Net zero and the Zero Carbon Act, explained

What the Zero Carbon Act actually does

The Climate Change Response (Zero Carbon) Amendment Act 2019 put New Zealand's climate targets into law. It sets a target of net zero for long-lived greenhouse gases by 2050, treats biogenic methane separately with its own reduction range, and creates the Climate Change Commission plus a system of five-yearly emissions budgets.

The split-gas approach matters and is genuinely unusual internationally. Methane from livestock is far more potent than carbon dioxide but breaks down in about a decade rather than lasting centuries, so the Act does not require it to reach zero.

The Act sets the destination. The Emissions Trading Scheme is the main tool for getting there, by putting a price on emissions from most sectors other than agriculture.

What ACT would change

ACT would repeal the Zero Carbon Act and scrap the 2050 net zero target, replacing it with an emissions cap benchmarked against New Zealand's major trading partners rather than a fixed domestic goal.

It would also remove the carbon price floor so ETS auctions can clear at lower prices, and return carbon auction revenue directly to households. On Paris, it wants the agreement renegotiated over how methane is treated, and would consider leaving only if those terms proved unreasonable.

The reasoning is that a country producing well under 1% of global emissions imposes real costs on itself for negligible climate effect. The counter is that trading partners increasingly attach climate conditions to market access, and that benchmarking to others removes any independent commitment.

Where everyone else stands

NZ First goes furthest in one respect: it would withdraw New Zealand from the Paris Agreement entirely, arguing that buying offshore carbon credits sends billions overseas without cutting a tonne domestically.

National remains committed to Paris and to net zero, while having softened the 2050 methane target from 24–47% to 14–24% and taken agriculture out of the ETS.

Labour supports the existing framework and would reinstate the offshore oil and gas exploration ban.

The Greens and Te Pāti Māori would go considerably further and faster, with the Greens campaigning on a rapid fossil fuel phase-out and mass electrification.

The question underneath the argument

Almost nobody in Parliament argues the climate is not changing. The live disagreement is about who bears the cost of acting, and how much a small country's action is worth.

If you think New Zealand's contribution is symbolic and the cost falls on farmers and motorists, ACT and NZ First are closest to you. If you think targets in law are what stop each government deferring the problem, the Greens and Labour are. National sits between, keeping the targets while easing the load on agriculture.