hide
Free keywords:
-
Abstract:
Climate impacts and adaptation research increasingly uses ensembles of
regional and local climate change scenarios. To do so, the ensembles are
examined to evaluate whether they describe a systematic difference
between present states (and impacts) and envisaged future states-and
such differences are often characterized as being statistically
significant. This term "significance" is well defined by statistical
terminology as the result of a test of a null hypothesis that is applied
to samples of observations that are obtained with a defined sampling
strategy. However such a statistical null hypothesis may not be a
well-posed problem in the context of the evaluation of climate change
scenarios. Therefore, the usage of terms such "statistically significant
scenario" may be misunderstood in the general discourse about the
certainty of projected climate change. We propose to employ instead a
simple descriptive approach for characterizing the information in an
ensemble of scenarios. Physical plausibility in the light of theoretical
reasoning often adds robustness to the interpretation of climate change
scenarios.
