IPCC reports have all that Fielding needs to know
letter blog published in The Australian Online, 11 June 2009
Steve Fielding ("I kept an open mind on the road to Washington”, Opinion, 8/6) believes we need a debate about whether climate change is the result of a variation in solar activity and not related to an increase of carbon dioxide. He says that he cannot remember this being debated in the media and that he attended the Heartland Institute conference in Washington to look at the science and facts behind global warming. The solar activity argument has had a little media exposure; perhaps as much as it deserved.
The argument is not new; it was addressed by the IPCC in both its 2001 Third Assessment Report and its 2007 Fourth Assessment Report. In 2007, the IPCC says that it’s very likely that the temperature fluctuations of the seven centuries prior to 1950 were caused by changes in solar irradiance and the effects of volcanic eruptions (the latter causing cooling). However, the IPCC concludes in 2007 that the effects of solar irradiance have a very small radiative forcing (or warming) effect compared with the human-induced or anthropogenic greenhouse gas emissions. Further, the IPCC’s 2007 report revised its estimates of this effect downwards to less than half that stated in its 2001 report. I suggest Fielding could better have used his time studying the IPCC reports rather than going to Washington. Maybe, having informed himself of contemporary scientific learning, he could turn his mind to defining a just solution to the problem of anthropogenic global warming that is now overwhelmingly accepted as real.
Alex Gardner
Shenton Park, WA