ONE week ago the Sydney Morning Herald published an opinion piece by Michael Raupach from CSIRO and fourteen other Australian scientists making four key claims to support the theory of anthropogenic global warming (AGW). A regular reader and commentator at this weblog, Cohenite, explains that the claims are not supported by the available evidence:
1. The world is warming
The first conclusion is that the world has been warming since 1850. This is generally correct but what Professor Raupach et al. don’t mention is the warming follows a particularly cold period called the Little Ice Age [LIA] which ended in 1850. The correlation of a decline in solar activity with the LIA is well established with various measures of solar activity showing an increase at the same time as the world warmed after 1850.
Professor Raupach et al. say that most of the warming since 1850 has happened since 1950. This is incorrect. The temperature data from both the official English agency, HADCRUT, and the land-based American temperature agency, NASAGISS, show an increase in temperature from 1910 to 1944 which is equivalent to the temperature increase from 1976 to 1998.
It is also problematic whether the temperature increase from 1976 onwards can be attributed to AGW. Two recent studies by Australian scientists throw doubt on AGW being a cause. The first is by John McLean, Christopher de Freitas and Robert Carter. They show that over the last 50 years from 1958 to 2008 the majority of the temperature trends, both warming and cooling, are from natural variation in the form of the Southern Oscillation Index which is a proxy for El Nino and La Nina climate patterns.
The second study is by David Stockwell. Dr Stockwell shows that the increase in temperature over the twentieth century occurred in the short interval between 1976 and 1978 and was due to the transition from a cool, La Nina dominated period called a negative Pacific Decadal Oscillation [PDO] to a warm, El Nino period called a positive PDO. Dr Stockwell also found a probable reverse transition in 1998 after which time world temperatures have declined consistent with the new negative PDO
2. Sea levels are rising
Professor Raupach et al. also refer to rising sea levels and increasing ocean heat content [OHC] as confirmation of temperature increase. In the recent reply by Senator Wong to Senator Fielding’s questions about temperature, Professor Steffen, a co-author of the article with Professor Raupach, stated that the increase in sea level rise and OHC was accelerating. This is incorrect. The sea level has been measured accurately by satellite since 1992. The satellite data shows a slight annual increase. Since 2005 this rate of increase has declined. This is simply shown by averaging the full data history and then showing how much each annual increase is above that average, or anomalous.
Recent studies by Ishii and Kimoto, Domigues, Willis and Loehle all show a decline in OHC since 2003. Even the official measurement from the National Oceanographic Data Center [NODC] shows no rise since 2003. In 2003 the more accurate measuring devices called ARGO were introduced replacing the less accurate ones.
None of the indices, atmospheric temperature, sea-level increase and rising OHC, support the theory of AGW. This means the increase in carbon dioxide during the twentieth century cannot be said to be the dominant cause of the warming which has occurred.
3. Tipping points
The third conclusion and prediction that “business as usual”, unchecked AGW will lead to temperature increases of up to six degrees and “climate tipping points” must be regarded as unsubstantiated alarmism, unsupported by any climate science, since it is well established that every extra carbon dioxide molecule has much less effect on temperature. Such computer based predictions have already been tested and found wanting. In his study Professor D. Koutsoyiannis and colleagues found that the IPPC’s computer predictions in its first report about future climate from 1990 to 2008 had a success rate of only one in eight, or about twelve per cent. This is not much better than random.
4. Warming is irreversible
The article’s fourth conclusion, that heating cannot be reversed for many centuries, is also problematic because OHC is already declining and if there is no increase in OHC there is nothing to sustain the predicted future heating.
Furthermore, for Professor Raupach and his co-authors to begin by claiming there is an overwhelming consensus of thousands of scientists who support the theory of anthropogenic global warming [AGW] is pure politics. Even if this were true it does not prove the science supporting AGW is valid. It only requires one fundamental disproof of a scientific theory for that theory to be invalidated.
In conclusion, the science is not settled and contrary to the claims of Professor Raupach et al. the available evidence does not support the theory of AGW.
Cohenite lives in Newcastle, Australia
Notes and Links
Climate change poised to feed on itself, by Michael Raupach and John Church, CSIRO; David Griggs, Amanda Lynch and Neville Nicholls, Monash University; Nathan Bindoff, Antarctic Climate and Ecosystems Co-operative Research Centre; Matthew England and Andy Pitman, University of NSW; Ann Henderson-Sellers and Lesley Hughes, Macquarie University; Ove Hoegh-Guldberg, University of Queensland; Roger Jones, Victoria University; David Karoly, University of Melbourne; and Tony McMichael and Will Steffen, Australian National University.
The Sydney Morning Herald
August 1, 2009
Read more from Cohenite here: http://jennifermarohasy.com/blog/author/cohenite/