OPEN LETTER to Dr Garth Carnaby, MNZM, FRSNZ, President Royal Society of New Zealand
Dear Dr Carnaby,
Faced with growing world-wide disbelief in the hypothesis of known as ‘anthropogenic (ie, man-made) climate change’
(AGW), the Royal Society of New Zealand, throwing caution to the winds, has staked its case on a blockbuster paper by
your Vice President, Professor Keith Hunter.
The paper is unusual in that Professor Hunter lays out the scientific arguments for all to see. But what is even more
unusual is the rather obvious fact that the arguments are transparently wrong – to the point of being a serious
embarrassment for both your author and your Society.
The case is based on alleged mathematical equivalences between measured increases in the use of fossil fuels, the carbon
content of the ocean and atmosphere, and ocean heat content (and consequent expansion). These increases are said to
match the AGW theory.
Professor Hunter’s evidence is expressed as bullet points, which appear in italics below – along with our summarised
1. It is a plain fact that human activities have significantly increased the concentrations of greenhouse active
gases in the atmosphere, particularly since the mid-20th century.
It is simple physics that these extra gas concentrations will trap an increased amount of outgoing solar radiation
reflected off the Earth’s surface, of the order of 1.5 watts per square metre of the Earth’s surface.
Rebuttal: Greenhouse gases (GHGs) have no impact on reflected solar radiation (albedo effect). Radiative forcings caused
by GHGs diminish on a logarithmic scale. Despite billions of research dollars, carbon sensitivity/feedbacks remain hotly
disputed, radical hypotheses. The “simple physics”of 1.5W/m2 is flat wrong.
2. The amount of extra carbon accumulated in the ocean and the atmosphere matches the known quantity emitted by the
combustion of fossil fuels.
Rebuttal: Oceanic carbon has never been measured, and cannot be estimated. The biosphere also takes up CO2 from fossil
fuels (eg forests). There is a well recognised “missing carbon sink”, estimated to be as high as three trillion tonnes
3. It is also clear that the oceans absorb about 85% of the excess heat resulting from this radiative forcing by
greenhouse gases (as well as about 40% of the carbon dioxide).
Rebuttal: Oceanic heat content has decreased steadily since the ARGO programme commenced measuring it in 2004 – despite
sharply rising GHG emissions.
4. Detailed measurements of the changes in oceanic heat content, and the temperature rise that accompanies this,
agree quantitatively with the predicted radiative forcing.
Rebuttal: This is physically impossible. Infrared energy recycled by GHGs involves wavelengths well in excess of the
3-micron ceiling of the ocean absorption spectra. The energy budget has never been balanced. In a Climategate email,
Kevin Trenberth says “..we can’t account for the lack of warming at the moment and it is a travesty that we can’t.”
5. Furthermore, satellite altimetry shows clearly that the sea level has risen by the amount expected as a result
of the warming-induced thermal expansion of the ocean.
Rebuttal: Sea levels have risen by about 18mm/decade for the past 100 years, having extremely poor correlation with
either GHG concentrations or fossil fuel use. Satellite measures show less warming, but higher sea levels, than
terrestrial measures, but show no acceleration since they commenced in 1992. ARGO buoys show that oceanic heat content
has not increased (see above) - so any significantly higher sea levels in recent years would be inexplicable. The
“amount expected” takes no account of ice melt.
6. Finally, in recent years it has become clear that salinity increases in the tropical ocean from enhanced water
evaporation, and parallel decreases in salinity at higher latitudes as the enhanced water vapour condenses again,
consistent with the higher heat content of the tropical ocean and with observed changes in the atmosphere.
Rebuttal: Quite. And why would it not? The earth’s water cycle is a key part of its natural thermostat system.
From a philosophical point of view, none of these lines of evidence “proves” the theory of AGW.
Rebuttal: How true.... or any other point of view, either. But is it fair to call this collection “evidence”? Professor
Hunter goes even further and refers to his bullet points as: ‘multiple independent lines of argument, each pointing in
the same direction”
Then, the Professor expresses doubts:
“In my opinion, the controversy over whether or not it is acceptable to adjust temperature readings from different
geographical locations to take account of locational differences ... or whether this is a fraudulent way to
“manufacture” a non-existent warming trend, is not by itself sufficient to invalidate the entire findings of IPCC”.
Well, maybe not “by itself” and perhaps not “the entire findings of the IPCC”, but the Royal Society is right to
question whether the ‘manufacture’ of warming trends should lead to most IPCC recommendations being treated with great
Finally, we welcome Prof Hunter’s admission that “science is never settled”. For not only does he destroy a popular, but
tragically incorrect, canon of the warmists, but also he opens the door to a dialogue where none has existed. It will be
with a sense of anticipation that we put our fact-based arguments over the very existence of dangerous human-caused
global warming to the gatekeepers of our public science academies and at last expect their reasoned response.
Our Coalition strongly recommends that your Society publicly distances itself from Professor Hunter’s deeply flawed
statement, and withdraws it from your website.