As a retired energy industry consultant and an ardent foe of CO2 emissions, I found John Richardson’s analysis on tar sands oil to be exemplary (“Tar sands battleground: South Portland,” July 20). It is objective, comprehensive, factually based and fair.

Too often the issue of tar sands oil is addressed by opponents on emotional rather than factual grounds. As I understand the workings of the industry, as long as we pay for oil to run our cars and heat our homes, the oil industry will produce it.

Making it difficult to bring tar sands oil to market will increase its cost, but it will not stop it. And ultimately we, the consumers, will pay the higher cost

What is needed is a carbon tax to discourage use of carbon-based fuel and increase the competitiveness of clean energy sources, thereby encouraging their development.

Only when alternative energy sources are in place will we reduce our dependence on oil from tar sands and other sources

Harleigh Tingley