The UN's climate chief has warned of what she called the urgent threat of climate change. <br />Patricia Espinosa urged delegates from nearly 200 nations gathered at a climate change conference in Poland to do more to tackle the issue.<br />Four former presidents of UN talks, including those behind the Paris climate accord, also issued a joint statement calling for decisive action. <br />The meeting in Katowice is being described as the most critical on climate change since the 2015 Paris agreement.<br />However, political divisions were apparent, with Brazil withdrawing its offer to host next year's talks.<br />At the G20 summit in Argentina, the U.S. also reiterated its withdrawal from the Paris deal. <br />
