Global warming refers to the ongoing increase in Earth’s average temperature over time. This phenomenon is primarily driven by the accumulation of greenhouse gases in the atmosphere, largely due to human activities. Agriculture finds itself deeply interconnected with global warming, as it is both significantly affected by these climatic shifts and a notable contributor to the greenhouse gas emissions that drive them.
How Global Warming Impacts Agriculture
Rising global temperatures directly influence agricultural systems by altering typical weather patterns. Increased temperatures can accelerate evapotranspiration, where plants lose more moisture from their leaves and soil evaporation increases, leading to greater water demand for crops. This often results in reduced yields because crops may speed through their development, producing less grain. Erratic changes in precipitation, including more frequent droughts and severe floods, further complicate farming, damaging crops and impacting water availability for irrigation.
Livestock also experience adverse effects, such as heat stress, which can reduce appetite and milk production in dairy cows. Warmer conditions also contribute to the increased prevalence and spread of pests and diseases, which can threaten crop health and livestock productivity, requiring greater pest control. Soil health is additionally compromised through accelerated erosion from heavy rainfall and increased decomposition of organic matter due to elevated temperatures, leading to nutrient loss and reduced fertility.
How Agriculture Contributes to Global Warming
Agriculture releases several greenhouse gases. Methane (CH4) is a significant emission, largely from livestock due to enteric fermentation, the digestive process in ruminants like cattle. This process alone accounts for over two-thirds of agricultural methane emissions, with methane being a potent greenhouse gas, approximately 28 times stronger than carbon dioxide over a 100-year period. Manure management, especially in liquid slurry storage systems, also produces methane when organic matter decomposes in anaerobic (oxygen-free) conditions.
Nitrous oxide (N2O) is another powerful greenhouse gas, with a global warming potential 265 to 310 times greater than carbon dioxide over a 100-year period. The primary source of N2O emissions in agriculture is agricultural soil management, especially from the application of nitrogen-based fertilizers. Manure management also contributes to N2O emissions. Carbon dioxide (CO2) emissions from agriculture primarily stem from land-use changes, such as deforestation for agricultural expansion, and soil disturbance through practices like tillage, which releases stored carbon. Rice cultivation in flooded paddies also releases substantial amounts of methane.
Adapting Agriculture to a Changing Climate
Farmers implement various strategies to build resilience against the impacts of global warming. Developing and using climate-resilient crop varieties, such as those tolerant to drought or heat, helps maintain yields under challenging conditions. Diversifying crops and livestock provides a buffer against single crop failures and helps spread risks associated with unpredictable weather patterns.
Efficient water management techniques cope with water scarcity. These include drip irrigation and rainwater harvesting for later use. Adjusting planting and harvesting times based on changing seasons and weather forecasts allows farmers to optimize growing periods. Improving soil health through practices like cover cropping enhances water retention and nutrient cycling, making soils more resilient to extreme events. Early warning systems for weather and pest outbreaks also empower farmers to make informed, timely decisions.
Reducing Agricultural Greenhouse Gas Emissions
Efforts to reduce agriculture’s contribution to global warming focus on mitigating greenhouse gas emissions. Improved manure management, such as anaerobic digesters, capture methane from manure and convert it into biogas, reducing atmospheric release. Composting manure can also stabilize it and lessen methane emissions.
Optimizing fertilizer use through precision agriculture minimizes the release of nitrous oxide. Using slow-release fertilizers and splitting applications also reduces nitrogen loss to the atmosphere.
Sustainable land management practices, including no-till farming and cover cropping, help sequester carbon in soils by reducing soil disturbance and increasing organic matter. These practices enhance soil carbon storage and reduce the need for synthetic fertilizers. Improving livestock feed through additives, such as certain types of seaweed, can reduce methane produced during digestion in ruminants. Agroforestry, which integrates trees into farming systems, also contributes to carbon sequestration and can improve animal welfare by providing shade. Reducing food waste across the supply chain additionally lessens the overall demand for agricultural production and its associated emissions.