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PubMed | University of Minnesota, Center for International Forestry Research, Scottish Food Security Alliance Crops, Pacific Northwest National Laboratory and 14 more.
Type: Journal Article | Journal: Global change biology | Year: 2016

More than 100 countries pledged to reduce agricultural greenhouse gas (GHG) emissions in the 2015 Paris Agreement of the United Nations Framework Convention on Climate Change. Yet technical information about how much mitigation is needed in the sector vs. how much is feasible remains poor. We identify a preliminary global target for reducing emissions from agriculture of ~1GtCO

Smith P.,University of Aberdeen | Haberl H.,University of Vienna | Popp A.,Potsdam Institute for Climate Impact Research | Erb K.-H.,University of Vienna | And 24 more authors.
Global Change Biology | Year: 2013

Feeding 9-10 billion people by 2050 and preventing dangerous climate change are two of the greatest challenges facing humanity. Both challenges must be met while reducing the impact of land management on ecosystem services that deliver vital goods and services, and support human health and well-being. Few studies to date have considered the interactions between these challenges. In this study we briefly outline the challenges, review the supply- and demand-side climate mitigation potential available in the Agriculture, Forestry and Other Land Use AFOLU sector and options for delivering food security. We briefly outline some of the synergies and trade-offs afforded by mitigation practices, before presenting an assessment of the mitigation potential possible in the AFOLU sector under possible future scenarios in which demand-side measures codeliver to aid food security. We conclude that while supply-side mitigation measures, such as changes in land management, might either enhance or negatively impact food security, demand-side mitigation measures, such as reduced waste or demand for livestock products, should benefit both food security and greenhouse gas (GHG) mitigation. Demand-side measures offer a greater potential (1.5-15.6 Gt CO2-eq. yr-1) in meeting both challenges than do supply-side measures (1.5-4.3 Gt CO2-eq. yr-1 at carbon prices between 20 and 100 US$ tCO2-eq. yr-1), but given the enormity of challenges, all options need to be considered. Supply-side measures should be implemented immediately, focussing on those that allow the production of more agricultural product per unit of input. For demand-side measures, given the difficulties in their implementation and lag in their effectiveness, policy should be introduced quickly, and should aim to codeliver to other policy agenda, such as improving environmental quality or improving dietary health. These problems facing humanity in the 21st Century are extremely challenging, and policy that addresses multiple objectives is required now more than ever. © 2013 John Wiley & Sons Ltd.

Reisinger A.,New Zealand Agricultural Greenhouse Gas Research Center | Meinshausen M.,Potsdam Institute for Climate Impact Research | Manning M.,Victoria University of Wellington
Environmental Research Letters | Year: 2011

Global warming potentials (GWPs) are the metrics currently used to compare emissions of different greenhouse gases under the United Nations Framework Convention on Climate Change. Future changes in greenhouse gas concentrations will alter GWPs because the radiative efficiencies of marginal changes in CO2, CH4 and N2O depend on their background concentrations, the removal of CO2 is influenced by climate-carbon cycle feedbacks, and atmospheric residence times of CH4 and N 2O also depend on ambient temperature and other environmental changes. We calculated the currently foreseeable future changes in the absolute GWP of CO2, which acts as the denominator for the calculation of all GWPs, and specifically the GWPs of CH4 and N2O, along four representative concentration pathways (RCPs) up to the year 2100. We find that the absolute GWP of CO2 decreases under all RCPs, although for longer time horizons this decrease is smaller than for short time horizons due to increased climate-carbon cycle feedbacks. The 100-year GWP of CH4 would increase up to 20% under the lowest RCP by 2100 but would decrease by up to 10% by mid-century under the highest RCP. The 100-year GWP of N2O would increase by more than 30% by 2100 under the highest RCP but would vary by less than 10% under other scenarios. These changes are not negligible but are mostly smaller than the changes that would result from choosing a different time horizon for GWPs, or from choosing altogether different metrics for comparing greenhouse gas emissions, such as global temperature change potentials. © 2011 IOP Publishing Ltd.

Rogelj J.,International Institute For Applied Systems Analysis | Rogelj J.,ETH Zurich | Reisinger A.,New Zealand Agricultural Greenhouse Gas Research Center | McCollum D.L.,International Institute For Applied Systems Analysis | And 5 more authors.
Environmental Research Letters | Year: 2015

Global-mean temperature increase isroughly proportionalto cumulative emissions of carbon dioxide (CO2). Limiting global warming toany level thus implies a finite CO2budget. Due to geophysical uncertainties, the size of such budgets can only be expressed in probabilistic terms and is further influenced by non-CO2emissions. We here explore how societal choices related to energy demand and specific mitigation options influence the size of carbon budgets for meetingagiven temperature objective. We find that choices that exclude specific CO2mitigation technologies (like Carbon Capture and Storage) result in greater costs, smaller compatible CO2budgets until 2050, but larger CO2budgets until 2100. Vice versa, choices that lead to a larger CO2mitigation potential result in CO2budgets until 2100 that are smaller but can bemet at lower costs. Inmost cases, these budget variations canbe explained bythe amount of non-CO2mitigation that iscarried out in conjunction with CO2,and associated global carbon prices that also drive mitigation of non-CO2gases. Budget variations are of the order of 10% around their central value. In all cases, limiting warming to below 2 °Cthus still implies that CO2emissions needto bereduced rapidly inthe coming decades. © 2015 IOP Publishing Ltd.

Attwood G.T.,Agresearch Ltd. | Attwood G.T.,New Zealand Agricultural Greenhouse Gas Research Center | Altermann E.,Agresearch Ltd. | Kelly W.J.,Agresearch Ltd. | And 5 more authors.
Animal Feed Science and Technology | Year: 2011

Methane emissions from ruminant livestock is generated by the action of methanogenic archaea, mainly in the rumen. A variety of methanogen genera are responsible for CH4 production, including a large group that lacks cultivated representatives. To be generally effective, technologies for reducing ruminant CH4 emissions must target all rumen methanogens to prevent any unaffected methanogen from expanding to occupy the vacated niche. Interventions must also be specific for methanogens so that other rumen microbes can continue normal digestive functions. Thus a detailed knowledge of the diversity and physiology of rumen methanogens is required to define conserved features that can be targeted for methanogen inhibition. Genome sequencing projects are underway in New Zealand and Australia on several ruminal methanogen groups, including representatives of the genera Methanobrevibacter, Methanobacterium, Methanosphaera, Methanosarcina, and the uncultured group, Rumen Cluster C. The completed Methanobrevibacter ruminantium genome and draft sequences from other rumen methanogen species are beginning to allow identification of underlying cellular processes that define these organisms, and is leading to a better understanding of their lifestyles within the rumen. Although the research is mainly at the explorative stage, two types of opportunities for inhibiting methanogens are emerging, being inactivation of conserved methanogen enzymes by screening for, or designing, small inhibitors via a chemogenomics approach, and identifying surface proteins shared among rumen methanogens that can be used as antigens in an anti-methanogen vaccine. Many of the conserved enzyme targets are involved in energy generation via the methanogenesis pathway, while the majority of the conserved surface protein targets are of unknown function. An understanding of the expression and accessibility of these targets within methanogen cells and/or microbial biofilms under ruminal conditions will be required for their development as CH4 production mitigations.This paper is part of the special issue entitled: Greenhouse Gases in Animal Agriculture - Finding a Balance Between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors: K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson. © 2011 Elsevier B.V.

Clark H.,New Zealand Agricultural Greenhouse Gas Research Center | Kelliher F.,Agresearch Ltd. | Pinares-Patino C.,Agresearch Ltd.
Asian-Australasian Journal of Animal Sciences | Year: 2011

Almost half of New Zealand's greenhouse gas emissions arise from agriculture and enteric methane (CH4) emissions arising from ruminant animals constitute 30% of total CO2-e emissions. Enteric CH4 emissions have increased by 9% since 1990. Extensive research has been undertaken to develop reliable methods for measuring enteric CH4 emissions. New Zealand studies using the SF6 tracer technique suggest that on average this technique yields similar values to the 'gold' standard of calorimetry, but with a larger variance. National inventory estimates based on results obtained using the SF6 technique will therefore overestimate the uncertainty. Mitigating emissions can be achieved by changing feed type but there are practical and cost barriers to the use of alternative feeds. Forages containing condensed tannins do reduce emissions but are agronomically inferior to the forages currently used. Rumen additives have shown some success in-vitro but results from in-vivo trials with both monensin and fumaric acid have been disappointing. The development of methods for directly manipulating rumen microorganisms are at an early stage and work to develop vaccines that can inhibit methanogenesis has yielded mixed results. The successful identification of sheep with contrasting CH4 yields raises the possibility that, in the long term, a breeding approach to CH4 mitigation is feasible.

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