Landfill carbon storage

Carbon in buried wood that WARM assumes stays in the landfill rather than decaying to gas.

Last reviewed October 27, 2026 by repallet.org editors.

Wood in a landfill decays slowly and incompletely, so much of its carbon stays buried. EPA's WARM model credits this as landfill carbon storage, calculated from laboratory measurements of carbon remaining in landfilled wood.

For dimensional lumber, the storage credit is −1.09 MTCO2E per short ton (Exhibit 12-15). It outweighs the landfill methane (0.15) and transport (0.02), which is why WARM's net landfill factor for wood is negative, −0.92.

Inventory factors from EPA's Hub leave storage out, giving landfilled dimensional lumber +0.17. Both are correct for their purpose. See why WARM credits landfilled wood.

Storage is an estimate of what stays buried over the long term, based on laboratory data rather than measurements at a particular landfill. It's the main reason WARM's gain from reuse over landfill is 0.74 MTCO2E per short ton rather than the full reuse credit of 1.66. Calculators that ignore storage will report much larger savings for the same switch.

Related

• Why WARM credits landfilled wood with carbon storage
• Pallets in landfills: rules, numbers and what WARM assumes
• Landfill gas (LFG)
• Biogenic CO2
• Source reduction
• All terms