It turns out the Prime Minister's bold plan to make New Zealand "carbon neutral" is somewhat less ambitious than it was initially cracked up to be.
The politically potent notion of New Zealand leading the world in cutting greenhouse gas emissions, just as it led the world in going nuclear-free, has finally been given a reality check.
At some stage, the Government was going to have to bridge the credibility gap between the Prime Minister's aspirational goal and what is actually achievable.
That point came yesterday with the release of the Government's draft energy strategy and Climate Change Minister David Parker being challenged to explain what he understands "carbon neutrality" to actually mean.
His definition restricts carbon neutrality to carbon dioxide emissions.
That might be acceptable if New Zealand was like most other countries which have signed up to the Kyoto Protocol on climate change and the great bulk of its greenhouse gas emissions were carbon dioxide-based.
But New Zealand is an exception. Nearly half of this country's emissions come from methane produced in the stomachs of ruminant farm animals.
When the Prime Minister grabbed the political initiative in October by suggesting New Zealand could become carbon neutral, most people, including the Greens, assumed she was talking about total emissions, methane included.
That is because "carbon neutrality" is widely defined as meaning zero net emissions of "carbon dioxide equivalents". Those include carbon dioxide, methane, nitrous oxide, and other gases like fluorocarbons.
To be carbon neutral requires that for every tonne of carbon dioxide equivalents that end up in the atmosphere as greenhouse gases, an equivalent amount must be extracted from the atmosphere either through being absorbed by trees or buried under ground.
The widely held view in political circles was that the Prime Minister had not realised quite what she was suggesting.
More likely she knew perfectly well what she was saying. Carbon neutrality is very much in vogue. It is also a huge ask.
Helen Clark was going far beyond anything the Greens have mooted. She did not correct people who were getting what now turns out to be the wrong impression from what she was saying.
It was left to Mr Parker yesterday to provide clarity - of sorts.
Speaking against a backdrop of solar panels, miniature wind turbines and electric-powered scooters, he seemed to argue that because carbon dioxide emissions worldwide are primarily to blame for global warming, New Zealand should concentrate on reducing its carbon dioxide emissions.
He also argued that because the technology to stop cows belching methane has yet to be invented, it would be unfair to expect the agricultural sector to cut its emissions at the same rate as other sectors.
The net result is the Government has narrowed the aim of carbon neutrality to concentrating on cutting emissions in the energy sector which, if transport is included, accounts for some 42 per cent of all emissions.
With forests and other carbon "sinks" removing nearly 33 per cent of all greenhouse gas emissions on 2004 estimates, Mr Parker could reasonably credibly talk of reaching carbon neutrality "far faster" than other countries - but only in the energy sector, not across the whole economy.
His logic is all just a little too convenient. Ignoring methane emissions means any claim of New Zealand becoming "carbon neutral" should be strictly read as "carbon neutral - well, only sort of".