Environmental Engineering Reference
In-Depth Information
wheat belt. Another 15 million hectares are at risk, including large areas of
natural vegetation and farms of the Murray-Darling Basin, the nation's bread-
basket. Salinity not only degrades agricultural lands, rivers and wetlands, it
affects houses, roads and water supply infrastructure.
Perhaps even worse than salinity, acidification degrades our soils. Cer-
tainly it has cost more, at over $1 billion in 2000 compared to $187 million
in lost agricultural production from salinity. These changes, as well as ero-
sion, altered fire and grazing regimes, and pests and weeds all contribute to
declining health of farms and rangelands.
It is climate change, however, that looms as perhaps the greatest environ-
mental threat. Since 1910, Australian average surface temperature has
increased by 0.76°C. Temperatures may rise anywhere from 1.4°C to 5.8°C this
century from 1990 levels. Global warming poses massive risks for Australian
biodiversity, in some cases even exceeding the average global losses. At higher
estimates of warming, for instance, Queensland forests could lose about 80 per
cent of their birds, mammals, reptiles and frogs by 2050. A team from the
Rainforest Co-operative Research Centre says that while there have been cli-
matic changes in the past affecting biodiversity, this time the effect will be
worse (Krockenberger et al. 2003). Climate change today, they say, differs from
past variability in two ways. First, the rate of change recorded in the late 20th
century, and predicted to continue, is considered by many scientists to be
unprecedented in the past 10 000 years. Second, many of the earth's ecosys-
tems are already stressed by other human impacts, such as land clearing and
the consequent fragmentation of natural vegetation.
Fossil fuel combustion is a major contributor to Australia's greenhouse
gas emissions. Our total consumption of energy over the 1990s grew twice as
fast as population growth. We are thus contributing to the very global
warming that may ultimately devastate our biodiversity. Greenhouse gas
emissions rose 17 per cent between 1990 and 1999 despite our signing
(although the Federal Government now refuses to ratify) the Kyoto Protocol
in which we committed ourselves to limit emissions to 8 per cent over 1990
levels by 2008-12.
The social environment in Australia
And what of the social environment? Australians' health is improving in
some ways - children born in 1999 are likely to live three more years on
average than children born in 1990 - and Australians are now amongst the
