Reuters: China hit back on Saturday at U.S. claims it was shirking in the fight against climate change, likening criticisms from the Obama administration’s top climate envoy to a pig preening itself in a mirror. Su Wei, a senior Chinese climate change negotiator, rejected comments from U.S. climate envoy Todd Stern as a week of U.N. talks on fighting climate change drew to a close in the northern Chinese city of Tianjin. Stern, in remarks at a U.S. university, said Beijing could not …