If I were introduced to Jonathan Porritt, or some other prominent environmentalist, and asked to explain why my views about what is necessary to achieve sustainability (and avoid catastrophe) are so much more radical than his, this is how I would reply:
Imagine that we are all standing on a beach and Jonathan Porritt and others have noticed an approaching tsunami on the horizon. They are going around trying to warn people, although most are not really interested; they want to carry on relaxing, doing what they came to the beach to do and enjoying the fine weather. "We need to get off the beach and at least a few 100 yards inland", Jonathan and the other environmentalists are saying, and slowly some people are beginning to take notice.
I, on the other hand, realise that the tsunami, although it may not look it, is much bigger and more powerful than most people are prepared, or perhaps able, to imagine. Moving a few hundred yards away from the shore is not going to help us (i.e. our children and coming generations): if we are to save ourselves (our children and coming generations), we have to go miles inland and up into the hills.
"But what about all our belongings (our jobs and materialistic lifestyles)? We cannot just leave them all behind!"
For most people it is hard enough facing up to the fact that they have to get off the beach. At the moment they are not prepared even to consider heading for the hills. They will not do so until the tsunami is much closer and its deadly power can no longer be denied. However, by that time, it will be too late.
Or am I just an "alarmist and a scare-monger", as those blind to the danger and fearful of such radical change claim?