Emissions reduction

FILE - In this June 25, 2019, file photo, President Donald Trump listens in the Oval Office of the White House in Washington. Over 20 state governors are backing California leaders in a showdown with the Trump administration over mileage standards. (AP Photo/Alex Brandon, File)

FILE - In this June 25, 2019, file photo, President Donald Trump listens in the Oval Office of the White House in Washington. Over 20 state governors are backing California leaders in a showdown with the Trump administration over mileage standards. (AP Photo/Alex Brandon, File)

FILE - In this June 25, 2019, file photo, President Donald Trump listens in the Oval Office of the White House in Washington. Over 20 state governors are backing California leaders in a showdown with the Trump administration over mileage standards. (AP Photo/Alex Brandon, File)

FILE - In this June 25, 2019, file photo, President Donald Trump listens in the Oval Office of the White House in Washington. Over 20 state governors are backing California leaders in a showdown with the Trump administration over mileage standards. (AP Photo/Alex Brandon, File)

FILE - In this June 25, 2019, file photo, President Donald Trump listens in the Oval Office of the White House in Washington. Over 20 state governors are backing California leaders in a showdown with the Trump administration over mileage standards. (AP Photo/Alex Brandon, File)

FILE - In this June 27, 2019 file photo, a woman rides a horse as truckers and loggers opposed to a carbon-capping bill hold a rally at the Capitol in Salem, Ore. When Democrats won a supermajority in the Oregon Legislature last November, it seemed they had a clear path ahead to combat global warming, enact gun control and pursue other liberal goals, but instead, it's been a bumpy road, and Democrats have learned the limits of power during the Oregon Legislature's most acrimonious session in memory as Republican lawmakers boycotted the Senate twice and also fled the state after Democratic Gov. Kate Brown ordered police after them. (Noble Guyon/The Oregonian via AP, File)

FILE - This June 27, 2019, file photo shows truckers and loggers opposed to the carbon capping bill holding a rally at the Oregon Capitol in Salem, Ore. When Democrats won a supermajority in the Oregon Legislature in the 2018 election, the party was excited. But now Democrats know the limits of that power after Republican senators staged the dramatic nine-day boycott that ended up killing major climate change legislation. (Noble Guyon/The Oregonian via AP, File)

Oregon Gov. Kate Brown speaks with the media at the Capitol in Salem, Ore., Monday, July 1, 2019. Brown said Monday that she's ready to use her executive power to lower carbon emissions following a political crisis in which Republican state senators fled the state for more than a week to thwart climate legislation. (AP Photo/Sarah Zimmerman)

Russian President Vladimir Putin, right, and Japanese Prime Minister Shinzo Abe attend a signing ceremony prior to their news conference on the sidelines of the G-20 leaders summit in Osaka, western Japan, June 29, 2019. (Kim Kyung-Hoon/Pool Photo via AP)

Russian President Vladimir Putin, right, and Japanese Prime Minister Shinzo Abe attend a signing ceremony prior to their news conference on the sidelines of the G-20 leaders summit in Osaka, western Japan, June 29, 2019. (Kim Kyung-Hoon/Pool Photo via AP)