President Biden on Thursday is set to announce a far-reaching, multipronged plan to make U.S. cars and light trucks more fuel-efficient and to begin a shift to electric vehicles over the coming decade, senior administration officials said. The move marks one of the administration’s most consequential pushes so far to combat climate change and tackle the nation’s biggest source of greenhouse gas emissions. The suite of new goals and mandates, forged after months of talks with car manufacturers, autoworkers and environmental groups, is meant to transform the kind of vehicles Americans drive and to reduce the country’s reliance on fossil fuels. The move comes with political risks for Biden, who has faced pressure from activists and industry representatives alike, but represents a key part of his promise to try to slow rising global temperatures and propel the country toward a future in which the vehicles on roads and highways rely on little or no gasoline.