Concrete future - Concrete Mix Design, Quality Control and Specification - page 276

focus to global cooling. The increase in global temperatures in the 1980s
resulted in modeling by Hansen (1988) and others that suggested alarm-
ing temperature rise if the output of anthropogenic carbon dioxide were
to continue unchecked. These predictions on expected temperature rise
provided an objective basis for assessment of the anthropogenic global
warming (AGW) hypothesis. The problem arose with the rush to politi-
cal action before confirmation of the hypothesis. Bypassing the normal
scientific debate and assessment process prevented the development of a
true understanding of the problem and exploration of possible remedies.
As a result, the AGW discussions have been full of “political passion and
prejudice” from the outset.
The AGW/CO 2 issue has now become a divisive impediment to the
crucial sustainability issues of resource depletion and damage to the
natural environment. At a recent meeting on adapting to the carbon tax in
Australia, which came into effect this year, the use of recycled aggregate
was considered not a viable option as it had the same carbon footprint as
virgin aggregate. However, increasing the efficiency of our built environ-
ment to minimise energy consumption, reducing the requirement for virgin
resources, facilitating renewable energy and developing truly sustainable
communities are examples where the concrete industry is making consider-
able progress. If we were to achieve realistic targets in each of these areas,
we would profoundly reduce fossil fuel consumption and CO 2 production
without the need for carbon taxes and alike.
Living on a planet with 7 billion people and limited resources, there is
virtually universal agreement on the importance of resource depletion and
damage to the natural environment, regardless of one's opinion on AGW.
Refocusing attention back onto the primary sustainability goal of meeting
the needs of the present without compromising the ability of future genera-
tions to meet their own needs would appear the best way to harness our
collective efforts for optimum benefit.
13.1.3 Risk aversion
Problems with risk aversion arise from limited data and engineers erring
on the side of caution. Adjacent to a major project, there was a plan to
extend a local waterway. It was suggested that this might raise the water
table, although it was deemed by one of the consultants involved to be
a “50:50 call”. Even though the construction was underway, the consul-
tants decided to increase the height of the pile caps over the massive site
at significant time, cost, and materials. If the announcement to extend the
waterway had been delayed by a few months, the project would have been
constructed based on the original design. The project would have had to
deal with the effect of the waterway on the water table in the same way as