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State of the Climate 2011 Report – Experts Respond

By Various experts

The US National Oceanic and Atmospheric Administration released a large global report on the state of the climate in July. The report involved 11 Australian scientists, and focused on extreme weather events and the strong La Niña that brought wet conditions to many parts of the world.

“Most notably, the Arctic continues to warm at a very rapid rate – around twice the rate of warming compared with the rest of the planet... Arctic sea-ice extent was the second lowest on record at the end of the 2011 summer, and is tracking at lowest on record for 2012. In addition, the ocean heat content, a measure of heat stored in the oceans, was also in record territory during 2011, and continues another well-established long-term warming trend.

Global atmospheric carbon dioxide concentrations topped 390 parts per million for the first time in the instrumental record, with individual readings from monitoring stations in 2012 topping 400 parts per million. These are very likely the highest concentrations of atmospheric carbon dioxide in the last 100,000 years, and perhaps the last several million years. Atmospheric carbon dioxide levels are now similar to those during the Pliocene, a much warmer period than any experienced by modern humans.

These indicators show that climate change, especially changes to atmospheric chemistry, are not just continuing but tracking at the more extreme end of possible scenarios.

It is against this backdrop that the increasing frequency of extreme weather events observed in the last decade should be gauged. Increasing greenhouse gases have warmed the entire climate system, such that all weather now occurs in a climate almost one degree warmer than a century ago. This warming will continue to load the dice in favour of extreme warm weather and climate events. Events experienced in recent times are therefore an important heuristic for future climate change impacts.”

Dr Karl Braganza is the Manager of Climate Monitoring at the National Climate Centre, Bureau of Meteorology

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“This annual report is of crucial importance in that it allows us to keep close tabs on the changing state and behaviour of the global climate system. The report now tracks 43 global-scale climate indicators, with a view to better understanding climate change and its complex causes and effects; one of these indicators is Antarctic sea-ice.

Every year, up to 19 million square kilometres of the surface area of the Southern Ocean surrounding Antarctica freezes, and the resultant sea-ice cover plays a key role in the global climate system. Not only this, but the sea-ice is also a sensitive indicator and modulator of change and variability in patterns of atmospheric and oceanic circulation and temperature, the effects of which are amplified at high latitudes. Moreover, close linkages exist between processes occurring in Antarctica and the Southern Ocean and Australian weather and climate.

In 2011, Antarctic sea-ice areal extent exhibited considerable variability about the long-term (30-year) mean, depending on season. Whereas the ice extent attained a record low in April, it was well above average in December. The latter reflects the prevalence at that time of low pressure systems and generally cool conditions around the Antarctic perimeter.”

Dr Rob Massom is with the Australian Antarctic Division and the Antarctic Climate and Ecosystems Cooperative Research Centre, and was one of the Australian authors of the report with his specific focus being Antarctica and sea-ice.

“This report on global and regional climate variations in 2011 is comprehensive and BIG! It provides detailed evidence of continuing climate change, including record-high global concentrations of carbon dioxide and ongoing warming of the upper layers of the ocean.

Many of the regional variations of climate in 2011, including in Australia, were dominated by the effects of La Niña. In Australia, this led to record-high 2-year totals of rainfall, many areas in eastern and northern Australia experiencing flooding, lower than recent average temperatures, but very dry and hot conditions in the south-west of WA.”

Professor David Karoly is a climate scientist from the School of Earth Sciences at the University of Melbourne.

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“This comprehensive and impressive State of the Climate in 2011 report... while a snapshot of climate last year, also places this into accurate historical perspective and provides information on the state, trends and variability of the climate system.

Australia’s climate in 2011 features prominently in the report, with our wettest 2-year period (2010–11) on record highlighted in the first paragraph of the report, a dramatic picture of the associated flooding of Rockhampton in January 2011 comprising the report’s back cover, and much in between. The report provides yet another international expert assessment showing our global climate changing.

While beyond the scope of this particular report, the adverse impacts of this changing climate are also clear and undeniable, and are with us already. The Australian government’s action on climate change through its introduction of the carbon tax is to be applauded and embraced by Australians. Such efforts will reduce the extent of, but not stop, future climate change.

Therefore, Australia and the rest of the world must also now adapt to climate change, with again the efforts of Australia’s National Climate Change Adaptation Research Facility vital both now and into the future.”

Associate Professor Paul Beggs is Deputy Head of the Department of Environment and Geography at Macquarie University.

Source: AusSMC