How is Organic Farming Both Better and Worse for the Climate?

photo (c) Oliver Moore

“Organic food worse for the climate” declared the Chalmers University of Technology press release in December, eager to trumpet what surely much be a novel, groundbreaking, counterintuitive piece of research.

But wait! “Organic farming mitigates climate change” the FiBL press team retorted in February. The Research Institute of Organic Agriculture (FiBL) must surely have found, in a study led by one of their former researchers, some new, fresh perspective on a familiar subject. 

Both were published by Nature – the former in Nature itself, the latter in Nature Scientific Reports.

So what gives – who is correct?

Contrasting stories of this kind have emerged for years. How can two sets of scientists say such a diametrically different things to each other?

When the former (Searchinger et al 2019) appeared, certainly the press release promised much.  This was a “new international study” using “new techniques” showing organic can result in “much greater emissions”.

Well, however novel the press release made this research seem, I’m afraid it’s yet again the same very old story – organic farming sometimes takes up too much land. This is because it doesn’t use artificial fertilizer, has a lower yield, and in turn results in deforestation, the researchers claim.

“The fact that more land use leads to greater climate impact has not often been taken into account in earlier comparisons between organic and conventional food,” says researcher Stefan Wirsenius.

Funny that, because many studies encountered in the fifteen years studying the organic sector have made this land use this claim, when the study finds organic is worse for the climate (and indeed for other environmental good such as biodiversity).

There is noteworthy naivety in the notion that this land use argument is somehow novel.

It’s also telling  that the authors focuses on two crops in Sweden – organic peas and wheat – an extrapolate out for the rest of the world and all crops from this. In the case of, for e.g. organic milk in the Netherlands, or organic maize in France, the yield gap is almost non existent. (see page eight of this EU Commission document from March 2019).

IFOAM EU present a range of issues with this research, including the land use model and what the organisation suggests is something of a solo run by one author Stefan Wirsenius. it also points out that the research wasn’t actually about organic farming – its called, after all “Assessing the efficiency of changes in land use for mitigating climate change” – organic farming was just a small part of the study – but the press and publicity was very much about organic farming and climate change.

By presuming business-as-usual, this research conveniently sidesteps the general unsustainability of current conventional agronomic practices, from ammonia (a form of Nitrogen)  and nitrogen pollution, from phosphorus pollution, antimicrobial resistance, biodiversity loss on the huge land area farming occupies in rural Europe, soil organic matter loss (pdf) and so on (note this latter pdf is by the same DOK team referenced below).

Indeed the yield gap gets shorter when bad practices get banned for the environmental destruction caused – how small will this yield gap be in Dutch milk when the ending of the nitrates directive comes into full effect?

Making the jump from organic farming to deforestation is also quite a leap, as is the presumption of no dietly change in a humanity hurtling towards climate breakdown and biodiversity collapse.

We simply cannot continue business-as-usual in farming, yet this study – like so many – carries on regardless with a climate-only focus, whatever the impact this has on other sustainability considerations.

It will come as no surprise that the other study (Skinner et al 2019) emphasises on emissions per hectare. This too is the same approach seen for many years from some researchers.

In a context of almost 40% of Europe’s land actually being farmland, per hectare matters. 

One noteworthy element is, however, that this second study is based on the DOK trials, now over 40 years old.

Much research suggests it can take some years  – up to seven perhaps – for organic systems to really come into their own, in terms of the benefits of the approaches employed. In particular it takes some years for all the beneficial microbiological activity underground to optimise – however farms and food can be certified organic and available on the shelves after a two year conversion period. 

 And this is where things get interesting. The organic systems employed in the DOK trails also see no loss in yield: “The amount of emitted gas is also lower per ton of yield or – in the case of maize cultivation – equal” the authors say.

They add: “the organically farmed areas had around 40 percent lower nitrous oxide emissions per hectare than the conventionally farmed field plots. In terms of yield, the “bio-dynamic” system had the lowest nitrous oxide emissions, the “zero fertilisation” control treatment the highest. The maize yield showed no difference in nitrous oxide emissions between organic and conventional farming.”

Furthermore: “this proves that it is not only the renunciation of larger amounts of chemical fertilizers that leads to reduced emissions in plant production, but also the targeted use of diverse crop rotations and farm based amendments such as farmyard manure and slurry to maintain important soil functions”.  They also found that, “in addition to N input, quality properties such as pH, soil organic carbon and microbial biomass significantly affected N2O emissions”.

This shortening of the yield gap is emerging more strongly in the academic literature: Schrama (et al 2018), in 13 year trials comparing organic and conventional, found “the yield gap between organic and conventional farming diminished over time; This coincided with higher nutrient use efficiency and spatial stability in the organic system; Transition from conventional to organic results in fundamental changes in soil properties.”

Indeed this study by Schrama et al is fascinating for helping our understanding of what happens after 10+ years: 

“We conclude that closure of the yield gap between organic and conventional farming can be a matter of time and that organic farming may result in greater spatial stability of soil biotic and abiotic properties and soil processes. This is likely due to the time required to fundamentally alter soil properties”

As with previous DOK trials, biodynamic performed better than other organic systems. And of course further research is needed, for different soil types, regions and cultivation systems, through long term trials, as is typical.

Whatever the case, expect more novel research in the years ahead. And expect one side to argue per kilo, and the other per hectare. 

A shorter version of this article by Oliver Moore also appeared in the Irish Examiner

More on organic farming on ARC2020

Organic Agriculture and the SDGs – Scientific Evidence from Comparative Research

Ireland’s New Organic Action Plan | Committed – to What?

Organic Outflanked? Conventional, Biological and Regenerative Challenge(r)s

“Batting Away the Baddies” – Organic Food, Cancer, Herbicides and History