Technological options are critical for economic viability of 2°C climate target

Example of transformation of the world-wide energy system for business-as-usual case and two climate protection targets (550 and 400 ppm). Source: Knopf et al. (2009). Historical data: IEA (2007).

“We have started from the assumption of a ‘first-best’ world where current and newly developed technologies are fully available,” says Ottmar Edenhofer, chief economist at PIK. “However, we have also investigated a ‘second-best’ world where some of the technologies are not available or have a limited potential,” adds the lead author of the article ‘The Economics of Low Stabilization: Model Comparison of Mitigation Strategies and Costs’. The scientists found that the costs of mitigation are substantially higher or that ambitious climate targets are actually unattainable in the second-best world.

As part of the EU-funded project “Adaptation and mitigation strategies: supporting European climate policy” (ADAM) the researchers have explored the technological options for reaching three different stabilization levels of atmospheric greenhouse gases. These correspond to carbon dioxide concentrations of 550, 450, and 400 parts per million (ppm) with a 15, 50, and 75 percent chance, respectively, to achieve the 2°C target. The scientists used five state-of-the-art energy-environment-economy models to illustrate the technological and economic scenarios and systematically compared the results.

“The models provide a number of technology pathways that have a high likelihood of achieving the 2°C target,” says Brigitte Knopf, the scientific coordinator of the ADAM model comparison. All models achieved the low stabilization at 400 ppm at moderate costs. Expressed as aggregated gross domestic product losses until 2100, the global mitigation costs are reported to be below 2.5 percent. But this requires a portfolio of technologies, the researchers found. “There is no silver bullet to tackle climate change, but, interestingly, the models agree on the ranking of importance of energy technologies,” says Knopf.

Without either carbon capture and storage (CCS) or the expansion of renewable energy beyond business-as-usual, stabilization of atmospheric greenhouse gases becomes significantly more expensive. Ambitious climate mitigation targets might not be achieved at all. In one model, the extensive use of biomass for heat and power production was another essential option for the feasibility of the low stabilization level. In two other models, costs doubled with a limitation of biomass use to a sustainable potential.

In contrast, the effect of nuclear energy as a mitigation option is limited as refraining from the expansion of nuclear energy is possible at almost no additional costs. Furthermore, the models show that even a global phase out of nuclear energy is possible at slightly increased mitigation costs.

“It is clear that a model analysis alone cannot address the full range of economic, political and risk management issues raised by the use of some of the technologies,” says Knopf. The feasibility and potential risks of CCS, for example, are largely unknown today and also to what extent the extensive use of biomass would compete with food production and nature conservation. But the study does indicate clearly that the development of a portfolio of technologies is crucial in order to keep mitigation costs low, paving the way for a global climate agreement.

Article: Ottmar Edenhofer, Brigitte Knopf, Terry Barker, Lavinia Baumstark, Elie Bellevrat, Bertrand Château, Patrick Criqui, Morna Isaac, Alban Kitous, Socrates Kypreos, Marian Leimbach, Kai Lessmann, Bertrand Magné, Serban Scrieciu, Hal Turton, Detlef P. van Vuuren (2009) The Economics of Low Stabilization: Model Comparison of Mitigation Strategies and Costs. The Energy Journal, Volume 31, Special Issue, http://www.iaee.org/en/publications/journal.aspx

Further reading: http://www.pik-potsdam.de/project-adam and http://www.adamproject.eu/