Sitting in traffic jams (for example) is neither comfortable nor convenient, although the price of the 4x4 in which you sit was certainly hard-won. Much of our unsustainable behaviour (much of our behaviour of any sort) is not particularly chosen, nor does it give us a huge amount of pleasure. We just do it because everyone else seems to be doing it, or because we seem to have no choice, or because we've just kind of ended up doing it, or because we don't see a better way to achieve some acceptable aim (even though such a way does or could exist). So it is not a simple question of asking for virtuous renunciation: change might bring gain and that means there is some leverage for change to be chosen.
I also suspect Greenstreet implicitly assumes that sustainable lifestyles involve some sort of blanket renunciation of technology, but in fact a sustainable lifestyle presents the opportunity to be technologically smarter than ever.
In fact Greenstreet gives the impression that he has only just been alerted to the climate change issue and is unaware that people have been chewing on the problem for quite some time. He thus provides a nice extra illustration of Mike Alder's comments in the same issue about uninformed but overconfident philosophers.