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Sustainability - Lecture 2

Australian Agricultural Sustainability Framework (AASF)

  • Environmental Stewardship Principles for Australian agriculture include:

    • Greenhouse Gases & Air: Limiting net anthropogenic GHG emissions; avoiding/minimising adverse air quality impacts.

    • Soil & Landscapes: Protecting/enhancing soil health; avoiding/minimising landscape degradation.

    • Biodiversity: Protecting/enhancing biodiverse ecological communities.

    • Water: Using resources responsibly and equitably.

    • Materials & Resources: Safeguarding finite resources in circular economic systems.

Greenhouse Gases (GHGs) and Global Warming Potential (GWP)

  • GWP measures how much heat a GHG traps in the atmosphere over 100 years compared to carbon dioxide (\text{CO}_2).

  • Key GHGs and their GWP (over 100 years):

    • \text{CO}_2: 1

    • \text{CH}_4 (Methane): 28

    • \text{N}_2\text{O} (Nitrous Oxide): 265

Australia's Emissions Targets and Projections

  • Paris Agreement Targets: 43\% below 2005 levels by 2030 and net zero by 2050. Australia is currently on track.

Agriculture's Contribution to National Emissions

  • Agriculture currently contributes 17\% of Australia's national emissions (June 2023 – June 2024).

  • Projected Shift: As other sectors decarbonise, agriculture's share of national emissions is projected to increase from 19\% to over 30\% by 2040, despite a slight decline in its absolute emissions.

    • This shift will increase pressure on agriculture for low-emission practices.

  • Agricultural Emissions by Gas (Australian Data):

    • Methane (77\%), primarily from livestock.

    • Nitrous Oxide (19\%), from crop residue burning and fertiliser use.

    • Carbon Dioxide (4\%), from lime and urea use.

Key Definitions

  • Agricultural Lifecycle: Encompasses pre-production (e.g., input manufacturing), production (on-farm activities), processing and transport, use and consumption, and end-of-life.

  • Carbon Sequestration: The process of capturing and storing atmospheric carbon dioxide (\text{CO}_2) in soils, vegetation, and other natural systems.

    • Soil Carbon: Pasture phases are more effective for increasing soil carbon; gains from practices like zero tillage are small and uncertain.

    • Vegetation Carbon: Planting trees (e.g., shelter belts, farm forestry) stores carbon and improves farm resilience.

  • Offsetting GHG Emissions: Purchasing recognised carbon credits or participating in certified offset projects when reduction or sequestration is impractical.

Australian Grains Industry Emissions & Mitigation

  • Emission Sources (Grains Sector):

    • Scope 1 (on-farm): 61.3\%. Includes fertiliser (32\%), operations (11\%), residue (8\%), lime (6\%), dams (3\%).

    • Scope 3 (off-farm): 38.6\%. Includes fertiliser & lime production (28\%), protection (7\%), capital goods (2\%, other (1\%).

  • Mitigation Strategies: Optimise nitrogen management, adopt controlled traffic farming, ameliorate subsoil constraints, increase soil carbon, use 'green' fertilisers, and offset emissions via reforestation.

Zero Net Emissions Agriculture CRC (ZNE-Ag) Focus Areas

  • Low Emissions Plant Solutions: New pasture seeds, novel fertilisers, decision support tools for cover crops/tree plantings, legume development.

  • Towards Methane-Free Cattle & Sheep: Novel methane measurement, genetic selection for low methane, low-cost reduction strategies.

  • Whole-Farm & Mixed Enterprise Systems Analysis: Baselines, data integration, life cycle assessments.

  • Delivering Value from Net Zero: Policy/governance, circular economy solutions, renewable energy integration, supply chain tracking, and education/training.