Fuzzy math is back, with a climate twist. From the halls of Congress to the Massachusetts Institute of Technology, experts and politicians are hoisting conflicting numbers describing the cost of a cap on greenhouse gases, with amounts from $3,100 to $324 to zero being touted as the annual hit on households. As Congress returns this week, it will find a cloud of numerical discrepancies hovering over climate change legislation. Go to story #1

The political calculus of climate change has fundamentally changed -- or at least that's what supporters of greenhouse gas emissions cuts hope. After U.S. EPA on Friday officially assumed responsibility for controlling the bulk of U.S. greenhouse gas emissions under existing law, industry representatives, politicians and environmentalists are wondering whether the agency will end up regulating greenhouse gases, or whether the decision alone will be enough to prompt the passage of climate change legislation. Go to story #2