KEY POINTS:
Climate-change policies are an air-mile ahead of the other pressing environment challenges facing the country this election.
All the parties, bar Act, take the threats of climate change seriously and it is the speed of New Zealand's response through the newly introduced emissions trading scheme that is causing the most debate.
But no matter how hard or softly New Zealand hits the brakes on its greenhouse gas emissions, the country seems set for a bumpy ride.
If we go slowly we put at risk our international reputation as a clean, green country and increasingly fussy overseas consumers may punish us in supermarket aisles and travel agencies, hurting our exports.
Our Kyoto Protocol commitments for 2008-2012 mean the taxpayer will, meanwhile, effectively pick up the lion's share of the bill for excess emissions from subsidised big-industry polluters including agriculture.
If we go too fast we could disadvantage exporters such as farmers in markets where their competitors are not yet having to wear the costs of their emission outputs.
And while the world economy takes a battering, foreign countries are increasingly showing signs of cold feet on their own commitments to turning around the Titanic of greenhouse gas emissions, globally steaming towards not so much an iceberg as a massive chunk of collapsed polar ice shelf.
There are also calls for a greater sense of urgency as the globe risks passing a tipping point if emission outputs are not turned around by as early as 2015.
Ralph Chapman, the director of environmental studies at Victoria University, says, for instance, that National's goal of a 50 per cent emissions cut by 2050 is not enough.
To avoid dangerous climate change New Zealand needs to be aiming for an 80 to 100 per cent reduction, he says.
Given New Zealand counts for less than 1 per cent of global emissions, National argues it is ridiculous that we try to set ourselves up as a world leader in cutting them.
Others point to Kiwis having one of the world's highest per capita emission rates.
New Zealand will be the first country to include agriculture in a domestic scheme but the sector will not be required to pay the full cost of its emissions until 2030.
From 2013 to 2018, the free allocation of credits will equate to 90 per cent of the sector's total 2005 emissions, phasing out gradually from 2019 to 2030.
Labour already decrees New Zealand a world leader on climate-change policy, while others comment we are only playing catch-up with the European Union.
National leader John Key points to Labour's record of rising emissions since 1990.
He warns of job losses, industry moving overseas and general damage to the economy if we try to somehow become a climate-change policy world leader.
How National would amend the scheme is short on detail but the party says it aims to halve emissions from 1990 levels by 2050.
National's environment spokesman, Nick Smith, says the emissions trading scheme legislation was recklessly rushed through.
He wants a workable, revised scheme with a "package of changes" in place by January 2010.
National would amend six key areas to better balance environmental and economic interests and set a more flexible timetable for change in line with major trading partners.
Labour's climate change spokesman, Energy Minister David Parker, says it is important to get the economic signals out there to create a disincentive for emitters to exceed their existing emission levels.
Without such measures New Zealand could be up to $500 million worse off by 2012, representing many millions of tonnes of emissions. Mr Parker says it is estimated the scheme will cut economic growth by just 0.1 per cent in that time and stresses the system does not cause costs but minimises them.
The Green Party has already ruled out working with National, which it has criticised for trying to separate environmental issues from economic arguments, when the two go hand in hand.
It wants to see a Labour-led Government speed up the scheme's implementation.
Alastair Hercus, a Wellington partner in legal firm Buddle Findlay and public law consultant, has given legal advice on the emissions trading scheme to both the Government and private sector clients.
He says the key message that seems to be overlooked is that the country as a whole has an obligation to front up to the problem.
"As a country we have to pay - taxpayers and the people who emit."
Effective economic modelling is needed to show what options are most cost effective with the least damage to "NZ Inc" as a whole, rather than the least cost to the agricultural sector alone, he says.
Mr Hercus says the point of the scheme is to increase the cost to people who emit carbon in order to change behaviour.
There are complex trade-offs, and problems for agriculture. It produces about half the country's emissions, yet science has not found a way of reducing methane emissions without cutting production.
WHAT IT MEANS
* The Emissions Trading SchemeUpholds commitments of zero increase in greenhouse gas emissions over 1990 levels by 2012.
* Shifts responsibility from taxpayers to polluters.
* Mostly targets oil and power industries who likely pass costs to consumers.
* Those who breach emissions have to buy credits.
* Electricity comes in 2010, transport by 2011 and agriculture gradually from 2013.
* Cost to country depends on price of carbon credits on international market.
IN A NUTSHELL
Should New Zealand aim to be a world leader in its action on climate change?
LABOUR LEADER HELEN CLARK
We are absolutely determined that as our country led with pride on being nuclear-free, led with pride on votes for women, led on social security, we will be prepared to lead on this. Whoever wanted to be a fast follower? Our country is better than that.
NATIONAL LEADER JOHN KEY
I don't think New Zealand should be a world leader or carbon neutral because that will cost our economy jobs, will export jobs ... at a time when we can least afford it.
GREEN CO-LEADER JEANETTE FITZSIMONS
New Zealand needs to lead to prevent the worst effects of climate change. The ETS (Emissions Trading Scheme) is a just a first step and needs to be followed by emission reduction work through regulation and community behaviour change, and renewed efforts at an international level.
