The devil lies in the murky details
TALKING POLITICS
OPINION: We all know to beware of ‘‘lies, damned lies and statistics’’ but statistical models are an even trickier proposition.
Inevitably, such models can have shock headline value – at least until you read the fine print about the conditions under which the outcomes might eventuate, if at all.
The early Covid modelling, for instance, indicated that even with a 75% vaccination rate, there could be 7000 Covid-related deaths and 60,000 hospitalisations a year in New Zealand unless – and here comes the fine print – other precautions were taken. Thankfully, they were.
In other words, modelling does not predict what will inevitably happen. Quite the reverse.
Yet last week provided a classic example of statistical models being used to stampede the public.
The National Party claimed that the Government’s proposed pricing mechanisms to reduce farm-based greenhouse gas emissions would put 20% of Aotearoa’s sheep and beef farmers (and 5% of dairy farmers) out of business by 2030.
Those scary outcomes were derived from modelling contained in the He Waka Eke Noa report, compiled from years of consultation between farmers, growers and government. That report enjoys wide political support, including – paradoxically enough – from National itself.
To put it mildly, the report’s modelled outcomes were less than precise. The impacts on sheep and beef profits for instance, could range from 2% to more than 44% , based on different methane prices and prices for carbon emissions.
To make things even murkier, competing models were being brandished last week as to what might transpire by 2030.
Dairy farmers would be less affected than sheep and dairy farmers (and Māori farmers) because their income per hectare is higher, thus enabling them to better afford any likely levy imposed on the emissions they generate. Since the Government has not required reductions in herd sizes or caps on emissions or fertiliser use, Greenpeace has slammed the proposals as greenwashing.
Much of the political heat last week came from the Government’s proposal that ministers should set the prices, on advice from the Climate Change Commission. This option was preferred to taking an ‘‘industry led’’ approach whereby farmers themselves would largely decide the prices they paid for farm emissions, and also the deductions available for any climate-mitigating vegetation they had on their farms.
To measure the emissionsmitigating vegetation on each individual farm, as Climate Change Commissioner Rod Carr has said, would be ‘‘expensive, complex, inequitable, and difficult to audit and enforce’’ – and would not significantly improve emissions-reduction outcomes. Instead, the Government has proposed managing the vegetation issue at a sectoral level, largely through the Emissions Trading Scheme.
If elected, however, National is promising that the prices for our agricultural greenhouse gas emissions will be ‘‘industry led’’ and is also advocating for farmers to be able to deduct the value of all carbon offsets present on each individual farm.
At this point, the Government proposals form part of a further consultation round to be finalised next year, with the levies due to start in 2025. It does not take a statistical modeller to predict the planet will continue to warm while the politicians continue to bicker over which price-incentive scheme is most likely to reduce our farm-based greenhouse gas emissions.