U2 have been criticised for generating a huge carbon footprint on their current '360°' world tour.
Environmentalist organisation Carbonfootprint.com said the Irish rockers were being excessive and had produced emissions equalling that of 90,000 people flying from Dublin to London.
The campaign's environmental consultant Helen Roberts, said: "The carbon footprint generated by U2's 44 concerts this year is equal to carbon created by the four band members travelling the 34.125 million miles from Earth to Mars in a passenger plane.
"You also have to add the carbon emissions from the same number of concerts again next year. Just looking at the 44 concerts this year, the band will create enough carbon to fly all 90,000 people attending one of their Wembley concerts to Dublin.
"To offset this year's carbon emissions, U2 would need to plant 20,118 trees."
U2 kicked off the tour in Barcelona, Spain last week and begin the UK leg at London's Wembley Arena on August 14.
