"Continual growth in the use of materials and energy would lead fairly quickly to absurdly high numbers that could never be sustained in the real world. In the last couple of centuries, humanity’s usage of energy grew at about 3% a year. If that rate of growth continues, regardless energy sources used, planet’s surface would reach boiling temperature in about 400 years—not due to CO2, but to the simple thermodynamic impacts of so much energy being transferred."