Climate change professor Tim Benton, from the University of Leeds in England, speaking from Intergovernmental Panel on Climate Change in Christchurch on Monday.

Some of the world's brightest minds have been in Christchurch this week to tackle the most pressing question of our generation – climate change. DOMINIC HARRIS listens in to find out what the future holds and how changing agriculture practices is vital.

Climate change is perhaps the most important issue of our age, a peril that threatens the entire planet and one that will likely define the next 100 years or so in the same way the world wars, nuclear crisis and international terrorism did the last.

The present occupant of the White House aside, there are few who choose to wilfully ignore the danger signs or blinker themselves from the abundance of evidence around them.

The effects of our rapidly changing climate are everywhere – from the hastened melting of the polar ice caps and rising temperatures in the Arctic to heat waves across Europe, coral bleaching in the Pacific and monsoons in Asia.

123RF.COM New Zealand prides itself on being green - but has a big problem with greenhouse gas emissions from agriculture.

New Zealand is no different. Earlier this month scientists recorded the lowest coverage of snow on record for the Southern Alps after a summer where January temperatures were nearly 3C above average.

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Rising sea levels are regarded as a certainty, with government estimates that they will soar 40cm by 2060 and communities on our coasts already at grave risk.

Biodiversity in rivers and streams is under threat, soils in some areas have become drier and our oceans are increasingly warmer and more acidic.

The grim reality is that climate change may already have had an irreversible impact on New Zealand's natural systems, and the effects are likely to worsen.

But while it may seem we are inexorably sliding towards environmental armageddon, plenty is happening behind the scenes to halt and hopefully reverse those trends.

This week Christchurch hosted 120 scientists from 59 countries – members of the Intergovernmental Panel on Climate Change (IPCC), a global coalition of experts who volunteered their time to draft a report that will influence governments as they tackle issues in the decades ahead.

The report has a specific focus – to advise policy-makers on sustainable management of land and water, how to ensure millions of vulnerable people around the world have enough food, cutting greenhouse gases (GHG) and how to address the growing problem of desertification.

Their task is mind-boggling – how do you tackle such complex issues on both a global scale and one that resonates with the individual?

ANDY JACKSON/STUFF Agriculture is responsible for almost 50 per cent of New Zealand's greenhouse gas emissions.

Some of the key themes are intrinsic to New Zealand's national identity and will strike a chord with people up and down the country – land use, how to reduce GHG emissions from agriculture and dealing with the impacts of climate change at the same time as producing more and high-quality food for a growing global population.

Some of the facts around New Zealand's agriculture are startling.

Dairy cattle increased 68.9 per cent between 1994 and 2015, up from 3.84 million to 6.49m, according to Stats NZ.

In 2015 there were 1,254,000 dairy cattle in Canterbury alone, a staggering rise of 490 per cent from the number in 1994.

New Zealand's farmers are among the most productive and efficient in the world, improving the emissions efficiency of production by about one per cent a year over the last two decades.

But agriculture still accounts for an astonishingly high proportion of the country's GHG emissions – almost 50 per cent, compared with around 10 per cent on average globally.

GEORGE HEARD/STUFF The impacts of climate change is increasingly clear, such as the record reduction in snow coverage of the Southern Alps.

Dr Andy Reisinger, deputy director (international) of the New Zealand Agricultural Greenhouse Gas Research Centre and vice-chair of the IPCC group working on reducing GHG emissions, says recent climatic extremes such as drought and heavy rainfall have had drastic impacts on the country's primary production sector.

"In an economy where one of the biggest export earners is livestock production, these things really matter for our economic development," he told Stuff.

"As we are trying to limit the amount of climate change and the amount of warming and negative impacts that the planet will experience, the question of how can we reduce greenhouse gas emissions from the land sector without negatively impacting on food security while enhancing the restoration of the degraded lands is of vital importance.

"For New Zealand that question is particularly sharp, because such a large part of our greenhouse gas emissions are coming from the land sector."

Reisinger said New Zealand is investing heavily in technologies to reduce GHG emissions and allow farmers to keep farming livestock but at substantially lower emissions levels, from methane inhibitors to vaccines and lower-emitting feeds.

"Given that many regions of the world are less efficient in producing food, but their food demand is growing, there is a real potential to reduce the growth in global emissions related to food production by helping those regions improve their productivity and efficiency."

Robert Charles Scientists believe changing farming practices are vital to help reduce emissions.

For Lincoln University agricultural economist and associate Professor Anita Wreford, an IPCC lead author, the challenges offer the chance for New Zealand to lead the way globally.

"I think it's a real opportunity to show leadership in this area. We are already leaders in understanding agricultural emissions but where we're not leaders is taking action and reducing them and in other forms of emissions reduction."

"So it's an opportunity for New Zealand to really take a stand, and also to address the impacts of climate change. We're only really beginning to do that.

"It's an opportunity to transform some of our existing systems so that not only are we addressing climate change impacts and reducing our emissions but we're also getting multiple other benefits such as increasing out biodiversity and improving our communities as well."

But Professor Tim Benton, a food security expert from the University of Leeds in England and the Royal Institute of International Affairs, warned of the dangers of relying on economic system that promotes such widespread reliance on livestock.

He said: "There are limits on a global basis to how much climate change we can cope with, and the Paris Agreement [which seeks to restrict the global temperature rise to 2C this century] codifies those limits.

"If the livestock sector, more or less by itself, could drive us over the Paris Agreement, we have a problem for society as a whole."

Jon Morgan New Zealand's growing expertise in tackling agricultural emissions could be exported around the world.

Benton argues that countries cannot continue to grow livestock numbers without reaching a tipping point over sustainability.

"Collectively that means we are going to break the Paris Agreement, and we are then in deep 'doodah' as a species.

"So somewhere the economics and market incentives are all wrong if they are driving every country to say you must produce more and more and more for our economy.

"There is nothing wrong with producing stuff for livelihoods, but our economic system is rewarding the wrong sorts of production in the wrong sorts of ways because it is creating the situation where the costs to producing are not being taken into account, and those costs are levied on a global basis."

There is, however, an argument that New Zealand's agricultural practices are already so green that it should be allowed to lead production on the global market.

Professor Annette Cowie, from the New South Wales Department of Primary Industries, said: "If you look at the carbon footprint of New Zealand produce compared to dairy coming from housed cattle in Europe that are fed entirely on concentrates, you see that the carbon footprint of the product from New Zealand, even if it is transported across the planet, is still lower.

"So I think there's at least a valid argument in saying that New Zealand should be allowed to grow clean, green, low-carbon lamb and milk for some of the rest of the world to share."

DAVID WALKER/STUFF Climate Change Minister James Shaw believes the dairy industry is making firm steps in the right direction.

But Benton urges caution and careful analysis of how livestock production is shared around the world.

"Production of meat is polluting – it is creating greenhouse gas," he said. "It is creating negative consequences for the local environments and production of the wrong sort of food is impacting on diets.

While geo-political discussions go on in the background, there are still things New Zealanders can do to make their own small difference in tackling climate change, from being discerning about food to making lifestyle choices over energy consumption.

Reisinger said: "If you are only a consumer of food then options are limited to dietary choices and minimising food waste.

"But many people are farmers or involved in other land-related professions. For those people other options apply, from being the best – the most efficient – farmer they can be, rather than the farmer with the highest total production level, or if not a farmer then engaging in community projects to restore native forests on marginal lands, or perhaps helping the restoration of wetlands."

The Government has also signalled its intentions to bring down emissions from agriculture.

James Shaw, the Minister for Climate Change, announced this week a temporary committee to get a head-start on addressing the problem before a climate change commission is established under the forthcoming Zero Carbon Act.

Politicians will also examine whether agriculture should be included in an emissions trading scheme.

Speaking after the opening of the IPCC meeting on Monday, Shaw said he believes the way New Zealand manages its relationship between agriculture and emissions can provide a "huge economic opportunity" for the country.

He said: "The Dutch are exporting their expertise in urban adaptation to sea level rise, which they've developed over the course of hundreds of years.

"I think that New Zealand has a real opportunity to develop an expertise in net zero emissions agriculture and then to export that to the rest of the world."

Shaw said it is vital for the country to demonstrate leadership and produce actual reductions in domestic GHG emissions if it is to have credibility as a green nation.

But he believes the dairy industry has already recognised the need for change and is making firm steps in the right direction.

And he is adamant New Zealand can still thrive economically while making positive changes.

He said: "The problem that I think we've had for the last 30 years when we've been talking about climate change is that we've tended to think about it as a sunk cost – we say, 'It's going to cost a lot of money to change and New Zealand's emissions as part of the global total are quite small, therefore we shouldn't bother, it's too expensive to worry about'.

"Actually, if you re-frame that and say this is an investment and an upgrading of our economy, then we can expect a return on that investment.

"Frankly, the single most important thing that we can do is to work out how to align the economic gain and benefit that we can see out of this with the environmental gain and benefit we can see."

"The problem we've had for the last 30 years is that we've assumed that those two things are pulling in different directions, and that's why we haven't gotten anywhere until now."

The challenge now is how to marry up academic analysis with decisive policy-making and action on the ground – one that each of us must take up if we can even begin to halt that slippery slope to irreversible climate damage.

What is beyond doubt is that the issues are more than food for thought – they demand urgent action from us all.

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