Mid- and long-term climate projections for fragmented and delayed-action scenarios

This paper explores the climate consequences of “delayed near-term action” and “staged accession” scenarios for limiting warming below 2 ° Celsius (C). The stabilization of greenhouse gas concentrations at low levels requires a large-scale transformation of the energy system. Depending on policy choices, there are alternative pathways to reach this objective.

An 'optimal' path, as emerging from energy-economic modeling, implies immediate action with stringent emission reductions, while the currently proposed international policies translate into reduction delays and higher near-term emissions.

In our delayed action scenarios, low stabilization levels need thus to be reached from comparatively high 2030 emission levels. Negative consequences are higher economic cost as explored in accompanying papers and significantly higher mid-term warming, as indicated by a rate of warming 50% higher by the 2040s.

By contrast, both mid- and long-term warming are significantly higher in another class of scenarios of staged accession that lets some regions embark on emission reductions, while others follow later, with conservation of carbon-price pathways comparable to the optimal scenarios. Not only is mid-term warming higher in staged accession cases, but the probability to exceed 2 °C in the 21st century increases by a factor of 1.5.

Authors

Michiel Schaeffer, Laila Gohar, Elmar Kriegler, Jason Lowe, Keywan Riahi, Detlef van Vuuren

Specifications

Publication title
Mid- and long-term climate projections for fragmented and delayed-action scenarios
Publication date
31 October 2013
Publication type
Publication
Magazine
Technological Forecasting and Social Change
Product number
1297