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One hundred and thirty greenhouse gas (greenhouse gas) mitigation focussed scientists, policy makers and industry representatives made the trip to the Palmerston North Convention Centre to attend the first joint NZAGRC-PGgRc New Zealand Agricultural greenhouse gas Mitigation Conference. 
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The day proved an excellent opportunity to reflect on the roles that both science and politics play in the drive to reduce agriculture&#8217;s environmental footprint in the face of climate change, and the progress that we have made.
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The day included 13 presentations from New Zealand policy makers, industry representatives, and both international and domestic scientists.
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Sir Peter Gluckman, Chief Science Advisor to the Prime Minister of New Zealand, opened the conference with a stark reminder that &#8220;while many would prefer not to have to address the challenge of climate change, we do not have that luxury&#8221;. He highlighted that it&#8217;s clear that we need to take action and should not put our collective &#8220;heads in the sand&#8221;. He indicated that politicians and scientists need to work closely together, with science providing the knowledge required to understand future choices and trade-offs. &#8220;There will be hard choices and science and technology will play a critical role in how, in coming decades, society makes these choices and reaches the essential compromises that protect our social and economic well-being while ensuring that the planet that can support our great-grandchildren.&#8221;
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David Wansbrough, Director Resource Policy (MPI), presented an overview of New Zealand&#8217;s greenhouse gas emissions since 1990 and a breakdown of those from the agricultural sector. He highlighted that the total greenhouse gasgreenhouse gases have been largely stable since 2005, mainly due to economic factors, and that whilst greenhouse gasgreenhouse gases have gone up by 21% since 1990, the economy has grown by ~80% in the same time period. A notable point is that New Zealand&#8217;s emission profile is significantly different to other Annex 1 countries.. New Zealand&#8217;s domestic climate change policy is being looked at in 2015 with three objectives: (i) to reduce global emissions; (ii) encourage responsible economic growth; and (iii) to adapt to climate and international actions. David also spoke about the need to encourage farmers to adopt current best practices and technologies to reduce their emissions and to think about shifting New Zealand agriculture from a production to a value focus. 
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Reiterating Sir Gluckman&#8217;s opening comments, Andy Reisinger, Deputy Director (NZAGRC), began with a very clear message that the global community needs to take action now in order to limit warming to two degrees. &#8220;If agriculture doesn&#8217;t take any effective action, we would have to actively remove carbon dioxide from the atmosphere before 2050 to remain within the 2&#176;C limit.&#8221; Taking mitigation from the agricultural sector seriously globally would allow just a little more space for global carbon dioxide emissions and keep the 2 degree goal feasible. Agriculture has already been reducing its greenhouse gas emissions by farming more efficiently, and if best practice were adopted by all farmers, this could make further significant reductions. More efficient farming also reduces emissions per unit of product, however this alone will not decrease total emissions. New agricultural technologies can be employed to drop emissions, and Andy indicated that these would be covered in later presentations. Additionally he noted that demand management will need to play a role in meeting the 2&#176;C goal. Reducing the current volume of global food waste (30-40%) and promoting dietary shifts towards grain from meat could provide potentially large gains. This was covered later by Professor Pete Smith.
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Jo Tyndall, New Zealand&#8217;s Climate Change Ambassador, provided a fascinating insight into the global political landscape in this area. At the end of this year, 40,000 delegates are expected in France and the hope is that a new global agreement will be finalised. With respect to this new legal agreement, Jo expects that it will be fairly basic. There have been four years debate about the form of the agreement, and it looks as if it will be different from the Kyoto Protocol to ensure it includes all parties. There are likely to be a number of obligations around reporting, but few hard penalties, rather a &#8220;name and shame&#8221; approach will be adopted. It is unlikely that there will be an agriculture section in the agreement, as it is just not a prominent issue for the other developed countries and it is a very sensitive issue for many developing countries. However agriculture may be referenced in order to provide an opening for the future. At a country level, Intended Nationally Determined Contributions (INDCs) or reduction targets, need to be tabled well before the Paris meeting. In many ways, this is being left up to individual countries who will be setting their targets before the &#8220;rules of the legal game&#8221; have been finalised. However, countries need to demonstrate that their new INDCs have progressed beyond their previous commitments and the US and China, who account for &#62;50% of global emissions, have already set ambitious targets, which is encouraging to others. There is growing pressure for the remaining big emitters to get their INDCs on the table and New Zealand is aiming to set its target by the mid-June deadline. Unfortunately, it is highly likely that the targets that are tabled will fall short of the 2&#176;C target. Therefore, there will be a need to set long term pathways. New technologies will be valuable tools in the medium to long term and adaptation planning is likely to become more mainstream. Overall, Jo concludes that she is optimistic that there will be a new global agreement by the end of 2015.
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Rick Pridmore, Strategy and Investment Leader for Sustainability (DairyNZ), provided the conference delegates with an overview of the New Zealand investment landscape for reducing agricultural greenhouse gasgreenhouse gases. He highlighted that New Zealand is putting in a great deal of effort into reducing agricultural greenhouse gas emissions and conducting top class science, which in many areas is nearing proof of concept. Rick also emphasised that there are a significant number of funders in this area covering government, industry, the universities and CRIs. At the research end, the plans and investment are fairly coordinated, in main due to the actions of the NZAGRC and PGgRc, however at the applied end there is room for improvement. This is primarily due to the fact that there are many issues to be considered on-farm and greenhouse gas emissions are just one of the factors in the mix. New Zealand farm greenhouse gas emissions intensity has been decreasing at approximately 1% per year due to increased efficiency and the goal is to keep this rate going into the future, but on top of that, reduce emissions intensity by a further 1.5% per year by additional technological options. This 1.5% may be achieved by step changes between 2020 and 2050, rather than a gradual decline. Rick then outlined the four key research aims of the NZAGRC-PGgRc methane programme: Animal Selection; Low greenhouse gas Feeds; Vaccine; and Inhibitors. In the last four months, 5 lead inhibitor compounds have been shown to reduce methane emissions from animals by 30-90%, which is very exciting. Once proof of concept has been firmly established, commercial partners will be sought to take prototype vaccines and inhibitors through into the hands of the farming community. Rick concluded by pointing out that 10 years ago, the task of reducing agriculture&#8217;s greenhouse gas emissions seemed enormous, and that we should all be proud that we are nearly there. 
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Pete Smith, Professor of Soils &#38; Global Change at Aberdeen University, then spoke on managing the demand for food in order to reduce greenhouse gas emissions. He clearly demonstrated that despite policies and global agreements, greenhouse gas emissions are still increasing and that agriculture, forestry and other land-use accounts for about a quarter of these. Over the past decade, agricultural emissions have increased but emissions intensity has decreased, primarily as Pete states because &#8220;we are getting better at doing agriculture&#8221;. However, the data shows clearly that there are big differences in the greenhouse gas intensities related to the production of different foods. The emissions from the production of meat, and growing vegetables out of season in glasshouses, are significantly higher than those from producing pulses for example. Considering the demand side of the equation, and modelling what would happen to total agricultural greenhouse gas emissions if there were significant dietary changes, is a growing area of research with a number of recent high profile papers. These all indicate that fewer animal products in global diets would allow everyone to be fed, and leave more land available for energy and nature conservation. Pete indicated that current practices need reform and relying exclusively on sustainable intensification will still not reduce greenhouse gases to the extent required. It will not be easy to encourage demand side changes for a whole raft of reasons, but it is something which is becoming a more mainstream issue. It&#8217;s important to remember that social norms have changed significantly in living memory and that they can change again. It is possible that New Zealand has an opportunity to provide high-quality, grass fed meat to fill a niche for a future society which eats meat as a more occasional, luxury, high premium treat.
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Pete&#8217;s talk gave much food for thought and the opportunity for many interesting discussions over the lunch break. Following the break, the presentations delved into the science currently underway in more detail.
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Peter Janssen, Principal Scientist (AgResearch), gave an interesting overview of how ruminants produce methane and the strategies that are being investigated for reducing, or even eliminating, this methane. Feeds which lead to reduced methane production have been studied and the science team now have a fairly good understanding of why feeding brassicas lowers methane emissions. It is due to changes in the rumen bacterial community. Breeding for low methane animals is also progressing well and a number of reasons for the differences in emissions have been discovered. Vaccine and inhibitor development involves in-depth knowledge of the rumen methanogens in order to decide how to target and knock them out. Genomic studies have aided this work and also investigating rumen contents from around the world has helped to identify the prime candidates. The vaccine and inhibitor programmes are currently in the midst of animal trials and, given recent positive results, the teams are hopeful that proof of concept will be established very soon.
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John McEwan, Principal Scientist (AgResearch), then provided further detail about the low methane emitting sheep breeding programme. There is excellent rationale for this strategy given that for most farmed species (plants and animals) genetics contributes around 50% of the farm system economic improvement. Genetic change is also extremely low cost, permanent and cumulative. The programme has established low and high emitting sheep lines and studied them intensely. The data shows that methane emissions from the low emitters are heritable and repeatable, with the low emitting sheep having similar or higher productivity, smaller rumens, different rumen microbial communities and lower VFA concentrations in the rumen. The programme has also investigated different options for measuring animal methane emissions, given than the respiration chamber method is time consuming and expensive. Alternative cheaper and more flexible options have been identified. The next step for this work is to investigate how best to incorporate the low greenhouse gas trait into the New Zealand sheep industry breeding programmes. The science team will then work on transferring their learnings to dairy cattle and deer.
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Tim McAllister, Principal Scientist at Agriculture and Agri-Food Canada, presented an international perspective on the methane research being conducted globally. There is research being conducted to investigate both (i) technologies to reduce emissions and (ii) ways to increase efficiency across the globe. It appears that New Zealand has one of the most focused and coordinated programmes. Tim then focussed on a couple of the more promising strategies including the methane inhibitor, 3-NOP, being developed by DSM Nutritional Products in Switzerland. This feed additive has shown a 60% reduction in methane when mixed with feed, but has to be fed continuously to achieve this reduction. The company are currently looking for any associated productivity changes that may be attractive to farmers. Nitrate is also being investigated as a feed additive. This has the potential to be toxic if fed in high quantities, therefore scientists are looking into possible encapsulated formulations to ensure slow release of the product. Probiotics are also an interesting area of research, with more studies required. Tim concluded his talk by indicating that there is still a lot to learn about the microbes in the rumen and what they are actually doing. Maybe we need to rewrite some of the textbooks based on new data that is emerging. He also proposed a suitable definition for sustainability &#8211; &#8220;when everyone is happy&#8221;. Greenhouse gas emissions are just one part of the whole picture of environmental, social and economic factors when it comes to &#8220;sustainable&#8221; future agriculture.
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Cecile de Klein, Principal Scientist (AgResearch), provided an overview of the nitrous oxide (nitrous oxide) research being conducted in New Zealand, with a focus on plant and animal interventions. She reminded the audience that animal urine is by far the largest source of nitrogen in the New Zealand farming system and that there are a number of key &#8220;intervention points&#8221; in the nitrogen cycle to target when trying to reduce nitrous oxide. Nitrate leaching is also a big issue, so any technology or intervention to reduce nitrous oxide emissions needs to be win:win with respect to leaching. Cecile outlined three options for reducing nitrous oxide: (1) reduce nitrogen excretion; (2) increase nitrogen uptake by plants; and (3) influence the plant effects on soil nitrogen processes. Starting with number three, New Zealand researchers are investigating the effects of pasture species and cultivars on nitrous oxide emissions. They have shown variability in pot trials and larger field trials are now underway. Researchers are also studying the effects of brassicas on nitrous oxide emissions and effects of diet on animal urine composition. For number 2, it appears that planting Italian Ryegrass, which continues to grow in the colder months of the year may have some benefits. When looking at reducing nitrogen excretion per urination, it appears that the quantity of nitrogen applied seems to be more important that the species that it is being applied to. The knowledge that we already have about &#8220;high risk&#8221; times for nitrous oxide emissions, urine being deposited under wet weather conditions with high pasture damage, is being incorporated into on-farm decision management tools. These may be helpful to farmers, but they will need to be able to assess the state of their paddocks easily. With respect to irrigation, it appears that if grazing is delayed until 6 days after irrigation, nitrous oxide emissions can be reduced by ~40%. Researchers continue to investigate win:win solutions and are working closely across organisations and programmes to achieve this.
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Frank Kelliher, Principal Scientist (AgResearch) and Professor (Lincoln University), covered the New Zealand work on soil carbon. He explained the concept that, like planting trees, increasing soil carbon stocks can &#8220;offset&#8221; greenhouse gas emissions and that if New Zealand could increase soil carbon stocks by 1 t of carbon/ha over 1 million ha, this could offset the rise in greenhouse gasgreenhouse gases since 1990. He also pointed out though, like trees, soil carbon can take decades to accumulate but this gain can be reversed quickly if land-management practices change again. Additionally it is difficult to measure and often &#8220;you don&#8217;t know what you&#8217;ve got until it&#8217;s gone&#8221;. Research into the New Zealand soil carbon situation has shown that although soil carbon stocks are high in many areas of New Zealand, there is strong evidence that more soil carbon could be stored. How can this be achieved? The team is running a major field trial at Troughton farm that is looking at farm management practices and determining the effects on soil carbon. Preliminary data suggests that pasture renewal depletes soil carbon, but that the lost soil carbon is &#8216;restored&#8217; within about a year. Pasture diversity also appears to increase soil carbon levels. Additionally, modelling indicates that supplementary feeding may increase soil carbon levels as more carbon is being applied to the soil via excreta. The effects of irrigation on soil carbon stocks are uncertain currently. 
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Keith Goulding, Professor (Rothamsted Research, UK), provided an international perspective on nitrous oxide and soil carbon research. With respect to nitrous oxide, he highlighted work on investigating the genes related to nitrous oxide emissions and noted that there is one clear message for reducing nitrous oxide, avoid excess N. The IPCC has recently indicated that biochar may have a part to play in reducing agricultural greenhouse gases and a number of research groups are searching for natural nitrification inhibitors. Keith indicated that soil carbon needs to be considered carefully. Data were published that could be interpreted to imply that grasslands could continue to sequester carbon indefinitely. However, this has been refuted and there is agreement that for a specific system there is an upper limit for carbon, and he noted the interesting work in New Zealand in this area. Deeper rooting species are being investigated as a means of delivering carbon to a greater depth in the soil. This hasn&#8217;t been proven yet, but it appears that the deeper roots also reduce run off significantly and thus could offer multiple benefits. Keith concluded with a warning that too much emphasis on soil carbon sequestration could risk taking our eyes off more important climate change threats, such as land clearance and wetland drainage. He also stressed that our priorities should be promotion of good land stewardship and integrated solutions that consider the whole system and do not merely &#8220;pollution swop&#8221;. 
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Robyn Dynes, Principal Scientist (AgResearch), had the last speaking slot of the day. Following on from Keith&#8217;s conclusions that we shouldn&#8217;t look at different aspects of a system in isolation, Robyn outlined her team&#8217;s plans for studying the &#8220;business unit of New Zealand farming&#8221; &#8211; the whole farm. The programme will build onto existing initiatives in the dairy and sheep and beef sectors to understand the impact of current practices on emissions intensity and to identify the win:wins. A lot of modelling has been done in the past and now is the time to translate this into on-farm measurement and dialogue with the farmers involved. Previous work has demonstrated that there are some farmers that have significantly lower greenhouse gas emissions intensities (and sometimes even absolute emissions) than others. The efficient farms also tend to have higher profit margins. The challenge is to see whether theory and practice align, and if not, why not? The team has just started taking measurements, is enthusiastic about the new programme and looks forward to sharing its findings in the future.
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Tim McAllister then returned to the stage to provide a few final comments. He noted that the world of science seemed to be moving towards &#8220;grand challenges&#8221; and, in his mind, there was no greater challenge than climate change and it is one that we will be facing for a long time to come. As Sir Gluckman stated at the start of the day, research is important to guiding and informing future choices. Tim also commented that the value of knowledge is often underestimated and the work being described today may have implications which range a long time into the future. He concluded the day by congratulating the agricultural greenhouse gas researchers for all their progress to date. 
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