By Kate Abnett BRUSSELS (Reuters) – Some European Union countries are trying to weaken the bloc’s planned law to cut methane emissions in the oil and gas sector, documents show, weeks after the EU pledged at the COP27 climate conference to do more to tackle the potent greenhouse gas. Methane is the second biggest cause of climate change after carbon dioxide and has a far higher warming effect, meaning rapid cuts in methane emissions are crucial if the world is to avoid severe climate change. The European Commission last year proposed legislation to require oil and gas companies in Europe find …