Age: VICTORIAN winemaker Brown Brothers has outlined critical environmental reasons behind its $32.56 million purchase of Gunns’ wine assets in Tasmania. Chief executive Ross Brown said the move south was spurred by global warming, and after deciding that the controversial $2.2 billion Gunns pulp mill project’s effect on Tamar Valley vineyards would be benign. Brown Brothers has bought 400 hectares over three vineyards, which produce about 3000 tonnes of fruit marketed under seven …