Chapter 4 — Calculating GHG Emissions and Choosing a Base Year 4.1 Tracking Emissions Over Time 4.1.1 Choosing a Base Year 4.1.2 Rolling Base Year 4.1.3 Recalculating Base-Year Emissions 4.1.4 Setting GHG Emission Targets and Energy Reduction Targets 4.2 Identifying and Calculating GHG Emissions 4.2.1 Identify GHG Emission Sources 4.2.2 Select a GHG Emission Calculation Approach 4.2.3 Collect Data and Choose Emission Factors 4.2.4 Apply Calculation Tools 4.2.5 Roll Up Data to Corporate Level 4.3 Reporting 4.3.1 Required Reporting 4.3.2 Optional Reporting 4.3.3 Ratio Indicators