Quantifying Greenhouse Gas Fluxes: Methods for Entity-Scale Inventory

Effective beginning 5/20/2025: Please note this site is under review and content may change.

2024 Update to USDA’s Entity-Scale GHG Methods Report

The second edition of Quantifying Greenhouse Gas Fluxes in Agriculture and Forestry: Methods for Entity-Scale Inventory is USDA’s continued response to Section 2709 of the Food, Conservation, and Energy Act of 2008, which directed USDA to “establish technical guidelines that outline science-based methods to measure the environmental service benefits from conservation and land management activities in order to facilitate the participation of farmers, ranchers, and forest landowners in emerging environmental services markets.”

This report provides users with the methods needed to quantify GHG fluxes from agriculture and forestry systems, including croplands and grazing lands, animal production, forestry, wetlands, and land-use change.

The methods in this report serve as the foundation for COMET-Farm, a publicly available web-based tool co-developed by USDA and Colorado State University. COMET-Farm helps users create a detailed GHG inventory of their operation and evaluate a range of alternative management practices that, if adopted, could reduce GHG emissions or increase carbon sequestration.

Introduction

Climate Change at USDA

Since the onset of the Industrial Revolution, human activities have driven increases in global atmospheric concentrations of greenhouse gases (GHGs), including carbon dioxide, methane, and nitrous oxide. These GHGs trap heat in the atmosphere, causing changes to temperature and precipitation patterns. Since 1880, the average global temperature has increased at least 1.1°C.

For more climate change related resources and information, please visit the OCE Climate Change website and the USDA Climate Hubs