ROME — Italy’s education minister, who had vowed to revitalize the country’s schools and introduce lessons on climate change in every grade nationwide, has resigned, citing a lack of funding.

The minister, Lorenzo Fioramonti, submitted his resignation on Monday after Parliament ratified a 2020 budget that fell a billion euros short of his request. The resignation was disclosed publicly on Wednesday.

Mr. Fioramonti, appointed in September, had announced ambitious plans to teach students about the climate and environmental sustainability, beginning next fall. “The 21st century citizen,” he said, “must be a sustainable citizen.”

But his resignation this week didn’t come as a surprise.

In an interview with the newspaper Il Messaggero last month, Mr. Fioramonti said he was seeking an additional 3 billion euros for the education budget and would quit if the request wasn’t met. The budget approved by Parliament added €2 billion, according to the economy minister, Roberto Gualtieri.