FOR my sins I am scientist, admittedly not a climate scientist but a
geologist, and I despair when I see letters such as that from Ian McNeish
(February 20). The basic thesis of his letter is that anthropogenic climate
change is a fallacy, unfortunately one supported by 97 per cent of the
world’s scientists. As one of the 97 per cent I can agree with Mr McNeish,
that the earth’s climate has been constantly changing, the geological
evidence is overwhelming, but after that we depart company.
I am hesitant to criticise a non-scientist with an interest in a science
but the high numbers of factual errors in his short letter calls into
question the depth of his scientific understanding. He both understates the
age of the earth by 3,600 million years as well as the length of time that
we have been keeping climate records by about 70 years. More significantly,
he ignores the excellent ice core record for CO2 and temperature levels
which go back 800,000 years, except to obliquely refer to the pseudo-fact
that 325,000 years ago CO2 levels were higher than today. For the record,
reliable and repeatable ice core data show that at 325,000 years CO2was far
lower at about 265ppm whereas at present day it is around 399ppm.
Nonetheless, as a scientist, I am all too aware that evidence of
correlation of CO2 levels with temperature is not in itself evidence of
causation, but in the case of climate change the greenhouse mechanism by
which increased CO2 may be linked to increased temperature is well
understood. Given that CO2 levels are rising to levels unknown for
geological millennia and at rates far higher than previously interpreted,
then if nothing else, even if you were dubious about the mechanism, the
reasonable person might take the precautionary view that reducing CO2
emissions is a good thing. To take a contrary view implies a wilful desire
to do so and I can only wonder at the non-scientific reasons that climate
change deniers have for doing this.
Bob Downie,
66 Mansewood Road, Glasgow.
IAN McNeish boldly asserts that “there is not one scintilla of scientific
evidence that relates rises or falls in global temperatures to the activity
of people'”. If by this he means recent climate change is natural and
within the realms of the Milankovitch cycles then he is wrong.
The greenhouse effect was discovered in 1824 by Fourier, the heat-trapping
properties of CO2 and other gases were first measured by Tyndall in 1859,
the climate sensitivity to CO2 was first computed in 1896 by Arrhenius, and
by the 1950s the scientific foundations were pretty much understood. The
following aspects of climate change are scientific fact: the concentration
of carbon dioxide in the atmosphere is increasing more rapidly than in the
last 3000 years, carbon dioxide is a greenhouse gas, carbon dioxide
persists in the atmosphere for a very long time, recent climate change is
not due to solar activity, climate change is not due to volcanic eruptions.
Any scientist, or any individual of an inquisitive bent, with a passing
acquaintance of thermodynamics, is therefore bound to ask – if the CO2
build-up on Earth is not associated with changes in the Sun’s output, or
the Earth’s core, what is causing it? The first and second laws of
thermodynamics have to be satisfied, and the only rational answer is that
the source is “ancient sunlight” released by the burning of fossil fuels.
While the direct heat released into the atmosphere from homes, power
stations, factories and vehicles is negligible the added carbon from
ancient forests is not. The thermal blanket which we are wrapping around
the globe is resulting in planetary warming, which is cogently explained by
quantum mechanics.
What is unknown, or difficult to predict, as the Fifth Working Report of
the Intergovernmental Panel on Climate Change makes perfectly clear, is how
warm it will get and how quickly.
Any discussion that remains revolves around the transition, which the human
race must make, to achieve a fossil fuel free mode of existence, so that
future generations of humans are bequeathed a habitable planet. The
available evidence points to a wholesale adoption of renewable energy
sources, backed by massive energy storage techniques, as probably the most
effective route forward.
Alan J Sangster,
37 Craigmount Terrace,
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