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Waste Scope 3 (Indirect — waste to landfill)

Garden and Green Waste to Landfill

Reviewed by Afonso Firmo, Co-Founder & Director · Updated 7 July 2026

Green waste sent to landfill carries a factor of 1.6 t CO₂-e per tonne under NGA Factors 2025. See worked examples, FAQs and a calculator for your reports.

Emission Factor Value

1.6 t CO₂-e/tonne

Try it with your own numbers

Estimated emissions

Emissions from waste you send to landfill are reported under Scope 3. Calculated as tonnes of garden and green waste × 1.6 t CO₂-e per tonne (NGA Factors 2025). Cubic metres are converted at 0.24 tonnes per m³.

Official Source & Citation

This emission factor is sourced from the Australian National Greenhouse Accounts Factors 2025 , Table 15 — Waste mix methane conversion and emission factors, published by the Department of Climate Change, Energy, the Environment and Water (DCCEEW).

Citation: DCCEEW (2025). Australian National Greenhouse Accounts Factors 2025. Commonwealth of Australia. Available at: https://www.dcceew.gov.au/climate-change/publications/national-greenhouse-accounts-factors-2025

Notes

Scope 3 factor for organisations sending garden and green waste to landfill, from the NGA Factors 2025. Emissions arise from anaerobic decomposition producing methane. 1 tonne of garden and green waste sent to landfill = 1.6 t CO₂-e. For volume records, apply 0.24 tonnes per cubic metre. The landfill operator reports the direct methane emissions under Scope 1.

Calculation Example

If a grounds contractor sent 60 tonnes of green waste to landfill during the year:

Working Result
60 t × 1.6 t CO₂-e/t 96 t CO₂-e (Scope 3)

Grass clippings and prunings feel carbon-neutral — they grew back last spring, after all. But send them to landfill and they decompose without oxygen, producing methane instead of compost. That is why garden and green waste carries a factor of 1.6 t CO₂-e per tonne on your Scope 3 inventory.

Councils, property managers, landscapers and campus operators generate this stream in bulk, and it is usually the easiest one to divert — which makes the number worth knowing.

Quick Verdict

Garden and green waste sent to landfill has an emission factor of 1.6 t CO₂-e per tonne under the Australian National Greenhouse Accounts Factors 2025, applying to the 2025–26 reporting year. The organisation that generates the waste reports it under Scope 3; the landfill operator reports the direct methane under Scope 1. Volume records convert at 0.24 tonnes per cubic metre. Composting the same material emits just 0.046 t CO₂-e per tonne, so diversion cuts this line by roughly 97%. A Scope 3 emissions calculator can apply the factor automatically from waste contractor data.

How to Calculate Garden and Green Waste Emissions

Emissions (t CO₂-e) = Waste to landfill (tonnes) × 1.6

Worked Example 1: Grounds maintenance contractor

A contractor maintaining council parks sends 60 tonnes of green waste to landfill over the year.

60 t × 1.6 = 96 t CO₂-e (Scope 3)

Worked Example 2: Landscaping business

A landscaping firm disposes of 15 tonnes of prunings and clippings to landfill.

15 t × 1.6 = 24 t CO₂-e (Scope 3)

Worked Example 3: Volume records only

A facilities team records 25 m³ of green waste sent to landfill. Using the NGA volume-to-mass factor of 0.24 t/m³:

25 m³ × 0.24 t/m³ = 6 t

6 t × 1.6 = 9.6 t CO₂-e (Scope 3)

Green Waste vs Other Landfill Streams

Waste stream (to landfill)Factor (t CO₂-e/t)
Paper and cardboard3.3
Food waste2.1
Textiles2.0
Garden and green waste1.6
Municipal solid waste (mixed)1.6
Wood waste0.7
Construction and demolition waste0.2

All factors from NGA Factors 2025, expressed in CO₂-equivalent.

NGER and AASB S2 Reporting

Because generator waste emissions are Scope 3, they sit outside NGER thresholds but inside AASB S2 disclosures, which require material Scope 3 categories to be reported. Keep contractor tonnage or volume records as your audit trail and apply the NGA Factors 2025 value consistently.

Frequently Asked Questions

What is the emission factor for garden and green waste sent to landfill in Australia?
Garden and green waste sent to landfill has an emission factor of 1.6 t CO₂-e per tonne under the Australian National Greenhouse Accounts Factors 2025. The emissions come from anaerobic decomposition of grass clippings, prunings and other organics producing methane.
Is green waste to landfill Scope 1 or Scope 3?
For the organisation generating the waste it is Scope 3, because the decomposition occurs at a landfill outside your operational control. The landfill operator reports the direct methane under its own Scope 1.
How do I measure green waste sent to landfill?
Contractor invoices or weighbridge dockets give the most reliable tonnages. If you only have truck or bin volumes, convert using the NGA volume-to-mass factor of 0.24 tonnes per cubic metre for garden and green waste before applying the 1.6 t CO₂-e per tonne factor.
How does landfilling green waste compare with composting it?
Landfilling emits 1.6 t CO₂-e per tonne, while composting emits just 0.046 t CO₂-e per tonne — roughly 35 times less. Most councils and commercial processors accept green waste for composting or mulching, so this is usually the easiest waste stream to divert.
Why does green waste generate emissions in landfill but not on the garden bed?
Mulched or composted green waste breaks down with oxygen, producing mostly biogenic CO₂. Buried in landfill, the same material decomposes anaerobically and generates methane, which has a much higher warming impact per kilogram — hence the 1.6 t CO₂-e per tonne factor.
Do I need to report green waste emissions under NGER or AASB S2?
Generator waste emissions are Scope 3, so they sit outside NGER thresholds, which are based on Scope 1 and 2. AASB S2 requires material Scope 3 categories to be disclosed, and waste to landfill is a standard category for property, facilities and grounds-heavy organisations.
Where does the 1.6 t CO₂-e per tonne factor come from?
It is published by DCCEEW in the Australian National Greenhouse Accounts Factors 2025 waste tables, reflecting the methane generation potential of garden and green waste in Australian landfills for the 2025–26 reporting year.

Disclaimer

This page is provided for general information, not professional or compliance advice. The factor shown is reproduced from the official publication cited above, and while we work to keep it current, government factors change — the publication is always the authoritative source.

  • Before using this value in any formal reporting — including under the National Greenhouse and Energy Reporting Act 2007 — confirm it against the current official publication and the methods specified by the Clean Energy Regulator.
  • NetNada is independent of the Australian Government, DCCEEW, and the Clean Energy Regulator. Government data is Crown copyright, Commonwealth of Australia.

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