Either the empirical evidence is deceptive or the models are inadequate» $» in their parameterization of feedbacks such as cloud processes and atmosphere» $» ocean couplings, for instance, or in their neglect of indirect responses by the stratosphere and amplification of naturally occurring internal modes of climate variability. (climateaudit.org)
Although the PNA pattern is a natural internal mode of climate variability, it is also strongly influenced by the El Niño / Southern Oscillation (ENSO) phenomenon. (judithcurry.com)
And given the inherent unpredictability of the internal modes of climate variability — as distinct from the external control imposed by the external drivers of climate, which themselves are also uncertain — such attribution statements will always be subject to uncertainty and therefore probabilistic. (dotearth.blogs.nytimes.com)