As several cities continue their suit against oil companies, The People of the State of California v. BP, Judge William Alsup has boiled the case down to its pivotal question. In March he ordered the legal counsels of both parties to help him weigh “the large benefits that have flowed from the use of fossil fuels” against the possibility that such fuels may be causing global warming.

We sent the judge, and posted online, a 24-page document that answers his question. The benefits of oil, coal and gas are rarely acknowledged...