The ABC Science Show about Ian Plimer is laregely an interview with David
Karoly, Federation Fellow on Climate Change at Melbourne University.
The main points he raises in relation to Plimer are as follows:
1. "He claims 'it is not possible to ascribe a carbon dioxide increase to
human activity' and 'volcanoes produce more CO2 than the world's cars and
industries combined'. Both are wrong. Burning fossil fuels produces carbon
dioxide enriched with carbon isotope 12C and reduced 13C and essentially no
14C, and it decreases atmospheric oxygen, exactly as observed and as Plimer
states on pages 414 and 415. Scientists have estimated emissions from
volcanoes on land for the last 50 years and they are small compared with
total global emissions from human sources.
2. Plimer even argues that the recent sources must be underwater volcanoes.
This is not the case, because the net movement of carbon dioxide is from the
atmosphere to the ocean, based on measurements that the concentration of
dissolved carbon dioxide in the ocean is less than in the atmosphere. In
addition, measurements show that the concentrations of two other long-lived
greenhouse gases with human-related sources, methane and nitrous oxide, have
increased markedly over the last 200 years, at the same time as the
increases in carbon dioxide. This is not possible due to sources from
underwater volcanoes.
3. Next, he states that CO2 does not drive climate. He then contradicts
himself by writing 'CO2 keeps our planet warm so that it is not covered in
ice'. There is ample geological evidence of increased CO2 causing climate
change, such as the Palaeocene-Eocene thermal maximum about 55 million years
ago. He writes 'land and sea temperatures increased by five to ten degrees
with associated extinctions of life' when methane was released into the
atmosphere due to geological processes and rapidly converted to CO2.
4. Plimer writes repeatedly that global warming ended in 1998, that the
warmth of the last few decades is not unusual, and that satellite
measurements show there has been no global warming since 1979. He is correct
that on time scales of the last 100 million years, the recent global-scale
warmth is not unusual. However, it is unusual over at least the last 1,000
years, including the Medieval warming. Plimer makes the mistake of using
local temperatures from proxy evidence rather than considering data from the
whole globe at the same time. The report of the US National Academy of
Sciences in 2006, cited by Plimer, states 'Presently available proxy
evidence indicates that temperatures at many, but not all individual
locations, were higher during the past 25 years than during any period of
comparable length since AD 900.'
5. We do not expect significant warming to always occur for short periods,
such as since 1998. Natural climate variations are more important over short
periods, with El Nino causing hotter global-average temperatures in 1998 and
La Nina cooler global temperatures in 2007 and 2008. Global-average
temperature for the current decade from surface observations and from
satellite data is warmer than any other decade with reasonable data
coverage. Plimer is wrong to write 'Not one of the IPCC models predicted
that there would be cooling after 1998'. Actually, more than one-fifth of
climate models show cooling in global average temperatures for the period
from 1998 to 2008.
6. Plimer writes that solar activity accounts for some 80% of the global
temperature trend over the last 150 years. This doesn't fit the
observational evidence. Increases in solar irradiance would cause more
warming in the daytime, in the tropics and in summer, as well as warming in
the upper atmosphere, and these are not observed. Changes in solar
irradiance and cosmic rays show a large 11-year sunspot cycle and negligible
trend, but observed global temperatures show a large warming trend and small
11-year cycle.
7. Plimer is wrong again when he writes 'An enrichment in atmospheric CO2 is
not even a little bit bad for life on Earth. It is wholly beneficial.' This
is contradicted when he writes that the Palaeocene-Eocene thermal maximum
was associated with mass extinctions. There are many other errors, both
large and small, including volcanoes emitting CFCs and that the Sun consists
mainly of the same elements as the rocky planets. Many of the figures have
mistakes, either in the caption or in the data, and have no sources
provided.
Given the errors, the non-science, and the nonsense in this book, it should
be classified as science fiction "
Pete
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