malrob: "the voice of reason again in the form of Don Aitkin"

Don Aitkin has, like Ian Castles, backed himself so far into a corner that he has nowhere to go but blind denial. Don Aitkin and Ian Castles are both like someone that turns up to an astronomy conference and says "so, was this lunar landing thing so fake or what". And they wonder why the science community doesn't respond to them with much more than silence punctuated by an embarrassed cough or two.

There is nothing wrong with the IPCCs credibility, and even if you accept such unsubstantiated quips on face value, you can't ignore that the list of the world's top-level science organisations, including the overarching science academies of the entire developed world, that endorse the theory that the current regime of climate change is human-caused (primarily by CO2 emissions):

The IPCC, NASA, CSIRO, The InterAcademy Council, the national science academies of Brazil, Canada, China, France, Germany, Italy, India, Japan, Mexico, Russia, South Africa, the United Kingdom, and the United States, National Research Council (US), European Science Foundation, American Association for the Advancement of Science, Federation of American Scientists, World Meteorological Organization, Royal Meteorological Society (UK), Australian Meteorological and Oceanographic Society, Canadian Meteorological and Oceanographic Society, Canadian Foundation for Climate and Atmospheric Sciences, International Union for Quaternary Research, Stratigraphy Commission of the Geological Society of London, International Union of Geodesy and Geophysics, International Union of Geological Sciences, European Geosciences Union, Canadian Federation of Earth Sciences, Geological Society of America, American Geophysical Union, American Astronomical Society, American Institute of Physics, American Physical Society, American Chemical Society, Engineers Australia, Federal Climate Change Science Program (US), American Statistical Association, International Council of Academies of Engineering and Technological Sciences, American Association of State Climatologists, The Network of African Science Academies, FASTS

Aitkin: "There is certainly voluminous stuff about climate change, but, as argued already, it does not point unequivocally to anthropogenic global warming."

It certainly does, unless you have abandoned modern science altogether. Go and look at climate science journals. There is no great debate raging over this at all.

Perhaps Yeats's words relate to Mark Twain's definition of education: "that which reveals to the wise, and conceals from the stupid, the vast limits of their knowledge." The best and the wise tolerate uncertainty and proceed with considered caution.

Sams can usually be relied upon to emerge with his bigoted and offensive ad hominem attacks when it comes to climate change.

Yes Sams, I was a believer in AGW until a year or so ago when I started to read the scientific journals. And I have failed to find any paper providing unequivocal observed evidence that anthropogenic CO2 is having a significant effect on global temperatures. On the contrary, even the influence of CO2 itself, whether anthropogenic or not, is suspect as a significant driver of temperature once concentrations exceed about 50ppm. It was thought there was such evidence prior to 2003 from work on the Vostok ice cores which indicated CO2 rising in step with temperature over an extended Pleistocene and Holocene time interval. But more detailed testing of the same ice cores since then has shown that the temperature increases preceded CO2 increases by 800-1000 years. And isn't it interesting that today is 800-1000 years after the Medieval Warm Period?

Sams, you are clearly unable to provide a specific journal reference implicating anthropogenic CO2 either, otherwise you would surely have done so to the various OLO contributors to whom you have directed comments. Instead you just regurgitate your list of scientific organisations with supposedly relevant expertise. If anyone wants to check the credibility of your list maybe they can start by googling 'American Federation of Scientists' and see what they get.

First we had Von Daniken with Chariot of the Gods.
Then Dan Brown and his Da Vinci Code.

Now we have Don Aitkin with “It seems pretty likely that the increase in carbon dioxide has contributed to the world's increasing food production, and that is just what the science says should happen, other things being equal.”

His comment is in marked contrast to Dr Mark Howden at the ATSE Crawford Conference of a week ago, who said that cropping yield rates have been increasing over the past 40 years, but the rate itself is declining. And that the decline has dropped since 1970 to a present zero increase. Asia has been declining from a rate of 3% increase to a present rate of 1%.

Don’s take on science is also at odds with another speaker at that conference, Dr Trevor Nicholls, who stated that elevated CO2 levels have differing impacts under differing conditions. Some are positive, but overall they are negative: In temperate zones increased crop yields are possible for limited elevations of CO2 , but decreased yields will occur beyond that limit. Any increase in other zones will decrease crop yields

ideas can come from anywhere, but only ideas of use to politicians are developed in a parliamentary society.

that is the great advantage of democracy: citizens with a good idea can put the idea to the electorate and if accepted by a majority cause that idea to be realized.

the labor party once knew this and supported the principle of citizen initiative. but about the time the party was taken over by professional politicians, this principle disappeared. thereafter, their policy has been: "no salvation without putting us in power."

so i don't pay any attention to labor pollies anymore, like whores, they do it for money. but unlike honest sex workers, we are unlikely to be pleased with politicians efforts.

ozzies don't understand democracy, never having had any. but it's not rocket science. it just needs a realization that leaving the nation in the hands of politicians is the cause of most of our problems, and the environmental aspect might literally kill us.

once you get that, the will for democracy may appear.

I'm happy to have politicians post on OLO. They're saner than some of the loons we've had.

I disagree with Don Aitkens remarks regarding crop output. Sure plants require CO2, they require a lot of other things too, like water for example.
Without adequate water plants eject CO2 (Liddel & Turton).
So it doesn't matter how much CO2 you give a plant, wihtout adequate water it won't use it.

I'd like to believe that Don has an abjective eye and isn't kneeling at the alter of denialism.