Dr Rajendra Pachauri, Chairman of the Intergovernmental Panel of Climate Change (IPCC) and Nobel Prize Winner, will be awarded the degree of Doctor of Science honoris causa and deliver the 2008 Wallace Wurth Memorial Lecture entitled: “Our Vulnerable Earth – Climate Change, the IPCC and the role of Generation Green” at the University of New South Wales, Sydney, on Thursday, October 23, 2008. Read more here.
Archives for October 2008
Temperature Trends and Carbon Dioxide: A Note from Cohenite
Hi Jennifer,
Looking at the temperature trends from 1900-2008, it is not clear that there is a carbon dioxide signal.
In a recent post I looked at how base periods can create an artificial upwards temperature trend;
https://jennifermarohasy.com.dev.internet-thinking.com.au/blog/archives/003303.html#comments
The 20thC featured 2 El Nino dominated climate patterns (+ve PDO), and one La Nina phase (-ve PDO) from 1940-1976. The temperature trend in the first +ve PDO is almost identical to the temperature trend in the second +ve PDO;
http://tamino.files.wordpress.com/2008/01/smooth.jpg
The similar slopes at the beginning and end of the 20thC represent warming WITHIN the +ve PDO’s, while the lower starting point for the first +ve PDO is an artifact of the 1951-1980 GISS base period. The GISS graph also shows post 1998 temperatures as increasing. This is contradicted by the other temperature data collectors, which show a decreasing trend consistent with the emergence of another –ve PDO post 2001 (discussed below). The issue is, what would be the temperature trend be with ENSO removed and what part would CO2 play in causing that residual trend?
In a recent paper, David Douglass and John Christy isolate a temperature trend due to CO2 forcing, independent of feedback (ie: the enhanced greenhouse) and natural factors such as ENSO and volcanic effect;
http://arxiv.org/ftp/arxiv/papers/0809/0809.0581.pdf
Douglass and Christy’s (DC) study is based on 1979-2008 UAH non-surface data. After extracting ENSO, volcanoes and allowing for latitude band effects, they isolate a CO2 signal of+0.070g/decade; where g is the gain due to any feedback. In respect of ‘g’ DC note “there is general agreement among climate scientists for the case of no feedback”. (p3).
DC estimate there is an undeducted solar irradiance forcing (SF) of 20% (p10), or +0.014C per decade. This generally agrees with AR4’s figure for SF of +0.12Wm-2, which translates to a temperature of +0.16C per century (see Chp 2 pp 187-193). AR4 has reduced this SF figure from TAR’s estimate of +0.3Wm-2, or a temperature increase of approximately 0.4C PC (see 6.11.1.2; FIG 6). The AR4 amount for SF is based on the period from 1750-present, but, according to FIG 2.17, the bulk of the SF has occurred in the 20thC. DC’s SF estimate seems about right then.
So, deducting DC’s SF from +0.07 – +0.014 = +0.056C PD for a CO2 signal in the period 1979-2008.
However, DC note that “the global atmospheric temperature anomalies of Earth reached a maximum in 1998 which has not been exceeded during the subsequent 10 years”. (Abstract). As noted above, GISS is showing increasing post 1998 temperature, so what is happening in the 21stC?
In an analysis based on the period 2001-2008 Lucia also removed ENSO from 5 of the temperature indices;
http://rankexploits.com/musings/wp-content/uploads/2008/07/ipcc-falsifies-gavin.gif
For a full discussion of Lucia’s analysis see;
http://rankexploits.com/musings/2008/gavin-schmidt-corrects-for-enso-ipcc-projections-still-falsify/
Lucia has applied 2 statistical approaches to all post 2000 data, GISS, HadCrut, NOAA, UAH and RSS, and obtained a combined result for OLS of -0.3C(+-1.6) PC, and for Cochrane-Orcutt, -0.6C(+-1.5) PC.
Averaging the 2 methodologies gives an ENSO free temperature trend for 2001-2008 of-0.45C or a decadal trend of -0.045C. Lucia has not adjusted for volcanoes as there were no proximate eruptions, or for SF. If an offset for SF of +0.014C is made, this would produce an underlying cooling trend of -0.059C PD, presumably due to CO2.
So, in summary:
1. AR4 notes that “Most of the observed increase in global average temperatures since the mid-20thC is very likely due to the observed increase in anthropogenic gas concentrations” (Executive Summary, CHP 2)
2. AR4 allocates a Radiative Forcing to the combined GHG’s of 2.63Wm-2; CO2 is allocated a RF of 1.66Wm-2, or 2/3’s of the total RF.
3. The RF for CO2 is estimated by AR4 to lead to an increase in temperature from a doubling of CO2 of ~ 3C. CO2 has increased ~ 40% since 1900. This should have produced a temperature increase of 1.2C or 0.12C PD.
4. Applying AR4’s quotient for CO2 RF of 2/3 to the findings of DC and Lucia we obtain the following CO2 signals; DC = +0.056 3 x 2 = + 0.037C PD for the period 1979-2000; for Lucia = -0.059 3 x 2 = -0.039C PD for the period 2001-2008.
5. A further complication applies to the first ½ of the 20thC temperature trends. There was less CO2 and GHG’s prior to 1976, yet the temperature trends at the beginning of the 20thC, as shown by GISS above and HadCrut are very similar; http://i32.tinypic.com/2s01m5y.jpg
6. Then, of course, there is the 30 year decline in temperatures from 1940-1976 when CO2 was increasing.
7. DC and Lucia have found a CO2 signal. It is inconsistent, I draw 3 conclusions;
a) The inconsistency found by DC and Lucia reflects the contrary movements of CO2 and temperature apparent during the rest of the 20thC and history generally.
b) IPCC forcing estimates for CO2 are grossly over-inflated. Even more so when enhanced greenhouse, “g”, is quantified with +ve feedback.
c) In respect of “g”; if the CO2 signal is larger than that found by DC and Lucia, then –ve feedbacks would have to be much greater. These –ve feedbacks cannot be aerosols (see DC p 12), or ENSO as suggested by Keenlyside et al. Perhaps climate sensitivity to SF is greater than AR4 assumes.
Cheers, Cohenite
Newcastle, Australia
Richard Lindzen on the Politicization of Science
Hi Jen, Have you read Richard Lindzen’s article about the politicization of science. Did you know Realclimate.org is an astroturf set up by a left-wing PR firm? Al Gore sued Fred Singer to remove a co-author. Numerous heads of climate science organizations are not really climate scientists at all.
It’s all there and much more…
Go here and download the PFD to the right of the site: http://arxiv.org/abs/0809.3762
Regards, Joe Cambria
After 10 Years, Still No Evidence to Convict Herbicide in Mackay Mangrove Dieback
About 10 years ago the Pioneer River which runs through the North Queensland town of Mackay flooded and some mangroves died. A few years later the World Wildlife Fund (WWF) launched its ‘Save the Reef’ campaign focusing on claimed impacts of farming on the Great Barrier Reef and an academic at the University of Queensland, Norm Duke, released a report implicating cane farming in the mangrove dieback at Mackay in particular farm runoff containing the herbicide Diuron.
The WWF campaign generated political momentum for some sort of action and a Reef Taskforce was formed to advise government. At the time I was working for the Queensland Sugar Industry and made a member of the Taskforce. It was clear that there was no substantial evidence for an impact from farming on the reef, but the government had committed itself to there being a problem and the Taskforce was to conclude as much.
Dr Duke’s unpublished report to the Queensland Fisheries Service became a key document for the Taskforce, purportedly providing evidence for “localized deterioration on individual nearshore reefs” from farm runoff.
At the time I explained that the Duke report, and the hypothesis that the dieback was a consequence of the herbicide Diuron, had some major flaws, including: “Only four of 21 potential sites were tested for Diuron. Traces of Diuron were found in the sediment at all four sites. This included the control site at which there was no mangrove dieback. In other words, Diuron was found at one site where there was no mangrove dieback as well as at three sites where there was mangrove dieback. No evidence was presented to indicate that the levels of Diuron at any of the sites were herbicidal.”
But the campaign against the farmers supported by a compliant media rolled on, politicians were elected on the basis they cared about the reef including mangroves, plans were developed to save the reef from farming, hundreds of millions of dollars provided for research programs to save the reef from farming. Indeed there is now a large bureaucracy including academics and sugar industry personnel associated with saving the reef.
There is ongoing monitoring of the stands of mangrove in the vicinity of Mackay but there is still no evidence implicating the herbicide Diuron in the mangrove dieback.
Indeed today I was assured by those who have spent years monitoring the mangroves that diuron can still be found in sediment, but it doesn’t seem to be affecting the mangroves that “there is no indication that the herbicides at the levels detected in the Pioneer River estuary have impacted on the health of the mangroves.”
I had a wander around the mangroves, including in the Bassett Basin near Barnes Creek, today with Carl Mitchell from Reef Catchments and John Abbot from the University of Queensland.
************************************
Additional reading:
Jennifer Marohasy & Gary Johns, 2002, WWF Says ‘Jump!’, Governments Ask ‘How High?’ Institute of Public Affairs, Occasional Paper
Canadians Want More Debate on Climate Change
“Canadians are deeply frustrated by the quality of politicians’ discussions of climate change and global warming according to a nationally representative poll carried out for the Frontier Centre for Public Policy by COMPAS Research and completed September 29, 2008. Such frustrations cut across regions and party groupings. Most Canadians tend to subscribe to the anthropogenic viewpoint that human activity is responsible for global warming and climate change. An overwhelming majority of the public nonetheless does not believe that the causes of climate change have been fully identified or that the debate has been settled. By a more than 4:1 margin, the public calls upon the media to provide more multi-sided reporting on the issue.” Read more here.
Dramatic Urbanization Warms California
Global warming due to increasing greenhouse gases is responsible for some of the overall heating observed in Los Angeles and the rest of California. Most of the increase in heat days and length of heat waves, however, is due to a phenomenon called the “urban heat island effect.” Read more here.
Jennifer Marohasy BSc PhD has worked in industry and government. She is currently researching a novel technique for long-range weather forecasting funded by the B. Macfie Family Foundation.
