Terms used
CO2-e refers to carbon dioxide equivalent which is the universal unit of measurement to indicate the global warming potential (GWP) of different greenhouse gases. Converting greenhouse gases to CO2 equivalents makes for easier comparison and evaluation of the relative thermal impact of different greenhouse gases. For example, one tonne of N2O is equivalent to 310 tonnes of CO2, expressed as 310 tonnes CO2-e.
IPCC is the Intergovernmental Panel on Climate Change (IPCC) which is an international body of climate change scientists. The role of the IPCC is to assess the scientific, technical and socio-economic information relevant to understanding the risk of human-induced climate change. Many of Rio Tinto’s greenhouse gas accounting methodologies are based on IPCC guidance and documentation.
On site emissions is a GHG accounting term for those emissions over which Rio Tinto can exert direct management control such as fuel use, onsite electricity generation, process emissions, land management and livestock. This equates to direct emissions and WBCSD Scope one emissions
Sequestration involves the capture and storage or reuse of carbon dioxide. In this report the only sequestration that occurs is from revegetation of mining affected land.
Total emissions are defined as on site emissions and emissions from purchased electricity and steam minus emissions associated with exported electricity and steam. It does not include indirect emissions that Rio Tinto cannot effectively exert management control over, such as emissions from third party product transport and the combustion of Rio Tinto’s coal product. This equates to scope one + scope two – electricity and steam net exports.
Other indirect emissions are emissions associated with third party product transport, offsets external to inventory boundary and product use (WBCSD scope three).
WBCSD Scope one direct greenhouse gas emissions that are owned or controlled by the company;
WBCSD Scope two indirect emissions from the imports of electricity, heat or steam from third parties; and
WBCSD Scope three other indirect greenhouse gas emissions.
Anodes and reductants are compounds generally containing carbon used in the smelting process to reduce metal oxides to the primary metal
Process gases are greenhouse gases emitted from industrial processes such as perfluorocarbons from aluminium smelting, fugitive methane and carbon dioxide emissions from coal mining.
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