Different explanations have been proposed as to why the range of climate sensitivity predicted by GCMs has not lessened substantially in the last decades, and subsequently if it can be reduced. One such study (Why is climate sensitivity so unpredictable?) addressed these questions using rather simple theoretical considerations and reached the conclusion that reducing uncertainties on climate feedbacks and underlying climate processes will not yield a large reduction in the envelope of climate sensitivity. In this letter, we revisit the premises of this conclusion. We show that it results from a mathematical artifact caused by a peculiar definition of uncertainty used by these authors. Applying standard concepts and definitions of descriptive statistics to the exact same framework of analysis as Roe and Baker, we show that within this simple framework, reducing inter-model spread on feedbacks does in fact induce a reduction of uncertainty on climate sensitivity, almost proportionally. Therefore, following Roe and Baker assumptions, climate sensitivity is actually not so unpredictable.
Geophysical Research Letters
- Pub Date:
- August 2009
- Atmospheric Processes: Climate change and variability (1616;
- Mathematical Geophysics: Uncertainty quantification (1873);
- Global Change: Global climate models (3337;