The Australian Climate Commissioner, Will Steffan, has defended the advance of climate science in a report issued on 23 May 2011 by the Australian Climate Commission.
In “The Critical Debate”, Professor Will Steffen acknowledges the areas in which he has made his own judgements, but also points out that there is much consensus among scientists:
“By contrast to the noisy, confusing “debate” in the media, within the climate research community our understanding of the climate system continues to advance strongly. Some uncertainties remain and will continue to do so, given the complexity of the climate system, and the impossibility of knowing the future pathways of human political, social and technological changes. Meanwhile there is much climate change science that is now well and confidently understood, and for which there is strong and clear evidence.”
The report includes some key facts, such as the 20cm rise in sea levels since the 1880’s and a 0.46ºC rise in surface air temperature over the last decade (2001 – 2010). Glaciers and ice caps are expected to recede further to an equivalent sea level rise of 55cm. Glaciers and ice caps have not yet warmed to the level of the present climate. That catch-up would lead to a sea-level rise of at least 18 cm.
The report also puts paid to arguments which explain global warming away as a natural phenomenon:
“There is no credible evidence that changes in incoming solar radiation can be the cause of the current warming trend.
“…solar forcing would produce a warming of the stratosphere, in addition to that of the troposphere. In fact stratospheric cooling has been observed, inconsistent with solar forcing but consistent with CO2-dominated forcing…
“Neither multi-decadal or century-scale patterns of natural variability, such as the Medieval Warm Period, nor shorter term patterns of variability, such as ENSO (El Niño-Southern Oscillation) or the North Atlantic Oscillation, can explain the globally coherent warming trend observed since the middle of the 20th century.”
