AAP: Christmas feasts are an environmental problem, according to an environmentalist. More than three million tonnes of food wasted every year rots on landfills and creates methane gas, said John Dee, founder of sustainable living group Do Something. He said each year we spend at least $5 billion on food we buy but don’t eat. `And December is the worst month. “What many Australians don’t realise is that methane from Christmas food waste is 20 times more potent a …