The United Nations body that oversees greenhouse gas reductions is reeling from another cap-and-trade scandal that may have put 600 million tons of carbon emissions into the atmosphere — roughly speaking, the annual CO2 output of Canada or Britain — while the emissions were ostensibly suppressed, according to an independent study. In the process, the fraudsters, largely in Russia and Ukraine, were likely able to transfer credits for more than 400 million tons of their apparently bogus greenhouse savings by April 2015 into Europe's commercial carbon trading system — the largest in the world — thereby undermining that continent's ambitious...