Business Green: French president Nicolas Sarkozy has vowed to make proposals for an international tax on financial transactions — designed to raise funds for climate-related projects — a central issue when France takes the chair of the G20 group of large economies next year. Speaking at a conference on forests yesterday, Sarkozy reiterated his support for a so-called Tobin tax. This would raise much of the $100bn a year in climate funding for poorer nations, set to be delivered from 2020 as part of …