Greenhouse between Pyoseon and Seogwipo,Jeju-do Island, South Korea www.yannarthusbertrand2.org
Agriculture is an important contributor to climate change, with the sector’s greenhouse gas emissions (GHG) comparable in volume to those of the transport sector. A 2006 study of the impacts of the food production chain across the European Union found it accounted for 31 per cent of all EU’s GHG emissions.
In the production, manufacturing, transport, storage, selling and consumption of food, considerable amounts of greenhouse gasses are emitted. First, there is the carbon emitted from tilling and deforestation. Then there is the use of fossil fuels in fertilizer production and other agricultural chemicals, for farm machinery in intensive agriculture, and for transporting animals and crops from farm to market.
The largest emissions from the agricultural sector are in fact from land conversion, which amounts to between 6 and 17 per cent of total greenhouse gasses emitted.
The main GHGs emitted in agriculture are methane and nitrous oxide, which underlies the need to become climate and not just carbon-neutral. This is mainly due to meat production. Cattle, water buffalo, sheep and other ruminants are animals with a special stomach that allows them to digest tough plant material. Digestion produces methane, which the animals get rid of by releasing it at either end. For instance, the annual methane emissions from the burps and farts of a cow amount to 3,500 kilograms.
Nitrous oxide release is mostly linked to the use of artificial nitrate fertilizers to improve yields. Nitrogen fertilizer in particular is extremely fossil fuel-intensive, requiring 1.5 tonnes of oil equivalents to make 1 tonne of fertilizer.
Our meal of choice also has direct consequences for the climate. Increasing numbers of livestock in modern energy intensive farming systems are given high-energy feed like soya, often produced in developing countries (and often used in developed ones). To till the land to grow it ranchers will sometimes turn forests to pasture. A report by the UN’s Food and Agriculture Organization found that, globally, livestock accounts for 18 per cent of GHG emissions (37 per cent of human-related global methane and 65 per cent of global nitrous oxide emissions), a figure that includes deforestation to clear land for animals, and associated emissions.
Rice, sugar and cotton production results in emissions of methane (CH4), a potent greenhouse gas with a high global warming potential. It is over 20 times more effective in trapping heat in the atmosphere than carbon dioxide (CO2) over a 100-year period. Approaches such as methane flaring and capture can reduce GHG emissions from the agri-food sector.
Food is one of the most transported goods in our globalised world. We have grown used to seeing strawberries almost all year round in our supermarkets. In the US food travels on average 1300 to 2000 miles (2100 to 3200 kilometres) before it reaches the consumer.
The industry’s trend towards economic efficiency is in many cases associated with negative environmental impacts. Current distribution practices to provide ‘just-in-time’ delivery of products have created an increase in road or rail journeys, often with half-empty loads. On a more positive note, Cadbury reduced by 75 per cent the impact of shipping cocoa beans from Ghana to its plants in England by changing transport modes and routes.
Traditional diesel-fuelled refrigerated transport systems add to current levels of CO2 and hydro fluorocarbons, the primary contributors to global warming and the depletion of the ozone layer respectively. The current demand for frozen rather than fresh foods means that refrigerators are used in the transport stage and the storage stage too. For frozen vegetables refrigeration is the key emission stage.
Food mile movements have emerged in response to protest at these long journeys and associated carbon emissions. For example, a Swiss supermarket chain places little airplane stickers on products that travelled by air, in order to raise customers’ awareness of the CO2 emissions involved and to give them the opportunity to limit their own climate footprint by avoiding products if they wished.
Supporting local food is one way people can reduce their carbon footprint. But beware. To really make sure that you or your country is improving its climate balance the entire production and supply chain needs to be assessed. A recent study showed that tomatoes grown in Spain and transported to the United Kingdom may have a lower carbon footprint in terms of energy efficiency than tomatoes grown in the UK itself, because of the energy needed to heat greenhouses there.
Dole Fresh Fruit International has pioneered the “c-neutral” branding for its bananas and pineapples. Launched in 2007, the project seeks to establish carbon neutral product supply chain, from their production in Costa Rica to the markets in North America and Europe. This will be achieved through more efficient transportation methods, changes to agricultural processes to reduce CO2 emissions, and partnering with local farmers to implement preservation and reforestation programs.
Promoting greener farming practices and organic agriculture can also help reduce carbon emissions by favouring carbon sequestration in soil reservoirs. Stopping subsidies to intensive farming could in many cases benefit the environment, as would limiting or controlling the use of fertilizers and pesticides.