AgriSustainability Matters - Issue 16

Ambassador’s word

At a time when the world is striving to reduce carbon emissions, the importance of identifying best practices and promoting low-carbon production systems cannot be overstated. However, without clear taxonomies and accurate measurement criteria for carbon emissions, the promotion of sustainable activities and the development of a relevant carbon market may be at risk.

In this edition of AgriSustainability Matters, researchers Camila Estevam, Eduardo Pavão and Eduardo Assad delve into the inadequacies of the metrics currently used to gauge agriculture and livestock carbon emissions in tropical regions. Turning a complex topic into a remarkably interesting analysis, the team of specialists show how broad accounting methodologies developed by countries in temperate climates skew the measurement of greenhouse gas (GHG) emissions in the agriculture sector of tropical countries.

According to the standardised methods established by the Intergovernmental Panel on Climate Change (IPCC), agriculture and livestock rank second in terms of GHG emissions in Brazil, accounting for nearly one third of all of its emissions. But agriculture is also about sustainability. Our authors argue that agriculture and livestock harbour the potential for significant mitigation of climate change. Sustainable practices such as biological nitrogen fixation, no-tillage agriculture and integrated crop-livestock-forestry systems drastically tilt the GHG balance closer to neutrality. These practices are widely adopted in Brazil, but remain invisible – or unaccounted for – in the metrics currently used.

This inaccuracy in accounting methodology can have far-reaching consequences. The authors note that the IPCC’s estimates for Brazil’s soybean crop emissions are three times higher than they actually should be. Such a wide disparity raises the question of whether Brazil would still be ranked as the 6th largest emitter (accounting for 2.4% of global emissions in 2022) should we adopt a more accurate methodology. On another level, the inaccuracies in current metrics could hinder the inclusion of agricultural activities in regulated carbon markets – a crucial incentive for sectors to reduce and offset their carbon footprint – and stifle the development of effective climate policies in tropical countries.

In GHG metrics as elsewhere, AgriSustainability Matters.

Enjoy the reading.

Antonio de Aguiar Patriota
Ambassador of Brazil to the United Kingdom

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Misplaced metrics: the challenges in measuring the carbon footprint of tropical agriculture

Camila Genaro Estevam
Researcher at the Bioeconomy Observatory and FGVAgro

Co-authors:

Eduardo de Morais Pavão
Researcher at the FGV Bioeconomy Observatory and FGVAgro

Eduardo Delgado Assad, PhD
Coordinator of the GHG Measurement Centre at the FGV Bioeconomy Observatory

Brazil stands out in the global climate debate not only because of its extensive vegetation, but also due to the significance of its agriculture, which positions the country as one of the world’s leaders in food production. It is therefore no surprise that Brazilian policies and practices concerning land use (such as efforts to combat illegal deforestation), agricultural production and environmental conservation have considerable effects on global goals for reducing greenhouse gas (GHG) emissions. Consequently, developing adequate metrics to measure the carbon footprint of tropical agriculture is fundamental for promoting more sustainable practices and formulating effective carbon capture programmes – not only in Brazil, but in all tropical countries worldwide.

In relative terms, when it comes to global CO2 emissions, the agricultural sector is overshadowed by the energy sector – which, alone, accounts for 75% of global emissions. However, when analysing nitrous oxide (N2O) and especially methane (CH4), agriculture gains prominence due to emissions from animal enteric fermentation processes.

When dealing with agricultural activities and the forestry sector, there is a point that is often overlooked: they are the only productive sectors capable of both emitting and removing carbon from the atmosphere.

Thanks to its vast territorial extension and geographic location, Brazil has unique agricultural characteristics. Its livestock farming is predominantly extensive, with cattle being raised freely in pasture areas, totalling 177 million hectares, which is equivalent to 20.87% of all Brazilian territory (1). In agricultural crops, the practice of using biological nitrogen fixers has been widely adopted, reducing the need for nitrogen fertilisers, which are major emitters in agricultural activities. The country also stands out for its capacity for soil carbon sequestration, through widespread adoption of no-till farming, present in approximately 33 million ha (2) – that is, 50% of Brazil’s entire crop area. For reference, in the United Kingdom, no-till farming is practiced only in 3% of the total agricultural area. Crop rotation, including cover crops such as signalgrass and oats, the use of green manures such as sunn hemp, and a favourable climate that allows more than one harvest per year, substantially increase carbon capture and have been promoted since 2010 by the ABC Plan (Low Carbon Agriculture Plan) public policy.

It is within this context that the central question of this article arises: why is Brazilian tropical agriculture the target of criticism for its impact on the environment, especially when it comes to greenhouse gas (GHG) emissions, in spite of the widespread adoption of sustainable practices? The complexity in measuring GHG emissions from agricultural systems offers a significant part of the answer to this question.

Measuring greenhouse gas emissions in agricultural systems

The accounting of GHG emissions follows a scientific approach based on guidelines from the Intergovernmental Panel on Climate Change (IPCC), which provides detailed guidance and standardised methods for preparing GHG emission inventories (IPCC, 2006; IPCC, 2019). Following IPCC guidelines, the following pillars must be considered for measuring GHG emissions: emission factors (values that measure the amount of GHCs released per specific unit of activity or production), conversion metrics (used to compare different gases in terms of equivalence to CO2 , a sort of “common currency”), calculation methodologies and monitoring.

It is precisely at the base of the accounting structure that we encounter the weak points of calculation methodologies, especially in the context of tropical countries.

This can be exemplified by the generic (default) emission factors from the IPCC guidelines, which are classified as the first level of available information, more broadly applicable, called Tier 1. These values, although important, do not reflect specific realities and are often adopted in international calculators to measure (and compare) different production chains worldwide.

In the case of soybean plantation emissions, a study conducted by Bayer as part of its ProCarbono programme, showed that, when using “default” values from the IPCC, emission results were 3 times higher than those obtained when the inherent practices of Brazil were taken into consideration, such as the adoption of no-till farming and biological nitrogen fixation. This outcome illustrates the losses generated by the lack of adoption of factors adjusted to tropical conditions, leading to an overestimation of emissions and, consequently, a distortion of the country’s agricultural reality.

Another important example of discrepancy between the metrics defined by the IPCC and the reality in the tropics relates to cattle farming. For the source of enteric fermentation, the IPCC provides, in its Tier 1 emission factors, a single emission value for the beef cattle class for all of South America. However, the data available on Brazil are more detailed, as they include emissions from different categories of animals, in addition to the age of the animal and the place where it has been reared. Consequently, the national emission factors (Tier 2) take into account the differences in climate and production systems specific to each state in the country. Such values can vary significantly depending on the international or national source (from 56 to 79kg methane/animal/year).

Furthermore, the adoption of integrated production systems, which combine agriculture with livestock and forestry production, has a significant impact on the accounting of emission balances from production operations. These systems have been expanding rapidly in the country, already accounting for 17 million ha, and have significant relevance for low-carbon agriculture. By ignoring them, profound distortions appear when accounting for Brazilian GHG emissions.

Removing emissions and carbon footprint from the system

Despite the challenges already mentioned, one of the most critical points, as well as being prone to distortion, is the issue of GHG removal by agricultural and forestry systems, namely the capacity of these systems to absorb carbon from the atmosphere. Understanding and properly calculating the balance of carbon emissions and removals coming from these activities is essential in developing better strategies to combat climate change.

The following figure details the accounting of carbon emissions and removals in agricultural production systems. Representing four different systems, each with their own capacity rates, production cycle times and pasture quality, the diagram provides a clear view of how emission factors influence the carbon balance. Initially, animal emissions are calculated based on data from Brazil’s National Communications to the UNFCCC. Subsequently, the condition of the pastures is assessed, which can be a source of emissions (in the case of degraded pastures) but also of removals (in the case of well-managed pastures).

This balance makes it possible to quantify the net impact of the system, which is the crucial value for measurement in agricultural production systems. Additionally, the diagram highlights the difference between emission and removal, as well as presenting carbon footprint values, a concept related to the environmental impact of emissions and removals per unit of product (e.g. kg of live weight of the animal, carcass equivalent or quantity of meat produced).

It is important to recognise that intensive systems, with higher capacity rates and shorter production cycles, tend to result in a greater volume of emissions. However, these systems require efficient pasture management to support such productive intensity, promoting an increase in biomass and, consequently, in rates of atmospheric carbon removal. Furthermore, production intensification has a positive impact on the carbon footprint, achieving greater yields with a relatively lower environmental impact.

In the figure below, the same diagram is analysed, this time using the IPCC – Tier 1 emission factors.

The main finding of this comparison is the presence of significant distortions in the measurement of emissions in intensified and well-managed systems. In systems with low degradation or stable conditions, the average emission values tend to be quite close to one another. However, it is precisely in the implementation of sustainable practices that the greatest distortions become evident. A comparative analysis between the results indicates differences in carbon footprints of 49.8%, -6%, -51.8% and -96.9%, respectively (in accordance with the order in the diagram), for the scenarios presented in the example.

It is essential to highlight that both diagrams contemplate the livestock system in isolation, not taking into account practices such as crop rotation systems, agroforestry systems, Crop-Livestock Integration and Crop-Livestock-Forest Integration - the latter, as previously mentioned, already accounting for 17 million ha (3).

Correctly assessing the balance of carbon emissions and removals is challenging, due to the complexity of production systems and variations in management practices adopted in the country. This is a field that requires ongoing research and methodological development to ensure that assessments are as accurate and representative as possible.

The accounting of carbon emissions that only takes into account gross emissions, that is to say, the emission component and not the balance of the systems, penalises production operations that either promote carbon removal at some point in the production system, or that have reduced carbon emission intensity. These particularities of tropical agricultural production are often overlooked in international measurements, assessments and comparisons. This fact is explained by the genesis and development of climate science, a process that occurred predominantly in European countries and the United States.

It is essential that local emission metrics and factors be considered when measuring GHG emissions and removals – especially when it comes to heterogeneous environments and production systems in the agricultural sector, which have profound biological, climatic and cultural variations. Only with accurate metrics will we be able to develop policies that encourage the adoption of low-carbon food systems and effective strategies to combat climate change.

Notes

1. Image Processing and Geoprocessing Laboratory (LAPIG), 2022
2. Federação Brasileira do Sistema Plantio Direto, 2021
3. Integration-crop-livestock-forest Network 2022

Bibliography

BRASIL. Ministério da Ciência, Tecnologia e Inovações. Secretaria de Pesquisa e Formação Científica. Quarta Comunicação Nacional do Brasil à Convenção Quadro das Nações Unidas sobre Mudança do Clima / Secretaria de Pesquisa e Formação Científica. – Brasília: Ministério da Ciência, Tecnologia e Inovações, 2021.

BRASIL. Ministério da Ciência, Tecnologia e Inovação – MCTI, 2020. Sirene - Sistema de Registro Nacional de Emissões. Available at: https://www.gov.br/mcti/pt-br/acompanhe-omcti/sirene

EMBRAPA – Programa Soja Baixo Carbono (SBC). Embrapa soja, 2021. Available at: https://contato.cbsoja.com.br/soja-baixo-carbono

Farmers Weekly. (2015) Many UK growers missing out on the benefits of zero tillage. Farmers Weekly. https://www.fwi.co.uk/arable/many-uk-growers-missing-benefits-zero-tillage

Federação Brasileira do Sistema Plantio Direto. Available at: https://plantiodireto.org.br

IPCC, Intergovernmental Panel on Climate Change. (2006). Guidelines for National Greenhouse Gas Inventories. Volume 1: General Guidance and Reporting.

The authors

Camila Genaro Estevam
Camila is a biologist and master’s student in Public Health at the State University of Campinas (UNICAMP). She has expertise in measuring GHG emissions in production systems, especially agricultural ones. Her experience includes spatial analysis through geoprocessing and GHG balance calculations in agricultural and agroforestry systems, adopting the GHG Protocol methodology. She served as a consultant on a project for UNDP, contributing to São Tomé and Príncipe’s national GHG-LULUCF inventory, presented to the UNFCCC. Co-founder of Geocarbon, she focuses on developing GHG inventories for national and international entities in various agricultural production systems. Currently, she is a researcher at the Bioeconomy Observatory and FGVAgro at Fundação Getúlio Vargas, specialising in measuring GHG emissions in different production systems, with an emphasis on improving metrics adapted to the tropical context.

Eduardo de Morais Pavão
Co-founder of Geocarbon, Eduardo holds an Agricultural Engineering degree from the Federal University of São Carlos (2011) and a Master’s degree in Agribusiness from Fundação Getúlio Vargas (2021, Brazil). Over the last decade, Eduardo has specialised in climate-related issues, focusing his work on GHG emissions and removal assessment, risk mapping and climate mitigation and adaptation recommendations. Eduardo has an extensive knowledge of GHG-related data collection, processing and interpretation. His current portfolio includes consultancy for the World Resources Institute (WRI), defining protocols of carbon accounting for the agriculture and forestry sectors.

Eduardo Delgado Assad, PhD
Eduardo holds an Agricultural Engineering degree from the Federal University of Viçosa, a Master’s and PhD in water management and sciences from the University of Montpellier, France. Between 1993 and 2006, he was national technical coordinator of the Agricultural Zoning of Climate Risks in the Brazilian Ministry of Agriculture, and created/coordinated the national agrometerorology network. He coordinated several projects on a national network and was the Head of Embrapa Informática Agropecuária from 2005 to 2009. He created and coordinated the climate and agriculture subnetwork of the MCT&I climate network until 2013. He is a member of the scientific committee of the Brazilian Panel on Climate Change. In 2011, he was Secretary of Climate Change and Environmental Quality at Brazil’s Ministry of the Environment. He is the coordinator of the GHG Measurement Centre at the FGV Bioeconomy Observatory (OCBio-FGV).

As in all articles in the AgriSustainability Matters bulletin, the views expressed are solely those of the author and do not necessarily reflect the official policy or the position of the Embassy of Brazil

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