Trump and his cabinet appointees did not believe the consensus of most scientists that climate change will have catastrophic impacts nor that carbon dioxide is a primary contributor to climate change. Trump pulled the United States out of the Paris climate accord, leaving the U.S. the only nation that was not part of the agreement. He avoided environmental discussions at both the 44th G7 summit held in Canada and the 45th G7 summit held in France by departing early from these conferences. In September 2019, the Trump administration replaced the Obama-era Clean Power Plan with the Affordable Clean Energy rule, which did not cap emissions. In April 2020, he issued his new vehicle emissions standards, which were projected to result in an additional billion tons of carbon dioxide, increasing annual U.S. emissions by about one-fifth. In 2020, environmentalists feared that a successful reelection of Trump could have resulted in severe and irreversible changes in the climate.