By Kate Abnett BRUSSELS (Reuters) -A European Union plan to charge fuel suppliers for the CO2 emitted by cars and heating buildings is emerging as the most contentious element in a raft of climate change policies the bloc’s member states are negotiating this year. EU policymakers proposed the new carbon market for transport and heating in July, as part of plans to meet the EU’s climate change target to cut net emissions 55% by 2030 from 1990 levels. EU countries are negotiating the package of measures, which Brussels says will both fight climate change and help cut dependence on Russian fossil…