Ian
Plimer was referred to as "contrarian" rather than "denier" and even the term
"climate change" was not used.
Does
this mean we can expect some real scientific debate on this topic rather than
the name calling that has characterised it in the past?
If
so I would like to make a few points. Certainly Plimer appears to get it wrong
when he compares Siple ice core CO2 concentrations with those measured more
recently at Mauna Loa. Surely Plimer has got the numbers back-to-front.
The
issue is not quite so clear-cut when it comes to global average temperature.
NASA data does indeed show 2010 as the hottest on record, but this is not the
case for the equally authoritative HadCRUT3 temperature record from the Hadley
Centre Climate Research Unit, which clearly shows that 1998 was the hottest
year.
It
is the trend that matters and both data sets indicate that the rapid global
warming of the 1970s and 80s has ceased. Sandiford seems convinced of the
heat-trapping effect of CO2. As a physicist I am sceptical for the reason that
convection, not radiation, controls lower atmosphere temperature.
I
would have thought active submarine volcanoes recently discovered along the
Gakkel ridge near the North Pole provide a more convincing explanation of Arctic
warming. Perhaps geologists are unaware that submarine tectonic heating is never
included in climate models.
John
Reid, Cygnet, Tasmania
I
AM disappointed with the level of debate on climate change as represented in
Mike Sandiford's article.
His
analysis of Heaven and Earth, by Ian Plimer, shows that the significant
difference of opinion on the causes of climate change continue to be subject of
claim and counter claim.
Sandiford
is entitled to contrarian views and to rightly assert that the climate has
warmed 0.68C in the past century, and that the past 10 years are the highest
recorded.
The
question of why we have had significant cool and hotter-than-now periods has not
been adequately explained. Sandiford could have assisted the debate by offering
an analysis of past climate changes, or do we await the next ice age
unprepared?
The
issue is not that the climate has warmed or that atmospheric carbon dioxide has
increased. Both of these facts are acknowledged by sceptics and warmers alike.
The issue is what proportion of that increase is attributable to ACO2 and
why.
The
Intergovernmental Panel on Climate Change reports the largest single driver of
global warming is not ACO2 but the consequent water vapour. Cloud cover and
solar radiation remain significant uncertainties.
We
would be wise to assess the IPCC uncertainties and, instead of jumping at
shadows, rationally, economically and scientifically assess our options. May
2012 be the year of rational debate.
Peter
Clark, Mount Gambier, SA
MIKE
Sandiford does not mention that CO2 has no correlation with temperature on any
time scale except for the last quarter of last century, and then only if the
sun's likely effect on cosmic rays and clouds is ignored.
Changes
in CO2 do not match temperature for the last decade, century, millennium or on
million-year time scales. There have been periods of the past when CO2 was low
and temperatures were much higher than the present, as well as periods when CO2
was a lot higher than today with temperatures much lower.
His
faith in the NASA Global Institute for Space Studies surface temperature record
is a little misplaced. This thermometer-based record has bad coverage and is
affected by local land-use changes. But the satellite record has global
coverage, is much more accurate and shows 1998 as being warmer than 2010.
Squabbling
over the odd hundredth of a degree is not significant.
With
ocean thermal expansion also at negligible levels and the CERN experiments
likely to confirm the link between solar activity and clouds in the near future,
the climate alarmist house of cards is starting to crumble.
Mike
Sandiford would do well to look more closely at the data.
Bob
Irvine, Buddina, Qld
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