Free trade is one of the greatest driving forces of wealth, development and democratization. Sustainable development depends on the lifelines of free trade to get the goods you need at the price you need them. Nothing in history or modern data says free trade is a bad thing at all.
Economy of scale may reduce emissions, but transport increases them. Optimal economies of scale are then achieved by taxing or capping all emissions equally using international agreements. Nations with low historical emissions should be given compensation for the lower total emissions per capita that will be allowed for them, because the early industrial nations already used up a larger share of atmospheric capacity than corresponds to their share of global population.