Volcanoes: local and global impacts

Here’s an unusual and interesting topic for a prepping and survival blog post: volcanoes. I know what you’re thinking. If a volcano erupts near my home, do I bug-out, or hunker down? I’m thinking maybe you should bug-out. But concern about volcanic eruptions is not limited to those very few preppers who live near a volcano. There are three effects that have a much broader reach, beyond the foot of the volcano.

1. A large volcanic eruption can interfere with air travel. The vast amount of ash and particulate matter that is puts into the atmosphere is harmful to jet engines. A few years back, there was an eruption in Iceland, and flights had to be cancelled or re-routed to avoid the large area that was affected by the ash.

Years earlier, a plane headed for Jakarta encountered volcanic ash and lost all four engines:

“The pilots managed to descend slowly by gliding and were preparing for the worst – an emergency landing on the sea – when the engines restarted and the aircraft regained height. The plane barely made it back to the airport of Jakarta. Only later the cause of this bizarre incident was discovered: the increased volcanic activity of Mount Galunggung the same night sent volcanic ash more than 16 km into the sky. The volcanic ash sucked by the compressor into the engines of the plane melted in the combustion chamber, but re-solidified on the turbine blades, clogging the jet engine.” [Scientific American]

Well, as long as flight paths are changed to avoid volcanic ash clouds, the danger is minimal.

2. But volcanic eruptions also emit vast quantities of sulfur dioxide, which interacts with water in the atmosphere to produce sulfuric acid and, subsequently, acid rain. The danger here is the possibility of lower crop yields and even crop failure over a vast area of arable land. The sulfur dioxide spreads in the atmosphere, with some percentage reaching even distant regions of the world. Here’s an article from Wired.com discussing the worldwide impact of an 18th century eruption in Iceland.

Lower crop yields over a large percentage of farmland could mean higher food prices, lower food availability, and perhaps even food rationing and runs on supermarkets. But it’s not just acid rain that could affect crop yield.

3. The combination of ash and sulphur dioxide from a large volcanic eruption can cause global cooling. The 1783 eruption in Iceland caused a substantial cooling of the weather, especially in northern latitudes (northern U.S., much of Europe, almost all of Russia, etc.) —

“Of the 122 Mt of sulfur dioxide released in the eruption, 95 Mt made it to the upper troposphere and lower stratosphere, so it entered the jet stream and was circulated around the entire northern hemisphere. The haze quickly reached Europe and by July 1, 1783, the haze was noticed in China. There are not many historical records from North America that mention the arrival of the Laki haze, but tree ring records from northern Alaska suggest that July and August 1783 were very cold….” [Wired.com]

A similar cooling event occurred in the early 19th century. The 1815 eruption of Mt. Tambora caused such a dramatic cooling of the weather that the summer of 1816 was called “the year without a summer”. History 1800′s. It takes about a year for the gases and particulate matter from a major volcanic eruption to spread around the world. The effect is that a little less sunlight reaches the earth, and so the atmosphere cools. The average cooling for the whole world is slight, but the further you get from the equator, the more pronounced the effect.

As a result, the summer of 1816 in the U.S. saw repeated hard frosts, and vast crop damage. The same occurred in England and the northern regions of continental Europe. The result was famine and many deaths.

It is ironic that, in the midst of the current socio-political debate about global warming and climate change, that global cooling is one possible natural disaster that we might face. Of course, another far worse possible disaster, of man and not nature, could also cause global cooling: nuclear winter. But that is a subject for another post. I prefer my global cooling disasters to be natural, not nuclear.

– Thoreau

One Response to Volcanoes: local and global impacts

  1. If, as you suggest, people decide to bug out they should do so before the eruption. Not only will volcanic ash ruin a jet engine but it will ruin an internal combustion engine.

    You are left with two problems. First, the air filter becomes plugged with ash and the engine quits due to lack of air. Second, a low quality air filter that lets the ash pass through allowing the highly abrasive ash to scour the cylinder walls and rings destroying the engine. Either problem leaves you stranded miles from your home and resources.

    If you live near or down wind of a volcano you need a plan.