The Government has announced a new target to reduce emissions by 50 percent by 2030, but several scientists say the actual commitment amounts to much less.
New Zealand's Nationally Determined Contribution (NDC), its target to help meet the Paris Agreement goal of limiting global warming to 1.5C above pre-industrial levels, has been changed from a 30 percent reduction in emissions by 2030 to a 50 percent reduction.
While that may sound straight-forward, the target baseline comparisons have been described as "apples and oranges", used to make the overall goal look better.
"The updated NDC announced today is expressed as a target to reduce net emissions by 50 percent below gross 2005 levels by 2030," a statement from Prime Minister Jacinda Ardern and Climate Change Minister James Shaw said on Sunday.
"This equates to a 41 percent reduction on 2005 levels using what is known as an 'emissions budget' approach."
Confused? Victoria University Climate Change Professor Dave Frame is too. He described the announcement as "unnecessarily opaque".
"All of this could be much more transparent if we stuck to announcing target tonnages, were clear about whether these are gross or net, and kept the short-lived stuff separate from the long-lived stuff."
Prof Frame joins a chorus of environmentalists who have accused the Government of using "clever accounting" to come up with a target that looks better than it is.
Prof Frame described the new target as "comparing apples and oranges", because the Government is comparing net emissions to gross emissions.
"As far as I can tell, gross emissions in 2005 were 81.27MtCO2e [metric tons of carbon dioxide], and net emissions were 55.94MtCO2e. A halving of the 2005 gross emissions is 40.64MtCO2e; which amounts to a 27 percent reduction on the 2005 net CO2e number."
NIWA climate scientist Dr Sam Dean also said the latest commitment by the Government "requires a decrease in net-emissions in 2030 of about 27 percent relative to 2005".
Worldwide Fund for Nature (WWF) New Zealand CEO Livia Esterhazy says New Zealanders will not be fooled by "clever accounting".
"It may technically be an increase but it's one that falls woefully short of achieving anything meaningful. New Zealanders aren't fooled."
Oxfam Aotearoa executive director Rachael Le Mesurier said the Government's change in the way they measure their emissions from an 'emissions budget basis' to a 'point year basis' means they can make it look like they have increased the target by more than they have.
"Each minister in Cabinet needs to take responsibility for the fact that our current plans for domestic action are completely inadequate. New Zealand is not taking the action necessary for the country to do its bit to protect our planet and our people from significant harm."
Oxfam Aotearoa is calling the new NDC target a "scandal" as the vast majority of it is being met by offshore carbon credits - planting trees overseas.
"Because we have not reduced emissions over the last 30 years, we have knowingly decided to pay billions of dollars overseas in carbon offsets rather than investing in Aotearoa and reducing our emissions domestically," says Esterhazy.
The Prime Minister's chief science advisor, Dame Juliet Gerrard, admitted to The AM Show there is a "bit of jiggery-pokery" with the numbers. But she said the reaction has been "quite extreme" for what is a "step in the right direction".
"If you look at the actual numbers, we're pledging to move from 623 mega tonnes to 571, so it's a definite reduction," she said.
"It's true that some of that will have to be offshore, and I guess I, along with most of the science community, will be pushing for as much of that as possible to be a genuine reduction in our domestic emissions.
"To meet those numbers we will need offshore contribution and a domestic contribution and it'll be up to people like the Climate Change Commission to guide the minister so that our emissions budget actually includes big chunks of reduction in our domestic emissions.
"I think there's lots of different ways that the Climate Change Commission could get to that number and the details will come out in the emissions budget next year."
The Climate Change Commission (CCC) advised the Government earlier this year that the NDC lodged by the previous National-led Government in 2016 was not consistent with global efforts to limit global warming to 1.5C above pre industrial levels.
The CCC recommended a new NDC should be "much more than 36 percent" reduction on 2005 levels by 2030.
Prime Minister Jacinda Ardern said the new target "represents our fair share" on the global stage. But an Oxfam report last year found that to meet its fair share, New Zealand's target needed to be between 80 to 133 percent below 1990 levels by 2030.
The Climate Change Minister says he hopes to "raise the bar for our NDC again in the future".