A while back, I posted a thread called the The Long Little Ice Age which posited the lack of a warm medieval period in the Earth's climatic period. As the causes of the warming and cooling of the Earth are little known and much argued over, I considered it as at least a feasible possibility. I even wrote up a brief timeline, but I'm not sure what happened to it. The problem was that it was such a vague PoD, with huge, general effects, that the only way to deal with it was broad strokes.
I started thinking about it again, and I realised it might be easier and more eminently researchable to have a similar event happen at a later period. So I was thinking. The Little Ice Age was said to extend from around the 16th century to the 19th century, though some date it as starting earlier with the expansion of the ice pack in maybe the 12th century. The coldest period extended from 1650 to around 1715, coinciding with the Maunder_Minimum of low sunspot activity, followed by a period of warming and more sunspots, then the Sporer Minimum for 1790 to 1830 and more cold winters and lower temperatures.
What I am suggesting is to somehow combine these two Minima into one long period of bitter cold extending from about 1650 to 1830. Now, I think it would be probably feasible to do this with just a handwave, blaming it on fickle sunspots. But this might be open to somewhat justified charges of ASB.
Another option would be volcanic eruption. The best candidate for my purposes would be a supereruption at Lake Taupo in New Zealand, as it's isolated location would reduce directly-volcano-related butterflies. It is also not implausible for such an event to occur, as it's all a matter of statistics.
So, let's say around 1715 or thereabouts, just as the Maunder Minimum is ending and global average temperature is going up, Lake Taupo goes up in a volcanic explosion two grades higher than Krakatoa, with a Volcanic Explosivity Index of 8. New Zealand is coated in ash and the inhabitants who survive beat hastic retreats (where to? Australia might be interesting). Meteorological disturbances are noticed worldwide. And a global cooling event, much worse than the OTL Little Ice Age, but not as bad as the Younger Dryas period, ensues as ash blankets the atmosphere.
I'm not sure if thermohaline circulation would necessarily be affected, as much of the currents near New Zealand are deep current. But if there is a global cooling, and it heavily affects the Southern Hemisphere, it may have enough of an impact to throw out both the Asian monsoon cycles and the Gulf Stream.
Consistently cold winters would see the Baltic Sea and Thames freeze over more regularly, and lower populations throughout northern Europe. I will do some more research, but from what I can see of other volcanic winter events there will be lots of agricultural damage and famine throughout the world. What would be the effects of a long period, from 1650 until around 1830 (but diverging significantly from OTL around 1715) of a long volcanic-and-sunspot induced period of long, cold winters?
An annually frozen Thames?
I started thinking about it again, and I realised it might be easier and more eminently researchable to have a similar event happen at a later period. So I was thinking. The Little Ice Age was said to extend from around the 16th century to the 19th century, though some date it as starting earlier with the expansion of the ice pack in maybe the 12th century. The coldest period extended from 1650 to around 1715, coinciding with the Maunder_Minimum of low sunspot activity, followed by a period of warming and more sunspots, then the Sporer Minimum for 1790 to 1830 and more cold winters and lower temperatures.
What I am suggesting is to somehow combine these two Minima into one long period of bitter cold extending from about 1650 to 1830. Now, I think it would be probably feasible to do this with just a handwave, blaming it on fickle sunspots. But this might be open to somewhat justified charges of ASB.
Another option would be volcanic eruption. The best candidate for my purposes would be a supereruption at Lake Taupo in New Zealand, as it's isolated location would reduce directly-volcano-related butterflies. It is also not implausible for such an event to occur, as it's all a matter of statistics.
So, let's say around 1715 or thereabouts, just as the Maunder Minimum is ending and global average temperature is going up, Lake Taupo goes up in a volcanic explosion two grades higher than Krakatoa, with a Volcanic Explosivity Index of 8. New Zealand is coated in ash and the inhabitants who survive beat hastic retreats (where to? Australia might be interesting). Meteorological disturbances are noticed worldwide. And a global cooling event, much worse than the OTL Little Ice Age, but not as bad as the Younger Dryas period, ensues as ash blankets the atmosphere.
I'm not sure if thermohaline circulation would necessarily be affected, as much of the currents near New Zealand are deep current. But if there is a global cooling, and it heavily affects the Southern Hemisphere, it may have enough of an impact to throw out both the Asian monsoon cycles and the Gulf Stream.
Consistently cold winters would see the Baltic Sea and Thames freeze over more regularly, and lower populations throughout northern Europe. I will do some more research, but from what I can see of other volcanic winter events there will be lots of agricultural damage and famine throughout the world. What would be the effects of a long period, from 1650 until around 1830 (but diverging significantly from OTL around 1715) of a long volcanic-and-sunspot induced period of long, cold winters?
An annually frozen Thames?