European Commission Vice President Maroš Šefčovič will be the European Union's temporary climate chief after Frans Timmermans quit to run as a candidate in Dutch national elections in November, the EU executive has said.
Mr Timmermans, who was the driving force behind the EU's Green Deal, a wide-ranging package of policies on climate change and the environment, and whose stint at the European Commission was due to end in November next year, will run as the candidate for the Dutch Labour and Green Left in the general election on 22 November.
Mr Šefčovič, 57, is perceived by many in Brussels as a heavyweight of similar stature to Mr Timmermans for upcoming international climate negotiatons.
The Slovakian oversees EU relations with Britain and the EU's joint gas-buying programme to replace Russian gas supplies, after previously being in charge of the bloc's energy policy.
He was appointed to the EU executive in 2009 as education and culture commissioner.
Mr Šefčovič will temporarily take over the climate portfolio until the appointment of a Dutch commissioner, the EU executive said. It was not clear whether the new Dutch official would assume the same post.
"Following a successful legislation phase, the focus of Executive Vice-President Šefčovič will be the successful roll-out of the European Green Deal as Europe's growth strategy," Commission President Ursula von der Leyen said in a statement.
Mr Šefčovič will face his first big test at the United Nations climate negotiations in November where countries will have to assess whether they have fallen short in curbing climate change and agree on a plan to get back on track.
Mr Timmermans played a key role in thrashing out a deal at last year's COP27 summit.

Ms bon der Leyen has asked the Netherlands to nominate a candidate to replace Timmermans as a commissioner.
Earlier today Timmermans was confirmed to lead the left-wing coalition in the November elections in which he will also run for the Dutch premiership.
Mr Timmermans, 62, was appointed to the top spot in the PvdA (Labour) and GroenLinks (GreenLeft) coalition after a ballot in which some 91% of more than 37,000 party members backed his candidacy.
"An overwhelming majority has agreed to have Timmermans as leader," the PvdA-GroenLinks coalition said in a statement.
"I want to become prime minister, because I think together we can do politics differently than it had been done in the past few years," Mr Timmermans told Dutch media last month.
The collapse of outgoing Liberal premier Mark Rutte's coalition over asylum issues triggered snap elections to be held on 22 November.

Mr Timmermans, whose social-democrat PvdA won a surprise victory in 2019 in European parliamentary polls in the Netherlands, was previously in charge of the EU's flagship "Green Deal" drive to bolster the environment.
The ecology-minded politician is seen as a heavyweight contender from the left for the position of Dutch prime minister, left open by the departure of long-time leader Mark Rutte.
Mr Rutte, the leader of the centre-right VVD party, stunned the Netherlands by announcing last month he was quitting politics after 13 years at the helm.
PvdA and Green-Left members voted last month to merge their parties to form a single left-wing bloc in the upcoming polls, which is expected to be dominated by climate and asylum-seeker issues.