# How do I count carbon dioxide from lime spread on acidic soil, and do quicklime and slaked lime count as well as limestone and dolomite?

Canonical: https://senseible.earth/answers/agricultural-lime-carbon-dioxide-limestone-dolomite-ipcc

The Intergovernmental Panel on Climate Change (IPCC) Tier 1 factor is 0.12 tonnes of carbon per tonne of limestone and 0.13 per tonne of dolomite, times 44/12. Oxides and hydroxides of lime contain no inorganic carbon, so they are not counted at soil application.

## The sum

1. Weigh the limestone (CaCO3) and dolomite (CaMg(CO3)2) spread in the year, in tonnes. Include lime applied in a mixture with fertilisers.
2. Multiply limestone by 0.12 and dolomite by 0.13. These equal the carbonate carbon contents of the materials, 12% and 13% (Equation 11.12).
3. Add the two and multiply by 44/12 to get carbon dioxide (CO2).

## What does not count

- Quicklime (CaO) and hydroxides such as slaked lime do not contain inorganic carbon. The guide says they are not included at soil application, because CO2 is produced in their manufacture, not after spreading.

## How firm the factor is

Tier 1 assumes all the carbon in the lime is emitted as CO2 in the year it is applied. The guide gives an uncertainty of minus 50%, based on approximations that emissions may be less than half the maximum. It adds that the CO2 emitted depends on site conditions and on dissolved inorganic carbon carried through rivers and lakes to the ocean. It also says a rise in soil or dissolved inorganic carbon after liming is not a net removal of CO2 from the atmosphere.

## Where it sits

On your own land it is a field emission. In a buyer's inventory it belongs to the emissions from growing the crop you supply. It is a CO2 line, separate from nitrous oxide on the nitrogen you apply, and from the urea CO2 line.

## 30 tonnes of limestone and 10 tonnes of dolomite in a year

- Limestone: 30 x 0.12 = 3.6 tonnes carbon
- Dolomite: 10 x 0.13 = 1.3 tonnes carbon
- Total: 3.6 + 1.3 = 4.9 tonnes carbon x 44/12 = 17.97 tonnes CO2
- 10 tonnes of quicklime in addition: 0 at the farm

Tonnages are example values. The 17.97 tonnes is the Tier 1 maximum, before any country-specific reduction.

## What Senseible does here

Senseible reads fuel invoices and electricity bills into emission records, so diesel for tractors and power for irrigation pumps show up once uploaded. The fertiliser, residue and field figures on this page come from your own farm records.

- [Which limestone uses release carbon dioxide](https://senseible.earth/answers/which-limestone-uses-release-carbon-dioxide)
- [Emissions from applying a tonne of urea](https://senseible.earth/answers/urea-application-emissions-per-tonne)
- [Tea estate fertiliser emissions per kg](https://senseible.earth/answers/tea-estate-fertiliser-emissions-per-kg-made-tea)

Sources: [IPCC 2006 Guidelines, Volume 4, Chapter 11, Section 11.3 and Equation 11.12](https://www.ipcc-nggip.iges.or.jp/public/2006gl/)

Last reviewed 2026-11-05. Factors are from the 2006 edition. The guide expects country-specific factors to give lower emissions than Tier 1.