Understanding Discrepancies in Food System Emissions Data
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Chapter 1: Introduction to Food System Emissions
How reliable are the statistics surrounding food system emissions that account for one-third of global greenhouse gas emissions? The answer often reveals a blend of estimations rather than concrete figures.
For anyone aiming to discuss emission reductions in the context of climate change, grasping some fundamental truths is essential. Here’s a concise summary:
- Emission figures related to food production are frequently incorrect.
- As a result, such statistics should not be taken at face value.
- If you encounter these figures, it's likely they stem from sources unfamiliar with their origins, akin to me discussing musical notation without expertise.
Many are aware that food systems contribute to roughly one-third of global emissions. This statistic serves as a foundation for evaluating its credibility.
A comprehensive inventory of greenhouse gas emissions from food systems was developed by the Joint Research Center (JRC) of the European Union, published in Nature under the title: "Food systems are responsible for a third of global anthropogenic GHG emissions" (Crippa et al., 2021). The research is also referred to as EDGAR FOOD. The study stated:
"It addresses the lack of precise data for numerous countries by providing sectoral contributions to food-system emissions, which are crucial for designing effective mitigation strategies. In 2015, food-system emissions were estimated at 18 Gt CO2 equivalent per year globally, accounting for 34% of total GHG emissions."
This information rapidly spread across social media and news outlets, leading to widespread acceptance as an unassailable fact. However, few have delved into the study's methodology and data sources. These figures are estimates derived from three tiers of data:
- Tier 1: Broad estimates based on regional averages, often lacking precision.
- Tier 2: More localized estimates.
- Tier 3: Exact figures based on precise measurements (the smallest proportion of the data).
Considering this, one must question the accuracy of the assertion that food systems are responsible for one-third of global emissions. The answer remains consistently the same: it’s a combination of estimates with a minor contribution from accurate data. I’ve found numerous ambiguous numbers devoid of clear mathematical backing, along with amusing notes in the dataset like, “To be completed by Francesco Tubiello”—a note dating back to 2015, which appears unresolved even in 2021. This study was published in a reputable journal! If any reviewer had scrutinized the data's consistency and quality, such comments would never have appeared. Remember, this data plays a critical role in shaping GHG emission reduction strategies, not just a score sheet for local sports.
Now, let’s delve deeper. The total of 18 Gt CO2e is broken down in the following analysis.
Section 1.1: The Basis of EDGAR FOOD Research
It's crucial to note that the EDGAR FOOD analysis was based on the IPCC AR5 (2014) methodology, focusing primarily on data from 2015, even while including data from 1990 onward. The study states:
"We have developed a new global food emissions database (EDGAR-FOOD) estimating greenhouse gas (GHG; CO2, CH4, N2O, fluorinated gases) emissions for the years 1990–2015."
This clarification prevents any misconceptions about comparing unrelated data sets. Even with this clarity, the data remains convoluted.
EDGAR FOOD identified a specific figure: 17.95 Gt CO2e in their paper (source data: 43016_2021_225_MOESM3_ESM.xls). The authors rounded this to 18 Gt CO2e for their conclusions, which is acceptable.
To ensure accuracy, the JRC released updated data in 2019 for the 2015 GHG emissions. The current EDGAR database adheres to the more recent AR6 methodology. Be mindful of what you are comparing! Comparisons must be made only within the same time frame to avoid misleading conclusions.
In 2015, total global emissions were recorded at 49.113 Gt CO2e (JRC/EDGAR DB v5).
Back to the calculations:
17.95 Gt of the total 49.1 Gt CO2e translates to approximately 36.6%—but the study claims 34%.
If 17.95 Gt is the accurate figure, then the calculation should have been based on 52.94 Gt CO2e. However, the EDGAR database could not register such emissions at that time. These numbers only emerged in 2018, amounting to approximately 51.2 Gt CO2. The JRC/EDGAR only recognized this in 2019, but the study relied on 2015 data. Thus, it seems there may have been a mix-up with the global GHG emissions figures during the study's compilation.
Chapter 2: Data Processing Challenges
The first video explains how to utilize StatCrunch for hypothesis testing regarding the ages of award-winning actors, shedding light on the importance of data accuracy in research.
If 52% of CO2 emissions resulted from the 17.95 Gt CO2e, that would suggest that fossil fuels contributed around 9.3 Gt CO2. This aligns closely with EDGAR's findings, which estimated food systems generated 9.2 Gt CO2 in 2015. Yet again, 9.3 is not equal to 9.2, despite coming from the same study.
In 2015, JRC/EDGAR DB v5 estimated CO2 emissions from fossil fuels at 36.3 Gt (again, based on estimates). This would imply that food systems accounted for 25.6% of global fossil fuel CO2 emissions.
Deep Dive: A Closer Look at Emissions
I attempted to categorize emissions from EDGAR FOOD into the same categories used by the JRC. The findings were surprising:
In 2015, global food systems in the power sector emitted 3,807 Mt of CO2, which is 13.3% less than the entire Chinese power sector's emissions of 4,396 Mt.
Would the global community respond with the same level of criticism toward China for its substantial power sector emissions as it does toward global food system emissions?
Similarly, transport emissions from the entire global food system (1,548 Mt) were 12% lower in 2015 compared to U.S. transport emissions (1,752 Mt). Would there be comparable criticism toward U.S. transport emissions as there is for global food system emissions?
I don’t think so.
In the past five years, have you noticed increased advocacy for ending livestock farming in favor of plant-based diets as a pivotal solution to climate change? Have you heard Bill Gates emphasize the need for China to reduce emissions from its power sector?
I don’t think so.
Countries responsible for half of the global GHG emissions from food systems (according to the EDGAR Food database) are:
China, Indonesia, United States, Brazil, India, Russian Federation, and Zambia.
These seven nations account for 50% of global food system GHG emissions.
Conclusion: The Importance of Informed Research
Anyone engaging in research or straightforward interpretation of emissions-related data without a solid understanding of its origins may inadvertently disseminate misinformation. This issue extends beyond Medium to various platforms. Many self-proclaimed emissions experts, after merely skimming keywords, lack the depth of knowledge necessary to contribute meaningfully to the discourse.
This discussion should serve as a reminder that articles or blogs that present random data should be viewed as superficial educational resources.
Some may perceive these critiques as indicative of a climate change denial stance. However, I am a staunch advocate for climate education. It is crucial to highlight and address the errors prevalent in climate change research across the board. Misleading data has historically served only those profiting from it.
Science is complex, and this complexity must be recognized and respected.
For a comprehensive overview of my content on Medium, you can explore my content navigator, which organizes various topics into coherent sections.
Enjoy!
References:
The second video features Dennis Meadows discussing the implications of "Limits to Growth" after 50 years, emphasizing the need for urgent climate action.