Measuring the Environmental Performance of Agriculture

Agricultural land in OECD countries covers over 1.2 billion hectares, which represents approximately 25% of the world’s total agricultural area. Pasture area accounts for approximately two thirds of the total agricultural land, with cropland accounting for the remaining third. The extent of cropland varies significantly across OECD countries, ranging from under 10% to over 99% of total agricultural land. 

The OECD is also a major region for livestock production, accounting for over 20% of global livestock population. However, livestock production patterns differ across countries,  with the share of livestock in total agricultural production ranging from under 20% to close to 90%.

The coverage of irrigation differs widely across OECD countries, reflecting different circumstances and growing conditions. While the median share of irrigated agricultural land remains low, some countries’ irrigation systems cover over two-thirds of total agricultural land.

The total agricultural land area in OECD countries has decreased slightly in recent years, with decreases being observed both across cropland and pasture areas.

Between 2013 and 2023, production has grown faster than input use.

Agricultural production has increased at an annual rate of approximately 0.8% per year. With regards to inputs, direct on-farm energy consumption and freshwater abstractions increased by 0.5% and 0.3% per year, respectively, whereas decreases were observed in fertilizer consumption for both nitrogen (-0.2% per year) and phosphorus (-0.5% per year) fertilisers, which are largely attributable to observed trends in 2022 and 2023.

Since 1990 the median nitrogen balance per hectare has decreased at an annual average rate of approximately 1.5% per year. During this period, large decreases were observed in 2009 and since 2021.

The maximum nutrient surplus per hectare declined markedly from over 300 kilograms per hectare in the early 1990s to below 200 kilograms per hectare by 2009, before increasing again above 200 kilograms per hectare from 2012 onwards.

Meanwhile, the minimum value has remained relatively constant and close to 0 since the 1990s, suggesting that some regions operate with minimal excess nitrogen inputs.

The median phosphorus balance per hectare in OECD countries has steadily declined since 1990, with the recent values falling to less than half of those recorded in the early 1990s.

The maximum phosphorus surplus per hectare also trended downward over the same period, with notable dips around 2008-2009 and again since 2021.

The minimum value has remained relatively constant during the period, however the negative values indicate that several countries experienced phosphorus deficit. 

Optimising nutrient use is an important lever to improving agricultural sustainability, with  higher levels of nutrient use efficiency indicating improved nutrient management and potentially lower associated environmental risks.

The median nitrogen use efficiency has exceeded 0.6 in recent years, improving on 1990s levels, but still implying that only about 60% of applied nitrogen is effectively converted into outputs, with persistent nutrient losses remaining.

Phosphorus use efficiency has exhibited a clearer upward trend since the early 2000s, reflecting improved nutrient management, and reaching efficiency rate of about 0.8 in recent years.

Agricultural GHG emissions have remained broadly stable at around 1 500 million tonnes of CO₂ equivalent since the 1990s, with methane and nitrous oxide emissions accounting for the overwhelming majority of agricultural GHG emissions.  

Since 1990, methane emissions in OECD countries have fluctuated between 850 and 950 million tonnes CO₂-equivalent, declining modestly until the mid-2010s, before rebounding and stabilizing at a level slightly exceeding their historical values.

Nitrous oxide emissions, which represent a smaller share of total emissions than methane, have been more variable, rising between 2012 and 2018 before declining in  recent years. 

These patterns coincide with the continued prominence of livestock production and fertiliser use, with methane primarily arising from enteric fermentation and manure management, and nitrous oxide from nitrogen-based fertilisers and soil-related processes.

While overall agricultural GHGs  emission levels have remained relatively constant over time, production has increased, resulting in  lower GHG emission intensities (measured as kilograms of CO₂ equivalent per USD of agricultural output).

Over this period, the OECD maximum emissions intensity declined steadily, decreasing from above 4 kilograms CO₂e/USD in 1990 to approximately 2.6 kilograms CO₂e/USD, reflecting improvements in productivity and gradual shift towards less emission-intensive practices.

The OECD median emission intensity also decreased by approximately 20%, from around 1.6 kilograms CO₂e/USD in the early 1990s to 1.25 kilograms CO₂e/USD in 2023. However, the rate of decline has slowed, with more rapid reductions observed in the1990s than since the 2000s.

The combination of stable aggregate emissions and declining emission intensity suggests a pattern of relative decoupling, where emissions grow at a slower rate than output. Ensuring a continuing downward trend in the absolute level of GHG emissions, however, is likely to require more transformative changes, as efficiency gains alone have not been sufficient 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.

In the case of emissions of agricultural ammonia, despite increases in production, the majority of OECD countries have reduced agricultural ammonia emissions between 2013-2023 period, with 24 countries (out of 34 reporting) recording negative average growth rate in agricultural ammonia emissions. 

Agriculture’s impact on biodiversity remains a significant challenge, as illustrated by the trends in farmland bird populations, which serve as an important indicator of ecosystem health in a subset of OECD countries. 

Among the 27 countries reporting the Farmland Birds Index, 22 experienced a decline in farmland bird populations between 2013 and 2023, signaling ongoing pressures from agricultural intensification, habitat loss, or land use changes. Only five countries reported a positive trend, suggesting localised improvements linked to 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.