The Intergovernmental Panel on Climate Change (IPCC) reported in 2021 that it is “unequivocal that human influence has warmed the atmosphere, ocean, and land.” Rapid and widespread shifts have occurred in the air, seas, ice systems, and ecosystems.
The report found that global surface temperatures between 2001–2020 were 0.99°C (1.78°F) higher than in the pre-industrial era (1850–1900). Looking ahead, projections suggest that by 2081–2100, depending on greenhouse gas (GHG) emissions, global warming could range between 1.0°C (1.8°F) and 5.7°C (10.26°F) above that same baseline.
For agriculture, these temperature increases carry two major consequences:
- More extreme weather: Each 0.5°C of additional warming raises the likelihood and severity of heatwaves, heavy rainfall, and droughts.
- Intensified storms: Extreme precipitation events are expected to grow stronger and more frequent, while the most intense tropical cyclones (categories 4–5) will likely become more common.
Although global trends are alarming, the impacts will vary across regions including within the U.S.
Read More: Boost Yields with Variable Rate Seeding: The Future of Precision Farming
The Greenhouse Effect: Natural vs. Enhanced
The greenhouse effect is a natural process: greenhouse gases trap some of the sun’s heat, keeping Earth warm enough for life. However, human activities have amplified this process. Burning fossil fuels, deforestation, and industrial agriculture have significantly increased greenhouse gas levels, creating what scientists call the enhanced greenhouse effect the driver of global warming.
Key greenhouse gases linked to agriculture include:
- Carbon dioxide (CO₂): Long-lived and the most abundant.
- Methane (CH₄): Shorter-lived but far more potent.
- Nitrous oxide (N₂O): Extremely powerful at trapping heat.
Climate Impacts on U.S. Agriculture and Rural Communities
The 2018 Fourth National Climate Assessment identified four main threats to U.S. agriculture:
- Declining productivity from drought, erratic rainfall, rising heat, water shortages, wildfires, and pest outbreaks.
- Soil and water degradation from flooding, runoff, leaching, and erosion.
- Health risks to farmers, ranchers, and livestock due to extreme heat.
- Limited resilience in rural areas, where poverty and fewer resources reduce the ability to adapt.
To address regional variability, the USDA has created 10 Climate Hubs, offering localized climate-impact guidance.
Agriculture’s Role in Greenhouse Gas Emissions
Agriculture both emits and absorbs greenhouse gases. While farms release CO₂, CH₄, and N₂O through soil management, livestock, and manure handling, they also act as carbon sinks through biological sequestration.
- In 2019, U.S. agriculture contributed about 9.6% of total GHG emissions (EPA, 2021).
- Major sources include fertilizer use, manure management, and livestock digestion (enteric fermentation).
- Additional emissions come from rice cultivation, liming soils, and burning crop residues.
Carbon Sequestration in Agriculture
Carbon sequestration is the process of capturing and storing atmospheric carbon in plants, soils, and forests. Agricultural soils are the largest terrestrial carbon sink, with potential to store vast amounts of carbon depending on climate, crop type, and management practices.
- Forests and grasslands serve as long-term carbon storage systems.
- Land-use change such as converting grassland to cropland or urban areas releases stored carbon back into the atmosphere.
Agricultural Practices for Climate Mitigation
Farming can play a significant role in slowing climate disruption. Practices fall into three main groups:
Soil Carbon Sequestration
- Avoiding deforestation and grassland conversion prevents massive carbon losses.
- Agroforestry integrates trees into farmland, improving soil stability and habitat.
- Optimized grazing balances livestock intensity to boost soil carbon.
Mixed Carbon Sequestration & Emission Reduction
- Biochar (charcoal added to soil) enhances fertility, stores carbon, and reduces fertilizer demand.
- Cover crops prevent erosion, improve soil health, and reduce synthetic fertilizer needs.
- Legume integration enriches pastures with natural nitrogen fixation, reducing fertilizer emissions.
Direct Emission Reductions
- Improved nutrient management cuts N₂O emissions from fertilizer use.
- Efficient irrigation reduces both water use and emissions.
- Biofuels and renewable energy offer alternatives, though their carbon neutrality is debated.
The Economics of Soil Carbon
As Mazza (2007) observed, creating agricultural systems that reward carbon storage could be central to climate stabilization. But for this to work, farmers need markets and fair prices for carbon.
Two policy approaches dominate the debate:
- Carbon Taxes: Charge emitters for each ton of carbon, incentivizing efficiency and clean energy. Revenues could fund conservation programs (e.g., EQIP, CSP) to reward climate-smart farming.
- Cap-and-Trade: Sets a national emissions limit while creating a marketplace for carbon offsets. Farmers could earn income by adopting practices that sequester carbon or reduce emissions.
A third option direct subsidies already exists through federal conservation programs but could be expanded and restructured to focus more directly on climate benefits.
| Table 1: Agricultural Practices and Benefits | ||
| Conservation Practice | GHG Objectives | Additional Benefits |
| CROPS | ||
| Conservation tillage and reduce field pass intensity | Sequestration, emission reduction | Improves soil, water and air quality. Reduces soil erosion and fuel use. |
| Efficient nutrient management | Sequestration, emission reduction | Improves water quality. Saves expenses, time, and labor. |
| Crop diversity through rotations and cover crops | Sequestration | Reduces erosion and water requirements. Improves soil and water quality. |
| ANIMALS | ||
| Manure management | Emission reduction | On-farm sources of biofas fuel and possibly electricity for large operations, provides nutrients for crops. |
| Rotational grazing and improved forage | Sequestration, emission reduction | Reduces quantity of nutrients. Improves water quality. More efficient use of feed. |
Benefits of Subsidies
Subsidies offer immediate incentives for farmers and ranchers to adopt practices that support climate stabilization. When programs are well-funded and include technical assistance and outreach, they can ensure broad participation, reaching farmers and ranchers regardless of their resources or location.
Subsidies also allow governments to prioritize regions or specific practices, making programs more cost-effective in achieving targeted climate goals. By directing resources strategically, subsidies can accelerate the adoption of climate-smart agricultural practices across diverse landscapes.
Downsides of Subsidies
Subsidies carry public costs and require careful assessment of their effectiveness. They rely on the assumption that government-funded practices will achieve the intended outcomes. For example, federal subsidies for corn ethanol have raised corn prices, affecting livestock feed costs and global food markets, while the impact on greenhouse gas (GHG) emissions and soil carbon sequestration remains uncertain.
If the science behind a subsidized practice is incomplete or inaccurate such as the link between continuous no-till farming and carbon sequestration public funds could be spent without achieving meaningful climate benefits.
Cost-effectiveness is another concern. In 2006, researchers estimated that offsetting 70 million metric tons of CO₂ equivalents would require a carbon price of at least $13 per ton of CO₂ equivalent ($50 per ton of carbon), totaling nearly $1 billion per year over 40 years. Yet, this would have addressed only about 4% of total U.S. GHG emissions in 2004. Could public dollars achieve a greater impact if invested elsewhere, such as in improving automobile fuel efficiency?
Uncertainty in carbon pricing further complicates subsidization. A 2018 analysis found carbon prices ranged from $3.30 to $150 per ton CO₂e, depending on the region and whether the market was voluntary or compliance-based. Determining a fair and effective price for carbon remains a challenge.
For example, in Montana, the NRCS’s COMET Planner estimated that cover crops sequester about 0.22 ton CO₂e per acre per year. A private company, Indigo Agriculture, offers $15 per ton, equating to $3.30 per acre, while NRCS provides $15.41 per acre for a multi-species cover crop. These discrepancies raise questions: what is the right price to motivate adoption without overspending?
Even accounting for regional variations in carbon sequestration potential, public costs for GHG reductions through subsidies could remain substantial, highlighting the need for careful program design, monitoring, and cost-benefit evaluation.
Frequently Asked Questions
What is the greenhouse effect, and how does agriculture impact it?
The greenhouse effect is the process by which gases in the atmosphere trap heat, keeping the Earth warm. Agriculture contributes to this effect by releasing greenhouse gases like CO₂, CH₄ (methane), and N₂O (nitrous oxide) through activities such as fertilizer use, livestock digestion, and soil management.
How does climate change affect U.S. agriculture?
Climate change can reduce agricultural productivity due to droughts, heatwaves, flooding, wildfires, and pest outbreaks. It also degrades soil and water resources, threatens the health of farmers, ranchers, and livestock, and limits the capacity of rural communities to adapt.
What is carbon sequestration in agriculture?
Carbon sequestration is the process of capturing carbon dioxide from the atmosphere and storing it in soils, plants, and forests. Practices such as agroforestry, cover cropping, and optimized grazing can enhance carbon storage and help mitigate climate change.
How can subsidies help farmers mitigate climate change?
Subsidies provide financial incentives for farmers to adopt climate-smart practices. They can fund technical assistance, outreach, and implementation of conservation methods, helping farmers transition without financial strain.
What are the challenges with subsidies?
Subsidies are costly for the public and rely on accurate scientific understanding to ensure practices achieve the intended results. Pricing carbon correctly is complex, and regional differences in sequestration potential can affect program efficiency.
What is a carbon tax, and how does it affect agriculture?
A carbon tax charges emitters for each ton of greenhouse gas released. It encourages more efficient fuel use and cleaner practices. For farmers, it can increase costs for fossil-fuel-based inputs but can also create incentives to adopt low-emission practices.
Conclusion
Agriculture sits at a critical intersection between climate disruption and climate solutions. While farming and ranching contribute to greenhouse gas emissions, they also have the unique potential to sequester carbon, enhance soil health, and support ecosystem resilience. Mitigating climate change through agriculture requires a combination of science-based practices, including cover cropping, agroforestry, optimized grazing, and improved nutrient and water management.