She brought Green ministers into government for the first time and put them in charge of the Kiwi response to the climate emergency.
Fast forward 18 months and the First Minister of Scotland is seeking to emulate her antipodean role-model with the appointment of Patrick Harvie and Lorna Slater, co-leaders of the Scottish Greens, to ministerial office.
Theirs is a pale imitation of the deal hatched on the other side of the world and thin gruel for a Green party that until now has characterised itself as radical.
For a start, the New Zealand deal was forged under the imperative of the climate crisis. It was signed amidst smoke that still hung in the air from the bush fires which had devastated their Australian neighbours. Ardern wanted to demonstrate to the world that her government was taking this global threat seriously and as such, the climate emergency formed the centrepiece of that deal.
After years of missed emissions reduction targets you would think that the Scottish Green party might take a similar approach.
Unsurprisingly to those of us who work in Parliament beside the Greens, but perhaps inexplicably to the majority of Green voters who (according to a poll in April) don’t support independence, the central mission of this deal is a second independence referendum.
This partnership exists to ask Westminster for another referendum and then to use its likely refusal to drive yet more grievance at the expense of all other public policy. It is not a deal with the climate in mind.
Ardern’s power-sharing agreement went beyond climate and looked to social justice as well, but where her partnership stretched for new and radical frontiers in social policy, the Scottish deal does not.
Ardern’s joint government immediately embarked on a brave new policy of testing pills at festivals to keep drug users safe, yet the nationalist coalition agreement here is entirely silent on Scotland’s drug-death catastrophe.
On a raft of other policy areas, like education reform, the abolition of the council tax, the decarbonisation of our homes; issues where you would expect Green MSPs to want to have a say, there is very little of substance.
They will not seek to trouble the SNP or subject it to effective scrutiny and there is even a clause in the agreement which demands the Greens offer “no surprises” to their partners.
There is no question that the Green party have surrendered entirely and for the life of this parliament, their opposition status. Nicola Sturgeon must be rubbing her hands at having got such a cheap deal.
When I think of the Greens in Scotland, I remember the party of Robin Harper; a movement focused on reform and dedicated to challenging the old order of things. Robin never swapped environmentalism for nationalism, because he supported Scotland’s place in the UK.
I really don’t know what’s happened to that radical zeal. By putting nationalism ahead of the climate emergency, Patrick Harvie and co have revealed their true colours. Those colours look far more like the acid yellow of the SNP.
Alex Cole-Hamilton is Scottish Liberal Democrat MSP for Edinburgh Western