PHILIP Foster seems to have been captured both by global warming deniers (April 23) and by the anti-windfarm lobby (April 9). Weather varies from year to year. Deniers like to start graphs or correlations in 1998, the hottest year on record. I suggest Ph

PHILIP Foster seems to have been captured both by global warming deniers (April 23) and by the anti-windfarm lobby (April 9).

Weather varies from year to year. Deniers like to start graphs or correlations in 1998, the hottest year on record. I suggest Philip looks at the 20 or 30 year record, maybe submitting a revised graph for publication. Because climate science is complex, governments set up the Intergovernmental Panel on Climate Change (IPCC), involving thousands of the most qualified scientists.

The sceptical US government keeps the IPCC reports pretty cautious, but they say man-made greenhouse gases are almost certainly the main cause of past and future global warming, although there is still uncertainty on its scale. Computer models agree well with past global temperatures and project into the future.

Philip is free to have his own interpretations, including dismissal of computer models, but I suggest readers give more weight to the IPCC.

Denying the importance of CO2 is popular, as well-heeled people with large CO2 footprints can feel comfortable.

Wind farms are an engineering and political issue. Opponents always bring up the intermittency of wind, but demand for electricity is also very non-uniform. Extra back-up is needed for only a few short periods and does not need to be efficient. Short-term wind forecasts are good, so "instant" back-up is not needed. The grid means that local power shortages can be covered, for example from France, from wind elsewhere, or from pumped storage. Extra back-up is only a significant issue when wind is more than 20 per cent of grid power. There are many other possibilities for low-carbon power.

STEWART REDDAWAY

Ashwell

Baldock