Abstract
Using global data for around 180 countries and territories and 170 food/feed types primarily derived from FAOSTAT, we have systematically analyzed the changes in greenhouse gas (GHG) emission intensity (GHGi) (kg CO2eq per kg protein production) over the past six decades. We found that, with large spatial heterogeneity, emission intensity decreased by nearly two-thirds from 1961 to 2019, predominantly in the earlier years due to agronomic improvement in productivity. However, in the most recent decade, emission intensity has become stagnant, and in a few countries even showed an increase, due to the rapid increase in livestock production and land use changes. The trade of final produced protein between countries has potentially reduced the global GHG₁, especially for countries that are net importers with high GHG₁, such as many in Africa and South Asia. Overall, a continuous decline of emission intensity in the future relies on countries with higher emission intensity to increase agricultural productivity and minimize land use changes. Countries with lower emission intensity should reduce livestock production and increase the free trade of agricultural products and improve the trade optimality.
Generated Summary
This research article examines the decline in carbon emission intensity of global agriculture. Using global data from approximately 180 countries and territories, the study analyzes changes in greenhouse gas (GHG) emission intensity, measured in kg CO2eq per kg protein production, over six decades. The primary methodology involves a systematic analysis of data from FAOSTAT, focusing on changes in GHG emission intensity (GHGi) at different levels of protein production: primary, semifinal, and final. The research categorizes countries based on their role in trade (importers or exporters) and the intensity of livestock production to understand how these factors influence GHG emissions. The study aims to identify the key driving forces behind changes in GHG emissions, particularly focusing on agricultural productivity, land use changes, and livestock production levels. By analyzing historical trends and spatial differences, the research seeks to understand the factors driving the changes in GHG emissions and their implications for future sustainability in the agrifood system.
Key Findings & Statistics
- Global GHG Emissions: Globally, GHG emissions from the agrifood system and land use changes were estimated at 17 Gt CO2eq per year in 2022, corresponding to nearly one-third of global anthropogenic GHG emissions.
- Food Demand Increase: Food demand is projected to increase by 35 to 56% between 2010 and 2050.
- GHG Emission Intensity Reduction: GHG emission intensity decreased by nearly two-thirds from 1961 to 2019.
- GHG Emission Stagnation: In the most recent decade, emission intensity has become stagnant and even increased in a few countries.
- Country Group Categorization: Countries were categorized into four groups: net exporters with high livestock production intensity (ExH), net exporters with low livestock production intensity (ExL), net importers with high livestock production intensity (ImH), and net importers with low livestock production intensity (ImL).
- Protein Production Increase: Final protein production increased from 0.11 to 0.37 Gt y−1 between 1961 and 2019.
- GHG Emission Intensity Decline: The GHG emission intensity of primary products decreased by nearly two-thirds globally from 60 kg CO2eq per kg protein in 1961 to 19 kg CO2eq per kg protein in 2019.
- GHG Decline Rate: The decline rate of GHGi-final decreased from 1.7 to 2.2 kg CO2eq per kg protein per year (1961-1979), to 0.49 to 0.82 kg CO2eq per year (1980-2006), and then to approximately zero during 2007 to 2019.
- GHG Differences by Country Group: The average GHGi-final was similar between ExL and ImL countries, at around 40 CO2eq kg−1 protein, which was approximately two times that found in ExH and ImH countries.
- Continental GHG Trends: GHG; decreased by around 80-90% in South and North America and Oceania from 1961 to 2019. GHG slightly increased in Africa, Asia, and European countries in the most recent decade.
- Trade Impact on GHG Emissions (1961-1979): Trade has potentially increased GHG emissions by 4.6 to 7.3 Gt CO2eq cumulatively.
- Trade Impact on GHG Emissions (2007-2019): Trade had a nearly neutral impact on reducing GHG emissions between 1980 to 2006, but reduced GHG emissions by around 3.6 to 6.9 Gt CO2eq for primary and semifinal protein production.
- Annual Reduction Rate Through Trade (2007-2019): The annual reduction rate through trade was much higher when protein production was at the primary (1.2 Gt CO2eq y−1) and semifinal (1.3 Gt CO2eq y−1) levels, compared with the final protein production level (0.46 Gt CO2eq y−1).
- GHG Reduced per kg of protein (2007-2019): 9 to 13 kg CO2eq was reduced when 1 kg of protein was traded.
Other Important Findings
- Livestock Production and Land Use Changes: The recent stagnation or increase in emission intensity in some countries is attributed to the rapid increase in livestock production and land use changes.
- Trade’s Role in GHG Reduction: The trade of final produced protein between countries has the potential to reduce global GHG, particularly in countries that are net importers with high GHG emissions.
- Need for Productivity and Land Use Changes: Continuous decline in emission intensity requires countries with higher emission intensity to increase agricultural productivity and minimize land use changes.
- Spatial Differences in Emission Intensity Changes: The decline in GHG emissions varied across different groups of countries and time periods.
- Primary Product Emission Intensity: The GHG emission intensity of primary products decreased by nearly two-thirds globally from 1961 to 2019.
- Impact of Trade: International agricultural trade has the potential to reduce GHG emissions, although this effect varies across different periods.
- Future Challenges: Meeting global food demands while reducing GHG emissions requires a multi-faceted approach.
- Key Drivers of Emission Intensity: The key drivers influencing GHG emission intensity are agricultural productivity, changes in land use, and livestock production levels.
Limitations Noted in the Document
- Data Availability: The study acknowledges limitations in data availability, particularly regarding the exclusion of certain factors like feed from pasture, crop residues, and swill, which could lead to an overestimation of GHG emissions.
- Trade Effects: The study’s assumption that net importing countries have sufficient resources to produce all imported agricultural products may overestimate trade effects.
- Data Consistency: There were challenges with data consistency, particularly the lack of consistent data for specific emissions sources (e.g., energy use in agriculture) across the entire study period.
- Simplified Calculations: Simplified calculations were used due to the constraints imposed by climatic conditions on the cultivation of specific crops, which might have impacted the accuracy of the findings.
- Transportation Emissions: The study did not fully account for the GHG emissions from the transportation of goods, which could impact the overall emissions reduction estimates.
Conclusion
The study’s primary finding is the halting of the historical decline in the carbon emission intensity of global agriculture, driven by the expansion of livestock production and land-use changes for crop cultivation. This trend poses a significant challenge to global climate change mitigation efforts, especially as the demand for food continues to rise. The research underscores the need for targeted strategies to address these challenges. Key strategies include increasing land productivity, minimizing land-use changes, and promoting global cooperation and policy interventions to reduce GHG emissions. Furthermore, the potential of international trade to mitigate GHG emissions has been recognized. The study suggests the enhancement of free trade of agricultural products between countries to reduce GHG emissions. For example, the study reveals that the contribution of protein import by high GHG importing countries increased over time. However, there is still room for improvement. In line with these findings, the paper highlights that the stagnation in reducing the agrifood system’s contribution to GHG emissions calls for more concerted and innovative approaches. This includes promoting concerted efforts and innovative strategies, thereby ensuring a more sustainable trajectory for food production. Additionally, the research points to the potential of increasing trade of feed protein from lower GHG-exporting countries to high GHG-importing countries as a key driver behind reductions in global GHG emissions. The study also highlights that, in the absence of trade, the actual GHG might be higher than the current level. The findings emphasize that addressing the challenges in the agrifood system necessitates the strengthening of mitigation policies and collaboration to ensure food security and promote a sustainable planet.