Actually, it’s much more than a problem of physics. It has vast policy implications.
If models are not useful in a decadal timescale, such as they can predict a strong warming for a period of minimal or even no warning, then what use is there for models? What government (apart from North Korea…) would make it difficult for people to heat up their homes in the next decade with the explanation that is going to be warm in 2070 anyway?
People do not average-out their lives across decades or centuries: each and every one of us have to go through each and every day first.
If I freeze to death today at -10C, I will not enjoy the warmth of July at +30C even if the average is +10C, perfectly compatible with human life. The same can be said of plants and animals. If I plant an olive tree in my London garden, it will die of cold in February even if the yearly average is in theory just enough to make olive trees survive in the open. If a nasty mosquito species migrates from warmer places during an August heatwave, still if that species cannot survive the following winter it will not be around until next migration opportunity during a future heatwave.
A purely statistical, multi-year approach to modelling the climate is in theory useless for policymaking (similar considerations could be made for non-regional projections, but that is too long a story here – read “How Space-Time Digested AGW” if interested). And if we end up with 15 years of incorrect projections without even a volcano for an excuse, then whatever physical explanation there is, policymakers would be much wiser in keeping climate scientists at arm’s length.