It remains to be seen whether this prognosis turns out to be true (there have been some doubts expressed), but since grand minima of solar activity did occur in the past, it is certainly interesting to explore what effects such a minimum might have on 21st century climate if it did occur. This is precisely the question Stefan Rahmstorf and I investigated in a study published last year... In our study we find that a new Maunder Minimum would lead to a cooling of 0.3°C in the year 2100 at most – relative to an expected anthropogenic warming of around 4°C. (The amount of warming in the 21st century depends on assumptions about future emissions, of course).

According to these results, a 21st-century Maunder Minimum would only slightly diminish future warming. Moreover, it would be only a temporary effect since all known grand solar minima have only lasted for a few decades. Critics of this result might argue that the solar forcing in these experiments is only based on the estimated change in total irradiance, which might be an underestimate, or that does not include potential indirect amplifying effects (via an ozone response to UV changes, or galactic cosmic rays affecting clouds). However, our model reproduces the historic Maunder minimum with these estimates of solar irradiance. Furthermore, even if one multiplied the solar effects by a huge factor of 5 (which is unrealistic), no absolute cooling would take place (the temperatures would be temporarily cooler than the base scenario, but the trends would still be warming).

So where does that leave us? At first, it seems that a solar activity minimum leads to cooling, but as I detailed painfully above, that connection isn’t straightforward. Volcanoes played a strong role, for example, and it’s not at all clear a minimum will lead to an ice age without them. You can’t make a one-to-one connection between a lack of sunspots and an oncoming ice age.

Moreover, it’s not clear the results from the studies indicate a weak cycle next time around. It’s possible, but not a sure thing. And a weak cycle, as Dr. Biesecker points out, doesn’t necessarily mean anything to our climate, volcanoes or not.

Also, keep in mind the Little Ice Age was not a global phenomenon, but a regional one. Even if a weak cycle occurs and it does affect us, the effects would be relatively contained. It would suck for those who got hit by it, but the Earth itself would weather through it. Haha.

And let’s not forget the elephant in the room: the amount of cooling we’d see from this even if it all came together would still be less than the global warming we’ve been experiencing since the 20th century. It might slow things down for a while, but the climate change we’re seeing now — and it’s real, folks — is more than enough to take on a little temporary cooling, especially local cooling.