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CO₂ equivalents

Different greenhouse gases warm differently. To add them up, they are converted to CO₂ equivalents using the global warming potential (GWP). Methane, for example, warms about 28 times as much as CO₂ over a hundred years.

m_{CO_2e} = \sum m_i\cdot GWP_i

conversion to CO₂ equivalents

Symbols

$m_i$	emission of gas i	kg
$GWP_i$	warming potential (CO₂ = 1)

Example

10 kg methane ( $GWP = 28$ ) and 100 kg CO₂:

$10\cdot 28 + 100 = 380$ kg CO₂e.

Check which time horizon the GWP value is for. The 20-year and 100-year values differ greatly.

Practise life cycle and carbon accounting for free →

← Functional unit · Emission factors →

Part of Technology, Ethics and Sustainability: Life cycle and carbon accounting.