Is Organic Farming Better for the Environment than Conventional Farming?

How do They Compare on Carbon Emissions Water Pollution Biodiversity, and Land Use?

Hannah Ritchie 

 

 

As someone who has studied the environmental impacts of agriculture for many years, there are a handful of questions that I get over and over. One of them is whether we are right to assume that organic farming is better for the environment than conventional farming.

I think this is a common assumption. When I eat with others, there is often an expectation that I will automatically choose the organic option. When I speak to friends, they are keen to tell me that they’ve started buying organic vegetables or beef. They are looking for a thumbs-up that this was the best choice.

While this choice might seem obvious and simple (organic is good, and conventional is bad), the research is far more mixed. In 2017, I wrote an article looking at the latest studies. I mainly drew on a meta-analysis by Michael Clark and David Tilman, which found little clear difference in some environmental impacts — such as carbon emissions and water use — between organic and conventional methods.¹ But it did find some areas where organic performed worse: specifically, water pollution and land use. Organic farming tends to get lower yields and therefore uses more land.

That article has been a popular one since then. But it’s now old and worthy of a refresh. Nine years on, do we have better data on these comparative impacts? How should we think about these differences in farming practices?

In this article, I take a fresh look at these questions.

Organic farming wins on ecotoxicity

Rather than looking at individual studies one by one, I’ll mostly rely on data from a large meta-analysis by Fatemeh Hashemi and colleagues, published in Communications Earth & Environment in 2024.⁴ It compiled data from 100 assessment studies.

On some environmental impacts, there was no clear winner. But let me start with two where there was.

Organic agriculture almost always proved better on the metric of “ecotoxicity”. This measures how harmful a farming system’s chemical inputs — which are mostly pesticides — are to plants, insects, and aquatic life in the local environment. Particular chemicals have an ecotoxicity score, which is multiplied by the amount of each substance applied. Across the studies that measured it, organic farming almost always had much lower ecotoxicity than conventional farming.

Since the key distinction between organic and conventional farming is the use of synthetic chemicals, ecotoxicity is really the measure where organic farming nearly always wins. There are a few exceptions, though. Some chemicals, such as copper sulfate, are allowed under organic certification. In a few of the studies where these were used, organic actually had a higher ecotoxicity score.

As a result, organic farming also tends to support greater biodiversity on the land it uses. Studies typically find greater diversity of plant, insect, and bird species on organic land.⁵ They also find that, on average, these organisms are more abundant.⁶

These positive results vary widely depending on the scale. Organic tends to perform better in terms of biodiversity at the level of a particular field. But studies have shown that these positive effects diminish when looking at biodiversity across an entire farm or the surrounding area.⁷

Conventional farming wins on land use

On the other hand, conventional agriculture consistently performed better on land use. It had higher yields of both plant and animal products, so producing one kilogram of food required less land.⁸

In the chart below, you can see the difference in average land use between organic and conventional products; one dot is equal to one study. The gray line marks where the land use between organic and conventional systems would be equal.

As you can see, almost all of the dots lie above the gray line; this means organic farming almost always uses more land. The median result was that organic practices used 64% more land.

 

 

 

Neither wins on carbon emissions nor on water pollution

Let’s then look at the environmental indicators where the answer is less clear-cut: carbon emissions (often referred to as “global warming potential”) and two metrics that capture water pollution: acidification and eutrophication (the leakage of nutrients into land and water bodies).

The first thing to note is that across all these metrics, organic farming performs better per unit of land. If I grow one hectare of wheat using organic methods, and the same using conventional methods, carbon emissions and water pollution will be lower on the organic hectare.

But as we just saw, organic farms tend to produce less food per hectare. When we look at impacts per kilogram of food (which is ultimately what we care about when it comes to food consumption and our own choices), those gains disappear.

The researchers found that across the 100 assessments, there was no statistically significant difference between organic and conventional farming when it came to greenhouse gas emissions, acidification, and eutrophication. The results were very mixed: in some studies, one won over the other, but almost just as many found the opposite effect.

In the chart below, I’ve shown the outcome of each of these studies. Those in pink on the right-hand side had lower impacts with conventional methods. Those on the left, in purple, found organic was better. You can clearly see the difference between the two methods in the top (ecotoxicity) and bottom (land use) panels, and the mixed results in the three middle panels.

 

 

The type of food and other factors of food production matter more for the climate

One of my other most popular articles on Our World in Data looked at the role of food miles in the carbon footprint of our food. It was titled: “You want to reduce the carbon footprint of your food? Focus on what you eat, not whether your food is local”, and that was the main takeaway.

Reducing food miles might change the carbon footprint of your food choices by 5% to 10%. Changing what you eat could change it by ten times or more. That’s because the difference in greenhouse gas emissions between animal products such as beef or lamb, and plant-based ones like soy is so large.

Not to be a broken record, but the conclusion here is the same. Across lots of different farms and products, there’s no significant difference in the carbon footprint of organic chicken versus conventional, or organic apples versus conventional ones. Even when differences do exist across individual studies, they are often on the order of 5% or 10%, or in more extreme cases, 50%. That goes both ways, so it’s not that organic or conventional farming consistently wins.

Those differences are small compared to the differences between foods. In the chart below, you can see the greenhouse gas emissions per kilogram of different foods. This comes from one of the large meta-analyses to date.⁹

Let’s say you’re fretting over whether to go for the organic or non-organic peas. Perhaps the carbon footprint could differ by up to 50% between them. Rather than the carbon footprint being 1 kilogram of greenhouse gases per kilogram, it’s 1.5 kilograms (again, you don’t know whether it’s the organic or conventional ones that are higher).

This is a rounding error compared to the difference between peas and beef. Choosing the latter would increase your carbon footprint not by 50%, but by 3,300% to 10,000%.

This is even true when comparing animal products. A 50% difference in the carbon footprint of organic versus conventional chicken matters less than choosing chicken over beef or lamb.

 

 

 

 

We also see substantial differences in the carbon footprints of the same foods produced under the same system (organic or conventional). Producing organic tomatoes in one location could have twice the carbon footprint of producing organic tomatoes elsewhere. That’s because a range of other production factors matter: the climate, the soil quality, and the specific techniques a farmer is using. These geographical differences in productivity can, again, dwarf any differences between organic and conventional systems.

What you eat, and all of these location and farm-specific factors, matter much more than whether it’s organic or not.

Land use matters

Organic agriculture is comparable to conventional agriculture in terms of carbon emissions. As we saw earlier, it may also have biodiversity benefits, specifically for the area of land that is farmed.

Its major downside is that it requires more land. The impact of land use is often underrated, both on climate and on biodiversity loss.

When it comes to climate, it’s not just the greenhouse gases we emit that matter. It’s whether we could otherwise suck more carbon out of the atmosphere and store it in vegetation if we were using the land in another way.

Most studies — and the meta-analysis we just looked at — do include the emissions from land use change in their results. That is, the carbon emitted from deforestation, or the conversion of grasslands into agricultural land. But they do not factor in what we call “carbon opportunity costs”: the fact that if it weren’t cropland or pasture, it might otherwise be natural grasslands or forest and would continually suck more carbon out of the atmosphere. When we factor in these opportunity costs, some conventional agricultural systems may be better for the climate than organic ones.

Lower yields and higher land demand can also have spillover impacts for the rest of the world. A country might think that an environmentally friendly thing to do is to go all in on organic farming. Laurence Smith and colleagues modeled what would happen if England and Wales had such aspirations.¹⁰

England and Wales’ greenhouse gas emissions from agriculture would go down. This is to be expected: as we saw earlier, organic practices did have lower climate impacts per hectare. But lower yields mean it would produce far less food, and have to import the shortfall from elsewhere. Effectively, its farmland use would expand overseas. When the researchers accounted for this spillover, the climate impact of its food consumption was higher under an organic-farming scenario than under the current one.

Nearly half of the world’s habitable land is used for agriculture. You can see this breakdown in the chart below. The expansion of this land over millennia has displaced around one-third of the world’s previously forested land. That has transformed landscapes and dramatically changed biodiversity in the process. If we want to preserve the world’s remaining forests and other natural habitats, we need to find ways to use less land for agriculture, not more. A dramatic shift to organic farming would move us in the opposite direction, at least without huge changes to what the world eats.

 

 

 This article has focused on the environmental impacts of different farming methods. But it’s worth noting that there is a strong human side to this, too. It’s estimated that around half of the global population today relies on synthetic fertilizer for the food they eat.¹¹ An organic world wouldn’t just mean more farmland. It would also lack the nitrogen needed to feed the 8 or 9 billion people in it.¹²

Conclusion

Where does this leave us on the original question: is organic better for the environment?

If we look at this through the question of “how do I limit the environmental impacts on this plot of land?” then organic methods will often be the better choice. The greenhouse gas emissions, water pollution, and biodiversity impacts on that hectare will often be lower.

It’s estimated that around half of the global population today relies on synthetic fertilizer for the food they eat.

That is different from the question of “how do we feed the world in a way that limits the environmental impacts of agriculture?” For that question, the per-kilogram metrics are more important. There, organic still wins on ecotoxicity, but conventional farming is no worse in terms of its climate or water pollution impacts, and is much better in terms of land use.

If the world were to move to a 100% organic farming system, we’d have to convert far more forest and natural habitat into farmland. This could ultimately work against our intention to reduce greenhouse gas emissions and preserve biodiversity.

A future with less agricultural land but more organic farming would only be possible with widespread shifts to more plant-based, less land-hungry diets and large reductions in food waste.¹³