IN reply to Mr Stowell and Mr Welsby, (Letters March 10), I wish to correct their assertions, which seem to be based on various discredited sources. The facts are that climate change caused by human activity is a reality demonstrated by overwhelming scientific evidence. Such change is happening in addition to any natural variations, and will disturb the fragile balance at a speed so alarming that immediate action to cut greenhouse gases, principally CO2, is required before climate change accelerates out of control. These cuts in CO2 emissions can only be achieved by moving our economy progressively away from dependency on fossil fuels (oil, coal and gas). We can afford the additional costs. What we can?t afford is the cost of runaway climate change. The significance of the Kyoto Protocol is that it provides the framework for binding international targets. It is a starting point. Renewable energy, including wind power is one of many solutions available to us. The problem of CO2 emissions is the accumulation of very small individual actions by each of us, whereas each wind turbine is a small step in the right direction to address that problem. All electricity generation, be it coal, gas or nuclear, requires back-up (spinning reserve) via the national grid, to cope with fluctuations in supply and demand. No additional back-up is required for wind energy while it provides less that 15-20% of electricity generation. Mr Welsby?s point that 20% of electricity from wind requires ?underpinning? by other sources to the tune of 80% is nonsense other than proving that 100 take away 20 = 80! As to taking issue with the fact that engineering companies developing our nation?s wind industry are in it for the money, well wouldn?t it be unrealistic to expect otherwise? They are responding to incentives provided for the common good. Studies in Germany and Denmark show that the marginal increase beyond 20% requires very little additional reserve, with the net CO2 savings still more than 90%. The Danes have developed the means to predict wind supply, and envisage increasing the proportion of their electricity from wind to 40%. I don?t have space here to list all the sources of my information (official or otherwise). If Mr Welsby doesn?t have faith in NGOs, then he can visit other websites such as Union of Concerned Scientists at http://www.ucsusa.org">www.ucsusa.org, University of East Anglia at http://www.cru.uae.ac.uk">www.cru.uae.ac.uk or the Met Office at http://www.meto.gov.uk/">www.meto.gov.uk/ research/climate/index.html or http://www.newscientist.com">www.newscientist.com It may be tempting to adopt a contrary position, but denying the reality of climate change is little more than burying your head in the sand. Andrew Clements Blackstreet House South Tawton MR Geoffrey M Stowell?s letter (Hitting Back At Wind Farms) is strong on statistics but weak on common sense. I do not take issue with him on prices per unit etc, but surely it is only sensible to take what measures we can when we can to protect our planet. I do not think anyone truly believes wind farms alone could ever replace conventional power stations but (to quote a current supermarket TV advert) ?every little helps?. Personally I would rather look at ten wind turbines than one smoking chimney. A company called Windsave Ltd are developing wind turbines suitable to install on residential homes. They will be no larger than a chimney and will generate sufficient electrical energy for the average household. Excess electrical power produced when the winds are strong will be fed back into the grid and power imported from the system in the usual manner when winds are slight (anyone interested in learning more will find details on http://www.windsave.com">www.windsave.com). As for Mr Stowell?s lofty comment ?it is about time that the old greenhouse theory was finally put to sleep? just suppose the independent scientists he quotes are wrong after all (it wouldn?t be the first time experts got it wrong would it?) and we do nothing. We may already be approaching the point of no return. In any case the issue is not solely about the greenhouse effect and global warming. What about pollution? None of us are breathing pure air, drinking pure water or eating uncontaminated food; they are being fouled by added chemicals, diesel and petrol fumes, industrial waste including power station emissions, both coal and gas turbine types as well as nuclear. I know because I worked in the (then) largest oil-fired power station in Europe for nearly 20 years and am sorry to say I have therefore contributed to the pollution problems I refer to. We cannot have everything our own way. If wind turbines are a visual blot on the countryside then there is a far worse blot somewhere else where the view is of a gigantic chimney 800 or more ft high, cooling towers almost 400ft in height, huge boiler house/turbine hall buildings and switch rooms the size of civic centres. By the time we have studied and understood the effects of solar warming as Mr Stowell suggests it may be too late. Finally, the time must come when wave power, hydro and solar power will replace most fossil fuelled and nuclear power stations. Until then wind turbines have a part to play ? like it or not. Trevor James Zeal Head House South Zeal