The whole 'Global warming' debate is most vexacious and controversial. It has just as many sceptics as it has converts. IMHO it remains a good idea for aviation and aviators to at least make some effort to try and curb our noise and emissions if only to show the 'environmentalists' that we are not totally irresponsible.
As has been alluded to in previous posts, the actual Co2 contribution made by aviation isbarely discernable compared to naturally occurring emissions from geothermal activity, plankton blooms, politicians etc. If Virgin Branson wish to investigate any options to be more environmentally sensitive, then more power to their elbows; and of course they will maximise any publicity they can glean.......that's good business!
What is a whole load more cynical and offensive is our government pretending to be 'green' while using the entire subject as another revenue generating exercise.