And with global emissions of carbon dioxide unlikely to slow anytime soon, they are calling for more focus on reducing methane emissions and adapting to change already locked in by our past actions.
"Humanity is on thin ice, and that ice is melting fast," UN secretary-general António Guterres said on Tuesday (NZ time), as the Intergovernmental Panel on Climate Change (IPCC) released its latest in-depth look at the science.
"Humans are responsible for virtually all global heating over the last 200 years... The climate time bomb is ticking."
New Zealand should be showing larger, more powerful countries how to address climate change by leading the way, according to Dr Kevin Trenberth, a visiting distinguished scholar from the National Centre of Atmospheric Research in Boulder, Colorado, and honorary academic at the Department of Physics at The University of Auckland.
He has also worked for the World Climate Research Programme and contributed to prior IPCC climate reports.
"There's a whole lot more that New Zealand could be doing," he told RNZ.
"I think the recent events, Gabrielle and the rain bomb that occurred on the 27th of January in the Auckland area - at my place we had 280mm of rain - I mean, the damage that has been done around the country with regard to this shows that we ought to be paying a whole lot more attention to what is referred to as adaptation. That is, you know, adjusting to the climate change that's already under way and which we have very little control over."
He said there is "not a lot" we can do to stop warming in the near future.
"There's going to be, you know, very little curbing of global warming in the next 20 years… if you look at all of the plans from industry and especially the fossil fuel industry… Even if we drop our emissions, that won't have an immediate impact on cooling the planet."
Carbon dioxide stays in the atmosphere for hundreds of years, so the damage there for the next few decades is perhaps already done - but methane, which is about 80 times stronger than carbon dioxide as a greenhouse gas, only lasts a bit over a decade.
"While carbon is the big problem, it lasts over the long-term," Bronwyn Hayward, University of Canterbury political science professor and IPCC report writer, told Morning Report on Tuesday.
'We're moving so quickly to 1.5C that we need to reduce our methane in order to be able to buy us some time to actually lower temperatures.
"This is hard for farmers in New Zealand - they say, 'Look, we're doing everything we can.' We actually have to do more."
She said other countries like the US and UK have managed to cut their emissions in recent decades, and we are now an "outlier".
"We're one of the only countries where our emissions are still rising. Our trade partners aren't going to accept that in the future. Negotiations are getting tough and people are looking really hard at high-polluting countries, and unfortunately we're one of them."
New Zealand ranks near the top in terms of per capita greenhouse gas emissions.
Half of our emissions are related to agriculture, and 40 percent to energy. Between 1990 and 2020, total emissions increased 26 percent. In the UK over that time, they nearly halved their emissions, while in the US it has been on a downward trend since 2008.
New Zealand's annual carbon dioxide emissions have been relatively flat since the early 2000s, a drop in the use of coal offset by rising use of oil.
Because we have a large agriculture sector, our methane emissions are higher than most other countries - nearly half our output.
The IPCC's report stated the less methane the globe emits, the easier we can go on reducing carbon dioxide.
"Transitioning towards net zero CO2 emissions faster and reducing non-CO2 emissions such as methane more rapidly would limit peak warming levels and reduce the requirement for net negative CO2 emissions," it read, "reducing feasibility and sustainability concerns, and social and environmental risks associated with [carbon dioxide removal] deployment at large scales."
Hayward said New Zealand "encouraged a lot of farmers to take a lot of debt and shift into dairy, because it was great".
"We kid ourselves that we're feeding the world and that we're really efficient as farmers - and we have got some fantastic farming practices - but we're also exporting an enormous amount of milk powder that goes into confectionery and products where we think actually, what else can we be doing that is high-value, makes a difference and emits less methane? Because methane is certainly in the sight of this report."
Global emissions have been rising for decades, with only a few years where overall emissions dropped since the mid-20th century (the latest, in 2020, due to the Covid-19 pandemic).
Hayward said even though New Zealand accounts for only a tiny fraction of overall emissions, we cannot expect large countries to do all the work - smaller nations combined account for about two-thirds of emissions, so they cannot all shirk their responsibilities.
Trenberth said we are "way behind" other countries in some areas, and still "doing silly things" like importing coal and not incentivising solar power.
"New Zealand can and should be a leader in the South Pacific and you know, I'd like to see stronger links with Australia. The previous prime minister, who I won't mention was not at all helpful, but the current administration… seems to be much more amenable and doing a lot better with regard to electricity and solar power and renewables.
"You know, we're the countries that can really represent in many ways, all of the smaller island states and so on in the southern hemisphere and especially in the South Pacific, and I think we have a role to play there."
