Climate and Energy
Due to the capacity of plants to absorb the greenhouse gas CO2 and soils to sequester carbon, agriculture could, in the long term, theoretically feed us in a climate neutral way and, in the short term, even sequester more CO2 than it emits. Instead, the agricultural sector is one of the main sources of anthropogenic greenhouse gas emissions accounting for more than 10 gigatons of CO2 equivalents. Almost half of these emissions result from land use changes due to the conversion of forests into arable or grazing land, as well as the drainage of peats and biomass fires. The other half stems from agriculture. Extremely potent greenhouse gases such as nitrous oxide result from the decomposition of mineral fertilizer, as well as methane from rice production and the digestive process of ruminants in livestock farming. Over the past 50 years, global emissions from agriculture have doubled."Agriculture contributes to climate change in several major ways including:
• Land conversion and plowing releases large amounts of stored carbon as CO2 from vegetation and soils. About 50% of the world's surface land area has been converted to land for grazing and crop cultivation resulting in a loss of more than half of the world's forests.
• Deforestation and forest degradation releases carbon through the decomposition of aboveground biomass and peat fires and decay of drained peat soils.
• Carbon dioxide (CO2) and particulate matter are emitted from fossil fuels used to power farm machinery, irrigation pumps, and for drying grain, etc., as well as fertilizer and pesticide production.
• Nitrogen fertilizer applications and manure applications as well as decomposition of agricultural wastes results in emissions of nitrous oxide (N2O).
• Methane (CH4) is released through livestock digestive processes and rice production.
• Altered radiative fluxes and evaporation from newly bare soils.
• Increased geographical distance between producer and consumer, together with regional agricultural specialization, has resulted in greater energy use for transportation." (Synthesis, p. 46-47)The latest report from the IPCC attributes 24% of global emissions directly to agriculture and land use. This share – but not the total amount of emissions from agriculture – has decreased compared to the previous IPCC assessment the IAASTD drew upon mainly due to higher emissions in the energy sector. However, if the emissions the IPCC ascribes to other sectors are also included, for example from fertilizer production, energy used to power tractors and irrigation pumps, as well as emissions from the processing of food, its transport, storage, cooling and disposal, an enormous share of emissions depends on the way we farm and eat. Agriculture therefore plays a crucial role if the target of limiting global warming to well below 2°C above pre-industrial levels is to be achieved.
Savings potentials and storage capacity
The climate footprints from different agricultural and food systems vary enormously."The highest emissions of greenhouse gases from agriculture are generally associated with the most intensive farming systems." (Synthesis, p. 47) In general, labor-intensive small-scale farming is better for the climate than industrial monocultures. Food production for local markets and direct consumption has a lower climate impact than a system with complex transport, processing and cold chains. The IAASTD sees the greatest potential in a more climate-friendly form of soil management: Arable land must not lie fallow and a permanent vegetative soil cover should be maintained. Tillage and the depth of plowing have to be reduced to a minimum. The systematic build-up of organic matter will increase the carbon-storage and water holding capacity, as well as the fertility of the soil at the same time. For this purpose, crop residues should be tilled into the ground instead of leaving them for decomposition at the surface or burning them. The integration of trees into farming through agroforestry systems could also make an important contribution."Some "win-win" mitigation opportunities have already been identified. These include land use approaches such as lower rates of agricultural expansion into natural habitats; afforestation, reforestation, increased efforts to avoid deforestation, agroforestry, agroecological systems, and restoration of underutilized or degraded lands and rangelands and land use options such as carbon sequestration in agricultural soils, reduction and more efficient use of nitrogenous inputs; effective manure management and use of feed that increases livestock digestive efficiency." (Synthesis, p. 9)In the end, the capacity of different soils to sequester carbon is of course limited. The actual prevention of greenhouse gas emissions is inevitable. The most important measures to achieve this are reducing the use of mineral fertilizer and substituting chemical fertilizer with green manure and organic matter. Further saving potential lies in the optimization of cultivation methods, irrigation systems and the keeping and feeding of livestock as well as using natural pest control instead of chemical herbicides and insecticides. Deforestation must be stopped and under-utilized or degraded land should be reforested. The drainage of moors and peat soils, which sequester large amounts of carbon, must be avoided and reversed. >>more
Facts & Figures
Agriculture and food production are major drivers of climate change: Agriculture, forestry and other types of land use accounted for 23% of human greenhouse gas emissions during 2007-2016. The sector was responsible for 13% of CO2, 44% of methane and 82% of nitrous oxide emissions from human activities globally. If emissions associated with pre- and post-production activities in the global food system are included, the estimated share in global anthropogenic emissions is 21-37%.
In 2022, global greenhouse gas emissions amounted to 57.4 gigatonnes of carbon dioxide equivalent (GtCO2e). Energy supply was the largest source of emissions at 20.9 GtCO2e (36%), followed by industry (14.4 GtCO2e or 25%), agriculture and land use, land-use change and forestry (10.3 GtCO2e or 18%), transport (14%) and buildings (6.7%). If all countries fully implement their emission cut pledges, global temperatures would rise by 2.9°C until 2100. If they fully implemented additional measures (conditional NDCs), the temperature rise could be limited to 2.5°C above pre-industrial levels. In order to get on track for the 2°C and 1.5°C goals of the Paris Agreement, predicted 2030 greenhouse gas emissions would need to be cut by 28% and 42 % respectively.
In 2017, the amount of greenhouse gases in the atmosphere surged to a new record. Carbon dioxide emissions reached 405.5 parts per million, up from 400 ppm in 2015. Atmospheric methane reached a new high of about 1859 parts per billion (ppb) - about 60% comes from human activities like cattle breeding, rice agriculture and landfills. The burden of nitrous oxide was 329.9 ppb, anthropogenic sources include biomass burning and fertilizer use. These values of CO2, CH4 and N2O constitute, respectively, 146%, 257% and 122% of pre-industrial (before 1750) levels.
Total greenhouse gas emissions in the EU (excluding Land Use, Land Use Change and Forestry) amounted to 4,333 million tonnes CO2 equivalent (MtCO2e) in 2017. The agricultural sector produced 440 MtCO2e, accounting for 10% of total EU-28 emissions. CH4 emissions from enteric fermentation from cattle and direct N2O emissions from agricultural soils make up 38% and 31% respectively of total agricultural emissions. Germany and France together produced 32% of agricultural emissions.
Each year, 30% of global food production - almost 1.3 billion tonnes - is lost after harvest or wasted in retail and households. The direct economic cost of food wastage is $750 billion in terms of producer prices. Environmental costs add another $700 billion. The carbon footprint of wasted food is 3.3 GtCO2e (without emissions from land use change). The global blue water footprint of food wastage is about 250 km³. Produced but uneaten food vainly occupies almost 1.4 billion hectares of land.
In the EU, food waste along the supply chain is estimated at 89 million tonnes or 180 kg per person per year. Households produce the largest share of EU food waste (42%), followed by agriculture/food processing (39%), food service/catering (14%), and retail/wholesale (5%). This calculation excludes agricultural food waste, which may amount to a similar volume.
In the EU, food waste along the supply chain is estimated at 88 million tonnes or 173 kg per person per year. The total amount of food produced in EU for 2011 was around 865 kg per person. This means that 20% of the food produced is being wasted, with associated costs estimated at 143 billion euros. According to the FUSIONS EU project, households produce the largest share of EU food waste (53%), followed by processing (19%), food service (12%), production (11%) and retail/wholesale (5%).
The livestock sector plays an important role in climate change. Livestock are responsible for 6 to 32% of greenhouse gases (Meat Atlas, p. 34), depending on whether the measurement is based only on direct emissions or includes emissions from the production of feed, fertiliser and pesticides, as well as forest clearance to grow soybeans. According to the FAO, the livestock sector emits 7.1 GtCO2-eq per year, representing 14.5% of all human-induced emissions.
Civil society organisations have voiced deep concerns about the growing influence of the concept of “Climate-Smart Agriculture” and urged decision-makers to support agroecology instead. In a joint statement, an international coalition of 355 civil society groups and farmers’ organisations warned that CSA is falling short of ensuring food and nutrition security, undermining the transformation of current food and agricultural systems that is urgently needed.
Food systems contribute 19%–29% of global anthropogenic greenhouse gas (GHG) emissions, releasing 9,800–16,900 megatonnes of carbon dioxide equivalent (MtCO2e) in 2008. Agricultural production, including indirect emissions associated with land-cover change, contributes 80%–86% of total food system emissions, with significant regional variation.
Organic agriculture provides environmental benefits through the sequestration of atmospheric carbon in soil organic matter. Soil organic carbon stocks were 3.5 metric tonnes per hectare higher in organic than in non-organic farming systems. Organic farming systems sequestered up to 450 kg more atmospheric carbon per hectare and year through CO2 bound into soil organic matter.
