In 1912, industrial pollution was 10,000 times worse than today. Luckily, it was also 10,000 times smaller in scope than today.
Britain of the 1890s epitomizes the ignorance of resource depletion and pollution. From that point forward to the present, the goal of government (and thus industry) has been to reduce both. The 1st world, and to a limited extent the second have achieved an unprecedented level of production at the same time as they have reduced pollutants to the point where the cost/benefit analysis simply does not work for minimizing them further.
All efforts should be put into improving efficiency and reducing pollution in the 3rd world, and this can only take place by bringing them more technology and education.
Carbon credits are just another bankster scam, and do nothing for the environment. They were a scam when the Republicans started them and they are a scam now when the Democrats favor them.
Economics drives efficiency, and efficiency decreases pollution. Create an economic incentive to reduce pollution, and pollution will be reduced. Trading allotments is not an incentive to efficiency, it is an incentive to traders.