James Shaw says he has confidence Prime Minister Jacinda Ardern can deliver on climate change - because if she doesn't, she'll literally be breaking the law.
The independent Climate Change Commission delivered its advice earlier this week, and Cabinet is obligated to do what it says or find another way to achieve the same emissions reductions, the Climate Change Minister told Newshub Nation on Saturday.
"If they don't accept the recommendations, they've got to come up with something better that produces the same outcome otherwise they are in violation of the law."
The Zero Carbon Act, passed in 2019, established the Climate Change Commission, required the Government to set emissions budgets and set rules for how the Government must respond to the commission's recommendations. If the Government decides to go against the commission's advice, it has to explain why.
"The law says we have to stick within that 1.5C pathway, to stick within those emissions budgets," said Shaw. "If they don't accept the series of policy recommendations for how to fit into that, they've got to come up with something that does do that, otherwise the Government itself is in violation of its own law."
Asked if he had confidence Ardern was the right person to deliver on climate change, Shaw said he did.
He also has confidence the country's economically vital agriculture sector will meet its methane reduction targets. Methane doesn't hang around in the atmosphere as long as carbon dioxide, but while it's there, has a much bigger warming effect.
"Cutting methane is the strongest lever we have to slow climate change over the next 25 years, and complements necessary efforts to reduce carbon dioxide," Inger Andersen, executive director of the United Nations Environment Programme, said earlier this week.
The current goal is a 10 percent reduction below 2017 levels by 2030, and between 24 and 47 percent by 2050.
"I actually think they'll sail through that with some of the innovations that are going on," said Shaw.
"I know that in some of the test farms they've had in different parts of the country have increased profitability and reduced methane output by over 10 percent - I think by about 14 percent - just with on-farm practise changes. No new technology, no kind of magic science, anything like that - just with improvements to how the farm works."
The commission's report didn't mention any need for a stock cull. Shaw said while that would work, it might not be needed in many cases - but farmers who have reduced their stock numbers have benefited.
"Some of the most innovative and profitable farms in the country have gone from a really high-cost, high-input model - a really intensive form of dairying which actually had pretty thin profit margins - and they've gone to things like once-a-day milking, they've gone to less-intensive stocking on the land which means they've got lower input costs. So a couple of things happen - the methane output goes down, the nitrous oxide goes down and their profits go up."
Shaw repeatedly talked about the need for a climate change plan that everyone can agree on.
"The model is kind of built in a way to maintain a level of social consensus because we are asking a lot of everybody. And there are some sectors that for various reasons are quite resistant to change or will find it very difficult to change - I'm not going to name anyone in particular - but... we've managed to create a level of social consensus that everyone can look at each other and go, 'Okay, I get that I'm going to have to take action - as long as everybody else does too.'"
He refused to answer a question from host Tova O'Brien on what parts of the commission's report he felt didn't go far enough.
"I'm not going to give you a response to that question, which I know that you're going to not find terribly satisfying... I'm not a patient person. I want to be moving a lot faster on climate change. But my job here is to make sure that actually New Zealand starts finally reducing emissions over the coming decades, and actually moves much quicker than we have in the past."
He noted the final report was tougher in places than some earlier drafts.
"In some cases what they have said is similar to what the industry itself has said, in some cases they've pushed industries to go further. In a couple of cases they low-balled it in the draft advice and the industry themselves came to them and said, 'Hey - we actually think we can go faster than you're describing,' so they've upped the ante."
If New Zealand - and the world - doesn't tackle global warming, Shaw said New Zealand can expect "more frequent and more severe droughts, more frequent and more severe storms, flooding, fires like the ones you saw on the Port Hills a few years ago or in the Nelson region".
"The impact on that is mostly on our agricultural sector. The really severe drought we saw in 2014 knocked about $1.5 billion off our agricultural exports."