The "Business-As-Usual" growth of global primary energy use and carbon dioxide emissions – historical trends and near-term forecasts

Abstract. We analyse the global primary energy use and total CO₂ emissions time series since 1850 and show that their relative growth rates appear to exhibit periodicity with a fundamental timescale of ~60 years and with significant harmonic behaviour. Quantifying the inertia inherent in these dynamics allows forecasting of future "business as usual" energy needs and their associated CO₂ emissions. Our best estimates for 2020 are 800 EJ yr⁻¹ for global energy use and 14 Gt yr⁻¹ for global CO₂ emissions, with both being above almost all other published forecasts. This suggests the energy and total CO₂ emissions landscape in 2020 may be significantly more challenging than currently envisaged.