Reuters: UN Secretary-General Ban Ki-moon said on Saturday that visiting Antarctica and the Amazon had brought home to him personally the critical need to tackle climate change. Nearly 200 nations meeting in Bali reached a deal to launch talks on a pact to fight global warming, but only after a reversal by the United States allowed a historic breakthrough. Ban, who has made climate change a priority, went last month to the tip of South America to see melting glaciers and the …