At http://phys.org/print355645261.html … we learn of a new 'model' of the Sun which claims to mirror the solar cycle (which is little understood) and not only that they say they can predict irregularities within the 11 year heartbeat. The model assumes a twin dynamo affect in two layers of the Sun, one near the surface and the other somewhere in the innards. Predictions derived from the model say that solar activity will fall by 60 per cent during the 2030s – to the kind of climate conditions last seen in the 17th century (when global temperatures were cooler and the Puritans word thick coats and long trousers with wide brimmed hats). These findings were presented to the National Astronomical meeting in Llandudno last week. What they found were magnetic wave components appearing in pairs and originating in two different layers of the Sun – and both have a frequency of around 11 years (but slightly off beam from each other). The model was made using a technique known as 'principle component analysis' and was applied to the magentic field observations from a solar observatory in California. However, they only examined the three most recent solar cycles (and the current one we may note is much less active) and they compared these with average sun spot numbers over the same period, 1976-2008. What they claim is that by cycle 26, during the 2030s, the two heartbeats will become out of sync with each other and this, they suggest, will cause a serious reduction in solar activity. It is of course a prediction – and something is required to explain the solar minimums. Note the assulption that solar minimums = cold weather. This fact has hardly been questioned alathough some solar physicists are somewhat sceptical that a reduction in sun spots necessarily means a drop in temperatures (to any great degree).
The same story is up at https://tallbloke.wordpress.com/2015/07/10/new-solar-model-claims-97-pre… …. where it is always worth reading the comments. (see also http://astronomynow.com/2015/07/09/royal-astronomical-societys-national-… …
Paul Hammond comments, we should not forget that the transition from the Medieval Warm Period to the Little Ice Age began around late 12th century and the Maunder and Dalton minimums were short period within a long period of cool weather and solar activity may have nothing to do with the drop in global temperature. This is a point worth noting as cold weather can be driven by an opaque sky (dust in the upper atmosphere as a result of heavy meteoric activity, volcanoes, and landscape fires etc). We don't know what caused the transition from warm to cool climates – in the 13th century, or in the 4th and 5th centuries AD. It has never been adequately researched. Assumptions have been made and these are generally accepted – and this will continue until we get low solar activity (a minimum) in conjunction with weather that is not as cool as expected. Hammond's point is that if we have a minimum and temperatures do not drop alarmingly the global warmers will claim that it is CAGW that is stalling the fall. In the longer term this would not work – but one can imagine it would press all the right buttons for a short while and the big money treadmill would go into overdrive.