Frans Timmermans is stepping down at a crucial time for European climate laws to become the lead candidate for a left-wing coalition in the Dutch elections in November.Frans Timmermans, the European Union’s climate chief, will leave his position in Brussels to become a candidate in coming elections in the Netherlands, the European Commission announced on Tuesday.Mr. Timmermans’s immediate departure comes as the European Union is focusing on meeting climate goals, reducing emissions on the continent as well as transitioning to clean energy.Mr. Timmermans served as the executive vice president for the European Green Deal, a set of proposals that aims to make the E.U.’s climate, energy, transport and taxation policies fit for reducing net greenhouse gas emissions by at least 55 percent by 2030, compared with 1990 levels.Last month, European lawmakers approved a key element of the Green Deal that would require member nations to restore 20 percent of natural areas within their borders on land and at sea.“Climate change is happening even faster than feared, battering our planet with no region left unaffected,” Mr. Timmermans said in a speech in July. “Radical, immediate, and transformative action must be taken by all of us.”Ursula von der Leyen, the president of the European Commission, praised Mr. Timmermans in a statement, saying he helped make strides toward “meeting the E.U.’s objectives to become the first climate neutral continent.” She also said he helped raise “the levels of climate ambition globally.”Ms. von der Leyen has appointed Maroš Šefčovič, a member of the European Commission from Slovakia, to succeed Mr. Timmermans as the executive vice president for the European Green Deal. Ms. von der Leyen also temporarily assigned the responsibility for climate action policy to Mr. Šefčovič, until the appointment of a new member of the commission of Dutch nationality, according to an announcement.Maros Sefcovic will succeed Mr. Timmermans as the executive vice-president for the European Green Deal.Tt News Agency, via ReutersOn Tuesday, Mr. Timmermans became the lead candidate for a left-wing alliance of the Green Party and the Labor Party, which are forming one bloc in the Netherlands’s parliamentary elections scheduled for Nov. 22. In that role, Mr. Timmermans could possibly become the Dutch prime minister. Members of the two parties overwhelmingly chose Mr. Timmermans as the lead candidate on Tuesday, according to Dutch media.Mr. Timmermans was scheduled to address members of the left-wing parties on Tuesday night as leader for the first time, according to the parties.“He is the right person to face the big challenges we stand for: protecting social security, tackle the climate crisis and restore trust in politics,” Attje Kuiken, the leader of the Dutch Labor Party in the House of Representatives, wrote on X, formerly Twitter. Ms. Kuiken has, like multiple other politicians since the government collapsed last month, announced her departure from Dutch politics.It’s not Mr. Timmermans’s first foray into Dutch politics. He has served as a member of Parliament for the Dutch Labor Party, as well as minister of foreign affairs from 2012 to 2014.The Green Deal has angered farmers on the continent, including in Mr. Timmermans’s native Netherlands. Last year, Dutch farmers protested against new goals and an announcement that some of them would have to shutter their farms to reach the E.U.’s climate goals, saying that they felt disproportionately targeted.The Dutch government collapsed in July after the parties in its ruling coalition failed to reach an agreement on migration policy. Other issues had been adding stress to the fractured coalition, including climate goals that aim to drastically reduce nitrogen emissions in the country, goals that have been partially set by the European Union.The Netherlands will soon have its first new prime minister since 2010, when Mark Rutte came into power. Mr. Rutte decided not to run again and said he would leave politics once a new coalition is in place after the November elections.Mr. Rutte’s departure from Dutch politics raised questions for the Netherlands, as well as the European Union, where Mr. Rutte found a stage to advance his country’s agenda: rules-based free trade and commerce, fiscal prudence, liberal social values.Who will take Mr. Rutte’s place as prime minister uncertain. The Farmer Citizen Movement, a Dutch pro-farming party that swept local elections in March, has been ahead in the polls, an indication of people’s dissatisfaction with mainstream political parties.On Sunday, Pieter Omtzigt, a popular Dutch politician who has been critical of Mr. Rutte, announced the creation of his new party, New Social Contract. A Dutch poll from this summer predicted that Mr. Omtzigt’s party could win as many as 46 seats in the Netherlands’s 150-member House of Representatives. More