Mr Shaw made the announcement in Wellington yesterday, foreshadowing an eventual resignation as an MP after the fate of a member’s Bill in his name has been decided.
Mr Shaw was elected to Parliament in 2014 and soon after was elected co-leader, alongside Ms Stanton Turei.
After her resignation at the start of the 2017 election campaign he led the party back to Parliament by clearing the 5% MMP threshold — it had been polling below that level just weeks earlier.
"James has made an incredible contribution to the Greens," Ms Stanton Turei, now a lecturer in the School of Law at the University of Otago, said.
"He has seen the party through very hard times, and also through times of growth, and also successfully out the other side from being in government, which is unusual for minor parties both in New Zealand and overseas ... He has helped the Greens thrive and it’s remarkable what he has done."
The Greens’ survival in 2017 was testament to Mr Shaw’s leadership skills, and the party electing a record number of MPs in 2023 showed how well he and current co-leader Marama Davidson had kept the party revitalised, Ms Stanton Turei said.
"The Greens have always had a diverse caucus — it was how we are built ... The key is not to make everyone the same, but to use everyone’s individual strengths and then finding that common ground, and that is the skill that he and Marama have."
Mr Shaw said he was proud of his time at the helm of the Greens.
"Ultimately for me, the job, my job, has been about taking us into government, doing a good job of it while we were there, and then taking us safely out the other side."
Mr Shaw was minister for climate change for six years, and under his watch the former government passed the Zero Carbon Act, a piece of legislation Prime Minister Christopher Luxon has pledged to retain.
"I came under a lot of heat while we were developing that and passing that legislation for the compromises that we made in order to win bipartisan support for it. You know, it did have major compromise in it — there are a number of things I was not happy with in that legislation, some of which has kind of come to pass in reality in the years since.
"But what we were always saying was the most important thing was that we had that commitment to that enduring framework, over multiple decades, multiple changes of government, where the long-term targets and the temperature targets and the institutions of the Climate Change Commission — that cycle of advice and decision-making — that was the most important thing," he said.
The Greens formerly required the party co-leaders to be a man and a woman, but that was recently changed so that one had to be a woman or Maori — criteria both met by Mr Shaw’s co-leader Marama Davidson.
Auckland Central MP Chloe Swarbrick would therefore be able to stand for the leadership, although she has previously shied away from speculation that she might want to be a co-leader one day.
One of the party’s most senior male MPs, Teanau Tuiono, has recently been named an assistant Speaker, a post unlikely to be compatible with a leadership role.
It is possible the Greens may look outside their caucus for Shaw’s replacement.
Former co-leader Russel Norman was elected to that role before being elected to Parliament.
The decision on co-leader is one made by the wider Green party membership, so the process of replacing Mr Shaw should take some time.
When Mr Shaw does eventually resign from Parliament, the Green’s Epsom candidate Dr Lawrence Xu-Nan is next on the party’s list.
Immediately behind him is the party’s Dunedin candidate Francisco Hernandez.
