sustainable for the medium to long run. Many commodities as well as our environment are finite resources and we should be more proactiv in their preservation. The only way to do it is to push for a global solution, less dependent on voluntary goodwill and self sacrifice.
The structure of the proposed tariff starts with a yearly assesment of each nation's environmental footprint as a proportion of GDP. A tariff reflecting the results of the asesment is then to be imposed on all goods exported from each country. Countries not willing to participate should be evaluated collectively, eliminating the freeloader's advantage phenomenon that currently punishes those willing to do more for the environment, while rewarding those who do less (The environment is a common good from many perspectives).
A paralel assesment of observance of basic human rights should be included in order to prevent some from replacing environmental abuse with human abuse as a means to lower costs for potential investors.
This tariff should be phased in gradually, in order to give us time to prepare, thus avoiding higher tariffs, which would cripple global trade.
I am the author of the book "Sustainable Trade"
I also have a blog called Sustainable Economics