The last ice age didn't even make it to southern Europe and the southern part of North America, so given the amount of food production in those areas as well as

The last ice age didn't even make it to southern Europe and the southern part of North America, so given the amount of food production in those areas as well as Australia and South America, it seems pretty plausible that another ice age would barely dent human progress. There would simply be a migration out of Canada, northern USA and northern Europe. Food will still be grown, and people will still survive.