Age: THIS week in Poznan, Poland, the world’s environment ministers are meeting to begin negotiations for a new treaty to reduce global warming. They are doing so in an unstable economic climate, with more countries moving into recession and unemployment rising. Traditionally, when times are tough, environmental issues take a back seat. In the words of Barbara Helfferich, the European Commission spokeswoman on the environment, “investing in reducing emissions is more difficult to do in times of …