Science and a bi-polar climate

By Kristy Henderson: Leading climate scientists declared last Tuesday night that the recent Australian floods are not necessarily attributable to climate change. According to Professor David Karoly, Professor Neville Nicolls, and Dr Karl Braganza from the Bureau of Meteorology, the scientific basis for human induced climate change is overwhelmingly compelling, yet more research will need to be done to quantify its impacts with regard recent extreme weather events.

The recent floods across Queensland and Victoria do represent a peak in precipitation; yet similar events have occurred in Australia’s past: vast and devastating floods occurred in 1950 for example. The correlation between the La Nina/Nino oscillation and increased rainfall in Australia is well established, and it has been suggested that rising sea surface temperatures could be intensifying the impact of the oscillation. However, Professor Nicolls was reluctant to pass judgement, arguing instead that whilst warming sea surface temperatures will definitely lead to changes in the climate system, the impacts may be subtle, and more data is needed to confidently make the link.

A study recently published in Nature has, however, directly correlated the floods in England and Wales in 2000 with anthropogenic climate change [1]. This study was significant precisely because it was able to prove that a specific extreme precipitation event was due to climate change. The study found that climate change almost doubled the risk of the extremely wet weather that caused the floods.

All climate scientists on the panel stressed that climate change will have impacts on the global climate system, which will have severe consequences for agriculture, biodiversity and human settlement. The International Panel on Climate Change (IPCC) predicts more drought and heavier precipitation events leading to flash flooding, for example. The 2009 Victorian Bushfires, Dr. Braganza warned, rather dramatically illustrate the human cost associated with climate change. Three hundred and seventy-four people died due to heat stress in the lead up to the fires of February 7th, 2009, with a further hundred and seventy-four people perishing as a result of the fires.

As infrastructure costs mount due to the recent extreme weather, planners and policy-makers - but too few politicians - are looking to climate change predictions to inform human adaptive management strategies. Yet Dr. Braganza was quick to stress that mitigation – directly cutting greenhouse gas emissions – should be the primary focus of policy, not necessarily adaptation.

From the scientific perspective, the case for mitigating greenhouse gas emissions to preserve the integrity of the planet and the diverse life forms it supports is both well established and irrefutable; whereas using empirical models to predict future wild weather is a naturally trickier task filled with a greater degree of uncertainty.

The recent resignation of the government’s chief scientific advisor, Professor Penny Sackett, who did not meet with Prime Minister Gillard during her two years in the role, shows that the scientific basis for the need to act on climate change is being hijacked by the economic agenda of big business. This sad fact makes the need to communicate the science of climate change ever more pressing.

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[1] http://www.nature.com/news/2011/110216/full/470316a.html