claim: U.S. Sen. Ron Johnson "led the fight to let polluters release unlimited amounts of carbon pollution and took nearly $225,000 from polluters."
evidence: The 1990 IPCC First Assessment Report estimated that equilibrium climate sensitivity to a doubling of CO 2 lay between 1.5 and 4.5 °C (2.7 and 8.1 °F), with a "best guess in the light of current knowledge" of 2.5 °C (4.5 °F).