"For some reason there is a consensus among apparently the...

"For some reason there is a consensus among apparently the majority of people, that climate change is something to be feared."

Apathy I would say, but yeah, fear is a useless state of mind.

"but the major industrialised and food-producing nations would be very seriously disadvantaged only if the changes were too rapid, not so much if they were to take place over the course of a century."

That's the problem. Significant changes over a century are unprecedented. A huge stumbling block with dealing with the issue is the premise that if it doesn't happen in my lifetime why should I care? Later generations can just adapt.

" Those calling for action to stop climate change are fantasizing, such outcome is completely unrealisable, and the cost of trying to force this fantasy on the world could be quite disastrous for our society."

Not really - it is realisable. The trade offs as to how much we prevent change and how much we adapt need to be assessed. But apathy will give us no choices anyway.