> Ryanair flights for ten quid where the carbon tax might well whack up the cost by orders of magnitude. It would be nowhere near that amount. I used a flight

> Ryanair flights for ten quid where the carbon tax might well whack up the cost by orders of magnitude. It would be nowhere near that amount. I used a flight estimator which says a return flight from London to Malaga would emit 0.3 tonnes of CO2. Project Wren charges $10 - $20 per tonne, so it would cost the same as the ticket at most, even including the cut Ryanair inevitably would take. If you take a more normal ticket price, it would be an insignificant extra.