There are certain moments when history is changed by the impetus of a truly great speech. Winston Churchill managed to achieve this on several occasions:
We shall go on to the end, we shall fight in France, we shall fight on the seas and oceans, we shall fight with growing confidence and growing strength in the air, we shall defend our Island, whatever the cost may be, we shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender.
John F. Kennedy (although not exactly a prime minister) had his moments too:
Let every nation know, whether it wishes us well or ill, that we shall pay any price, bear any burden, meet any hardship, support any friend, oppose any foe -- to assure the survival and the success of liberty.
Then there are the more run-of-the-mill speeches, such as this no-frills effort from Michael Joseph Savage when he announced that New Zealand would follow Britain into World War II:
Where she goes, we go. Where she stands, we stand.
And then there are the truly ordinary speeches such as this one:
I believe we can aspire to be carbon neutral in our economy and way of life...
"I believe we can aspire"? It's hard to imagine Winston Churchill employing this particular turn of phrase. Helen Clark's unassuming words are perhaps unfortunate -- because her proposal for New Zealand to become a carbon-neutral country is every bit as challenging as fighting a world war.
There are two possible pathways to carbon neutrality , and neither of them are easy. Both pathways necessarily involve a dramatic transformation of New Zealand's energy sector. This is because the vast majority of our man-made atmospheric carbon emissions are due to energy use: the coal we burn in industry, the natural gas we burn to generate (some of) our electricity, and the petrol and diesel we burn in cars and trucks. These carbon-emitting fossil fuels represent about 70 per cent of New Zealand's total energy consumption .
One possible pathway would be to continue the use of these fossil fuels, but to capture and sequester the carbon so that it does not enter the atmosphere. Unfortunately, there are a number of cost issues and practical difficulties associated with sequestration. Furthermore, the hydrogen fuel that results from this process is not compatible with our existing transportation infrastructure  (indeed a low-cost method for on-board storage of hydrogen in cars and trucks has not yet been developed). This represents a significant obstacle because transportation accounts for the majority of New Zealand's fossil fuel energy usage .
The other option would be to avoid burning fossil fuels altogether. This can't be done overnight, of course -- if most of New Zealand's energy supply were suddenly eliminated then our society and economy would be thrown into turmoil. But it's possible that the energy that we currently get from fossil fuels could be gradually replaced with energy from renewable carbon-neutral resources.
Which option is better? At the moment the option of renewable energy is the most technically feasible. This approach also has the advantage of eliminating New Zealand's dependence on unreliable energy imports , as well as offering protection from the future effects of a diminishing petroleum supply. The elimination of our fossil fuel consumption would not only make a small (but important) contribution towards the health of the planet  and our society , but would also prevent our trading partners from holding our carbon emissions against us -- as Helen Clark noted in her speech:
More than any other developed nation, New Zealand needs to go the extra mile to lower greenhouse gas emissions and increase sustainability.
In our high-value markets in Europe, we face increasing pressure on our trade and tourism, from competitors who are all too ready to use against us the distance our goods must travel to market, and the distance tourists must travel to us.
It sounds like a great idea -- but let's put the scale of her proposal into perspective. A carbon-neutral New Zealand would require tripling the energy that we currently produce from renewable resources . That's the equivalent of two more Clyde dams, two more Manapouri hydro schemes, two more Wairakei geothermal stations -- two more of everything renewable that we've already got. And don't forget that our existing infrastructure has taken decades to build. Helen Clark is proposing a truly mammoth task.
Of course, no one expects it to happen overnight. And no-one expects too many more hydroelectric dams -- the new carbon-neutral energy would come primarily from wind, geothermal, marine, solar, and above all biofuels. New Zealand is fortunate to have vast resources of renewable energy. In fact, it has been estimated that the long-term potential of wind energy is 360 petajoules (100,000 gigawatt hours) per annum -- enough (on a net basis) to supplant all of our current fossil fuel consumption by itself .
So it's technically feasible -- but is it economically sensible? Well, surprisingly, perhaps yes. If carbon emission rights become successful as an internationally tradable commodity, and if energy prices continue to rise over the long term (as widely predicted), and if the implementation is carried out in a sensible manner over a reasonable timescale -- then the proposal may well be of net economic benefit to New Zealand.
Of course, that's a lot of 'if's, and comparison with Muldoon's 'Think Big' policies will be inevitable. But there are some important differences -- not least that 'Think Big' was based on the exploitation of a finite resource using borrowed money. A better comparison might be New Zealand's investment in the network of hydroelectric dams that were constructed in the first two-thirds of last century (and which continue to pay dividends today).
In fact, components of the proposed carbon-neutral energy infrastructure might even be attractive to the government's own superannuation fund as an alternative to investing in cigarettes and nuclear weapons. It's even possible that New Zealand industry might export the carbon-neutral technology and know-how that it develops. This certainly occurred when the Danish government made a similarly bold decision to exploit its wind energy resource -- and the clever Danes have now become the largest producers of wind turbines in the world.
So might Helen Clark's audacious proposal become a reality?
No... of course not.
Here's why: the development of energy infrastructure on this scale isn't a technical problem so much as a political one. It would take decades to implement, and in meantime two things will almost certainly happen.
Firstly, opposition parties will use any long-term energy plan -- however sensible -- as a stick to beat government. In fact, even minor parties within government will exploit this issue as a point of difference (witness the embarrassing temper-tantrum already thrown by Peter Dunne over the innocuous carbon-tax proposal). And both groups will promise to dismantle the plan when they are voted into power. In all likelihood even the timid and inoffensive proposals in the New Zealand Energy Efficiency and Conservation Strategy will meet this same fate.
Secondly, fear of voter backlash will prevent the government from implementing any policy that forces us to pay the true cost of energy use and carbon emissions. It will be too tempting to take the well-worn path of previous administrations: dither, do nothing, and let the next government deal with the problem. It hardly needs to be pointed out that over the last seven years -- despite its achievements in other areas -- the current government has only dealt with energy issues on a fire-fighting basis. And it is depressing to note that the next large energy scheme to come on-stream will be the carbon-emitting Huntly E3P project.
If carbon neutrality is a desirable goal then it will need to be delivered by some other mechanism than our three-year political cycle. A multi-party accord is an obvious approach, although a more successful option might be a referendum on a carbon-neutral New Zealand -- perhaps with the bicentenary of the Treaty of Waitangi (2040) as a completion date. This would send a clear message to future governments that they need to engage with the long-term plan to meet the country's energy needs in a sustainable manner.
But frankly, neither of these alternatives has much chance of coming to pass. Not unless our politicians manage to put aside their differences, and work together to achieve what's best for New Zealand in the long run, rather than what wins elections in the short term.
So Helen Clark was probably sensible to whisper her plans for a carbon-neutral country. In another few years they will be all but forgotten. The government of the day will still be passing hasty legislation to shore up our energy supply -- and New Zealand's carbon emissions will continue their relentless rise.
 It is sometimes suggested that carbon neutrality can be achieved by absorbing an amount of carbon from the air that is equivalent to New Zealand's emissions. This sounds simple: we just plant trees. But the hitch is that the trees must remain as permanent forests -- because if we remove the forests then the stored carbon will be returned to the atmosphere. This approach is unsustainable in the long run, because if we keep planting new forests then eventually we simply run out of room.
 It is a little difficult to extract information for this reference: (i) Go to this URL (ii) Select "What fuel was used to generate the energy?" from the 'Questions' drop-down menu (iii) Select "PJ" from the 'Unit' drop-down menu (iv) Select "Delivered energy" from the 'Energy types' drop-down menu (v) Select all the energy sector boxes ('Agriculture', 'Household', 'Commerce', 'Industry', and 'Transport and Storage'). Click the 'submit' button.
 An alternative approach would be to sequester only a portion of the carbon, and to store energy for transportation applications in the form of low-carbon fuels such as ethanol or methanol. This would not decrease carbon emissions from petroleum-based fuels, but it would significantly reduce emissions from coal-based transportation fuels. This could theoretically enable New Zealand to replace oil imports with our indigenous coal resources without increasing our net carbon emissions.
 According to the current scientific evidence.
 There is mounting evidence that the fossil fuel emissions have a significant impact on human health. Some researchers have claimed that air pollution from vehicles kills over 800 New Zealanders per year.
 This assumes the current amount of fossil fuel consumed by New Zealand. In fact, by reducing our nation's colossal wastage we can avoid having to produce anything like this quantity of renewable energy. To give one example: if most New Zealanders drove a car such as the Audi A2 5-door or the Volkswagen Lupo then we would immediately reduce our total energy consumption by more than 10 per cent.
PLEASE NOTE: DAVID HAYWOOD IS AN ENERGY ENGINEER & RESEARCH SCIENTIST. THE VIEWS EXPRESSED HEREIN ARE HIS OWN, AND DO NOT PURPORT TO REPRESENT THE OPINIONS OF HIS EMPLOYER IN ANY WAY.