Reuters: The world’s rich countries should set a goal of cutting planet-warming gases by 2020, not by 2050 as some have suggested, so businesses can get a clearer signal on actions they need to take to fight global warming, the UN’s top climate change official said on Monday. In UN climate talks in Bali late last year, Washington rejected stiff 2020 targets for greenhouse gas cuts by rich nations as part of a roadmap to work out a new global pact to fight climate change. The new pact would …