Field of native grass in Texas

Glossary of Terms: Climate, Carbon, and Agriculture

By Nina Prater, NCAT Sustainable Agriculture Specialist; Lee Rinehart, NCAT Northeast Regional Director; Katherine Favor, NCAT Sustainable Agriculture Specialist; and Elise Haschke, NCAT Climate and Agriculture Program Manager

The words and terms in the conversation around climate change can be confusing or unclear. The terminology being used to represent the relationship between climate and agriculture is equally confusing. Because it is so important for producers to both understand climate change and communicate their climate-beneficial practices to their customers, we developed a glossary to make relevant terms more clear. In this glossary, we define many common climate-related words and phrases and describe how they relate to agriculture.

Climate Change and Carbon – General

Above-ground Carbon Storage: The storage of carbon in above-ground plant biomass. Carbon can be stored temporarily above ground in herbaceous grasses and plant stems, leaves, and flowers. Carbon can be stored long-term above ground in woody biomass such as wood, bark, and branches.

Below-ground Carbon Storage: The storage of carbon below ground in plant roots and soil organic matter. Carbon can be stored temporarily below ground in plant roots. Long-term below-ground carbon storage occurs when plant matter is turned into humus: stable organic matter at the final stage of decomposition.

Carbon Cycle: Carbon is the chemical carrier of solar energy. Like the water cycle or other nutrient cycles, the carbon cycle is the movement of carbon between gas, solid, and liquid forms in the atmosphere, living things, soil, water bodies, and even the Earth’s crust. Before the industrial revolution, the carbon cycle was generally in-balance, with approximately as much carbon being emitted into gas form as was sequestered back into solid form. Human activity over the past few centuries has caused the carbon cycle to be out of balance. We currently emit more carbon into the atmosphere than we are sequestering back into solid form.

Carbon Dioxide Equivalent (CO2e): Although carbon dioxide (CO2) is the most prevalent greenhouse gas (GHG) in the atmosphere, there are other important GHGs, including methane (CH4) and nitrous oxide (N2O). These gases absorb more solar energy and warm the Earth significantly more than CO2. In order to easily compare the effects of different gases, a standardized unit of measurement, the carbon dioxide equivalent (CO2e), was created. One CO2e equals the global warming potential of one ton of CO2 over a 100-year time period. Using this unit of measure, amounts of different GHGs can be expressed as CO2e in order for their impact on climate change to be understood more readily. For example, one ton of N2O is equivalent to almost 300 tons of CO2.

Carbon Footprint: The amount of greenhouse gases (often expressed as CO2 or CO2 equivalents) that are emitted by a particular activity, event, entity, etc. The smaller the carbon footprint, the better.

Carbon Sequestration: The process of removing carbon from the atmosphere, transforming the carbon from gaseous forms into solid forms either temporarily or indefinitely. Carbon sequestration occurs naturally in many Earth systems, including geological, biological, and hydrological. On farms, plants sequester carbon dioxide (CO2) when they photosynthesize. Through photosynthesis, atmospheric CO2 becomes solid above- and below-ground plant biomass. Certain agricultural practices can enhance a farm’s ability to store this biomass in solid form in the long-term, which helps mitigate climate change.

Carbon Sink: Anything that absorbs or accumulates atmospheric carbon dioxide and stores it in a stable form where it cannot easily be released back into the atmosphere. Forests and soils are examples of potential carbon sinks.

Climate: The long-term average of weather events, as opposed to weather, which is atmospheric conditions as they occur.

Climate Adaptation: Making changes in response to climate change, in order to increase resilience in an unpredictable climate, with the goal of being able to continue farming despite climate change’s negative impacts. Climate adaptation on farms can prepare them to withstand both current and future climate change impacts.

Climate Change: The many rapid and adverse changes Earth’s climate is experiencing, including erratic and adverse precipitation, temperature, and wind patterns. While some climate change occurs naturally, the frequency and intensity of the climate change occurring now is primarily the result of human activity, such as the burning of fossil fuels and the destruction of natural resources.

Climate Change Mitigation: Strategies and actions that work to slow down and reduce the severity of climate change. Climate mitigation on farms refers to farming practices that can inhibit climate change by reducing greenhouse gas emissions and sequestering carbon dioxide from the atmosphere into above- and below-ground biomass.

Climate Resilience: The ability to withstand and recover from the negative impacts of climate change. Climate resilience on farms refers to a farm’s ability to survive and thrive in the face of climate change and to bounce back after climate change-related damages occur.

Drawdown: An optimistic forecast of a time in the future when greenhouse gases will be removed from the atmosphere, or “drawdown,” at a greater rate than they are released into the atmosphere, thereby halting human-caused climate change. Achieving drawdown in the future depends entirely on what actions humans take now.

Global Average Temperature: A unit of measure used to understand global temperature trends over time. It is a long-term average of temperatures taken around the globe. With a global average temperature, it is possible to compare past and current global average temperatures and predicted future temperatures to understand the magnitude of climate change.

Global Warming: The warming of Earth’s surface (the global average temperature) in response to increased amounts of greenhouse gases in the atmosphere as a result of human activity.

Greenhouse Gas (GHG): Any gas that absorbs radiant energy and reflects it back to the earth. Earth’s primary greenhouse gases include water vapor (H20), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3). Earth needs greenhouse gases at balanced levels to maintain the right temperature to sustain life on Earth as we know it. When greenhouse gases are emitted into the atmosphere at a greater rate than they are sequestered in solid form, Global Warming occurs. Currently, the amount of greenhouse gases emitted into the atmosphere far exceeds the amount being sequestered, and, as a result, the planet is projected to warm by 2°C, which will have widespread damaging impacts.

Natural Climate Solutions/Nature-Based Climate Solutions: Solutions to the climate crisis that are based on the natural processes found in Earth’s forests, grasslands, wetlands, and agricultural working lands. Nature-based solutions can mitigate climate change in two ways: 1) Reducing greenhouse gas emissions associated with the stewardship of these natural lands; or 2) Sequestering and storing carbon dioxide naturally through the processes of photosynthesis and other naturally occurring chemical and mineral processes. Successfully mitigating climate change through natural climate solutions will require habitat preservation and creating agroecological food and fiber production systems.

Soil Health: Soil health is defined by USDA’s Natural Resources Conservation Service as “the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans.” The term “soil health” recognizes that soil is a living system, as opposed to an inert accumulation of minerals. NCAT promotes five principles of soil health that, if applied holistically and appropriately in the context of the farm or ranch, can build and maintain soil health:

  1. Minimize physical and chemical disturbances to the soil
  2. Increase biodiversity
  3. Keep the soil covered
  4. Keep living roots growing in the soil as much of the year as possible
  5. Incorporate animals (or their manure/compost) in the system

Healthy soils tend to be higher in soil organic matter than degraded soils and, thus, tend to contain more organic carbon. Therefore, increasing soil health is a critical part of climate change mitigation, as well as being important for long-term farm productivity.

Soil Organic Carbon (SOC): Carbon stored in the soil that is biological in origin. Approximately half of soil organic matter is made up of organic carbon. SOC levels can change slowly over time, based on soil management. SOC is often what people measure in the carbon marketplace, whereas soil organic matter is usually what is measured in a typical soil fertility test.

Soil Organic Matter (SOM): SOM includes living and dead microbial tissue; plant, animal, and fungal residues; charcoal; plant root exudates; decomposition by-products; and humus. Humus is organic matter that has reached the final stage of decomposition, and, because of its stable form, it has the ability to store carbon long-term in the soil, in a form that is not easily released back into the atmosphere. Humus is what gives healthy soil its characteristic dark-brown color. Soil organic matter is usually concentrated in the topsoil layer, but also can accumulate at much greater soil depths.

Weather: Atmospheric conditions as they occur, as opposed to climate, which is the long-term average of weather events.

Terms of Practice and Marketing Claims Related to Climate Change

Agroecology: The formalized conception of the farming sector as an ecosystem where culturally evolved, decentralized local knowledge from indigenous cultures is combined with modern science, environmentalism, and rural sociology to ensure community sustainability and resilience. Agroecology reflects the influence human decision-making has within natural systems and relies on social and ecological diversity. Agroecology is based on three principles: society (markets, land use, local governance, energy, labor, economic conditions, etc.), biology (soil rhizosphere, crops, livestock, wildlife, etc), and environment (ecological relations, nutritional pathways, topography, weather, climate, water, etc). Agroecology has a robust and inclusive constituency across the world, including small farmers, nonprofit organizations, and academics, but has been neglected in food, agriculture, climate, and biodiversity summits worldwide.

Carbon Farming: An integrated conservation farming framework that explicitly recognizes that it is solar energy that drives farm ecosystem dynamics and that carbon is the carrier of that energy within the farm system. Carbon farming utilizes practices such as cover cropping, agroforestry, or planned grazing (among others) with the goal of capturing and storing more carbon in the above- and below-ground carbon sinks than is emitted from its farming practices.

Carbon Negative: Emitting less than zero net carbon dioxide and carbon dioxide equivalent (CO2e) greenhouse gases. Because one cannot emit a negative amount of carbon, “carbon negativity” can only be achieved by capturing more carbon than one emits, either through carbon sequestration, carbon capture, or carbon offsets.

Certified Carbon Neutral: An independent marketing label certifying that member companies measure, reduce, and offset carbon emissions in their supply chains. Standards of this certification are based on the standards outlined in the PAS 2060 environmental standard and are verified by independent verification companies. This marketing label verifies that a product has achieved a carbon footprint of zero through a combination of means, including reductions in emissions and/or carbon offsets.

Climate Beneficial: Among the terms of practice used to describe an agricultural system that mitigates and adapts to the effects of climate change (e.g., climate smart, carbon farming, climate friendly, etc.), NCAT aligns with the term climate beneficial. Climate-beneficial practices are those that reduce or prevent GHG emissions and/or sequester carbon by improving soil health, above-ground biomass, and water quality; restoring natural ecosystems; and promoting biological diversity and agroecosystem resiliency.

The Climate BeneficialTM Verification program and label are a trademark developed by the nonprofit organizations Fibershed and Carbon Cycle Institute to describe agricultural fiber products that are “sourced from land stewards who are enhancing carbon drawdown through agricultural practices that regenerate soil health.”

Climate Forward: Used in reference to the act of looking ahead to the climate-crisis horizon, “climate forward” places climate as a priority in planning, decision-making, and action. Climate-forward strategies and actions are meant to transform current systems to meet and mitigate future climate challenges.

Climate Friendly: Systems or practices that benefit the climate by sequestering CO2 from the atmosphere and by reducing GHG emissions. Most of these practices provide other ecosystem benefits, as well, beyond just helping mitigate climate change. While “climate smart agriculture” is an agency-developed term with a specific definition, “climate friendly” is a more general term.

Climate Neutral: The achievement of net-zero greenhouse gas emissions, through sequestering an equal or greater amount of greenhouse gases than are emitted.

Climate Smart: An agency-led approach to land management focused on productivity, resilience, and reduced carbon emissions. The World Bank Group, through the Climate Change Action Plan, contributes 52% of its financing in agriculture to developing countries to use for climate adaption and mitigation and to help implement the countries’ Nationally Determined Contributions and achieve their Sustainable Development Goals.

For the USDA, Climate Smart means those practices that farmers can implement with NRCS financial and technical-assistance support to mitigate the impacts of climate change by delivering potentially quantifiable reductions in emissions and/or increase carbon sequestration.

In 2022, COP27 brought 300 partners from 40 nations together to address climate and food systems with a Climate Smart initiative. However, COP27 leaders focused on fostering efficiencies within the current industrial system rather than formalizing smallholder agroecological development that is known to promote reduced emissions and carbon sequestration through biodiversity and reduced synthetic inputs.

Climate-Smart Commodity: The U.S. Department of Agriculture (USDA) has defined a climate-smart commodity as “any agricultural commodity that is produced using agricultural (farming, ranching, or forestry) practices that reduce greenhouse gas emissions or sequester carbon.” The USDA defines commodity crops broadly as “traditional agricultural crops like fruits, grains, cotton, peanuts, oilseeds, livestock, dairy, forage crops, and vegetables, as well as timber and other forestry products, and can also include other specialty, organic, or indigenous crops.”

Organic Agriculture: The USDA National Organic Program outlines in great detail the requirements producers must follow to be able to claim their products are certified organic. Although climate change is not mentioned specifically in the National Organic Standards, many practices required in the organic standards (specifically, in the Soil Fertility and Crop Nutrient Management Practice Standard 205.203, Subparts a, b, and c) lead to soil carbon sequestration or result in reduced greenhouse gas (GHG) emissions. For example, synthetic nitrogen fertilizer, a large contributor to GHG emissions in agriculture, is prohibited in organic production. Using manure, compost, or cover cropping for soil fertility is generally less energy intensive. However, every organic farm is different, making it impossible to make specific claims about climate impacts of organic production. Broadly speaking, though, following organic production standards can be more climate beneficial than conventional production that relies on synthetic fertilizer and pesticides.

PAS 2060: A standard for verifying the carbon neutrality claims in the internationally recognized “Certified Carbon Neutral” marketing label.

Regenerative Agriculture: There is no broadly agreed-upon definition of “regenerative,” but most definitions describe it as agriculture that improves the health of the landscape. Included in the agroecological landscape are the farmers, farmworkers, and communities, so improving their well-being is critical, as well. Regenerative agriculture strives to improve the land and human well-being, all while improving the economic resilience of farms and communities.

Two cornerstones of regenerative agriculture are: 1) increasing and maintaining biodiversity; and 2) continual improvement of soil organic matter. These two cornerstones improve ecosystem function in a wide variety of ways, including, but not limited to, reducing environmental contamination, maintaining functional water cycles, improving soil fertility, and sequestering carbon to mitigate climate change.

Sustainable Agriculture: Agricultural systems that foster continued farm productivity, environmental integrity, and farm profitability through the efficient use of ecosystem services and on-farm resources. As opposed to regenerative agriculture practices, which improve farm vitality, profitability, and farmer wellbeing, sustainable agriculture practices prevent existing conditions from worsening.