Growing numbers of New Zealanders believe climate change is real and that humans are driving it.
Kiwi scientists say the finding is encouraging when climate research is under renewed threat.
In a just-published study, University of Auckland and Victoria University researchers examined the two key climate-change beliefs between 2009 and 2015, finding that belief in both steadily increased over time, and particularly from 2013 onward.
"Overall, belief in the reality of climate change was higher at all times than agreement with the idea that climate change is caused by humans," said study leader and Victoria University psychology researcher Dr Taciano Milfont.
"But people who tended to increase their level of agreement in one climate-change belief also tended to increase their agreement level in the other belief."
The research used data from the New Zealand Attitudes and Values Study, a national probability sample study that has been tracking New Zealanders' social attitudes, personality and health outcomes since 2009.
It is the first longitudinal study indicating that climate-change belief is increasing over time.
Past research has relied on a snapshot of data from one-off public opinion polls, which were based on distinct individuals.
One survey, published by Wellington-based public policy research group Motu in 2015, found only half of those polled agreed they were certain that climate change was happening, 24 per cent were undecided and 28 per cent disagreed.
Further, just over half agreed there was a scientific consensus on climate change.
But most respondents were concerned about the potential the effect of climate change on themselves (63 per cent) and society (58 per cent), and 87 per cent were at least somewhat concerned about the effects of climate change on society in general.
"We are the first to examine whether climate-change beliefs held by the same group of individuals, in this case, more than 10,000 New Zealanders, are changing or not," Milfont said.
The observed increase in climate-change beliefs could be attributed to several factors.
"Other studies suggest that climate-change beliefs and concerns may change after exposure to extreme weather events as well as mainstream media and awareness campaigns."
Other studies also suggested that political affiliation and political ideology were the main predictors of climate-change belief - and self-reported conservatives showed low agreement levels in climate-change reality and its human causation.
This suggested that the observed increase in climate-change beliefs was greater among politically liberal individuals.
"We expect that levels of climate-change beliefs will fluctuate over time," Milfont said.
"With the ongoing nature of the New Zealand Attitudes and Values Study, in the future we will be able to pinpoint whether particular socio-economic circumstances directly result in fluctuations on climate-change beliefs."
Associate Professor Craig Stevens, president of the New Zealand Association of Scientists, said the research was timely and important.
"It is good to be looking at what New Zealanders think and this needs good long-term data to be collected and carefully analysed," he said.
"There is a danger that climate science can be operating in a bubble but clearly New Zealanders are understanding the message coming out from a vast majority of climate science both here and abroad."
Unfortunately, he added, it appeared extreme weather events were already helping motivate this change in how New Zealanders were understanding climate and climate change.
"These new results give me confidence that New Zealand science will continue to play a role internationally."
Stevens said recent developments in United States politics had "potentially disastrous" implications for climate stability and the environment in general.
"There has never been a more important time to hold fast to the science and knowledge about how our planet works," he said.
"It is so critical to future generations that we make decisions based on knowledge."
The new research, recently published in the international journal PLOS ONE, was supported by a Templeton World Charity Foundation grant to Sibley and a Marsden Fast-Start grant from the Royal Society of New Zealand to Milfont.
Research jointly co-ordinated by Milfont in 2015 found that if people from 24 countries believe that addressing climate change will result in a more caring and moral community, they are more likely to take action.
"Given that climate-change beliefs and concerns are key predictors of climate-change action, our findings indicate that a combination of targeted communications endeavours may successfully convey the urgency of the issue," Milfont said.
NZ researcher: Trump move won't derail Paris Agreement
A leading New Zealand climate researcher says a dramatic policy roll-back just signed off by US President Donald Trump won't derail the landmark Paris Agreement.
Trump this week pushed through an executive order to unravel former President Barack Obama's plan to curb global warming, by suspending, rescinding or flagging for review more than a half-dozen measures in an effort to boost domestic energy production in the form of fossil fuels.
But Victoria University climate-change researcher Professor Dave Frame said the carbon-cutting goals of the Paris Agreement, signed by nearly 200 nations including the US, ultimately wouldn't be undone by a weakening in US climate policy.
"I don't think it will derail the Paris Agreement, which is much less vulnerable to the defection of a single actor than the previous version [the Kyoto Protocol]," Frame said.
"Climate policy turns on what everybody does - the US can have a holiday from climate-change policy for four years, but the problem will just be worse when they come back to it.
"It's a bit like somebody who's got a debt problem and who decides to go and indulge in a bit of retail therapy - it might be satisfying for a little while, but you just wake up in the morning with a worse version of the problem.
"So I expect it's a blip. The problem keeps evolving according to our scientific expectations - the last two years were the warmest on record - and the incentives remain what they were."
While the development was "regrettable" from a global environmental perspective, it did create opportunities for other nations, he said.
"If the technology leader refuses to lead, that lets other people step into their shoes and it's an opportunity for China to show global leadership, and it's an opportunity for European manufacturers and low-carbon innovators elsewhere."
New Zealand and climate change
• Under present projections, the sea level around New Zealand is expected to rise between 50cm and 100cm this century. Temperatures could also increase by several degrees by 2100.
• Climate change would bring more floods (about two-thirds of Kiwis live in areas prone to flooding); worsen freshwater problems and put more pressure on rivers and lakes; acidify our oceans; put even more species at risk and bring problems from the rest of the world.
• Climate change is also expected to result in more large storms compounding the effects of sea-level rise.
• New Zealand, which reported a 23 per cent increase in greenhouse gas emissions between 1990 and 2014, has pledged to slash its greenhouse gas emissions by 30 per cent from 2005 levels and 11 per cent from 1990 levels by 2030.