Business Green: The consolidation of the global carbon offset market stepped up a notch yesterday, after Goldman Sachs’ purchase of a stake in US offset specialist Blue Source was followed by news that French energy giant GDF SUEZ Energy International has all but completed its long-running takeover of carbon reduction project operator Econergy International. Suez tabled a £39m bid for UK-listed Econergy back in June, gazumping a £27m bid from carbon trading specialist Trading Emissions …