week 10 Flashcards
(8 cards)
1) Explain how agriculture contributes to climate change through greenhouse gas emissions? Identify the three main gases involved and their primary sources.
Agriculture contributes to climate change through various practices that release greenhouse gases (GHGs) into the atmosphere. The sector makes up a little over 10% of total greenhouse gas emissions globally
-Methane (CH₄): Agriculture is the largest emitter of anthropogenic CH₄ emissions. It accounts for approximately 40% of global methane emissions
-Methane is produced predominantly from the digestive system and fermentation processes in ruminants, which leads to microbes producing and releasing methane
Nitrous Oxide (N₂O): Agriculture is the largest emitter of anthropogenic N₂O emissions. N₂O is a powerful greenhouse gas with 300 times greater warming potential than CO₂
-source of fertiliser in agriculture
- Practices like ploughing and tilling, which disrupt the soil, can also release N₂O into the atmosphere
Carbon Dioxide (CO₂): Compared to other sectors like energy and transport, CO₂ emissions from agriculture are smaller but still significant
-Clearing forests for farmland releases stored carbon from the soil into the atmosphere and removes a natural carbon sink (trees)
How does climate change affect crop yields? Discuss two key climate-related factors and how they impact agricultural productivity in different regions.
Temperature Extremes:
-rising temperatures can shorten growing seasons, causing crops to mature faster but potentially not developing fully, leading to lower yields. Heat stress weakens plants, reduces quality, and further decreases crop yields. Extreme heat can also lead to total crop failure
-cooler, more northern regions, warmer temperatures can actually extend the growing season and create environments where certain crops can thrive that were previously limited by frost
Changes in Precipitation:
-Climate change makes rainfall patterns less predictable
-Droughts can severely reduce yields
-Flooding damages crops and can decrease crop yields
Describe how land-use change contributes to carbon dioxide (CO₂) emissions in agriculture. What are two key strategies to mitigate these emissions?
deforestation, is a primary source of CO₂ emissions from the agricultural sector
-Clearing forests for farmland releases large amounts of stored carbon that were held in the soil and vegetation
-eliminates a natural carbon sink
Two strategies to mitigate:
1. Agroforestry:
This involves planting trees alongside crops. Agroforestry improves soil structure and prevents soil erosion= maintain soil fertility and improves resilience to climate extremes
- No-till farming:
-practice limits how much the soil is disrupted, contrasting with traditional ploughing or tilling used for weed control or fertiliser application
-helps maintain stored carbon within the soil, preventing its release as CO₂
Methane (CH₄) is a significant agricultural greenhouse gas. Explain two strategies for reducing methane emissions from livestock and evaluate their feasibility for large-scale implementation.
Dietary Changes:
-adding substances like seaweed (specifically Asparagopsis) has shown significant success, with some studies demonstrating up to a 90% reduction in methane
-higher fat content in their diet can alter the fermentation process, again reducing methane.
-feeding tannins and essential oils can also inhibit the methane-producing microbe
(feasability= Availability and cost of supplements like seaweed for large-scale farming operations are significant factors. )
Manure Management:
-Implementing anaerobic digesters is a strategy to capture the gases released from manure
-captured gas, effectively biogas, can then be used for energy, potentially offering a financial benefit to farmers
(feasability=Anaerobic digesters require significant initial investment and infrastructure, which might be a barrier for small-scale farms)
Nitrous oxide (N₂O) is a powerful greenhouse gas emitted from agricultural soils. Explain how nitrogen fertilisers contribute to N₂O emissions and describe a method for reducing these emissions.
-Nitrous oxide (N₂O) is a potent greenhouse gas primarily emitted from agricultural soils.
-Nitrogen fertilisers are a major source of these emissions
-under low oxygen conditions, the denitrification process can be incomplete, resulting in the release of N₂O into the atmosphere
-reducing these emissions is using fertiliser inhibitors. Specifically, nitrification inhibitors= slow down the microbial conversion of ammonium to nitrate= reduce the pool of nitrate available for denitrification, thus decreasing the potential for N₂O emissions
What is climate-smart agriculture (CSA)? Provide two examples of CSA practices and explain how they help farmers both adapt to and mitigate climate change.
Climate-Smart Agriculture (CSA) is an integrated approach that combines sustainable agricultural practices with climate change mitigation and adaptation
Two examples:
- Improved Manure Management (e.g., using Anaerobic Digesters):
-mitigate= captures methane released from decomposing manure
-adaptation= by capturing biogas, it can provide an alternative energy source for the farm, potentially reducing reliance on external energy infrastructure that might be vulnerable to extreme weather events - Agroforestry:
-mitigation= Trees sequester carbon dioxide from the atmosphere as they grow
-adaptation= Trees provide shade and windbreaks, which can protect crops and livestock from temperature extremes and harsh weather conditions, helping them cope with heat stress and strong winds
Why might some northern latitude regions experience increased crop yields due to climate change? Discuss two key factors that contribute to this trend.
Extended Growing Seasons: Warmer temperatures in northern regions can lead to longer periods suitable for crop growth
Reduced Frost Limitations: Historically, northern regions often experience significant periods of frost, which can damage crops and limit the types of crops that can be grown. As temperatures rise, these regions may experience fewer frost days or a shorter frost season
What role does consumer behaviour play in reducing agricultural emissions? Discuss two ways in which individuals can reduce their carbon footprint through dietary choices or food consumption habits.
Reduced Consumption of High GHG-Intensive Foods:
-Meat and dairy are identified as being particularly intensive in terms of GHG emissions. By reducing the consumption of these foods, individuals lower the demand for agricultural practices that produce significant amounts of methane (from livestock) and nitrous oxide (from manure and feed production), as well as CO₂ (related to land use for pasture and feed)
Reducing Food Waste:
-Approximately a third of the food produced globally is wasted. Wasting food contributes to emissions at various stages: the emissions from producing the food that is never eaten, and the emissions generated when wasted food decomposes, particularly in landfills (producing methane)
