It's not a solution to merely suggest that the population of the planet forego stuff. Forego meat because it's carbon intensive. Forego their own cars because public transport is better. Forego holidays ditto. For many continents, development has been slow and for decades they have been aping the west in their food, travel and lifestyle choices. And now we say to them "ok - we are now rich enough and have had all of our experiences, you can't have yours". It's just plain wrong.
But we do also need a planet to pass onto other peoples grandchildren.
It's right that Europeans and Americans cut back and start to make more appropriate choices. They already had their cake and ate it to the detriment of everyone. But just foregoing fun is not the solution. Travel is more than just a holiday, it's a way of bringing people together so that we all know that "others" are just like us. What we need is sustainable travel - and sustainable in the sense that you can still do a weekend trip.
We have clients who are working on technologies such as special strains of algae that produce a hydrocarbon which is similar to jet-fuel and is already being tested in some planes. Hydrogen is a fuel that can be produced entirely by renewable energy sources (can, not is). There are plenty of people developing new industries to combat this problem. They are not going to be able to do that if the travel industry is decimated by the "thou shalt not travel" brigade before these technologies commercialise.
I totally agree with Kim's comment that all of these decisions need to be based on facts, not environmental religion. Because for some people it is far more akin to religion than science and yet climate change is more amenable to science than faith.
I'm seeing my industry change by the day and am quite confident that in 10 years the world will look different from today; in 50 unrecognisable. Without the need to forego fun.