Original sentence: Al Gore cited drunken trees caused by melting permafrost in Alaska as evidence of global warming, as part of his presentation in the 2006 documentary film An Inconvenient Truth; but Marlo Lewis, a senior fellow of the Competitive Enterprise Institute  wrote that "drunken trees may partly be a consequence of the PDO shift," referring to the 1976 switch to the warm phase of the Pacific decadal oscillation (PDO)
Edited sentence: Al Gore cited drunken trees caused by melting permafrost in Alaska as evidence of global warming, as part of his presentation in the 2006 documentary film An Inconvenient Truth; but Marlo Lewis, senior fellow of the Competitive Enterprise Institute who is opposed to spending money to halt or slow climate change, claims that "drunken trees may partly be a consequence of the PDO shift," referring to the 1976 switch to the warm phase of the Pacific decadal oscillation (PDO)