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"It feels good," the MP said ahead of the vote to replace him at the party's AGM tomorrow afternoon.
"I'm pleased I've made the change. I'm pretty happy with what I've done but I'm also happy with moving on as co-leader."
He will begin a new chapter next week when he takes his place among the back seats of Parliament's debating chamber.
"I've never been a backbencher before," he said, relishing the opportunity to focus on a narrower range of responsibilities.
His new portfolios will be determined under the new co-leader - likely to be either Kevin Hague or James Shaw - but he says he wants to maintain his deep interest in climate change and green economics.
He plans to spend more time with his young family and has a long reading list he hopes to get into now that his workload is quieter.
It is not exactly recreational reading - top of the list are reports on low-carbon growth by the OECD and the World Bank.
"I'm not a big novel reader," he said.
When Dr Norman announced his resignation in January, his colleagues appeared shell-shocked and disbelieving. But Dr Norman believed that whoever gets the top job tomorrow, "the cause is in good hands".
He did not believe the Green Party needed to make a drastic change of direction after its disappointing election result.
But he said the new co-leader would need to continue the party's innovation, and would need to be able to communicate green ideas in an accessible way.
Dr Norman, 47, took on the top job in 2006 after the death of Rod Donald - the party's lowest-ever point, he said.
He steps down having helped to double the Greens' share of the party vote to 11 per cent.
During that time, the Greens have not only become more a mainstream party, but the Green economics they have preached has become more commonplace.
Dr Norman lights up when speaking about the demise of the coal industry, and the growing investment in green technology.
"So much of the world is embracing it. You know there was US$36 billion in green bonds bought last year? The tragedy is that New Zealand is not part of it."
He came into the debating chamber in 2008 warning that "oil will never be cheap again" and urging action on climate change.
This week, he finished the same way, using his final slot at Question Time to challenge the Prime Minister on the burgeoning costs of failing to cut greenhouse gas emissions.
His successor will be put in charge of new, intensified campaign on climate change which the party is expected to unveil this weekend.
Dr Norman says he has not looked beyond the next few months and helping the new co-leader settle in, and he has made "no firm decisions" on his political future.
UPS AND DOWNS
- Co-leading the Greens to more than 10 per cent of the party in successive elections.
- Helping to insulate 15 per cent of New Zealand's housing stock in joint policy with National
- Rod Donald's death in 2005 and the aftermath
- The aftermath of Donald's death: a poor election result and the party in debt
- By Isaac Davison of the New Zealand Herald