The Environmental Impact of Buying Organic Food

28 March 2018


Agriculture and climate change

The agriculture industry occupies a unique place in the climate change debate. In 2007, although it was responsible for 14% of global greenhouse gas emissions[1] some research indicated that it had the potential to be used to mitigate up to 20% of global emissions by sequestering carbon (i.e. putting it back into the soil)[2]. But these researchers pointed out that the current models of intensive industrial farming would not achieve this; instead they were likely to have the opposite effect. Unfortunately, this is exactly what has happened. 

Climate change is driven by an increase of carbon dioxide, methane and nitrous oxide in the air. Emissions of all these gases have been increasing and globally agriculture is now responsible for 24% of greenhouse gas emissions[3]. This is rising more rapidly than any other sector because of the continuation of industrial farming. 

In Aotearoa-New Zealand the situation is even more stark – 47.9% of our greenhouse gas emissions come from agriculture. Emissions from the agricultural sector have increased by 16% since 1990, mainly due to an 88.5% increase in the national dairy herd size since 1990 and an approximately five-fold increase in the application of nitrogen-containing fertiliser[4]

The release of methane gas from ruminant livestock (sheep and cattle) amounts to almost 1/3 of New Zealand's greenhouse gas emissions, and it is the largest contributor. Methane also accounts for over 40% of all emissions in terms of global warming potential[5].

So what can be done?

One solution is to change our system of agriculture away from an intensive industrial model to a regenerative model, which sequesters carbon, protects the land and waters of the country, increases biodiversity and provides a good long-term financial return to the farmers and good value to consumers. In short - to farm organically!

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The Benefits of Organic Farming

Organic farming is a development of traditional methods. The essential principle is to co-operate with nature and not attempt to dominate it. This requires:

  • building up and maintaining soil fertility by recycling organic materials including crop residues and livestock wastes; 
  • using green crops to return nitrogen to the soil;
  • minimizing the use of non-renewable resources. Organic farmers use no soluble mineral salt fertilisers and very few chemicals. Weed, disease and pests are controlled by crop rotation, the use of natural predators, biological diversity and the use of limited mechanical and chemical intervention;
  • creating good conditions for livestock, which allow for their behavioural needs.

Practices such as planting cover crops, residue mulching, composting and crop rotation can all help to sequester carbon and mitigate the effects of greenhouse gas emissions. In some countries like the US and Australia where the soils are old and the carbon has been depleted, regenerative organic practices may go a long way to counteracting emissions from other sectors, but only if such practices apply to all cropland and pasture. In the US the Rodale Institute found that, if all conventional agricultural land started using organic farming practices, such as mulch tilling and seasonal crop rotations, agriculture could – in theory – capture 100% of annual carbon emissions.

In Aotearoa-New Zealand the soil is richer in carbon and there is not such a great opportunity to sequester great amounts of carbon in the soil. But there is evidence that current intensive farming practices are depleting carbon from our soils [6]. If we moved to regenerative organic systems and include conservation tillage and a move towards polycultures rather than monocultures we would be farming in a way to preserve and enhance the carbon and this could start to reduce our greenhouse gas emissions. 

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In order to achieve this it is vital that organic farming moves from its position as a ‘niche’ farming system to the primary system of farming within the land. And this makes financial sense. In 2010 there were 29,000 organic cows being milked in this country, but Fonterra decided this was not a good area to invest in and drastically cut their support for organic dairy farmers. By 2017 there was such a surge in demand for organic milk that Fonterra paid out $9.20 per kg of milk solids to organic dairy farmers - more than twice as much as the pay out to conventional farmers (unfortunately by then the organic herd had dropped to 17,000 cows compared with over 6 million non-organic cows)[7].

It’s Our Future

All of us depend on the land for our food and our survival. It is critical that we develop an economic system that places preservation (rather than exploitation) of our resources at its heart. We need to diversify, we need to eat seasonally, we need to restore our waterways and we need to live a little more humbly on the land. And this is the whole point of organic agriculture - to work in harmony with the earth and not presume to dominate it. 

A certified organic land of Aotearoa-New Zealand would help us address our emissions, clean up our soil and water pollution and make this country genuinely clean and green again.

Our Choices Matter

Our current economic model works on a system of market signals. Fonterra cut their support for organic dairy farmers because they did not realise the demand for organic milk would grow so rapidly. Consumer choices send powerful messages, so by choosing organic food, and, if it is not available in your area, asking retailers and restaurants to stock more organic food we’re showing that there is support to make positive change. 

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To find out more head to

[1]  IPCC (2007) Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III quoted in

[2] Smith et al (2007), Greenhouse gas mitigation in agriculture