Volcanoes and their influence on our climate

Fathom wrote: »

Low silicon. Non-explosive. Kilauea Volcano in Hawaii. Would this volcano have a lesser impact on weather than the high silicon explosive type?

Aerosols and particulate matter from large explosive eruptions are what have the biggest influence on climate. The Volcanic Explosivity Index (VEI - https://volcanoes.usgs.gov/vsc/glossary/vei.html) is used to categorise events - a rule of thumb would be that those ranked at least 5 on the scale have the potential to cause a change in weather patterns.

Also, and probably more importantly, the height of the eruption column is key. A large volcanic eruption, where the material ejected stays in the lower atmosphere (troposphere) will have little impact beyond the surrounding area (this includes Eyjafjallajökul) because the aerosols, dust, etc. are likely to fall back to ground level either as a result of gravity or being incorporated into drops of rain.

However, eruption columns that extend into the stratosphere (~15-20 km in elevation, depending on where you are in the world) will find it easier to remain suspended there as there as clouds do not form at this elevation so they're far less likely to fall back down to ground level in raindrops.

Air movement in the troposphere then allows the volcanic matter to be spread throughout the planet, where it can remain for months or even years. If the eruption is large enough (like Tambora) then there can be enough material suspended in the atmosphere to change the albedo of the planet; here, the amount of incoming solar radiation is reduced as it is reflected back into space.

The bottom line is that it is the aerosols in volcanic clouds that are the principal influencers on climate.