In 2008, agricultural greenhouse gas sources accounted for about 6% of total U.S. greenhouse gas emissions. The U.S. Agriculture and Forestry Greenhouse Gas Inventory: 1990-2008 was developed to provide a comprehensive assessment of the contribution of U.S. agriculture and forestry to greenhouse gas emissions and carbon sequestration. It provides extensive, in-depth emissions and sinks estimates for livestock, cropland, and forests, as well as energy consumption in livestock and cropland agriculture. Estimates are provided at State, regional, and national scales, categorized by land ownership and management practices where possible. Charts and tables. This is a print on demand edition of an important, hard-to-find publication.

Measurement guidelines for forest carbon sequestration were developed to support reporting by public and private entities to greenhouse gas registries. These guidelines are intended to be a reference for designing a forest carbon inventory and monitoring system by professionals with a knowledge of sampling, statistical estimation, and forest measurements. This report provides guidance on defining boundaries; measuring, monitoring, and estimating changes in carbon stocks; implementing plans to measure and monitor carbon; and developing quality assurance and quality control plans to ensure credible and reproducible estimates of the carbon credits.

Global climate change is a natural process that currently appears to be strongly influenced by human activities, which increase atmospheric concentrations of greenhouse gases (GHG). Agriculture contributes about 20% of the world’s global radiation forcing from carbon dioxide, methane and nitrous oxide, and produces 50% of the methane and 70% of the nitrous oxide of the human-induced emission. Managing Agricultural Greenhouse Gases synthesizes the wealth of information generated from the GRACEnet (Greenhouse gas Reduction through Agricultural Carbon Enhancement network) effort with contributors from a variety of backgrounds, and reports findings with important international applications. Frames responses to challenges associated with climate change within the geographical domain of the U.S., while providing a useful model for researchers in the many parts of the world that possess similar ecoregions Covers not only soil C dynamics but also nitrous oxide and methane flux, filling a void in the existing literature Educates scientists and technical service providers conducting greenhouse gas research, industry, and regulators in their agricultural research by addressing the issues of GHG emissions and ways to reduce these emissions Synthesizes the data from top experts in the world into clear recommendations and expectations for improvements in the agricultural management of global warming potential as an aggregate of GHG emissions

As a signatory to the United Nations Framework Convention on Climate Change (UNFCCC), the United States has reported an inventory of greenhouse gas (GHG) emissions and removals by sector, as defined by the Intergovernmental Panel on Climate Change (IPCC), since the mid-1990s (U.S. EPA 2023). In 2021, United States net GHG emissions increased by more than 6.4 percent relative to 2020 net emissions, which had decreased substantially from previous years and was due, in large part, to the global pandemic. Forest land, harvested wood products (HWP), woodlands, and urban trees within the land sector collectively continue to represent the largest net carbon sink in the United States, offsetting the equivalent of more than 12.4 percent of total (i.e., gross) GHG emissions in 2021 (U.S. EPA 2023). Estimates of GHG emissions and removals are compiled by U.S. Department of Agriculture (USDA), Forest Service researchers and partners and are based primarily on National Forest Inventory (NFI) data collected and maintained by the Forest Inventory and Analysis (FIA) Program within the Forest Service. This resource bulletin provides an overview of the status and trends of GHG emissions and removals from forest land, woodlands in the grassland category, HWP, and urban trees in settlements in the United States from 1990 to 2021. The estimates for the United States summarized here are based on the compilation reported in the “Land Use, Land-Use Change, and Forestry” chapter of the U.S. EPA (2023) submission to the UNFCCC. Most of the national scale estimates are also developed and reported at the individual State level (fig. 1) for the entire 1990–2021 time series and are available in a published research dataset (Walters et al. 2023). This report also includes regional carbon stock and stock change estimates by broad ownership category (i.e., private or public land) and National Forest System region.