Switching to organically farmed food

Last updated Thursday 8 January 2009

The natural solution to food's carbon footprint?

If you believe its most enthusiastic advocates, organic farming is better for you, better for the animals, and better for the planet. But does the science support the sales pitch?

Farming is a major contributor to the UK's greenhouse gas emissions. It accounts for more than two thirds of our nitrous oxide emissions alone and a tenth of the UK’s total climate impact.

On the face of it, organic farming looks like a good bet to lower that tally. For example, it doesn't require the synthetic fertilisers used in conventional farming. These fertilisers are manufactured from fossil fuels and so produce a large amount of CO2. In reality, however, the picture is far more complicated.

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It's Not Easy Being Green: organic gardening

James Strawbridge discusses how to make sure your garden is organic

In this article:

How will it make a difference?

Pub Fact

  • Agriculture contributes more than 10% of global emissions, according to estimates by the Intergovernmental Panel on Climate Change
  • Sixty percent of farmers surveyed in England said they were already affected by climate change and 63% expect to be affected in the next 10 years, a survey by Farming Futures (September 2008) found
  • Non-organic, loose, 'classic' tomatoes have the lowest climate impact, while organic, on-the-vine specialist tomatoes have the highest, according to a study by Cranfield University
  • Organic milk has 20% more of an impact on the climate than regular milk, according to a study by Cranfield University
  • A hectare of regular farmland produces 2.5 times more potatoes than organic farmland, according to the Department for Environment, Food and Rural Affairs
  • UK fertiliser production accounts for 1% of the UK’s total climate impact, according to the Food Climate Research Network
  • Some 77% of the UK's land area is dedicated to agriculture, according to DEFRA
  • Organic kiwis contain higher levels of anti-oxidants than conventional kiwis, a 2007 study in the Journal of the Science of Food and Agriculture found
  • Organic spelt wheat is healthier (containing higher levels of 'resistant' starch, a source of dietary fibre) than common wheat, a 2008 study in the Journal of Food Chemistry found
  • A decade-long German study found that organic food can contain higher levels of minerals. The largest differences were for potassium and iron, but magnesium, calcium, phosphorus and vitamin C levels were also higher in organic vegetables
  • Every tonne of synthetic fertiliser manufactured emits seven tonnes of CO2, according to a study by Cranfield University
  • Cattle generate more than 40% of the farming industry's nitrous oxide emissions, with beef contributing significantly more (23%) than dairy cattle (17%)
  • Only 32 of the 290 food additives approved for use across the European Union are permitted in organic food
  • UK livestock produce 90 million tonnes of manure per year, according to the Department for Environment, Food and Rural Affairs
  • UK retail sales of organic produce are now worth about 1.2bn per year, according to the Department for Environment, Food and Rural Affairs
  • Between 1990 and 2000 the organic market in Europe grew at average of 25% a year, according to the Soil Association

First the (relatively) easy part - the scale of the problem:

  • Food accounts for at least 20% of the UK's greenhouse gas emissions, according to the Food Climate Research Network (FCRN) - and almost half of that is produced by farms
  • Emissions of nitrous oxide and methane alone account for almost 90% of UK farms' climate impact, the FCRN found
  • Almost 70% of the UK's nitrous oxide emissions arise from farming - producing 4% of the UK's total greenhouse gas impact (FCRN)
  • Fertilisers are the single largest global source of the greenhouse gas nitrous oxide, and the largest source of agricultural CO2 emissions (FCRN)

Now it gets trickier. How does organic farming help? Instead of synthetic fertilisers, organic systems use 'natural' methods to give plants the nitrogen they need, such as planting legumes and adding manures or composts to fields in the months leading up to sowing. This cuts out the greenhouse gas emissions and energy associated with manufactured fertilisers. For example, farming organic corn uses 60% less energy than regular corn, according to research published in the journal Environmental Management, 2008.

But some scientists like Keith Goulding at Rothamsted Research (a UK agricultural research centre) believe that using manure, while lowering CO2 emissions, can actually produce higher nitrous oxide emissions because it is less efficient at its job than synthetic fertiliser. The nitrogen in manure needs to be broken down by microbes in the soil before it can be absorbed by crops, a process that occurs very slowly and is affected by the weather, so the release of usable nitrogen from manure doesn't always coincide with crop uptake and can instead be lost to the climate in greater quantities than the equivalent amount of nitrogen applied as fertiliser.

Another problem with organic farming is that it requires far more land to grow the same amount of produce, because it doesn't prioritise maximum yield from the smallest area. In fact, researchers at Cranfield University found organic required anywhere between 65 and 200% more land than non-organic. More land means more ploughing, which affects emissions in three ways:

  • Higher energy use from powering machinery
  • Ploughing causes the soil to emit CO2 into the atmosphere. Studies estimate that a single pass of a plough can increase CO2 loss from the soil by anything from three to 14 times.
  • Ploughing is so energy-intensive in organic systems that it largely cancels out the energy savings made from not using fuel to manufacture fertiliser, a study by Cranfield University has found.

Because organic farming does not use herbicides, it relies on ploughing and flame-weeding to control weeds. These techniques add to energy use and therefore emissions. According to unpublished research by the University of Nottingham, organic potato farmers use twice as much energy and emit three times more CO2 in controlling weeds than regular farmers.

The picture is similarly unclear with meat and dairy production. While studies show that organic meat farming cuts energy use by almost 30% on average, there are many exceptions. For example, farming organic chicken uses about 30% more energy than farming regular chicken, on average.

But that is only primary energy - the energy that goes into making fertilisers, generating electricity and powering machinery. Scientists have found that while organic farming often uses less primary energy than regular farming, it can produce more greenhouse gas. In organic systems, the yield of meat and milk per sheep or cow is lower yet organic animals produce as much (and some argue more) greenhouse gas - belched methane, nitrous oxide from their manure, and CO2 from the cultivation of feed - as regular animals, but for less end product. As a result, the climate impact per unit of organic beef, milk or lamb may be as high, or higher, than that of conventional foods.

The Soil Association - a leading advocate of organic methods - maintains that UK organic farming is on average 15% more energy-efficient than conventional farming. But evidence seems to suggest that it might merely reduce demand for energy in some areas while increasing it in others. Overall, it has not been demonstrated that organic production achieves lower greenhouse gas emissions.

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What's the debate?

Can organic farming produce enough food?

With less and less land available globally to grow human foods (because more and more is used to grow biofuels and animal feed), critics say that the world cannot afford the reduction in farming intensity that organic methods would bring, regardless of its impact on climate change. In short, say some, it would simply lead to widespread starvation and deforestation. Read more in this Guardian article.

Other scientists counter that the way to tackle starvation is not to make farming still more intensive, but to scale down production of crops for biofuels and livestock feed, both of which are responsible for climate-damaging deforestation anyway. Some scientists are even more bullish about organic methods. Controversial research published in 2007 maintains that a global switch to organic systems could still feed the world.

How can organic food be climate-friendly if we're flying it here?

The UK is nowhere near self-sufficient in organic produce and relies heavily on air-freighted goods. In fact, 50% of organic produce sold here is grown overseas, according to one expert, Dr Vic Shorrocks. On the other hand, say some, the transport emissions are mitigated by foreign organic food's lower carbon footprint during production (because hand labour often replaces machine labour).

Is organic food actually any healthier?

Long before anyone made claims about the climate-friendliness of organic food, its principal merit was that it was supposed to be better for our health - nutritionally superior and without all that nasty pesticide residue. In reality, there is no consistent evidence that organic food is more nutritious than conventional foods. If you want to eat healthily, say critics, you're better off eating those fruit and vegetables proven to be richer in vitamins, antioxidants and minerals than narrowing your choice to organic options. The benefit of organic food over non-organic food is negligible compared to the overall health benefits of simply eating more fresh fruit and vegetables, according to research published in the journal Crop Protection, 2004.

Likewise, the consensus is that there are no measurable health risks from the small amounts of pesticides and veterinary drugs found in conventional foods. The government's Pesticide Residues Committee found in 2005 that over 40% of all non-organic fruit, vegetables and bread contained pesticides: the worst cases were oranges (100%), pears (95%), bread (90%) and grapes (72%). Pesticides have not been found officially responsible for any deaths in the UK, and there's no evidence that farmers, who regularly come into contact with pesticides, are more prone to cancer, according to research by Dr Shorrocks.

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How do I do it?

  • From a climate change perspective, your best bet is to eat more local and seasonal food - it has more of an impact on your emissions than going organic
  • Rather than switching to organically reared meat, just eat less of it. The balance of evidence suggests organic beef and lamb may actually produce more methane than conventionally reared equivalents
  • If emissions are weighing on your mind, then organic milk, eggs, chicken, potatoes and tomatoes are not a smart buy
  • Get your organic produce straight from the farm or via box schemes, minimising additional transport and packaging emissions
  • Try growing your own food

Look on the Department for Environment, Food and Rural Affairs' website for a list of certified organic producers.

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Rob, Devon 2009-03-03

This is one of those things that we know we should all be doing. Organic is better for the environment, better for the body, and tastes better. The focus should be on more quality, less quantity. Once you get used to buying organic local produce you will never go back.

Anonymous 2009-03-01

See the World Health Organisation's 20 Questions on genetically modified foods (www.who.int/foodsafety), for a more balanced consideration of many of the wider issues. The Soil Association (www.soilassociation.org) will tell you why they believe organic farming is better (and less carbon-intensive) than intensive farming methods. You should probably look at Obama-Biden's report on GM crops: biotechnology companies admit that GM crops do in fact increase rather than decrease overall pesticide use: http://otrans.3cdn.net/8aff1631318dccb3d9_j9m6bhkvs.pdf
Do we honestly believe that relying on multinational businesses for seed, fertiliser, herbicides and pesticides will do less harm to our environment, and will ultimately emit less carbon than growing crops in a way that adapts to local conditions, with higher welfare standards for animals, using principles of reduce (chemicals), reuse (seed), recycle (waste)?

Anonymous 2009-03-01

There are wider arguments to be understood, and it is extremely damaging to those promoting proper debate around farming methods and bioscience to discourage people from understanding wider problems: food security, famine, cash crops, F1 sterility, unforeseen risks to other species from cross-pollination, biodiversity, the increased use of fertilisers, pesticides, herbicides for GM crops, exploitation of farmers, dependence on biotechnology companies.
Intensive farming will not feed the world. It never has and never will. The world already produces enough food, but economics mean that it flows towards the rich (consumers) from the poor (producers). Read more at www.wfp.org (the World Food Programme). Economics, not farming, is the problem, but biotech promoters continue to ignore that.
It is in bad faith to focus exclusively on simplistic and partial arguments focussing exclusively on carbon emissions in the case of a consumer's choice to buy organic or non-organic food.

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Glossary terms used on this page
Fertilisers are given to plants to promote growth. They can be naturally occurring compounds (such as peat) or they can be manufactured - either through natural processes (such as composting) or chemical processes. Fertilisers commonly contain nitrogen, and the use of such fertilisers emits the potent greenhouse gas, nitrous oxide (N20). Using animal manure as fertiliser, though organic, releases another potent greenhouse gas, methane into the atmosphere.
Fossil fuels
Fossil fuels are the deposits of crude oil, natural gas and coal formed by the decay, over millions of years, of organic material (plants, trees animals and bacteria). Because the combustion of fossil fuels releases carbon that has been out of the natural carbon cycle for so long (unlike with living or more recently dead organic matter, known as biomass) it affects the balance between stored carbon and carbon present in the atmosphere as CO2, a greenhouse gas.
Methane is a hydrocarbon, the main component of natural gas and among the six greenhouse gases to be curbed under the Kyoto protocol. As a greenhouse gas it is estimated to have a warming effect about 25 times as great as CO2. (Compared to CO2 its effects are greater but last for a shorter period). As a fuel, it is used in electricity generation and in the form of compressed natural gas it can be used as vehicle fuel. Methane is produced during the decomposition of many materials in landfill, while about 16% of methane emissions are caused by livestock's digestive processes.
Nitrogen oxides
Nitrogen oxides are compounds of nitrogen and oxygen, two elements that do not normally react with each other but will do so during high temperature combustion – such as in a car engine. Examples include nitric oxide (NO) and nitrogen dioxide (NO2), which contribute to air pollution, and nitrous oxide (N2O), which is a major greenhouse gas. Although its warming effect is far less than CO2, it persists in the atmosphere for far longer, so measured over 100 years its impact is 298 times greater.
Nitrogen oxides
Nitrogen oxides are compounds of nitrogen and oxygen, two elements that do not normally react with each other but will do so during high temperature combustion – such as in a car engine. Examples include nitric oxide (NO) and nitrogen dioxide (NO2), which contribute to air pollution, and nitrous oxide (N2O), which is a major greenhouse gas. Although its warming effect is far less than CO2, it persists in the atmosphere for far longer, so measured over 100 years its impact is 298 times greater.

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