There might be economic benefit in the long run. I saw several models that show the situation in Canada and Siberia improving significantly for agriculture. But there will also be consequences for people affected, and those are things we need to equip ourselves to deal with.
Or it could lead to programs which bring full employment.
The alarmist stance is built on a foundation of sudden disaster rather than slow and continuous change. Society can deal with changes over thousands of years without need for 100 generations previous to get paranoid over.
Also, your models are packed with so much speculation that they're utterly useless. How are sun spot activity and volcanoes accounted for in them?