk eval-
uation promises advantages for those seeking a market edge.
Third, there is incomplete understanding of the interactions between
natural climate variability and greenhouse gas-induced warming. A key
example in this regard is the uncertainty as to just how much the perceived
severity of the current drought has been affected by not just deficit of rainfall
- the overly simplistic current measure of drought - but also by the impact
of higher temperatures (in a greenhouse-warmed world) on evaporation
rates and ultimately on soil moisture availability affecting agriculture and
natural ecosystems. For argument's sake, if we knew that half of the produc-
tivity loss during this event in the last 12 months was related to that expected
from the natural variability of rainfall, and that half was incurred due to
increased temperatures related to greenhouse warming, then we would have
a quantitative basis for assessing the cost of climate change in dollar terms. It
would highlight that the impact of what is perceived to be a 'small' and 'slow'
warming may well be felt through extreme events manifesting through non-
linear sensitivities to climate. This warming is occurring now and is not
something for concern in the distant future.
In fact, it is not so easy to rigorously draw this connection. But a chal-
lenge for science is to do so. The challenge for the community is to then
incorporate these changes into their planning for future activities. At the
moment this is not happening, by and large as a result of a lack of sufficient
and convincing understanding.
