Measuring the Environmental Performance of Agriculture

Agricultural land in OECD countries covers 1.23 billion hectares, accounting for approximately 25% of the world’s total agricultural area. Of this, 414 million hectares are cropland, while around 821 million hectares are primarily used for pasture. The extent of cropland varies significantly across OECD countries, ranging from 6.8% to 99.1% of total agricultural land, with a median share of 64.4%.

The OECD is also a major region for livestock production, with a total of 445 million livestock units, representing about 24% of global livestock population. However, livestock production is not evenly distributed across countries, with the share of livestock in total agricultural production ranging from 25.6% to 88%, and a median of 43.9%.

Irrigation plays a key role in crop productivity, though its use varies widely across OECD countries. In 2022, the median share of irrigated agricultural land was 2.8%. Some countries have extensive irrigation systems, with the highest share reaching 67.2% of total agricultural land, while others report little to no irrigation.

Changes in land use patterns provide insights into how agricultural landscapes are evolving over time. The total agricultural land area in OECD countries remained relatively stable over the past decade, with an average annual change of +0.02% between 2011 and 2021. However, this stability masks contrasting trends between cropland and pasture areas.

Between 2011 and 2021, cropland area declined by an average of -0.68% per year, while pasture area expanded by 0.39% per year. These changes suggest a shift in land use dynamics, potentially reflecting factors such as land conversion, changes in agricultural production systems, and policies aimed at preserving or restoring natural ecosystems. 

Between 2009-11 and 2019-21, agricultural input use in OECD countries exhibited varied trends.

Direct on-farm energy consumption showed a modest annual increase of +0.4%. 

Fertiliser use grew at higher rates, with nitrogen fertilisers increasing at an annual rate of +1.5%. Phosphorus fertiliser use grew at a slightly higher rate of +1.7% per year. 

Water abstraction also saw an increase (1.0% per year), indicating rising pressures on water resources across OECD countries.

These trends reflect shifts in production practices and underscore the evolving pressures on natural resources and the importance of enhancing input use efficiency in OECD agriculture.

Between 1990 and 2021, nitrogen balance trends in OECD countries varied across regions. The highest nutrient surplus showed a significant decline from over 300 kg/ha in the early 1990s to around 200 kg/ha in the 2010s, reflecting improvements in nutrient management or reduced fertiliser use in countries with the highest surpluses.

However, since 2010, this downward trend appears to have reversed, with recent years indicating a resurgence in nitrogen surpluses in the highest-emitting countries. Meanwhile, median values remained relatively stable, fluctuating around 50 kg/ha, while minimum values hovered close to zero, suggesting that some regions operate with minimal excess nitrogen inputs.

While some improvements are evident, persistent surpluses in many OECD countries continue to raise concerns about nutrient runoff, water pollution, and greenhouse gas emissions.

The phosphorus balance in OECD countries has shown mixed trends over time. 

The maximum value followed a mostly downward trend until early 2010s, but progress has stalled over the past decade. The median values remained relatively stable, although on a relatively lowering trend close to zero. Meanwhile, the minimum value shows that one or more countries have been facing deficit in phosphorus since 2004, with a small decrease again in 2020. 

Further monitoring is needed, as excess phosphorus can accumulate in soils over time, posing long-term risks to water quality through runoff and leaching.

The trends in nitrogen and phosphorus surpluses across OECD countries reflect shifts in fertiliser use and environmental pressures, highlighting ongoing efforts to improve nutrient use efficiency in agriculture. Optimising nutrient use is an important lever to improving agricultural sustainability, yet there remains significant margin for improvement. Higher efficiency levels indicate better nutrient management which reduces environmental impacts, while lower values highlight persistent challenges to minimise nutrient losses. 

Nitrogen use efficiency, measured as the ratio of outputs to inputs, has shown slight improvements over time, though fluctuations persist. The median efficiency has reached 0.6 in recent years, meaning however that only about 60% of applied nitrogen is effectively converted into outputs. This suggests ongoing challenges in reducing nutrient losses and optimising fertiliser use with 40% of nutrients lost to the environment through soil, water or air.

Phosphorus use efficiency has exhibited a clearer upward trend since the early 2000s, reflecting improved nutrient management overall, reaching about 80% in the most recent years.

These trends underscore the progress achieved in nutrient use efficiency, while emphasising the need for further improvements to reduce nutrient losses and their environmental impact. 

Agriculture remains a significant GHG-emitting sector through its methane and nitrous oxide emissions.  

Since 1990, methane emissions in OECD countries have fluctuated around 850–900 million tonnes CO₂-equivalent, with a slight decreasing trend until the mid-2010s, exhibiting however a rebound since then, to stabilise at a level slightly exceeding their historical values.

In contrast, nitrous oxide emissions make up a relatively smaller proportion of total GHG emissions from agriculture but show greater variability, particularly with a noticeable rise between 2012 and 2018, followed by a decrease in the recent years. 

These trends reflect the ongoing influence of livestock production and fertiliser use on agricultural GHG emissions, with methane primarily linked to enteric fermentation and manure management, while nitrous oxide emissions being largely driven by nitrogen-based fertilisers and associated soil processes.

While agriculture also generates CO₂ emissions, these are comparatively much smaller and result mainly from soil processes.

Overall, GHG emissions have increased from 1 453 million tonnes of CO₂ equivalent in 2009-11 to 1 515 million tonnes (+4.3%) in 2019-21, which corresponds to an average annual growth rate of 0.4% over the period. Annual GHG emissions from agriculture have remained above 1.5 billion tonnes of CO₂ equivalent per year since 2017.

One way to reduce GHG emissions is to limit emission intensity of agricultural products — measured in kilograms of CO₂ equivalent per unit of agricultural output (USD).

From 1990 to 2021, the OECD maximum emissions intensity steadily declined, decreasing from above 4 kg of CO₂e/USD in 1990 to less than 3 kg CO₂e/USD since 2014, reflecting improvements in productivity and adoption of less GHG-emission intensive practices.

The OECD median has also declined by approximately 12%, from around 1.5 kg CO₂e/USD in the early 1990s to 1.3 kg CO₂e/USD in 2021. However, the rate of decline has slowed down over the recent period, from -0.6% per year in the 1990s and 2000s to -0.2% per year since 2010. The OECD minimum, in comparison, has remained consistently low.

Despite these improvements in emissions intensity, total emissions from the sector have continued to rise. This suggests a situation of relative decoupling, where emissions grow at a slower rate than output. However, achieving absolute decoupling — a reduction in total emissions — would require more transformative changes, as efficiency gains alone have not been sufficient so far to compensate for the growth of agricultural production. 

Manure from livestock production and fertiliser use can also generate ammonia emissions contributing to air and water pollution.

Agricultural ammonia emissions across OECD countries declined moderately after 2001 with slight fluctuations until the mid-2010s. As from 2015, the trend on emissions began to reverse with an average annual growth rate of 2.8%, leading to a record high level in 2021 over the last two decades.

This trend reflects ongoing challenges in managing emissions from fertiliser application, manure handling, and livestock production. This could be the source of potential environmental threats in the most affected regions. 

While efforts to improve environmental performance continue, the persistence of ammonia emissions highlights the need for further mitigation strategies to reduce agriculture's impact on air quality and ecosystems.

The impact of agriculture on biodiversity also remains an important challenge, as observed with farmland bird populations serving as an important indicator of ecosystem health in a subset of OECD countries. 

Of the 27 countries within OECD countries reporting the Farmland Birds Index, 22 experienced a decline in farmland bird populations between 2009-11 and 2019-21, signaling ongoing pressures from agricultural intensification, habitat loss, or land use changes.

In contrast, only five countries reported a positive trend, suggesting localised improvements in conservation efforts or habitat management.

The overall pattern underscores the continued challenges in maintaining farmland biodiversity and the need for targeted agri-environmental policies to support bird populations. More effort is ongoing to complement this indicator, including in non-covered countries, with the monitoring of farmland habitat biodiversity.