Climate science, greenhouse gas accounting, and reporting
Climate science, GHG accounting, and reporting tests your ability to translate climate science into inventories and disclosures: boundaries, scopes, CO2e, targets, and climate risk.
Core rules
- The greenhouse effect is driven by radiative forcing; IPCC scenarios link cumulative CO2 emissions to warming. GWP100 converts non-CO2 gases to CO2e over 100 years.
- Set organizational and operational boundaries. Consolidate by equity share or control. Include all seven Kyoto gases where relevant.
- Scope 1: direct emissions from owned or controlled sources. Scope 2: purchased electricity, steam, heat, cooling; report location-based and market-based. Scope 3: all other value-chain emissions across 15 GHG Protocol categories.
- Avoid double counting across entities and scopes; report gross emissions before offsets. Offsets are not reductions.
- Science-based targets align with 1.5°C pathways; net zero requires deep cuts plus neutralization of residual emissions.
Worked example
A factory burns 100,000 kWh natural gas at 0.20 kgCO2e/kWh: 20,000 kg = 20 tCO2e (Scope 1). It buys 500,000 kWh electricity at a location-based factor of 0.40 kg/kWh: 200 tCO2e (Scope 2). Business travel of 50,000 passenger-km by air at 0.15 kg/passenger-km: 7.5 tCO2e (Scope 3, category 6). Location-based total = 227.5 tCO2e. If renewable certificates cover the electricity, market-based Scope 2 may be lower, but the location-based figure still reports grid emissions.
Traps
- Mixing GWP100 and GWP20.
- Counting the same Scope 3 activity in two categories.
- Treating renewable certificates as zero without market-based rules.
- Claiming carbon neutrality through offsets alone.
- Omitting fugitive emissions or boundary changes.