If success in politics is measured by practical achievements rather than the volume of noise made, James Shaw has been the Greens’ most successful politician yet.

His unchallengeable legacy will be the zero-carbon legislation. Shaw knew that the key to that progressing was not only persuading the then major party of government, Labour, but far more importantly, the National Opposition, to support his plans to ensure the policy momentum was maintained when a change of government occurred. Shaw also understood that he needed at least tacit, if not more active, support from the business community, and major greenhouse gas producers like industry and agriculturalists.

To that end, he skilfully steered New Zealand to a position where, following the passage of the Climate Change Act in 2020 and the establishment of the Climate Change Commission, the future direction of New Zealand’s climate change response was broadly settled. Although there will be inevitable modifications under future governments and as international circumstances change, the approach established by Shaw will remain, at least for the foreseeable future.

In a Newsroom Column in July 2022 – when Shaw’s co-leadership of the Greens was under challenge – I speculated that he could decide to leave Parliament at the 2023 election (or shortly afterwards, if the government was defeated) and that either a re-elected Labour-led government or an incoming National-led coalition might see fit to appoint him as the next Climate Change Commissioner when that position becomes vacant later this year. While Shaw had given no hint yet of his next career moves, that appointment remains an open possibility. It would certainly be an astute move by the new government, were it to happen, and would lock-in the climate change response that Shaw oversaw over the last six years.

Shaw’s departure – and hints from co-leader Marama Davidson that her position should not be taken for granted after the end of this year – raise serious leadership issues for the Greens. However, the party is not without talented people who could step into vacant leadership positions. Auckland Central MP Chloe Swarbrick is the obvious contender to replace Shaw. She has long featured in opinion poll preferred Prime Minister ratings (ahead of both Shaw and Davidson) and has clear popular appeal, as her wins in Auckland Central in 2020 and 2023 show. The only outstanding question to be resolved is whether she wants the role, otherwise it seems hers for the taking.

Rongotai MP and former Minister Julie Anne Genter is another contender, either now or post-Davidson. Significantly, both Swarbrick and Genter have won well-off, well-educated electorates, so are clearly able to appeal to the middle ground of New Zealand politics, where elections are usually decided.

However, the bigger question arising from Shaw’s departure is what it means for the future policy direction of the Greens. Despite his ability to build support across political lines for his issues, Shaw was criticised by many within the Greens for his moderation and pragmatism. Whatever future leadership combination emerges within the party is unlikely to be as moderate and pragmatic as Shaw. That means that potentially the Greens could be less influential in the future.

While some will lament the loss of Shaw’s style, others will see opportunity. Given their best-ever election result in 2023 and the disarray evident within the heavily depleted Labour Party, the Greens are well-positioned to challenge for the role of the major Opposition party at the next election. A more sharply defined position on environmental and social justice issues, that resonates with “teal” voters in middle class electorates – like Auckland Central, Rongotai, Wellington Central and more – is an important next step the Greens need to take.

Recent events within the Labour Party are also relevant. The steady exodus of former Labour Ministers – three have gone since the election – is part of the process of renewal (well, sort of – the replacement MPs were all ones defeated at the election). That was not unexpected. More significant has been the election of a new Labour Policy Council which now includes economic left-wingers like former Minister Michael Wood and CTU economist Craig Renney (who reportedly aspires to be Minister of Finance in a future Labour-led government). Labour looks set for a time of significant internal debate – no bad thing in itself – but one that has the capacity to widen further the divisions already evident within the party. All of which creates new opportunities for the Greens.

James Shaw may well say he is leaving because his “work is done”. Not only has his legacy been secured through his climate change achievements, but he has also created the conditions which now allow the Greens to challenge seriously to be the major party of opposition. Not bad for someone who always seemed to be an outsider within the Greens’ movement!