As of Monday afternoon, many other large districts in the country were debating what position to take. A spokeswoman for the Los Angeles Unified School District said officials were “still finalizing our plans.” In the smaller Cambridge, Mass., City Council members on Tuesday will discuss a motion to excuse students.

By itself, the turnout for the protest in New York — including the city’s 1.1 million public school students — is a test of the movement’s ability to make itself felt by disrupting everyday life and getting noticed by the political leaders who are gathering in New York for the climate summit and the General Assembly meeting that follows it.

Demonstrators as young as 9 had already turned up to greet the 16-year-old Swedish climate activist Greta Thunberg when she arrived last month by an emissions-free yacht in New York Harbor. Greta has inspired Friday student protests in at least 100 countries.