Sustain. Sci. http://doi.org/hv5 (2012)

Long-term climate targets are being discussed at the international level. At the 2009 G8 summit, the participating nations agreed to strive for a 50% reduction of 1990 levels of global greenhouse-gas emissions by 2050. However, the costs associated with achieving such a cut could be a limiting factor in reaching that goal.

Osamu Akashi, of Musashino University and the National Institute for Environmental Studies, Japan, and colleague Tatsuya Hanaoka investigated the technological feasibility of a 50% reduction by 2050.

The 50% target is technically achievable, but will require great mitigation efforts. The cost to achieve this goal reaches US$600 per tonne of carbon dioxide equivalent and requires a reduction in energy consumption per unit of gross domestic product of 55%. Major changes to energy systems will be required, as carbon dioxide emissions per unit of energy consumption need to be reduced by 75% — meaning switches to renewable energy. The additional investment required for greenhouse-gas abatement technologies would be in the region of US$73 trillion, with the largest investment required in the power generation sector.