President Obama hailed the landmark climate accord reached this weekend as “the best chance we’ve had to save the one planet that we’ve got.” To the Republicans vying to succeed him, it was almost as if the deal never happened.

In a stark display of the partisan divide in the United States over climate change, the Republican presidential candidates have said almost nothing about the Paris Agreement, even though whoever succeeds Mr. Obama will be tasked with carrying it out. Of the nine who will participate in Tuesday’s prime-time debate on CNN, only Gov. John Kasich of Ohio would provide an assessment of the deal when asked on Sunday.

The near-silence among Republicans is a striking illustration of the vastly different roles that climate change is playing in the presidential primaries for the two major parties. In some ways, the ardor among Democrats to address it — and the lack of interest among Republicans in discussing it — makes it seem as if the parties are on different planets.

“It’s willful ignorance,” Daniel J. Weiss, a senior vice president for the League of Conservation Voters, said of the Republicans, predicting that such dismissiveness of climate change would be a liability in the general election.