He said the figure of 36.4 million tonnes probably referred to a figure in the Ministry for the Environment's Greenhouse Gas Inventory 1990-2007. It referred to 36.4 megatonnes of CO2 EQUIVALENTS.
In correspondence with the NZ Herald he said CO2 equivalents were not a greenhouse gas, "they are a figure in a piece of paper".
He said six greenhouse gases were measured; the two associated with agriculture were methane and nitrous oxide. Methane production was 1,139,000 tonnes and nitrous oxide 40,990 tonnes.
"Stating that agriculture produces 36.4 million tonnes of greenhouse gases, and then stating that two-thirds of the emissions were methane, which is 'worse still', 25 times more damaging than CO2, draws the reader to an incorrect conclusion that two-thirds of the 36.4 million tonnes produced are methane, which is 25 times worse than CO2."
In his letter to the NZ Herald, Mr Grieve said he would prefer to deal with the inaccuracies by way of a reasoned response to the newspaper.
However, despite this being suggested to him by Herald deputy editor David Hastings, Mr Grieve's letters to the editor had not been published.
The newspaper's response
Mr Hastings denied that writer had got his facts wrong. He cited the Greenhouse Gas Inventory, saying New Zealand's agriculture greenhouse gas emissions were 36.4 million tonnes.
Mr Hastings also referred to a large graphic published on the first page of the Herald's four-page climate change spread. It used the word "equivalents".
He suggested Mr Grieve's concern was "with the science, not the reporting". He considered Mr Grieve's views unsubstantiated.
He said the term greenhouse gases in the Herald feature was "shorthand" for "greenhouse gas emissions calculated as CO2 equivalents".
He said the Press Council should bear in mind such "elliptical usage" was not uncommon among scientists discussing global warming questions.
Further comment from the complainant
Mr Grieve objected to the "shorthand" claim, citing the context of its usage in the Herald feature.
"It is far more credible that he [the writer] was talking about the greenhouse gases methane and nitrous oxide which are far more detrimental than CO2. If that is the case the figure he should have used was closer to 1 million tonnes, not the 36.4 million tonnes he did use."
He said the Herald graphic did not negate the inaccuracies in the text.
He disputed Mr Hastings' reference to "elliptical usage" by scientists and said that, even if true, it did not excuse the Herald from presenting misinformation.
"Official documents do not contain such usage, research material and information does not either and I think it has been put forward to excuse a lowering of standards to allow misrepresentation, either intentional or unintentional.
In any case, what terminology scientists use is quite irrelevant here because the article was written by [a reporter], not a scientist, and it was written to be read by non scientists. It needed to be accurate.
"Readers are entitled to truthful, accurate information from their newspapers, they should not have to be wary that what is said in the newspaper could actually mean something else altogether."
Discussion and decision
The Press Council commends the NZ Herald on its comprehensive look at Climate Change, and the effects it may have on New Zealand.
This is relatively new information for many readers and the newspaper provided a service in bringing such information to the public in terms they can understand.
However, it is important that terms that have particular meaning are used in the correct sense. Greenhouse gases and CO2 equivalents are not synonymous.
CO2 equivalents, as a measure, have been developed to take into account the emissions from various greenhouse gases based on their global warming potential (GWP) or degree of detriment to the atmosphere.
Relative to CO2 at 1, methane has a GWP of 21 and nitrous oxide 310, as noted in the Inventory. CO2 equivalents are therefore somewhat analogous to stock units in the farming sector.
While tempting to say this complaint is an argument over science - not the reporting - and semantics, the report's loose wording was inaccurate. The graphic, published three pages earlier than the disputed phrases, made only one mention of the words "Carbon Dioxide equivalents".
The statement "In 2007 agriculture produced 36.4 million tonnes of greenhouse gases" was incorrect (though the contribution made by agriculture does represent 48 per cent of New Zealand's emissions).
The figure of 36.4 million tonnes relates to CO2 equivalents, as noted in figure 8 of the Inventory graphic, which was quoted as the source. Without the reference to CO2 equivalents readers would not know that every tonne of methane had been counted 21 times and every tonne of nitrous oxide had been counted 310 times, based on their GWP.
To then go on and say "worse still these gases ... are far more detrimental than CO2". While true in itself, it again does not indicate that in the figure given in this article this additional impact has already been factored in. This is misleading. The complaint is upheld.
The statement "The graphic, published three pages earlier than the disputed phrases, made only one mention of the words Carbon Dioxide equivalent" is incorrect.
The graphic prominently displayed the term twice. Altogether the term appeared five times in the series, including, as was pointed out to the Press Council, once on the page of the disputed phrases. - Ed.
