Campaign group Friends of the Earth (FoE) is urging people to buy food from local shops to cut greenhouse gases.
Supermarkets are contributing to climate change, says Friends of the Earth
FoE says government research shows the average supermarket produces as much carbon dioxide as 60 greengrocers.
It says supermarkets are less efficient and encourage people to produce more emissions by travelling further to shop - an average of 890 miles a year.
The British Retail Association disputes FoE's claims, saying supermarkets produce less CO2 than small food shops.
FoE supermarkets campaigner Sandra Bell said supermarkets produced three times as much carbon dioxide per square metre of floor space as greengrocers and twice as much as the average independent butcher or corner shop.
But British Retail Association director general Kevin Hawkins said the research, carried out for the government by Sheffield Hallam University, did not back FoE's claims.
He said: "For example, the average supermarket produces three times the carbon dioxide that a greengrocer does but in terms of floor space, the average supermarket in Hallam's research is 20 times bigger than the average greengrocer - 1,500 square meters against 76 square meters.
"So the efficiency with which the average supermarket uses energy is much better than the performance of the average greengrocer."
He said the research showed the UK's 7,000 supermarkets produced an annual total of 2.3m kg of CO2 compared with 4m kg produced by its 26,000 delicatessens and greengrocers and convenience stores and 7,000 butchers.
He said: "Whether you're looking at energy efficiency at store level or total carbon dioxide emissions, the supermarkets win hands down."
He added that supermarkets typically carried more frozen and chilled foods than greengrocers, requiring refrigeration, which would account for much of the difference in emissions.
Ms Bell said the amount of CO2 produced by shoppers travelling to out of town supermarkets and by supermarkets transporting food around had to be taken into account.
She said: "They're encouraging people to travel further to out of town stores to do their shopping, they're flying in produce from all over the world, they're transporting it up and down the country through their central distribution systems....
"If you take all that into account then it's clear that local shops are going to be more efficient than big supermarkets."
But Mr Hawkins said central distribution systems had superseded a system under which each individual supplier transported its goods direct to each retailer, which he said was "certainly not environmentally friendly".
He added that research by the Department for Environment Food and Rural Affairs showed that "food miles", including long haul air travel, accounted for less than 2% of the UK's carbon dioxide emissions.
FoE claims food from local shops is less likely to come weighed down with thousands of air miles.
It says figures from the Countryside Agency have suggested that more than half of food produced locally is also sold locally.
But an FoE spokeswoman said independent shops were being driven out of business as more people turned to large supermarket chains.
"Popping to your local shop for a pint of milk will no longer be an option unless more shoppers change the way they shop," she said.
"If we all Shop Local First, then we can help save our local shops, boost the local economy and also help to tackle climate change."
The group's supporters aim to create directories of local shops and work with their owners to create loyalty cards, discounts and other customer promotions.
However, the campaign comes amid booming supermarket profits which suggest that, for many of us, the weekly supermarket shop is still the most attractive option.
On Tuesday, supermarket giant Tesco reported an underlying £2.25bn profit for the past year - 17% higher than the year before.