If fast and substantial reduction of greenhouse gas emissions is postponed further, there are fewer options available to stay below a 2 °C warming at the end of the century. Delayed action is likely to require measures that remove CO2 from the atmosphere by planting forests and/or using bioenergy in combination with carbon capture and storage in order to meet the 2 °C target. The latter technique still involves considerable challenges. Climate policy decisions in the next years are therefore likely to have long-term implications.
Delaying substantial emission reductions limits climate policy choices
Several policy proposals have indicated that the world must reduce greenhouse gas emissions by 40% to 70% compared with 2010 levels by 2050 for it to be likely (66% chance) to stay below a 2 degree warming, quoting the recent IPCC report.
However, the wide range from 40% to 70% is, to a considerable extent, a reflection of policy choice. Policy strategies that do not want to rely on removing CO2 from the atmosphere should be at the higher reduction end (60 to 70%) of the range. This is illustrated by the observation that scenarios reflecting such strategies show emission reductions of more than 60% in 2050.
The PBL report ‘Implications of long-term scenarios for medium-term targets (2050)’ was written at the request of Norwegian Environment Agency.
Norway Environment Agency report number: M-449|2015