Table 1.

World energy statistics and projections

Quantity	Definition	Units	2001*	2050†	2100‡
N	Population	B persons	6.145	9.4	10.4
GDP	GDP§	T $/yr	46	140¶	284‖
GDP/N	Per capita GDP	$/(person-yr)	7,470	14,850	27,320
Ė/GDP	Energy intensity	W/($/yr)	0.294	0.20	0.15
Ė	Energy consumption rate	TW	13.5	27.6	43.0
C/E	Carbon intensity	KgC/(W·yr)	0.49	0.40	0.31
Ċ	Carbon emission rate	GtC/yr	6.57	11.0	13.3
Ċ	Equivalent CO2 emission rate	GtCO2/yr	24.07	40.3	48.8

*Ė = (403.9 Quads/yr)·(33.4 GWyr/Quad)·(10^–3 TW/GW) = 13.5 TW; and Ċ = (24.072 GtCO₂/yr)·(12/44 GtC/GtCO₂) = 6.565 GtC (adapted from ref. 1).

^†Ė = (869 EJ/yr)·(10⁶ TJ/EJ)/(60·60·24·365 s/yr) = 27.5 TW [adapted from ref. 2 (Scenario B2), pp. 48–55].

^‡Ė = (1,357 EJ/yr)·(10⁶ TJ/EJ)/(60·60·24·365 s/yr) = 43.0 TW [adapted from ref. 2 (Scenario B2), pp. 48–55].

^§All in year 2000 U.S. dollars, using the inflation-adjusted conversions: $₂₀₀₀ = 1/0.81590 $₁₉₉₀ (adapted from ref. 1), and ′purchasing power parity′ exchange rates.

^¶In year 2000 U.S. dollars: (113.9 T$₁₉₉₀)·(1/0.81590 $₂₀₀₀/$₁₉₉₀) = 139.6 T$₂₀₀₀.

^‖In year 2000 U.S. dollars: (231.8 T$₁₉₉₀)·(1/0.81590 $₂₀₀₀/$₁₉₉₀) = 284.1 T$₂₀₀₀.