YESTERDAY atmospheric scientist, Professor Marvin Geller, explained to Leigh Dayton, science writer at The Australian newspaper, that the sun could not be driving “recent global warming as climate change sceptics claim” because solar radiation has not changed very much since 1978.
But climate change sceptics do not claim there has been recent global warming. They claim there has been a levelling off, or fall in temperatures, over the last 10 years since the 1998 El Nino-driven peak. [Click on the chart for a larger view of global temperature trends.]
As regards the El Nino event of 1998, according to Professor Geller, El Ninos cause a temporary increase in global temperatures, not the steady and consistent upward trend typical of warming from greenhouse gases like carbon dioxide.
But there has been no “consistent upward trend”.
Indeed, Professor Geller misrepresents the position of global warming sceptics and the available global temperature data.
It is apparent from the satellite data that there has been no consistent recent warming trend and the 1998 El Nino effect does not appear to have been temporary. Indeed since 1998 there has been a one-step warming shift of about 0.2 degrees. [Click on the chart for a larger view.]
Interestingly the same day ‘The Australian’ quoted Professor as dismissive of the role of the sun, the journal ‘Geographical Research’ published a paper suggesting a correlation between solar magnetic phases and the state of the El Nino- Southern Oscillation Index (SOI).
The paper by Robert Baker emphasis the influence of the sun’s magnetic field through the rate of ionisation – the rate of ionisation being affected by solar cosmic ray showers whose incidence follows the inverse of the sunspot cycle – not solar radiation as suggested by Professor Geller. Dr Baker claims his discovery has important implications for future drought predictions in Australia recognising the relationship between the SOI and rainfall in Australia and the periodicity of the strength of the sun’s magnetic field.
Professor Sheds Light for Climate Change Sceptics by Leigh Dayton, The Australian, December 4, 2008, http://www.theaustralian.news.com.au/story/0,25197,24748258-11949,00.html
The chart of satellite temperatures is from Roy Spencer’s website, http://www.weatherquestions.com/Roy-Spencer-on-global-warming.htm
Robert G. V. Baker, 2008, ‘Exploratory Analysis of Similarities in Solar Cycle Magnetic Phases with Southern Oscillation Index Fluctuations in Eastern Australia’ in Geographical Research (Vol 46, pp380-398)