W anjiang WANG

Department of Business and Trade，Southwest University Rongchang Campus，Chongqing 402460，China

1 Introduction

Climate change poses a serious threat to sustainable development of the ecological environment and human society，causing widespread concern in the international community.In 2003，the British government released the Energy White Paper 2003：Our Energy Future-Creating A Low Carbon Economy，first proposing the＂low carbon economy＂concept.The commitment of the London G20 summit in 2009 to economic recovery and low carbon transition，aswell as the controversy of Copenhagen Climate Conference，has promoted the dissemination of the＂low-carbon economy＂conceptworldwide.The academic world has not yet given a uniform definition of＂low-carbon economy＂at present，but based on various definitions，it is generalized thata low-carbon economy（LCE），low-fossil-fueleconomy（LFFE），or decarbonised economy is an economy based on low carbon power sources that therefore hasaminimal outputof greenhouse gas（GHG）emissions into the environment biosphere，but specifically refers to the greenhouse gas carbon dioxide.GHG emissions due to anthropogenic（human）activity are increasingly either causing climate change（globalwarming）ormaking climate change worse.Scientists are concerned about the negative impactsof climate change on humanity in the near future.Nationsmay seek to become low-carbon or decarbonised economies as a partof a national climate changemitigation strategy.A comprehensive strategy to mitigate，if that is possible，climate change is carbon neutrality and geoengineering.The aim ofa LCE is to integrate all aspectsof itself from itsmanufacturing，agriculture，transportation，and power-generation，etc.around technologies that produce energy and materials with little GHG emission，and，thus，around populations，buildings，machines，and devices thatuse those energiesandmaterialsefficient-

ly，and，dispose of or recycle its wastes so as to have aminimal output of GHGs.Furthermore，it has been proposed that tomake the transition to an LCE economically viable we would have to attribute a cost（per unit output）to GHGs through means such as emissions trading and／or a carbon tax.Since agriculture accounts for a substantial proportion of the global fossil energy consumption and it is one of the major sources of greenhouse gas emissions.Meanwhile，crop can absorb and fix the carbon dioxide in the atmosphere through photosynthesis，so it has carbon sequestration function.In the area of agriculture，the promotion of energy-saving and bio-sequestration technologies and development of biomass energy and renewable energy technologies can transform traditional agriculture into the new LCA with new featuresof low energy consumption，low emission and low pollution.

2 Foreign LCA developmentmodel

2.1 Developing LCA development strategyAccording to statistics，there were 25 countries in Europe started to develop or study the national strategy to make agriculture adapt to climate change aswell as the LCA development strategy in 2009.Finland，Spain，F(xiàn)rance，Sweden，the Netherlands，Britain and Norway developed the special development strategy.In addition，Japan issued The 21st New Agricultural Policy in 2008，which proposed the acceleration of flexible use of rural biomass energy.Russia promulgated Agricultural Development，Agricultural ProductMarket Regulation and Rural Development Planning（2008-2012），to support the key linksof LCA and fund the technological innovation related to ecological agriculture.

2.2 Building the carbon tradingmarket platformIn 2003，14 companies and institutions including Ford and DuPont jointly set up the Chicago Climate Exchange，the world's first market transaction platform themembers voluntarily joined.Chicago Climate Exchange is North America's largest and longest running greenhouse gas emission reduction program.At present，there have been more than 200 companies involved in this program，mostly using agriculture carbon sequestration to compensate for the unfinished emission reduction targets.In 2007，1230 farmers registered agriculture carbon sequestration projects in the Chicago Climate Exchange and got the benefits through the implementation of zero tillage.

2.3 Establishing the low carbon measurement standard for agricultureIt isextremely important to establish uniform standards and rules for carbon emission reduction.The United States set up the Environmental Service Standards Committee and established the carbon sequestrationmeasurement standards for agricultural soilmanagement.In June 2007，the USEnvironmental Protection Agency and Duke University jointly issued the Harnessing Farms and Forests in the Low-Carbon Economy（Duke Standard），the world's first checking standard and operatingmanual concerning agricultural carbon emission trading.

2.4 Promoting the field system which can reduce carbon em issionsThe technological innovation and mode transformation of various links of agricultural production can effectively reduce agricultural greenhouse gas emissions.Canada carries out the crop farming reform and implements the mixed crop rotation，thereby reducing carbon dioxide emissions.Australia implements the precision agriculture and use the slow release fertilizer，which greatly improves the nitrogen fertilizer use efficiency and reduces the nitrous oxide emissions.For 66%of livestock greenhouse gas emissions，Australia improves the feed formulation and establishes the biological factories in livestock management，to strengthen the livestock manure recycling.Japan accelerates the pace of improvement in livestock species and grass varieties and strengthens the breeding management to produce better emission reduction efficiency.

2.5 Increasing the agricultural carbon sequestration capacityLCA focuses on giving play to the crop photosynthesis to absorb and fix atmospheric carbon dioxide and seal it in the soil to achieve carbon sequestration function.The United States adopts protective tillage and fallow ground in the farmland under longterm weathering and erosion and re-covers the fallow ground with vegetation to increase the storage capacity of soil organic carbon.Canada uses legumes to reduce nitrogen fertilizer inputs，implementsmoderate rotation between main crops and legumes，and creates temporary vegetation cover between vine crops to reduce nitrous oxide emissions and improve soil carbon sequestration capacity.

2.6 Implementing the agricultural production safety certificationLCA products do not have competitive advantages in production and prices，and the government should make mandatory provisions on agricultural product specification and food standards and guide consumers to change their ideas.In 1997，the European Retailers Association developed the Good Agricultural Practices to clearly define the agricultural product traceability，food safety，environmental protection，laborwelfare and animalwelfare.In addition，it also developed the code of conduct for farmers.These have promoted the development of LCA from all aspects.In 2004，the farming area of organic agriculture of EU was5.4million ha，the farming area of bio-energy crops reached 1.4 million ha，and 0.6 million ha of agricultural land lay fallow.

3 Current situation of agricultural greenhouse gas em issions in China

3.1 Excessive use of chem ical fertilizers leads to an increase in greenhouse gas em issionsChina is a country consuming the largest amount of chemical fertilizer in the world.Recent studies show that the average application rate of chemical fertilizer per unit area of arable land in China has risen to 434.3 kg／ha，but the utilization rate is only 40%.The main raw material for the production of synthetic ammonia in China is coal，and 1 t of ammonia will cause 3.4 t of carbon dioxide emissions，resulting in the release of a large amount of carbon dioxide during the fertilizer production.Meanwhile，improper fertilization also exacerbates the greenhouse effect.

3.2 High consumption of fossil fuels causes high greenhouse gas em issionsIn recent years，the data show that the consumption elasticity of coal，oil and electricity in the agricultural sector is greater than 1，and the energy use efficiency in agricultural production declines.In addition，the share of coal in China's agricultural energy consumption constantly rises，and the carbon emissions are higher than emissions of other energy resources.In 2007，the coal consumption in farming，forestry，animal husbandry，fishery and water conservancy causes nearly 1673 t of carbon emissions.

3.3 The agricultural carbon em issions are significantly correlated w ith consumption of chem ical fertilizers and energy

With the steady increase of total agricultural output value in China，the application rates of agricultural chemical fertilizer and total agricultural energy consumption have showed a upward trend，which gradually increases the agricultural carbon emissions.From the average annual growth rate during 1990-2006，the average annual growth rate of total agricultural output value，chemical fertilizer application rate and total agricultural energy consumption was6.2%，3.5%and 3.2%，respectively.By comparison，it is found that the growth rate is strongly synchronized，and the fluctuation in increase of carbon emissions ismost sensitive.

4 Recommendations for LCA development in China

4.1 Strengthening macroeconom ic policy guidance（i）Strengthening the leading role of planning.It is necessary to include LCA development in themedium-term and long-term development planning，make the management departments responsible for the related organization and coordination work，and include the LCA development in the performance appraisal.（ii）Improving policies and regulations.It isnecessary to study the corresponding subsidy system to encourage farmers and businesses to reduce chemical fertilizer application，and establish greenhouse gas reduction certification mark system.

4.2 Transform ing the agriculture developmentmode（i）Implementing conservation tillage.It is necessary to vigorously promote conservation tillage which can retain and conserve soil moisture，improve soil fertility and save agricultural fuels.Through the implementation of returning straw to farmland can effectively preventand control straw burning and reduce carbon dioxide emissions.（ii）Optimizing the energy structure.It is necessary to reduce the fossil energy use in agricultural production and make full use of solar，wind and geothermalenergy and other renewable energy sources；it is also necessary to vigorously promote the use of biomass，encourage the development of rural household biogas，and accelerate the construction ofwaste incineration power plant.（iii）Developing circular agriculture and ecological agriculture.It is necessary to promote interplantingbased three-dimensional crop planting mode，and increase the application of organic fertilizer to protect farmland ecosystems.

4.3 Promoting carbon sequestration technology（i）Improving the carbon-sequestrating agricultural varieties.China needs to develop or introduce the drought-resistant and pest-resistant crop varieties aswell as new crops thathave strong ability to absorb greenhouse gases.（ii）Developing agricultural carbon sequestration technologies.It is necessary to protect the existing carbon pools and use the ecosystem management techniques to strengthen the sustainable management of farming，animal husbandry，forestry and fishery，in order tomaintain the long-term carbon sequestration capacity of ecosystems.（iii）Rationally applying chemical fertilizers.It isnecessary to implementscientific fertilization and increase the application oforganic fertilizer to reduce nitrous oxide emissions；use scientific irrigation technology to reducemethane emissions from rice paddies；carry out biogas utilization and control the growth ofanimalhusbandrymethane emissions.（iv）Updating the agriculturalmachinery and technology.It is necessary to eliminate the backward agricultural and fishingmachinery and use advanced diesel fuel-saving technology to reduce the diesel fuel consumption.

4.4 Establishing the interestsguidingmechanism（i）Setting up the carbon trading platform.It is necessary to establish the carbon tradingmarket platform，build professional organizations，setup technical standards，and improve the supporting environmental capacity management and ecological compensation mechanisms.（ii）Achieving the sharing of interestsamong farmers.The formation of a reasonable interests sharing mechanism for farmers is an importantway to promote the smooth implementation of agriculture carbon sequestration projects.After signing the carbon sequestration project order，the farmers'specialized cooperative economic organizations should be directly involved in the distribution of benefits from carbon trading to achieve efficiency increase.