Reuters: The United States urged a U.N. climate meeting on Monday to drop a 2020 target for deep cuts in greenhouse gases by rich nations from guidelines for a new pact to slow global warming beyond 2012. "It’s prejudging what the outcome should be," chief U.S. negotiator Harlan Watson said of a draft text suggesting that developed nations should aim to axe emissions of heat-trapping gases by between 25 and 40 percent below 1990 levels by 2020. The United Nations wants the …