When climate scientist James Renwick was asked, for a Herald on Sunday feature , what steps people could take to live a more sustainable lifestyle, he mentioned some of the more obvious: House insulation, solar panels, use of public transport.
But if you do nothing else, he said, "Talk about climate change and the climate emergency. Make it normal in your house to speak about what's happening with the climate."
It is remarkable that someone still needs to say that. For more than 30 years we have been hearing and reading warnings of catastrophic climate change yet somehow it has not "sunk in" to the extent that a popular consensus demands action.
Renwick is right, it is not yet normal for the subject even to be discussed in most households or other social gatherings. Some do of course but if the subject is raised at all in general conversation it is likely to be treated as a bit of a bore, inviting humour or argument. Disbelief still runs deep.
On Sunday, the sky over Auckland turned sepia yellow. Around 2pm the sun disappeared in an eerie twilight for the rest of the day. Southern regions of New Zealand had seen something similar a few days earlier. The intensity of Australia's latest bush fires became evident this far away.
Bush fires are not unusual in an Australian summer but not even climate sceptics there can deny the number and scale of the outbreaks this summer are worse than any they remember. It's rare for the effects of Australia's heat to be seen, let alone felt, from this distance.
But last week many thousands of New Zealand cricket fans who went to Melbourne for the Boxing Day test felt the heat too, and not only on the pitch. It was fortunate for the fans and the players that the match ended a day early. The next day the mercury went above 40C. The sun was so sizzling it became a wonder anything combustible was not catching fire.
Australians stay indoors on such days with the air conditioning running hard. Visitors seek refuge in hotels, shopping arcades, museums, coffee bars, anywhere with air conditioning. Temperatures above 40C are common in the tropics but heat is fiercer in the air of a dry continent.
Australia ought to be a leading global voice in efforts to meet climate change. It stands to suffer perhaps more than any temperate country from a sustained increase in average temperature. Yet the subject divides its politics like no other in recent times, especially its governing party.
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A Prime Minister, Malcolm Turnbull, was toppled for trying to mitigate carbon emissions. His replacement, Scott Morrison, is taking deserved political heat over the bush fires but less than a year ago Australians re-elected his government.
New Zealand has an interest in Australia's climate change debate that goes far beyond hazy skies. Anything we can do to reduce our carbon emissions would be better done in harmony with our nearest and largest economic partner.
Maybe voters in both countries have seen enough evidence now to demand action.