Wratt is a senior member of the IPCC, the Inter-governmental Panel on Climate Change, and is in agreement with the majority of the world's climate scientists who say human-induced climate change is happening all around us and that the warming of the Earth and acidification of the oceans is reaching a critical stage.
The New Zealand sceptics and various groups and individuals in other countries deny humans are the cause of climate change.
Wratt won't even take a guess at the numbers of hours wasted in defence of Niwa's science rather than getting on with research.
But he is "really pleased" the High Court has tossed out the sceptics' case in its entirety while validating Niwa's scientific methodology.
Wratt's frustration is not just at the sceptics but also at the attention they receive, given they are the minority.
He explains that more than two years ago the coalition brought out a paper claiming New Zealand had not warmed over the past 100 years and that Niwa, which found it had warmed by 0.9 degrees, had got this wrong.
Niwa (the Crown-owned National Institute of Water and Atmospheric Research) responded publicly, then the parliamentary questions started. Part-way through, the coalition formed an entity called the Climate Science Education Trust to take Niwa to court, seeking a judicial review of some of Niwa's decisions and actions.
There followed a long process, says Wratt, who this year received a Queen's Service Medal for services to science, of responding to their first statement of claim then having them change their submission the day before the scheduled hearing.
The argument revolves around weather station temperatures and the sceptics' belief Niwa has adjusted data to show warming.
Three sceptics gave affidavits. One of them is Terry Dunleavy, a retired journalist and stalwart of the wine industry. His family has a vineyard on Waiheke Island and he has an MBE for services to the wine industry.
Justice Geoffrey Venning was particularly critical about Dunleavy's expertise, or lack of it, in the science of meteorology and/or climate.
"He is not [an expert]. He has no applicable qualifications. His interest in the area does not sufficiently qualify him as an expert."
Justice Venning described some of the Trust's evidence as prolix (tediously lengthy) and said they had also relied on a series of parliamentary questions and answers - but this "rather prescriptive form of debate... is particularly unsuited to a satisfactory resolution of a difference of opinion on scientific matters".
THE SCEPTICS, however, appear unfazed. Since Justice Venning's ruling, they have responded in detail on websites and to this newspaper.
We approached Dunleavy, who said he would not comment but did answer some questions via email.
When asked if he was embarrassed the judge called his credibility into account, Dunleavy said: "The case was never about 'science' but about process. My affidavit did not cover 'science' but comments on events and processes that ought to be able to be understood and analysed by experienced journalists."
Asked how the legal action was funded, he said it was from the group's own pockets and a considerable amount of voluntary input. As for how much it had cost, he said, "That's our business."
He said the Heartland Institute - an American organisation that has been backed by fossil fuel interests - had not made a donation (though it has funded the coalition in the past) and neither had New Zealand billionaire Alan Gibbs, who is on the policy advisory panel for the coalition's parent body, the International Climate Science Coalition, and donated $200,000 to the Act Party before the 2008 election.
Justice Venning ruled that the trust must pay costs but Dunleavy said it was waiting until there was a request from Niwa. It had not decided whether to appeal.
When asked what next, Dunleavy said: "We will continue to challenge the still unproved hypothesis that human/animal emissions of carbon dioxide can or will cause dangerous 'global warming."'
A statement from Brian Leyland, an engineer and trust member, said they had been so frustrated by a lack of informative response "we felt that we had no option but to seek a High Court ruling invalidating Niwa's temperature record".
Justice Venning indicated in his judgment the court should not seek to resolve scientific questions demanding the evaluation of contentious expert opinion.
Wratt told the Herald he found it strange that the people who brought the case in the first place and whose evidence had been "hugely" about the science were now saying it had not been about the science at all.
"And although the judge can't pronounce on the science, he did actually pronounce on the fact that in his view Niwa had used credible scientific processes and done things properly."
Others in the science world and a large group of doctors are delighted with Justice Venning's ruling.
The New Zealand Climate and Health Council, which says it has 150 medical professionals as members, said groups like the Climate Science Coalition were "still peddling lies that kill, they are delaying action essential to protect human health".
Council spokesman, oncologist and Auckland University lecturer Dr George Laking told the Weekend Herald the court case was "a pretty sorry chapter" in New Zealand's history.
Human-induced climate change is the number one threat to health this century, he says, and the approach of the sceptics is "incredibly, incredibly irresponsible".
Health risks would begin with injury from heatwaves and storms, go through more tropical illnesses and then impact with threatened food supplies and political instability.
"It's pretty basic stuff. Currently we think of health as cancer and other chronic conditions. But longer term, what we're talking about is pretty basic stuff relevant to people's health, like whether there's a food supply."
Laking believes the sceptics have done damage and affected policy, saying the provisions of the Emissions Trading Scheme have again been watered down, and thinks that because the potential consequences of global warming are so scary it is easier for some to believe it is not happening.
Author and journalist Gareth Renowden, who runs the website Hot Topic and has published a book by the same name, predicts it won't be long before sceptics - who he calls cranks and deniers - won't have much influence.
"My own feeling is that the rate of climate change is going to become so undeniable over the next few years that these guys are going to be just totally irrelevant."
Renowden says the court ruling won't chasten them. "I think the psychological term is 'epistemic closure'. What it means is that they have created for themselves a sort of reality bubble, in which they can only approach the issue from their own pre-established conception of what the issues are."
He says the other day he came across the concept of the face bubble on Facebook - that people on Facebook live in their own bubble of friends and acquaintances - and thinks this is true of the sceptic web.
"Because there are hundreds of these websites around the world and inside that bubble climate change isn't happening, the fact that the Arctic ice has melted is not important."
Wratt says it is hard to know how much damage sceptics have done in sidetracking the debate, because so much of their information circulates on the internet "and I think a lot of that is self-referential. You know, a whole lot of people that agree on something kind of just reading each other's blogs and essentially confirming their own views. I'm not sure how much that stuff really influences outside opinion."
But the diversion has kept Niwa from important work, such as publishing an update on what is happening to New Zealand's extreme temperatures and looking at projections for future climate, impacts and options for how to adapt.
Niwa had been accused of making things up, which is offensive, says Wratt. But the judgment was very clear, which was great.
He says while it is important for scientists to have an open mind, the research and data from around the world showed the big picture, which is that the climate has warmed and this is very likely due to increases in greenhouse gases.
"When the vast majority of climate scientists, who are all fairly sceptical people in their own rights as far as science goes, are all coming from this direction I think it's pretty strong evidence there's an issue there."
ON THE WEB
Court ruling: Niwa v Climate Science Coalition
Niwa
Climate Science Coalition
Gareth Renowden's Hot Topic site
Climate and Health Council
