Scotland’s first minister, Humza Yousaf, on Thursday abruptly ended a coalition agreement between his Scottish National Party and the Scottish Green Party, creating a new set of challenges for an embattled leader whose party has been engulfed in a funding scandal since last year.

A decision by the Scottish government to soften climate change targets, and a disagreement within the coalition over trans rights policies, had increased tension between the two parties, which have governed together since August 2021.

But Mr. Yousaf’s decision to scrap the coalition appeared to take Lorna Slater, a co-leader of the Greens, by surprise on Thursday morning. She accused the S.N.P. of “an act of cowardice,” adding that Mr. Yousaf could “no longer be trusted.”

Does this mean the end of the Scottish government?

Not for now. The Scottish Conservatives are pressing for a vote of no confidence in Mr. Yousaf, which the opposition Scottish Labour Party has signaled it would support, and that could take place next week. But that vote relates to confidence in Mr. Yousaf, not the government, so its implications would be unclear even if he were to lose. In general terms, the rules make it difficult to force an early election that could drive the S.N.P. out of government in Scotland.

For now, the collapse of the coalition means that Mr. Yousaf leads a minority administration. But it is not the first time the S.N.P. has governed as a minority: It did so after the 2007 and 2016 elections. The Scottish Parliament has a more proportional electoral system than the U.K. Parliament, as it was created with the explicit aim of representing the diverse needs of the population and to encourage compromise between political parties.

Mr. Yousaf said on Thursday that he hoped to continue to cooperate with the Greens but in a less formal way. In the acrimonious aftermath of Thursday’s split, the Greens said they would vote against Mr. Yousaf in the confidence vote.

Assuming the government survives, the S.N.P. will be two votes short of a majority and will have to reach out to other political parties in the Scottish Parliament to ensure that its key legislation passes.

Where did it all go wrong?

Mr. Yousaf said on Thursday that the coalition deal had “served its purpose,” but the main tension between the S.N.P. and the Greens was over climate policy after the government’s decision to rein in its commitments.

When Nicola Sturgeon was first minister, the Scottish government made the ambitious pledge of cutting emissions of greenhouse gases by 75 percent by 2030, compared with 1990 levels.

But a critical report from an independent government-appointed commission in March found that goal was “no longer credible,” and last week, the S.N.P. said it would scrap its annual targets.

After that statement, Patrick Harvie, a co-leader of the Greens, said that he was “angry and disappointed” but that he favored retaining the coalition because it had made significant achievements on climate and other policies. However, the Scottish Greens were planning to give their members a vote on whether to stay in or leave the coalition, and no one knew how that would go.

Was climate policy the only disagreement?

Policy on transgender issues was also contentious, with unhappiness among some Greens about a decision by the National Health Service in Scotland to pause the prescription of puberty blockers and other hormone treatments for minors. That followed an independent review of gender services in England by Hilary Cass, a pediatrician. “Many young people will be concerned about the effect of the decision to pause puberty blockers on their health care journey,” said Gillian Mackay, a Green member of the Scottish Parliament, adding, “Our solidarity should be with them.”

Why now?

The coalition deal was struck when Ms. Sturgeon was Scotland’s first minister and leader of the S.N.P., which campaigns for Scottish independence. She resigned last year, and her husband, Peter Murrell, was recently charged with embezzlement of party funds while he was its long-serving chief executive. Ms. Sturgeon was arrested and questioned in connection with the same investigation last year but was released, and no charges were brought.

The police investigation into S.N.P. funding plunged the party into crisis. Since taking over the leadership, Mr. Yousaf has struggled to assert his authority, and with a U.K. general election expected later this year, opinion polls show that Britain’s main opposition Labour Party is mounting a renewed challenge in Scotland, where it was once dominant.

For Mr. Yousaf, who already faced criticism on various issues, the options were narrowing. Faced with the choice of waiting to be told the outcome of a vote on whether the coalition deal with the Greens would survive, he decided to take the initiative. After announcing the end of the pact on Thursday, he told a news conference, “This is leadership.”

Asked by one reporter whether his approach had been that “breaking up is better than being dumped,” Mr. Yousaf replied, “I wouldn’t know, personally.”