Totally agree with you on this Clive. On the Left Coast they have hundreds of greenhouse operations that produce cucumbers, tomatoes etc. Each one of these operations contains CO2 generators that increase the CO2 level within the greenhouse to 3 times the ambient level outside of it. But they aren't airtight so I'm betting that there is a significant escape into the atmosphere. Greenpeace hasn't made mention of that. I am all for sustainability and conservation but lets get some realistic perspective going. Renewables are very trendy right now, just like gluten free.