New Zealand's Climate Change Minister hopes King Charles will be an "influencer" bringing his environmental activist legacy to the throne.
Convention dictates the monarch keeps quiet on political issues but there may be ways the King can still be heard.
Ridiculed as "rather dotty" for talking to plants, King Charles is a pioneer in promoting organic products and railing against plastic waste.
Despite reportedly having the biggest carbon footprint of all the Royals, King Charles helped to turn green thinking mainstream.
He's known for being outspoken, last year warning world leaders the climate crisis requires a military-style campaign.
"We have to put ourselves on what might be called a "warlike" footing," King Charles said.
And New Zealand's Climate Change Minister is hopeful the new monarch will continue to use his platform to keep sustainability high on the public's radar.
"I think the Royals are the original social influencers," Climate Minister James Shaw said.
But in his first speech to the nation as King, His Majesty hinted he may need to rein that in.
"It will no longer be possible for me to give so much of my time and energies to the charities and issues for which I care so deeply," he said.
Constitutional experts say he'll have to follow the convention of being impartial.
"He won't be able to take the same public advocacy role that he was playing, he will have to basically keep his thoughts to himself and not express them in public anymore," University of Otago Law Professor Andrew Geddis said.
"The King is Head of State - he has to be politically neutral and stand above political debate as a symbol of unity for the whole country," Former New Zealand Prime Minister Geoffrey Palmer said.
But does the world's biggest existential threat trump convention?
"I think everyone should be an advocate for action on climate change, it's not a political issue it's an issue of the survival of global society," climate scientist James Renwick said.
While climate change is no longer a partisan issue, how it should be tackled - including how much wealthy countries should pay for the damage caused by their carbon emissions - remains very much political.
But there are ways the King could more subtly show support for environmental causes.
"If he does visit New Zealand, try to make sure his visit includes the sorts of issues and sorts of places he's concerned about, places like Tiritiri Matangi for instance or other wildlife preserves," Geddis said.
Or he may be able to influence behind closed doors.
"He's entitled to express his views because he will meet with the Prime Minister every week," Palmer added.
Keeping his place as the climate King.
