The council could choose not to set a target, its strategy and regulation manager Nic Peet said, or it could set an interim target. He recommended setting the same target as Government and revising that later.
It could also set a higher target, like the Greater Wellington Regional Council, which aims for net zero emissions by 2030.
Whanganui councillor Nicola Patrick wanted to set an interim target and get an emissions inventory done.
"There's no legal requirement to do this, but looking at the way government legislation is heading I think it's highly likely that councils and other organisations will be required to do this work," she said.
"Every time we put something off we increase the risk of irreversible damage."
Rangitīkei councillor John Turkington told his colleagues "and all the millions watching on livestream" that it was important to know the council's emission level, but setting a target would expose the council to unquantified costs and potential failure.
Adopting Government's target was okay with Palmerston North councillor Jono Naylor. But he didn't want to spend on an emissions inventory until it could be discussed with other costs in the Long Term Plan.
The council should provide leadership on this, Horowhenua councillor Sam Ferguson said.
"The top 200 companies will now need to be reporting on their carbon emissions. This organisation should have been doing this a number of years ago."
Not spending on the inventory would be "putting off the inevitable", Palmerston North councillor Fiona Gordon said. If Horizons set a target before Long Term Plan consultation began submitters might suggest a more ambitious target.
Horowhenua councillor Emma Clarke wanted the inventory done, but not a target higher than Government's.
Rangitīkei councillor Bruce Gordon said he didn't doubt climate change was happening, but said the cause of it is disputed by some. He wanted ratepayers consulted before money was spent.
Ruapehu's Weston Kirton agreed and said people weren't calling out for this spending.
All the councillors except Gordon voted to adopt Government's target of reducing emissions 30 per cent by 2030.
Patrick, Ferguson, Gordon, Clarke, Te Awe Awe and Keedwell - voted to spend $80,000 on the inventory. The vote was carried, despite the opposition of Turkington, Naylor, Benbow, Gordon and Kirton.