Reuters: Recession has set the stage for the sharpest fall in world greenhouse gas emissions in 40 years, an estimate on Monday showed, as world leaders gathered in New York to seek a way forward on a new climate change treaty. The International Energy Agency said global output of carbon dioxide, the most common greenhouse gas produced by burning fossil fuels, would fall by about 2.6 percent this year amid a tumble in industrial activity. It expressed hope that the world would seize on …