German environmentalists mull red-green alliance against Merkel Tax the rich, end the austerity, dump Merkel - the rallying cries at the German Greens party congress in Berlin. With a national election in September, the Greens - who are scoring about 15 percent in opinion polls - could be king-makers and their policies sound a lot like those of the centre left Social Democrats. Greens co-chair Claudia Roth told delegates: "We are the party for the economy, because we realise the historical link between economy and ecology. And that's the material basis for our society for the 21st century. The leader of the Social Democrats, the SPD, came calling on the conference hoping to persuade the environmentalists that a red-green alliance can oust Merkel's coalition. SPD chairman Sigmar Gabriel said: "I believe a coalition between us is about change in this country, and also in Europe, taking a different route and thinking about tomorrow; what we want to happen to our children and grandchildren. We need to bring that back into politics. Merkel's coalition do politics without tomorrow. The SPD and the Greens do share policies like a wealth tax and challenging the financial markets, but many in the environmental camp want to keep their options open for now.