Volcanic Climate Forcing

Anyone who has followed my investigations regarding the climatic temperature ranges experienced during the Holocene or since the end of the Ice Age should be aware of two things. The first is that the case for apparent solar variation as a forcing mechanism is weak. Part of the reason for this is that we have one apparent correlation in the Maunder minimum and no other really convincing data that cannot be attributed to noise.

My major concern though is that a one degree shift in Global temperature is perhaps measuring a tenth of a percent of the actual influx of energy. That means that the temperature should be way more responsive to solar variation if it is truly responsive. Instead we have a sea of energy flowing in that the atmosphere sheds handily to maintain an equilibrium that varies one degree per century over a two degree range. This is pretty amazing. It is a good bet that the attempts to link climate variation to solar variation may be a lot weaker than thought. Never underestimate researchers’ ability to cherry pick data.

The other side of this argument is that the capacity of the earth to offset climate variation is also grossly underestimated. It is as if we have protective barriers that cost more and more effort to over come. They are not linear at all. Even CO2 runs into a wall of diminishing returns as the percentage rises.

The second very clear fact is that every major temperature drop that we have been able to identify save the Little Ice Age has been associated with known major volcanic activity. This is the one certain way in which to lower global temperatures. In most cases, this effect lasts for a couple of years. Hekla gave us a generation of foul weather in the northern hemisphere after 1159 BCE. Thera was even bigger and caused a general collapse in Mesopotamia centuries earlier.

We have already commented on the loss of global heat as a result of the conversion of the Sahara into desert during the Bronze Age. The wrecking job was completed with the 1159 BCE blast and our northern climate has since varied between the Bronze Age optimum and the various temperature declines induced by volcanism since. We have seen that it takes about two centuries to recover to the optimum from a major low. Obviously restoring the Sahara would likely shorten this recovery time.

That returns us to the Little Ice Age. All the evidence to date is arguing forcefully that the only engine capable of lowering global temperatures is volcanism. It is also arguing that the engine for a cold northern climate is northern volcanism. It is obvious that a major injection of dust and sulphur dioxide into the polar air mass would be several times more effective than Mount Pele on the equator. In fact a major volcano that performed for a century would be able to keep the arctic several degrees colder for decades and cause a resultant buildup of polar ice, to say nothing of providing Europe with a much colder climate.

Hekla has already shown us such a result in 1159 BCE, and in a much smaller way in the late eighteenth century.

The only remaining question left is where is the volcano(es)? Here we have no problem whatsoever. The volcanic belt in the Aleutians and Kamchatka is home to the scariest set of explosive volcanoes outside of Indonesia. There are forty in Alaska, and they are active as hell. There is one going of every couple of years and we are likely in a quiet period.

Even more importantly, they are well positioned to inject gas and dust into the polar air mass and surprise! It has been a hundred years since we have had a major eruption up there that blew away twenty cubic kilometers of dust. Perhaps our northern warming trend reflects the moderate level of eruptions over the past one hundred years.

The point that I want to make is that while no Europeans even knew these volcanoes existed, they were quite capable of producing all the climatic effects experienced in Europe while not causing a measurable effect over the rest of the globe. Maybe we even have a Thera out there unrecognized and undated.