30 June 2010

Climate change: no need for an inquiry on the science

In a letter to the editor published in today’s edition of The Australian Financial Review, former Treasury Deputy Secretary Des Moore, now Director, Institute of Private Enterprise, writes about Prime Minister Gillard’s comments on the need for a “lasting and deep community consensus on climate change”, and concludes:

Gillard would demonstrate her capacity as a leader if she established an independent public inquiry to test her belief in the need to reduce emissions of CO2.

I have news for Des Moore. An independent public inquiry on the effect of atmospheric carbon dioxide has been in progress for over 150 years, through the normal processes of peer reviewed published science.  To the extent that any science is ever settled, the core science of global warming is; it is very basic undergraduate physics, which has been confirmed experimentally for over 150 years. The arguments and uncertainties are about the secondary effects and the consequences.

-  A paper about the warming effect of the planet’s atmosphere was first published in 1824 by the great French mathematician and physicist Joseph Fourier, with a follow-up paper in 1827. Fourier established the concept of a planetary energy balance, a balance between the planet’s heat gain and its heat loss, and proposed that the atmosphere shifts the balance towards higher temperatures by slowing the heat loss.

-  Beginning in the late 1850s, the 19th century Irish physicist John Tyndall FRS undertook reliable experimental work which established that the warming effect was due to the absorption and re-radiation of infra-red radiation by a number of gases, notably water vapour, carbon dioxide and methane.

-  A quantitative analysis was undertaken in the 1890s by the Swedish physicist Svante Arrhenius, who was the first to predict that emissions of carbon dioxide from the burning of fossil fuels and other combustion processes would cause global warming.

-  The black body temperature of the earth – the temperature at which it would stabilise if all incoming radiation were absorbed and re-radiated - is 5.5 °C. Since the Earth's surface reflects about 28% of incoming sunlight, in the absence of the greenhouse effect the planet's mean temperature would be far lower - about -18 or -19 °C instead of the much higher current mean temperature, about 14 °C.

-  Given all of this, I think that the onus is on the climate change deniers to explain to the rest of us why adding about 30% to the burden of carbon dioxide in the atmosphere would not raise the temperature of the planet.

The theory is supported by a great deal of direct observation and measurement of global warming and of the secondary effects of that warming.

If Julia Gillard were to announce an independent inquiry into “the need to reduce emissions of CO2”, most reasonable Australians would draw a perfectly reasonable conclusion that she had taken leave of her senses.

There is a legitimate role for economists in the climate change debate, but their role begins where the science leaves off. Science can tell us what we need to do; economics can tell us the most economically efficient ways to do what we need to do. We would all be better served, however, if people whose training is in law and economics rather than science would refrain from raising confusion about matters which they are equipped neither to understand nor debate.  The economics is challenging enough; leave the science to the scientists.

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