Mother Nature throws a curve ball to the climate modelers: Mount Eyjafjallokull

How will the eruption of Mount Eyjafjallajökull in Iceland affect the climate, and climate change predictions?  Mount Eyjafjallokull in Iceland continues to send a plume of ash, dust, and gases up to 40-50 thousand feet into the air, spreading towards Europe by jet stream winds. Silica in this volcanic dust melts and hardens on jet turbine parts, affecting flight paths to and from Europe while the volcano remains active.

This was not as big an event as the eruption of Mt. Pinatubo or Mt. St. Helens. According to Washington state meteorologist Cliff Mass, whose comments were an inspiration to this blog, “The weather effects will be modest and short-lived.” Large dust particles disappear from the atmosphere in a matter of days. The loss of solar radiation due to those particles reflecting the incoming radiation means some daytime cooling, but at night dust can also contribute to warming by reducing infrared radiation losses. Mt. St. Helen's eruption, for example, caused 10-15F of cooling but only in eastern Washington for the 24 hours following the eruption. 

However, volcanic eruptions can also affect climate. Sulfur dioxide gas produced by volcanoes that reaches the stratosphere can combine with water to form sulphuric acid and sulfate particles, producing haze for several (1-3) years, scattering sunrays back to space and cooling the planet.  The "Year Without a Summer," following the 1815 eruption of Mt. Tambora, featured June frosts in the northeastern U.S. and Europe that caused devastating crop failures. Mt. St. Helens on the other hand was relatively sulfur poor and had virtually no impacts on climate.

Geoengineering enthusiasts who have been advocating spreading dust particles in the stratosphere are likely rejoicing at the possibility that Nature might be providing its ultimate global warming mitigation tool. On the negative side, rarely mentioned in geoengineering mitigation articles, the above-mentioned sulfur emissions from volcanic eruptions also contribute to the destruction of the ozone layer, causing problems for UVB-sensitive life at the surface of our planet, including humans. But the rejoicing might be optimistic anyway as reports show that the sulfur content of the Iceland eruption is relatively low, and that while low-latitude eruptions have large climatic impacts by spreading emissions in the stratosphere of both hemispheres, Iceland eruptions are likely only going to affect northern latitudes.

This Nature show provides us once again with the evidence that even if our climate models were projecting future climate perfectly accurately they would have to be once again recalibrated to take into account such unpredictable events as volcanic eruptions. We have yet to invent the perfect crystal ball.