Is organic food good for the planet ?

With regards to organic food the only firm answer is that there is no consensus on whether organic agriculture reduces greenhouse gas emissions overall.* **  While organic agriculture certainly uses less inorganic fertiliser and increases biodiversity (which seems to have no direct impact on greenhouse gas emissions), organic food may cause higher greenhouse gas emissions, at least in some cases. For example, organic cows produce less milk than conventionally farmed cattle so the methane output per litre of milk tends to be much higher. Nevertheless, most research suggests that organic agriculture has marginally lower emissions than conventional methods. But the results are debatable and depend on the crop, the soils, and the skill of the farmer. It is often remarked that comparisons are difficult because organic farmers may well be better at their job, i.e. good farmers become organic farmers. This may artificially advantage organic methods.*

The argument that locally sourced food causes less greenhous gas emissions than globally sourced food is based on the "food miles" concept, which purports to measure how far food has travelled from producer to consumer. It is naive to conclude that all food which has travelled a long distance always causes more greenhouse gas emissions than locally sourced food when there is actually much more to it. For example, a case study showed that it can be more energy efficient and therefore less carbon intensive to import tomatoes from Spain than to produce them in heated greenhouses in the UK outside the summer months.*** The reason is that the food miles argument takes no account of the energy use/CO2 emissions in the production phase and assumes that a given product is produced to the same level of energy efficiency everywhere it is produced. A recent study**** showed that New Zealand agriculture, for example, tends to apply less fertilisers (which require large amounts of energy to produce and cause significant CO2 emissions) and animals are able to graze all year round outside eating grass instead large quantities of brought-in feed such as concentrates. This study found that lamb raised on New Zealand’s pastures and shipped 11,000 miles by boat to Britain produced 1,520 pounds of carbon dioxide emissions per ton while British lamb produced 6,280 pounds of carbon dioxide per ton, in part because poorer British pastures force farmers to use feed. However, with the volume of air-freighting of food growing, these transport emissions are likely to become even more important in the future.

Sources :

* www.carboncommentary.com/2007/09/15/7

** DEFRA, Environmental Impacts of Food Production and Consumption, 2006

*** DEFRA, The Validity of Food Miles as an Indicator of Sustainable Development, 2005

**** Saunders C. et al., Food Miles – Comparative Energy/Emissions Performance of New Zealand’s Agriculture Industry, 2006