As far as courtroom dramas go, Lawyers for Climate Action New Zealand  (LCANZ) vs Climate Change Commission, heard in Wellington’s High Court, last week was hardly gripping stuff.

Evidence – provided by a who’s who of scientists and other experts on the intricacies of carbon accounting – was mind-numbingly complicated.

But the stakes couldn’t have been higher: New Zealand’s responsibilities in the existential fight against climate change.

LCANZ – a group made up of about 350 lawyers -  argued the Climate Change Commission’s carbon accounting was flawed and if followed would result in New Zealand failing to meet its Paris Agreement Commitments.

The commission, LCANZ argued, had misapplied the modelling conclusions of the IPCC landmark 2018 Special Report on Global Warming of 1.5C.

In a case of apples and oranges, LCANZI said, the commission applied the report’s conclusion that CO2 emissions levels need to be reduced by 40-58% from 2010 levels by 2030 and by 94-107% by 2050 to New Zealand’s gross emission rather than our net emissions.

LCANZ’s line-up of experts taking issue with the commission’s methodology included Professor Piers Forster - an IPCC coordinating lead author and a lead author of the relevant chapter of the 2018 Special Report.

In a written affidavit, Forster said; “[a]dopting the Commission's proposed framework and their proposed emission reduction target would give New Zealand an unambitious 2030 target that does not align to meeting global ambitions of holding global temperature rise to 1.5C.”

LCANZ said the commission wrongly interpreted its responsibilities under climate change legislation to be “only or primarily” to recommend carbon budgets consistent with 2050 targets and didn’t take take into account the country’s commitments to the global target of remaining below 1.5 degrees of warming by 2030.

And the commission’s use of gross accounting isn’t allowed under the Act which prescribes the use of net accounting, LCANZI told the court.

 “The proposed Budgets are irrational, unreasonable and inconsistent with the purpose of the Act,” LCANZI claimed in its “Road-map to interested parties.”

Climate Change Commission position

The Climate Change Commission said the point of difference between it and LCANZ was not the destination – Net Zero by 2050 – but the steepness of cuts needed by 2030.

“LCANZ want the New Zealand government to move faster than the 2050 zero carbon target set by Parliament.

“They want deeper and steeper cuts in emissions in the next eight years, before 2030, regardless of the potentially catastrophic (and in real terms unnecessary) impact on communities – particularly rural and Mâori communities which rely heavily on the sectors that will feel the impact most – and the economy,” the Commission said.

Justice Jillian Mallon now has to weigh up the evidence and decide whether LCANZ is right and the commission’s advice on the nationally determined budgets were unlawful due to the alleged errors.

If she decides in LCANZ’s favour, the lawyers group has proposed that a two-step process is followed where the parties are given an opportunity to seek further orders as to the next steps on the basis of the court’s finding.