Anthony Moore (Letters, August 10) calls for more debate on climate change , but this is not helped by his trotting out the same old, often-refuted denialist debating points.
He implies scientists have supported anthropogenic climate change because they have been on government payrolls.
This ignores the fact that many such scientists have worked for governments, such as George W. Bush's, that desperately wanted there not to be evidence of climate change, so the pressure on them has been the opposite of what he claims.
He says that ''on average C02 rises and falls hundreds of years after temperature does''. Is he making the ridiculous suggestion that the unprecedented rise in C02 since 1750 is caused by global temperature rises hundreds of years ago, and not the massive burning of fossil fuels by humans as part of the industrial revolution? His argument was soundly refuted a few weeks ago in letters to The Canberra Times.
He refers to climate models not finding the expected ''hot spot'' above the tropics, but this ignores the fact that at a broader level a number of global climate models now correlate very well with measured global temperature changes.
They can thus broadly explain global temperature increases, and validate greenhouse science understanding about the climate. They point to increased greenhouse gases as the main factor in global warming, along with the positive and negative influences of some other lesser factors, such as aerosols, solar radiation and volcanic activity.
He refers to ''the recent cooling'' of the Earth. This is nonsense in view of the fact that the latest decade has been the hottest in thousands of years.
Incidentally, he says it only took one scientist to prove the world was not flat. This never happened astronomers from several cultures realised the world was a sphere thousands of years ago, by seeing that the moon was a sphere, and the round shadow of the Earth in eclipses. Surely he means Copernicus (or Galileo) who showed the Earth circled the Sun, not vice versa.
Paul Pollard, O'Connor
Bob Turner (Letters, August 10) worries that federal politicians may vote blind on the Government's [greenhouse gas] emissions trading scheme.
A properly informed politician or constituent will know that the ETS aims to cut emissions by 5 per cent (of the 2000 level) in the period 2011 to 2020.
If appropriate global agreement is reached, the Government may increase the cut to as much as 25 per cent: such a globally-agreed emissions target would not be kept in the dark.
In addition to ''new'' alternative energy sources such as solar, wind, biomass and tidal, Australia has a potentially major, but under-appreciated, tool to help achieve emissions-reduction targets: geothermal energy.
Geothermal energy is extracted by pumping water at very high pressures down deep (up to 5 km) drill holes into rocks such as granite that are abnormally heated by decay of radioisotopes (notably K40 potassium).
These hot rocks are thereby fractured, and the injected water, now heated to temperatures up to 250-270C), is recycled through turbines via return drill holes.
When fully operational, geothermal uses no water, produces no greenhouse gas or other pollution, and, unlike solar, etc., is a constant source of (base-load) energy.
Australia is host to sufficient accessible geothermal energy to supply all our energy needs for at least 20,000 years at current consumption rates.
Dr Douglas Mackenzie, Queanbeyan, NSW
Declaration: The writer is a shareholder in Geodynamics Ltd, a geothermal energy company operating in NE South Australia.
Fund nuclear fusion
While Kevin Rudd is disbursing his borrowed billions he should include the ANU, or similar institution, to get it into international research into nuclear fusion the process of fusing hydrogen atoms together to form helium and large amounts of power.
An international consortium, working in France, hopes to have a first generation nuclear fusion power station on line by 2023. The problems at this stage include the generation and containment if the extremely high temperatures required to maintain the process.
The main hydrogen isotope involved, deuterium, occurs naturally in sea water. The early designs will fuse deuterium with tritium, another hydrogen isotope which occurs naturally in some rocks, or can be ''bred'' from lithium.
The ultimate design will fuse deuterium atoms together, requiring much higher temperatures, but enabling a bucket of sea water to provide a household power requirement for a year, and countless kids' birthday balloons full of helium. Both coal and uranium can then be left in the ground.
B. Woodman, Greenway
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