However, in the headlines about localised flooding, let us not lose the wood for the trees. While a full dam is undoubtedly excellent news for the immediate prospects of Sydney's water supply, it is worth remembering that just five years ago, the dam was below 35% and it has not been full since 1998. The situation was threatening enough in 2007 to lead the NSW State government to build a major desalination plant as a precautionary back-up.
Australia has long been known as a land "of droughts and flooding rains". The intensity of our hydrological cycle, regularly bringing both extremes, is one of the challenges faced by our ecosystems (including the human social system). Our familiarity with the dangers of this intensity can numb us to the warnings of climate scientists, that our continued pollution of the atmosphere is likely to bring even more intensity to the hydrological cycle. Simply saying that we've had floods and droughts before does not excuse us from paying attention to the increasing threat these now represent. When combined with rising human population (and rising consumption levels) in a land of fragile soils and ecosystems already significantly modified and degraded by human impact, the implications of these climate projections should not be ignored.
The last 24 months have been the wettest in Australia's recorded history, and they have followed one of our most severe droughts. As always, these have been associated with the El Niño-Southern Oscillation (ENSO) cycle, however, this natural cycle now has a strong warming trend superimposed on it, bringing more moisture into the atmosphere and redistributing it differently in space and time to familiar patterns from the past. We Australians are not immune from the changes our actions are helping to cause.
And if we are tempted to minimise our contribution to this global problem, keep in mind three factors:
(a) Australian per capita emissions are higher than all other countries except some micro-nations and petro-states with heavily subsidised oil prices. Our historical emissions put us in the top ten emitters worldwide (not per capita). These figures exclude both coal exports and our propensity to take frequent overseas flights.
(b) We are the world's largest exporter of coal and have plans to continue greatly expanding our coal production on a scale that will, by 2050, use up more than 10% of the global carbon budget required to have a decent change of keeping us below 2ºC warming. Indeed, expansion of coal exports will lead to carbon dioxide emissions 11 times greater than the projected savings of the recently passed carbon pricing legislation.
(c) As a nation with one of the highest standards of living in the world (being regularly placed in the top ten for quality of life in various surveys), we can afford serious action more easily than almost any other nation, having almost greater freedom from other pressing concerns than anywhere else.
So let us thank God for a full dam, pray for those affected by flooding and love our neighbours in how we use our precious fresh water - and in how we minimise our climate impact.