パリ協定２℃目標から見た我が国の2050年排出削減目標に関する分析

抄録

The Paris Agreement describes “To hold the increase in the global average temperature to well below 2 °C above pre-industrial levels.” The Plan for Global Warming Countermeasures by the Japanese Government includes the emission reduction target of 80% by 2050 corresponding to the 2 °C target although several conditions including compatibility with its economic growth are imposed. This paper firstly estimated the global emission pathways for the 2 °C target considering scientific and policy uncertainties. Then, based on the global emissions in 2050, emission reductions required of Japan were estimated under the condition of equalized marginal abatement costs across countries in 2050 by using a global energy and climate change mitigation model having regionally disaggregated. The result shows emission reduction required of Japan varies widely ranging from +0 to -77% relative to 2010. In addition, for the 80% reductions by 2050, the mitigation measures and costs were estimated. The CO₂ marginal abatement costs were found around six thousand $/tCO₂ and the annual mitigation costs were 29−72 trillion JPY. The 80% reductions by 2050 in Japan are very difficult to be achieved.