Environmentalists have held protests around the world demanding stepped up measures against climate change, ahead of a summit in California next week. Politicians, business leaders and celebrities will attend the Global Climate Action Summit, whose sponsors include the UN, Facebook and Google. Thousands protested in Paris, days after France's environment minister quit over perceived policy failures. The demonstrations have been organised by the group 350.org. In all, more than 900 protests were held in 95 countries, the group said. On Friday, Pacific island nations declared climate change to be the "single biggest threat" they face. The protests began on Saturday...