Biofuels policy speeds change.
Britain's Renewable Transport Fuels Obligation (RTFO), which comes into force in April, will require 2.5% of vehicle fuels to come from renewable sources, rising to 5% by 2010.
But the RSPB claims the drive to replace fossil fuels with biofuels is leading to food shortages in Africa and causing the destruction of rainforest and other precious wildlife habitats.
The charity wants the Government to postpone the RTFO until it can prove that it will significantly cut greenhouse emissions.
The adverts, published in The Guardian and The Times, read: "We're destroying our planet while pretending to save it. It makes no sense."
RSPB chief executive Graham Wynne said: "The Government is forcing oil companies to sell fuels that could be making climate change worse and making us buy fuel that could be responsible for the loss of wildlife across the world.
"This legislation should be delayed until it includes greenhouse gas measures that show the emissions savings of every biofuel are at least 60% above their fossil fuel equivalent."