A methodology for greenhouse gas emission and carbon sequestration assessments in agriculture: Supplemental materials for info series analyzing low emissions agricultural practices in USAID development projects

As many countries are increasing commitments to address climate change, national governments are exploring how they could best reduce the impact of their greenhouse gas (GHG) emissions. Agriculture is a major contributor to GHG emissions, especially in developing countries, where this sector accounts for an average of 35% of all GHG emissions. Yet many agricultural interventions can also help to reduce GHG impacts. This paper presents the methodology to estimate impacts of agricultural interventions on GHG emissions and carbon sequestration. This methodology is used in an analysis of several development projects supported by the United States Agency for International Development (USAID) and presented as a series of case studies. The methodology allows users to estimate (1) GHG impacts at project scale, (2) GHG emissions by agricultural practice, and (3) GHG emissions per unit of output (i.e., GHG emission intensity). The presented approach is a rapid assessment technique that is well suited to provide an indication of the magnitude of GHG impacts and to compare GHG impact strength of different field activities or cropping systems. It is well adapted to a context of data scarcity, as is common in agricultural investment planning where aggregate data on agricultural land use and management practices are available but where field measurements of GHG and carbon stock changes are missing. This approach is instrumental to inform agricultural investment, project, and policy planners about challenges and opportunities associated with achieving and accounting for GHG emission reductions in agricultural development projects

Reducing food loss in agricultural development projects through value chain efficiency

Food loss and waste (FLW) reduces the amount of food available for distribution and consumption, decreases food security, and increases the environmental burden of food production. Combating FLW addresses the key pillars of climate-smart agriculture for farmers by increasing productivity, promoting adaption to climate change, and mitigating greenhouse gas emissions. Although studies of interventions to reduce FLW exist, almost no research systematically investigates FLW interventions across value chains or in multiple countries, most likely due to challenges in collecting and synthesizing multi-country estimates. Our research team investigated changes in FLW in projects supported by the United States Government’s global hunger and food security initiative: Feed the Future. This provided a unique opportunity to conduct ex-ante estimates of the impacts of interventions across 20 value chains in 12 countries based on interviews with United States Agency for International Development (USAID) and project staff. We provide specific examples of interventions used in each value chain and country context. The results provide an evidence base of interventions that successfully decreased FLW at multiple points along the food value chain, from upstream producer-dominated stages to downstream consumer-dominated stages. Results also show that no single FLW solution or intervention works across agriculture sub-sectors, value chain stages, and countries. Amongst the sub-sectors studied, results showed that FLW interventions directed at extensive dairy systems could provide meaningful greenhouse mitigation. In the dairy supply chain, FLW estimates ranged from 5-50% in the business-as- usual approach and declined 4-10% as a result of intervention

Agricultural development addresses food loss and waste while reducing greenhouse gas emissions

Food loss and waste (FLW) reduce food available for consumption and increase the environmental burden of production. Reducing FLW increases agricultural and value-chain productivity and may reduce greenhouse gas emissions associated with feeding the global population. Although studies of interventions that reduce FLW exist, almost no research systematically investigates FLW interventions across multiple value chains or countries, most likely due to challenges in collecting and synthesizing data and estimates, let alone estimating greenhouse gas emissions. Our research team investigated changes in FLW in projects supported by the United States Agency for International Development\u27s (USAID) global hunger and food security initiative, Feed the Future. This was a unique opportunity to conduct ex-ante estimates of the impacts of FLW interventions across 20 value chains in 12 countries, based on project documents and interviews with USAID and project staff. This paper describes specific interventions in each value chain and country context, providing insight to interventions that decrease FLW at multiple points along food value chains, from upstream producer-dominated stages to downstream consumer-dominated stages. Amongst the sub-sectors studied, FLW interventions directed at extensive dairy systems could decrease FLW by 4–10%, providing meaningful greenhouse gas mitigation, since these systems are both emission-intensive and experience high FLW. More modest emissions reductions were found for other key agricultural products, including maize, rice, vegetables, fruits and market goods

Analyzing the greenhouse gas impact potential of smallholder development actions across a global food security program

This article analyses the greenhouse gas (GHG) impact potential of improved management practices and technologies for smallholder agriculture promoted under a global food security development program. Under \u27business-as-usual\u27 development, global studies on the future of agriculture to 2050 project considerable increases in total food production and cultivated area. Conventional cropland intensification and conversion of natural vegetation typically result in increased GHG emissions and loss of carbon stocks. There is a strong need to understand the potential greenhouse gas impacts of agricultural development programs intended to achieve large-scale change, and to identify pathways of smallholder agricultural development that can achieve food security and agricultural production growth without drastic increases in GHG emissions. In an analysis of 134 crop and livestock production systems in 15 countries with reported impacts on 4.8 million ha, improved management practices and technologies by smallholder farmers significantly reduce GHG emission intensity of agricultural production, increase yields and reduce post-harvest losses, while either decreasing or only moderately increasing net GHG emissions per area. Investments in both production and post-harvest stages meaningfully reduced GHG emission intensity, contributing to low emission development. We present average impacts on net GHG emissions per hectare and GHG emission intensity, while not providing detailed statistics of GHG impacts at scale that are associated to additional uncertainties. While reported improvements in smallholder systems effectively reduce future GHG emissions compared to business-as-usual development, these contributions are insufficient to significantly reduce net GHG emission in agriculture beyond current levels, particularly if future agricultural production grows at projected rates

Making trees count in non-Annex I countries: Measurement, reporting and verification (MRV) of agroforestry in the UNFCCC

Key messages ◼ Many developing countries recognize that agroforestry offers benefits for both people and planet and have integrated it into national policy to help meet development and climate goals. ◼ Despite this interest, technical and institutional barriers often prevent trees outside forests and agroforestry from being recognized in United Nations Framework Convention on Climate Change (UNFCCC) measurement, reporting and verification (MRV) processes, such as national greenhouse gas inventories and REDD+. ◼ This lack of inclusion means agroforestry is less likely to receive financial investments and other support to match its potential significance in addressing climate change. ◼ Some countries have found ways to overcome these barriers, providing lessons for others to follow. Successful arrangements include: development of policy and regulations directly addressing agroforestry; farmer and producer groups are involved in the process; there is a collaborative research environment; and coordination among the diverse institutions involved with land use

Making trees count: Measurement and reporting of agroforestry in UNFCCC national communications of non-Annex I countries

Agroforestry—the integration of trees with crops and livestock—generates many benefits directly relevant to the UNFCCC\u27s Koronivia Joint Work on Agriculture, including: (i) building resilience, (ii) increasing soil carbon and improving soil health, (iii) providing fodder and shade for sustainable livestock production and (iv) diversifying human diets and economic opportunities. Despite its significance to the climate agenda, agroforestry may not be included in measurement, reporting and verification (MRV) systems under the UNFCCC. Here we report on a first appraisal of how agroforestry is treated in national MRV systems under the UNFCCC. We examined national communications (NCs) and Nationally Determined Contributions (NDCs) of 147 countries, REDD + strategies and plans of 73 countries, and 283 Nationally Appropriate Mitigation Actions (NAMAs), as well as conducted interviews with representatives of 12 countries in Africa, Asia and Latin America. We found that there is a significant gap between national ambition and national ability to measure and report on agroforestry. Forty percent of the countries assessed explicitly propose agroforestry as a solution in their NDCs, with agroforestry being embraced most widely in Africa (71%) and less broadly in the Americas (34%), Asia (21%) and Oceania (7%). Seven countries proposed 10 agroforestry-based NAMAs. Of 73 developing countries that have REDD + strategies, about 50% identified agroforestry as a way to combat forest decline. Despite these intentions, however, agroforestry is not visible in many MRV systems. For example, although 66% of the countries reported non-forest trees in the national inventory, only 11% gave a quantitative estimate of number of trees or areal extent. Interviews revealed institutional, technical and financial challenges preventing comprehensive, transparent inclusion of agroforestry in MRV systems. The absence has serious implications. If such trees are not counted in inventories or climate change programs, then a major carbon sink is not being accounted for. Only if agroforestry resources are measured, reported and verified will they gain access to finance and other support. We discuss four recommendations to better match ability to ambition

An evaluation of emerging feed additives to reduce methane emissions from livestock

The inclusion of feed additives in livestock diets or supplements is a routine global nutritional management practice. Consequently, the existing commercial feed additive marketing and delivery pathways will be able to deliver rapid market penetration of feed additives specifically developed to reduce enteric methane emissions. So, the delivery path is clear, but are the methane mitigating additives available, effective, and are there any constraints or risks associated with their use? To answer these questions an assessment of the ten leading classes of compounds being studied for methane mitigation efficacy in ruminants was made. The assessment is provided as a concise resource that can serve as an evidence base to guide investment and management decisions by all actors in the livestock additive supply chain

Mineralization of ancient carbon in the subsurface of riparian forests

Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 113 (2008): G02021, doi:10.1029/2007JG000482.Microbial activity in saturated, subsurface sediments in riparian forests may be supported by recent photosynthate or ancient (>500 ybp) soil organic carbon (SOC) in buried horizons. Metabolism of ancient SOC may be particularly important in riparian zones, considered denitrification hot spots, because denitrification in the riparian subsurface is often C-limited, because buried horizons intersect deep flow paths, and because low C mineralization rates can support ecosystem-relevant rates of denitrification. Buried horizons are common where alluvial processes (stream migration, overbank flow) have dominated riparian evolution. Our objectives were to determine: (1) the extent to which ancient SOC directly supports subsurface microbial activity; (2) whether different C sources support microbial activity in alluvial versus glaciofluvial riparian zones; and (3) how microbial use of ancient SOC varies with depth. In situ groundwater incubations and 14C dating of dissolved inorganic carbon revealed that ancient SOC mineralization was common, and that it constituted 31–100% of C mineralization 2.6 m deep at one site, at rates sufficient to influence landscape N budgets. Our data failed to reveal consistent spatial patterns of microbially available ancient C. Although mineralized C age increased with depth at one alluvial site, we observed ancient C metabolism 150 cm deep at a glaciofluvial site, suggesting that subsurface microbial activity in riparian zones does not vary systematically between alluvial and glaciofluvial hydrogeologic settings. These findings underscore the relevance of ancient C to contemporary ecosystem processes and the challenge of using mappable surface features to identify subsurface ecosystem characteristics or riparian zone N-sink strength.We are grateful to the Cornell Program in Biogeochemistry for graduate research grants and to the U.S. EPA for a STAR Graduate Fellowship to Noel Gurwick. Support for radiocarbon analyses also came from USDANRICGP grant 99–35102– 8266, NSF cooperative agreement OCE-9807266, and an Andrew W. Mellon Foundation grant to the Institute of Ecosystem Studies. A graduate research grant to N. Gurwick from the Theresa Heinz Scholars for Environmental Research provided salary for Pete Seitz-Rundlett

National mitigation potential from natural climate solutions in the tropics.

Better land stewardship is needed to achieve the Paris Agreement's temperature goal, particularly in the tropics, where greenhouse gas emissions from the destruction of ecosystems are largest, and where the potential for additional land carbon storage is greatest. As countries enhance their nationally determined contributions (NDCs) to the Paris Agreement, confusion persists about the potential contribution of better land stewardship to meeting the Agreement's goal to hold global warming below 2°C. We assess cost-effective tropical country-level potential of natural climate solutions (NCS)-protection, improved management and restoration of ecosystems-to deliver climate mitigation linked with sustainable development goals (SDGs). We identify groups of countries with distinctive NCS portfolios, and we explore factors (governance, financial capacity) influencing the feasibility of unlocking national NCS potential. Cost-effective tropical NCS offers globally significant climate mitigation in the coming decades (6.56 Pg CO2e yr-1 at less than 100 US$ per Mg CO2e). In half of the tropical countries, cost-effective NCS could mitigate over half of national emissions. In more than a quarter of tropical countries, cost-effective NCS potential is greater than national emissions. We identify countries where, with international financing and political will, NCS can cost-effectively deliver the majority of enhanced NDCs while transforming national economies and contributing to SDGs. This article is part of the theme issue 'Climate change and ecosystems: threats, opportunities and solutions'

CARBON IN RIPARIAN SUBSURFACE ECOSYSTEMS: SOURCES, LABILITY, AND SPATIAL PATTERNS

Numerous studies suggest that denitrification in riparian zones removes nitrogen from groundwater as it moves from terrestrial to aquatic ecosystems. However, removal rates vary widely among sites complicating the incorporation of riparian zones into models of nitrogen movement across landscapes. Because denitrification in the riparian subsurface is often limited by the supply of microbially-available carbon, explaining how and why carbon supply varies among riparian zones using mappable landscape attributes holds practical and theoretical appeal. First principles suggest three carbon sources for subsurface microbes: (1) dissolved organic carbon leached from surface soils; (2) deep plant roots; and (3) buried, carbon-rich soil horizons deposited long ago. Working in Rhode Island USA at riparian zones mapped as outwash and alluvium, I investigated the relative importance of different carbon sources to 3 meters depth. Field and laboratory experiments showed that both roots and buried horizons can supply carbon in the shallow subsurface (40-75 cm), but that buried horizons dominate below 75 cm. Radiocarbon dates and results from ingrowth cores showed that roots 40-75 centimeters deep grow and decompose on decadal time scales and form patches of organic matter that may influence nitrogen removal from groundwater. However, in both alluvial and outwash profiles, most roots below 80 cm are relics (usually > 140 years old) and therefore do not act as direct carbon conduits between the surface and deep subsurface. Laboratory incubations of buried soils from many sites demonstrated that high rates of carbon mineralization associated with these soils are common. In-situ groundwater incubations and 14C dating demonstrated that metabolism of ancient carbon constitutes at least 31% of total carbon mineralization >2 meters below the surface at some sites. My results suggest that: (1) the depth of the biologically active zone extends as deep as buried horizons; (2) on outwash and alluvium the riparian surface and subsurface are largely decoupled on time scales of months to years; (3) functional classifications of riparian zones intended to support management need to include buried horizons and recognize the limited influence of surface vegetation on subsurface biogeochemistry over short time frames