From the Cover: Near-linear cost increase to reduce climate-change risk |
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Authors: | Michiel Schaeffer Tom Kram Malte Meinshausen Detlef P van Vuuren and William L Hare |
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Institution: | aEnvironmental Systems Analysis Group, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen, The Netherlands; ;bClimate and Global Sustainability Group, Netherlands Environmental Assessment Agency, P.O. Box 303, 3720 AH Bilthoven, The Netherlands; and ;cPotsdam Institute for Climate Impact Research, P.O. Box 60 12 03, 14412 Potsdam, Germany |
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Abstract: | One approach in climate-change policy is to set normative long-term targets first and then infer the implied emissions pathways. An important example of a normative target is to limit the global-mean temperature change to a certain maximum. In general, reported cost estimates for limiting global warming often rise rapidly, even exponentially, as the scale of emission reductions from a reference level increases. This rapid rise may suggest that more ambitious policies may be prohibitively expensive. Here, we propose a probabilistic perspective, focused on the relationship between mitigation costs and the likelihood of achieving a climate target. We investigate the qualitative, functional relationship between the likelihood of achieving a normative target and the costs of climate-change mitigation. In contrast to the example of exponentially rising costs for lowering concentration levels, we show that the mitigation costs rise proportionally to the likelihood of meeting a temperature target, across a range of concentration levels. In economic terms investing in climate mitigation to increase the probability of achieving climate targets yields “constant returns to scale,” because of a counterbalancing rapid rise in the probabilities of meeting a temperature target as concentration is lowered. |
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Keywords: | abatement costs climate targets mitigation probabilistic framework risk approach |
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