The SCC values were compared for their coverage against a risk matrix
(Figure 1), in relation to
1. The uncertainty of climate change impacts, covering:
Impacts that can be predicted with relative confidence and where the
confidence in the direction of effect is certain (e.g. average temperature);
Impacts where prediction is more uncertain, and where models often
give different levels of impacts, or even predictions of a different sign
(positive/negative), as with for example regional estimates of levels
of precipitation, or frequency or magnitude of extreme events;
Impacts where prediction is highly uncertain, notably around the
major ‘tipping points’ commonly identified (major climate discontinuities
or irreversibilities, such as the West Antarctic ice sheet,
methane hydrates, etc, as in (Schellnhuber et al 2005).
2. The uncertainty in valuation, covering:
Market effects (e.g., estimates captured through markets such as energy
and agriculture);
Non-market effects (e.g., estimates for health and ecosystems which
rely on other economic approaches, as advanced through the environmental
economics literature);