Reuters: The White House on Monday dropped prospects for revenue from a climate cap-and-trade system opposed by many lawmakers, but its proposed budget still called for a “market-based” policy to fight climate change. Last year the administration forecast revenues of $646 billion for 2012-2019 from a program in which the output of greenhouse gas would be capped and polluters would be forced to buy, and could later trade, emissions permits. “Unlike last year, we do not show an assumed …