By Barbara Lewis BRUSSELS (Reuters) - Europe's abdication from climate leadership would stunt growth in the region and hand a huge economic advantage to China and the United States as they carve out their share of a multi-billion low-carbon market, a German thinktank said on Thursday. The report's release coincides with U.N. climate talks running until the end of next week. They are hosted by Poland, one of the EU member states to have embraced the counter-argument that the European Union should be only a part of, not the leader of global climate efforts and that acting alone will damage competitiveness. Germanwatch, a thinktank used by German government ministries to carry out research, says such a shift would only harm Europe's ailing industrial sector and it is no longer true to say the European Union is an isolated environmental leader.