The government has unveiled its plan to combat climate change, under which methane will be treated differently to other greenhouse gases, in response to push back from the agricultural industry.

Photo: RNZ / Dom Thomas

The Climate Change Response (Zero Carbon) Amendment Bill - introduced to Parliament today - sets out a plan for the next 30 years.

The government has also set a new emissions reduction target for all greenhouse gases, except methane, to net zero by 2050, in line with New Zealand's commitments under the Paris Agreement.

"The government is today delivering landmark action on climate change - the biggest challenge facing the international community and New Zealand," Prime Minister Jacinda Ardern said.

Agriculture was "incredibly important to New Zealand", Ms Ardern said, but also needed to be "part of the solution".

"That is why we have listened to the science and also heard the industry and created a specific target for biogenic methane" and adopted what's known as a "split gas" approach.

Climate Change Minister and Green co-leader James Shaw said the government had heard the students who went on strike to protest the lack of action on climate change.

"The Zero Carbon Bill outlines our plan to safeguard the future that those school students will inherit," Mr Shaw said.

"The critical thing is to do everything we can over the next 30 years to limit global warming to no more than 1.5 degrees Celsius and the Zero Carbon Bill makes that a legally binding objective.

"Carbon dioxide is the most important thing we need to tackle - that's why we've taken a net zero carbon approach," he said.

The Bill sets a target for 10 percent reduction in biological methane emissions by 2030, and aims for a provisional reduction ranging from 24 percent to 47 percent by 2050.

That provisional range will be reviewed by the independent Climate Change Commission, to be established under the Bill.

"The split gas target that we've got is informed by the science about what needs to happen in each class of greenhouse gas in order to get us there," Mr Shaw told Nine to Noon.

He said that farming practices can be adapted to curb emissions and there won't necessarily be any need for stock reduction.

"The most important thing is that we're doing a collective effort across every sector of the economy, and every gas, to live within 1.5C of global warming. That's the outcome we're trying to take," he said.

Photo: RNZ / Rebekah Parsons-King

The commission will provide advice, guidance and regular five-yearly emissions budgets, Mr Shaw said.

The Bill also creates a legal obligation on the government to plan for how it will support New Zealand towns and cities, business, farmers and iwi to adapt to the increasingly severe storms, floods, fires and droughts this country is experiencing as a result of climate change, he said.

"New Zealanders have made it clear they want leadership and consensus on climate change legislation," Mr Shaw said.

"We're delighted that the three government partners have reached an agreement over such a significant piece of legislation after lengthy consultation."

Mr Shaw also acknowledged National Party leader Simon Bridges for his involvement in working through the Bill.

"The fact that, across Parliament, all parties have engaged constructively in this process signals mutual interest in creating enduring climate change legislation that will stand the test of time and deliver long-lasting commitment to action on climate change for future generations," he said.

In his report in August last year the Parliamentary Commissioner for the Environment, Simon Upton, said to prevent global warming, methane emissions would have to fall by a much lower rate - 10 to 22 percent below 2016 levels by 2050.

The Bill itself does not set out an enforcement regime for individual industries; that level of detail will be contained in emissions reduction plans to be created subsequently by ministers.

Political agreement

Photo: RNZ / Rebekah Parsons-King

After delaying the introduction of the bill, New Zealand First has reached an agreement with Labour and the Greens on its climate change policies.

New Zealand First leader Winston Peters said the process began when the last National government signed the country up to the Paris Agreement.

From the beginning of this government, NZ First has had the agriculture sector's interests at heart. New Zealand has an internationally unique methane profile given our sheep and dairy farming sector.

"In negotiations, New Zealand First sought to balance the interests of the agricultural sector and the need for the government to take strong action and show leadership on climate change.

"We paid careful attention to, and respected, the weight of officials' advice around a methane target," Mr Peters added.

The 10 percent reduction target for methane includes a waste component, which Mr Peters says lands the overall target "squarely inside a wide range of officals' advice'' which his party was pushing to do.

"New Zealand First will fully consult with the agricultural sector about how it wants the free allocation to agriculture to be fed back to the sector. What proportion of the assistance New Zealand First has secured in this agreement does the sector want [to be] channelled directly to farmers to assist their mitigation efforts and what proportion of the free allocation be directed to fund sector-wide research and development into methane inhibitors, vaccines and other new technologies?

"We will listen very closely to, and work with, the agriculture sector about their preferences," Mr Peters said.

Some of the conditions set by the party in negotiations with the Greens and Labour were that the Climate Change Commission not be granted statutory independence like the Reserve Bank and that split gas targets were established.

Mr Peters also said unnecessary advisory groups support the Climate Change Commission were also removed through his party's negotiations.

Photo: RNZ / Rebekah Parsons-King

As for the National Party, the leader Simon Bridges said today's announcement was a positive step forward but the Opposition had "serious reservations about the expected rate of reduction for methane''.

"National was clear on its position, as I outlined at my speech at Fieldays last year. We have taken a principled approach to these negotiations, including seeking different treatment for separate gases, and I am pleased to see this reflected in the Bill.

"We are not convinced that the proposed 24-47 per cent reduction for methane meets our test in terms of science, economic impact or global response,'' he said.

"We're committed to taking short term politics out of climate change policy, by having an enduring Commission which will give science-based advice for successive governments.

Mr Bridges said New Zealand has been a global leader so far but the methane target "goes beyond credible scientific recommendations''.