Garnaut Review Economic Model

On a quick first reading of the supplementary report, this seems to be the key data related to the modeling results. For the more moderate 550ppm CO₂ objective, the costs of a 10% cut in 2000 carbon emissions to 2020 are estimated at 1.1% of GDP (1.8% cut to consumption) comprising a net decrement of about 0.1+% of GNP per year. In other words, the expected net benefits are somewhere toward the end of the century (and seem to comprise assumptions about 'avoiding catastrophies').

Despite the boost to growth in the second half of the century, the sacrifice in the first half of the century is substantial, though the loss to GNP is fully recovered with a margin by the end of the century. The benefits that are purchased by this sacrifice take several forms. One is insurance against the effects of severe and possibly catastrophic outcomes on material consumption during this century. Another is increased protection against loss of non-market services this century. Yet another is avoidance of all of the rapidly increasing costs in through the 21st and into the 22nd century and beyond: the rapidly increasing negative impact on material consumption; the risk of outcomes much worse than the median expectations from the applied science (although beyond the 21st century, the median outcomes include more and more of the severe and possibly catastrophic); and the impacts on non-market values.