“I, as majority leader, will introduce bold and far-reaching climate legislation,” he wrote. “The proposal for electric cars would be a key element of that bill.”

The senator’s clean car plan is the first specific climate policy proposal he has put forward since an interview with The Times in March, in which Mr. Schumer laid out plans for Democrats to “go on offense on climate change” in the 2020 political campaigns.

President Trump sought this week to highlight his own efforts on the climate front, talking up his moves to roll back President Barack Obama’s regulatory efforts to control carbon emissions from power plants and cars, and his signing of the international Paris Agreement on climate change: “I withdrew the United States from the terrible, one-sided climate accord, was a total disaster for our country,” he told a crowd of cheering men and women in hard hats on Wednesday at a natural gas conference in Pittsburgh.

Mr. Trump’s potential Democratic presidential challengers have drafted ambitious climate change plans, many drawing from the Green New Deal, which calls for the elimination of all additional emissions of carbon dioxide in the United States by 2030. But the Green New Deal offers few specifics on how to achieve that target.

Mr. Schumer’s new plan is not nearly so ambitious, but it is specific and is aimed at rapidly replacing 63 million of the 270 million cars on American roads with zero-emissions or near-zero-emissions vehicles. If enacted, it would take a significant slice out of carbon dioxide pollution from automobiles, America’s largest producer of planet-warming emissions.