Too often we forget that humanity is fundamentally at the whim of nature. Someone must have angered Vulcan, because the Icelandic volcano Eyjafjallajokull ground Europe to a halt last week. I was following the eruption quite closely as I was set to fly to London for a conference. I was relieved last week when I heard that airspace was being opened – just in time for my flight.

Source: NASA Earth Observatory

What I found most interesting about the eruption was how the closure of European airspace illustrated how dependent western civilization is on air travel and transport. Fresh produce and flowers grown in Kenya could not be flown to markets in Europe. Thousands of travelers, grown used to being able to get from one end of the globe to the other in a matter of hours, were suddenly stranded. (I met a English gentlemen last night who was stuck on vacation in Italy for an extra week – the horror!)

I had a few people ask me about the environmental effects of the eruption. So I did a bit of research. As far as I can tell, the eruption of Eyjafjallajokull has the potential to influence the climate in two direct and one indirect way:

1) Volcanoes blow stuff up into the air. Eyjafjallajokull shot a vast quantity of particulate matter up into the high atmosphere. A significant component of this “stuff” is sulfur dioxide, which in sufficient quantities, can increase the albedo (light reflectivity) of the upper atmosphere. Think of this as akin putting one of those shiny silver car shades in your windshield to keep your car from heating up in the parking lot of JC Penny.

This phenomenon can be significant, as evidenced by the eruption of Mt. Pinatubo in the Philippines in 1991. That eruption shot so much aerosol matter into the stratosphere that it reduced the amount of sunlight coming in through the atmosphere by 10%. You can see on the global temperature record (below) that there was a dip in temperatures after 1991.

Source: NASA-GISS

Unfortunately (or fortunately, depending on how you look at it) Eyjafjallajokull is a vastly smaller eruption compared with Mt. Pinatubo, and did not shoot particulates as high up into the atmosphere, so the aerosol cooling effect is expected to be insignificant.

2) Volcanoes also directly release a large amount of CO2 into the atmosphere. It was estimated that Eyjafjallajokull was emitting between 150,000 and 300,000 tons of CO2 per day.

3) The closure of European airspace led to the cancelation of over 100,000 flights. Roughly 60% of the flights in European airspace were cancelled during the closure. Estimates on the amount of CO2 that was avoided due to all of these planes being grounded ranges from 200,000 – 340,000 tons.

What does all this add up to? Even given the large uncertainties in these estimations, it is likely that the volcano actually caused a net decrease in CO2 emissions.

Unfortunately, this is just a drop in the bucket. Global emissions in 2006 were 28 gigatons (or 28 billion tons). Potentially, the Eyjafjallajokull volcano reduced CO2 emissions by 0.0007%.

In other news, the weather in London is quite nice.