Reuters: The U.N. panel of climate scientists will look at the costs of “second best” ways of fighting global warming amid doubts that all countries will sign up to U.N.-led action, a leading expert said on Tuesday. Ottmar Edenhofer, co-chair of the U.N. working group looking at the economics of global warming, said the last U.N. report in 2007 had assumed that all countries would take part and that new technologies for curbing greenhouse gases would be available. The next reports in …