One could give a very long answer to that, but let me just tell you a small anecdote to help answer it.
I gave a lecture on climate change to the final graduating class of humanists at Carleton University. At the end of it, one of the students said that, yes, this is a threat and we need to take it seriously, but they wouldn't give up their lifestyle. I felt very sorry for that person, because that person wasn't able to imagine any other lifestyle than the one he or she had then—a lifestyle that, to some extent, has actually been sold to them.
There are people in different countries in this world who have very different lifestyles from those of the students at Carleton University. There are people of my generation who had a very different lifestyle when they were growing up, when compared to the lifestyle of the young people today. There is nothing absolute in the lifestyles we have. There is nothing absolute in our aspirations. We can have lifestyles and aspirations that I believe are a lot more sustainable than the ones we have today.