The Swedish news agency TT broke the news on Monday, hours after a press conference in Stockholm which followed weeks of doubts about the party's leadership, with polling numbers dropping to a ten-year low.
A nominating committee from the Green Party told reporters earlier in the day that it would propose to the annual party conference on Friday that co-leader Gustav Fridolin stays at the helm, but that it wanted to replace Romson with Isabella Lövin.
Lövin is currently the Minister for International Development Cooperation.
“I am humbled and grateful for the nominating committee's trust in me,” said Fridolin at the press conference.
“I am happy and honoured,” added Lövin.
Gustav Fridolin and Isabella Lövin. Photo: TT
With the party's annual congress looming later this week, Romson and Fridolin had been under increasing pressure to make way for a new duo.
At a press conference two weeks ago they said that they wanted to lead the party out of its crisis but would step aside if colleagues wanted them replaced, putting the decision in the hands of the party's nominating committee.
It has been a stressful few weeks for the party, as evidenced by the reply a busy member of the nominating committee sent to a Swedish reporter on Monday morning, responding to a request for a short interview with the words: “…are you stupid? Have a nice day.”
Hög nivå i Miljöpartiets riksvalberedning pic.twitter.com/NBNrRBkF4G
— John Granlund (@johngranlund) May 9, 2016
The junior party of Sweden's Social Democrat-led coalition government was first plunged into crisis when it emerged in mid-April that the then housing minister, Mehmet Kaplan, had kept company with Turkish extremists.
Fridolin and Romson deflected the criticism, even when a clip emerged of Kaplan comparing Israel to Nazi Germany, and they continued to back the minister after he announced his resignation at a joint press conference with the prime minster, Stefan Löfven.
More trouble came when a rising star in the overtly feminist party, Yasri Khan, refused to shake a female journalist’s hand. He resigned but commentators were left wondering what had happened to the sweet little junior partner in Sweden’s government.
As if all that wasn't bad enough, the party's environmental credentials also suffered a blow when Sweden's state-owned Vattenfall sold its brown coal operations, a move the Greens had pushed hard to block when in opposition.
Romson too found herself in the eye of the storm when she referred to the 9/11 terrorist attacks as “accidents”. She later clarified to The Local what she had meant but for many, the damage was done.
It was not the first time the Swedish minister has grabbed headlines over ill-advised comments.
Last year she was at the centre of controversy after she twice made ill-advised comments about the Nazi concentration camp Auschwitz, and after it was revealed she had used toxic paint on her houseboat.
Romson sparked a huge wave of criticism at the time when she described the migrant crisis in Europe as “the new Auschwitz” in a live television debate. She was later forced to apologize after commentators accused her of disrespecting the victims of the Holocaust.