Starbucks even has its own Shared Planet initiative aimed at reducing the company's environmental impact and promoting high-quality fair trade beans.
But an Edinburgh scientist has revealed the best way for coffee lovers to help save the planet – drink old-fashioned instant.
Dr Dave Reay, a world-renowned expert on carbon emissions, has calculated that filter coffees pump 50 per cent more carbon into the atmosphere than cheaper instant coffees.
And he says that ditching expensive filter coffees could help reduce your carbon footprint by the same amount as a gas-guzzling flight across Europe.
Dr Reay, a senior lecturer in carbon management at Edinburgh University, claims that the average cup of black filter coffee is responsible for 125 grams of carbon emissions. But the figure for a regular cup of black instant coffee is around 80g.
The reality of coffee's carbon footprint was at odds with the "green" image painted by the coffee chains, he said, adding: "Coffee vendors are in the vanguard of those promoting more 'sustainable' products, with organic and fair trade options now widely available.
"Starbucks even boasts a programme it calls Shared Planet – the irony of that trademark appears to be lost on them – which has the declared aim of minimising the company's environmental impact and increasing involvement with local communities.
"But the average cup of black filter coffee is still responsible for 125g of emissions. Of this, two-thirds comes from production and most of the rest from brewing. Opting for the more prosaic joys of instant coffee reduces that figure to around 80g."
Dr Reay calculated that a six-a-day coffee habit clocks up more than 175 kilograms of each year – the equivalent of a flight from London to Rome.
Add milk to your morning coffee, and the methane belched by dairy cows means you increase your coffee's climate-changing emissions by more than a third.
Dr Reay added: "The environmental group WWF has calculated it takes 200 litres of water to produce the coffee, milk, sugar and cup for just one regular takeout latte. If everyone ditched their pre-work coffee fix that would do wonders for the planet."
A spokeswoman for Starbucks, the most famous coffee chain around the world, said last night they were surprised by Dr Reay's findings. "Starbucks's Shared Planet is our approach to doing business the right way," she said.
"This means being responsible for all elements of our business, including how we strive to mitigate our environmental impact.
"As part of Starbucks Shared Planet we are continuing our ten-year partnership with Conservation International, a non-profit environmental organisation that aims to protect life on earth."
Dr Reay has issued a five-point guide for consumers to reduce their carbon footprint.
He also highlighted the fashion industry, toilet rolls, clothes washing and food waste as other areas where consumers could easily change their habits to help reduce carbon emissions.
Dr Reay said: "You might think you are doing your bit for the environment, but even if you shun bottled water, buy local produce and reuse your plastic bags, chances are that you have some habits that are far more environmentally damaging than you realise.
"What's more, if everyone else is doing these things too, their detrimental effects really add up."
… AND A BREW COULD LOWER RISK OF DEVELOPING PROSTATE CANCER
DRINKING coffee could help reduce the risks of developing an aggressive form of prostate cancer, researchers said yesterday.
A study found that drinking over five cups a day seemed to have the greatest protective effect against the most severe form of the disease. But even drinking one or two cups appeared to reduce the risk.
However, the researchers said it was too early to start advising men to develop a coffee drinking habit.
The team, speaking at the American Association for Cancer Research Frontiers in Cancer Prevention Research Conference, said the protective effects of coffee were found with the most lethal and advanced prostate cancers.
They examined the coffee intake of nearly 50,000 men every four years from 1986 to 2006. During this time 4,975 of the men developed prostate cancer.
They also looked at the links between coffee consumption and levels of hormones in blood samples collected from some men.
The researchers found men who drank the most coffee had a 60 per cent lower risk of aggressive prostate cancer than men who drank none.
Helen Rippon, head of research management at The Prostate Cancer Charity, said:
"There is still more research to do to confirm this and to uncover which component of coffee could be responsible."
EATING oily fish containing long-chain omega-3 fatty acids could reduce the risks of bowel cancer, researchers said yesterday.