Kiwis think of New Zealand as a small, relatively minor polluter, but its reliance on agriculture and tourism make it a "huge player" that can make a difference on climate change, despite political opposition overseas, IPCC authors say.
This week’s IPCC report warns that even the most optimistic scenario for climate change, limiting warming to 1.5 degrees Celcius brings dire risks.
Australian National University's climate change institute director Mark Howden has been involved in the report from the start: he was vice chair and review editor of the IPCC Working Group 2 and has contributed to half a dozen major IPCC reports.
He tells Nine to Noon's Kathryn Ryan global emissions are presently going up - exactly the opposite direction to that which is needed to avoid catastrophic climate change.
"We are way off at the moment in terms of the trajectory of the emissions we need them to be going down and down fairly quickly instead we are going up.”
"[Emissions] are increasing reasonably quickly, and they are much more consistent with 3 or 4 degrees of warming than they are with 1.5 or 2 degrees."
Under the Paris Agreement countries have agreed to limit warming to below 2 degrees Celcius above pre-industrial levels by the end of the century, with an ideal target of 1.5 degrees Celcius.
This latest IPCC report lays out the benefits of that 0.5-degree improvement: Up to 30 percent of coral reefs could be retained rather than ceasing to exist entirely, and sea levels would be about 10cm lower - sparing about 10 million people from the related impacts.
Prof Howden says that to have a shot at restricting warming to 1.5 degrees Celcius, New Zealand's emissions have to come down by 45 percent in the next 12 years.
“Those are the trajectories of change, and they are very substantial, but there’s various analyses which actually show that meeting those emissions targets is much cheaper than not meeting them and suffering the impacts of climate change.”
The report says that to achieve this, unprecedented changes are needed in energy consumption, travel, building methods and the food we eat.
Some scientists are already warning the lower cap is not achievable in New Zealand because of the economic reliance on the meat and dairy industry. It would also require technology that does not yet exist to extract carbon dioxide from the air.
However, Prof Howden says a steady reduction in emissions over the next few decades is a better soft landing than a drastic cut over a short time frame.
The report is a framework that offers “pathways” for governments to follow and political will is now needed, he says.
“The best time to start reducing emissions was 15 years ago, we knew enough then to start this trajectory. The second best time is today.”
He says it's also possible in spite of political headwinds - such as those from the from the Scott Morrison government in Australia and the Donald Trump administration in the US.
“California is the fifth biggest economy in the world and is aiming for net zero [emissions] by 2045,” Prof Howden says.
He says countries that get on board will reap economic benefits too.
“Even though you’ve got some who say 'no' [to change], others say 'yes' and ones that say yes are on the front foot and will be making money out of this very quickly.”
How can an economy such as New Zealand’s transform?
University of Canterbury political science and international relations researcher Bronwyn Hayward was the only New Zealand contributor to the IPCC Special report and says New Zealand faces particular problems.
“In New Zealand we often talk about ourselves as a small country but actually in terms of agriculture, as an exporter, New Zealand firms are responsible for 40 percent of cross-border world trade in milk and dairy.
"We are a huge player. And individually our carbon a greenhouse gases are very significant.”
As well as relying heavily on methane-producing agriculture, the country's other main industry is highly pollutive long-haul tourism.
Dr Hayward says international collective action could keep sea level rise to about 10cm, and the effects on New Zealand beyond that are unknown.
“For a country that is low-lying - with a lot of coastal property that’s affected by sea level rise - this becomes a big issue.”
She has some optimism there is the political will for change in New Zealand.
“I am a bit surprised that we are so slow to take action but on the other had in New Zealand we haven’t got that deeply polarised debate that’s going on in countries like America.
“That’s what makes me more confident we will find a pragmatic way to actually cooperate especially with the opposition both looking at this [carbon neutral] bill.”
The report writing process was significant, she says, with 60 authors, 30 editors and 100 contributing authors going through 6000 research papers and reports written since 2014.
They then had to respond to 42,000 comments before the final report was scrutinised twice by governments.
“The IPCC isn’t an activist group, it’s a very conservative group of scientists who have come to consensus and says this is, on balance, what we know now.
“The IPCC has stepped up and delivered what governments have asked for, now it’s over to governments whether they step up and what they choose to do.”