Excerpts from interview with Professor Storch conducted by Olaf Stampf and Gerald Traufetter published in SPIEGEL on June 20 2013 … (my text colouring for emphasis) …
Storch: … We’re facing a puzzle. Recent CO2 emissions have actually risen even more steeply than we feared. As a result, according to most climate models, we should have seen temperatures rise by around 0.25 degrees Celsius (0.45 degrees Fahrenheit) over the past 10 years. That hasn’t happened. In fact, the increase over the last 15 years was just 0.06 degrees Celsius (0.11 degrees Fahrenheit) — a value very close to zero. This is a serious scientific problem that the Intergovernmental Panel on Climate Change (IPCC) will have to confront when it presents its next Assessment Report late next year.
Storch: … If things continue as they have been, in five years, at the latest, we will need to acknowledge that something is fundamentally wrong with our climate models. A 20-year pause in global warming does not occur in a single modeled scenario. But even today, we are finding it very difficult to reconcile actual temperature trends with our expectations.
Storch: … There are two conceivable explanations — and neither is very pleasant for us. The first possibility is that less global warming is occurring than expected because greenhouse gases, especially CO2, have less of an effect than we have assumed. This wouldn’t mean that there is no man-made greenhouse effect, but simply that our effect on climate events is not as great as we have believed. The other possibility is that, in our simulations, we have underestimated how much the climate fluctuates owing to natural causes.
Storch: … Among other things, there is evidence that the oceans have absorbed more heat than we initially calculated. Temperatures at depths greater than 700 meters (2,300 feet) appear to have increased more than ever before. The only unfortunate thing is that our simulations failed to predict this effect.
Storch: Certainly the greatest mistake of climate researchers has been giving the impression that they are declaring the definitive truth
… It’s not a bad thing to make mistakes and have to correct them. The only thing that was bad was acting beforehand as if we were infallible.
… We still have compelling evidence of a man-made greenhouse effect. There is very little doubt about it. But if global warming continues to stagnate, doubts will obviously grow stronger.
Storch: … according to the models, the Mediterranean region will grow drier all year round. At the moment, however, there is actually more rain there in the fall months than there used to be.
Storch: … we are certainly going to see an increase of 2 degrees … by the end of this century, mind you. That’s what my instinct tells me, since I don’t know exactly how emission levels will develop. Other climate researchers might have a different instinct. Our models certainly include a great number of highly subjective assumptions … You can expect many more surprises.
Storch: … Quite apart from our climate simulations, there is a general societal consensus that we should be more conservative with fossil fuels.
Storch: … I was accused of believing it was unnecessary to reduce greenhouse gas emissions. This is not the case. I simply meant that it is no longer possible in any case to completely prevent further warming, and thus it would be wise of us to prepare for the inevitable, for example by building higher ocean dikes. And I have the impression that I’m no longer quite as alone in having this opinion as I was then. The climate debate is no longer an all-or-nothing debate …