The Efficiency Scenario avoids the emission of 493 Mt CO2/y in 2050, which would correspond to the emissions for the entire mainland energy system in a BAU Scenario and would signify an increase of 24.3% over 2007, mainly due to the high level of fuel usage.
The Efficiency Scenario follows scientific advice to achieve zero emissions by the middle of this century. But the effects on climate do not depend only on the scenario by 2050, but on the path followed to achieve it, because all the CO2 emitted into the atmosphere during the transition period will contribute to the greenhouse effect for a long time.
The sooner emissions are reduced, the lower the impact of human activity on climate change will be. If the transition is delayed, emissions will continue to rise until the 2030s; a responsible transition would achieve near-zero emissions over a decade in advance.