The relationship between volcanoes and Central England Temperature in recent years


Mount Pinatubo June 1991 Courtesy of Wikipedia

Now that I’ve discovered the VEI database from the NCEI, I can now overlay volcanic eruption events on top of the monthly CET anomalies and chart the results. In the above chart (fig 2) I’ve overlaid all the VEI 4 events or greater from 1980, and was surprised to find that there seemed little in the way of correlation between them. The Pinatubo eruption of the 15th of June 1991 for example was the first VEI 6 event since Tambora in 1815 (fig 1), and lifted more than 5 cubic kilometres of material 25 miles straight up into the stratosphere, coincidentally a typhoon that was passing close by to the Philippines at the same time scattered the ash from the volcano to the four winds. I thought the effects of this would have had a dramatic cooling effect on CET in 1992, but not that you would notice. Of course any cooling in a local temperature series may well be masked by other regional and global factors that influence CET that are going on at the same time, global climate is complicated.

Figure 2

Latest global temperatures and volcanoes…

Mount Pinatubo June 1991 Courtesy of Wikipedia

I was just going to post the latest GISS global temperature anomalies for October 2016, and thought it might be a great idea to overlay the graphs with the volcanic activity of the last 136 years that would have impacted on global temperatures. Finding the source of the raw data on the internet was not easy, but there were some interesting Wikipedia articles about a term called the Volcanic Explosivity Index [VEI]. The VEI is a relative measure of the explosiveness of volcanic eruptions devised by Chris Newhall of the United States Geological Survey [USGS] and Stephen Self at the University of Hawaii in 1982. The scale runs from zero to eight, and there have only been 42 VEI 8 mega-colossal explosive eruption events in the last 36 million years. To give you an idea of the VEI scale Mount St Helen’s in 1980 was a type 5 event, Mount Pinatubo was a type 6 event in 1991, and Mount Tambora was a type 7 event in 1815. Anyway I finally tracked down the data to NOAA, and what’s now called the National Centers for Environmental Information [NCEI], they maintain a  database they call ‘The Significant Volcanic Eruption Database‘ and I’m very grateful to them because I can now use the data in my global temperature application, and will add it to the graphs in my daily and monthly CET applications as time permits.

The caldera of Mount Tambora – courtesy of Jialiang Gao (

Here’s the full monthly GISS anomalies and a 12 month running average since 1880. The first event volcanic in 1883 was the eruption of Krakatoa, which may have resulted in some cold winters in the 1880’s, and undoubtedly some very colourful sunrises and sunsets.

And below is a zoom into the GISS global temperatures since 1980. As you probably know 2016 will undoubtedly be the warmest year in the series, although the 12 month running average has already peaked. The three volcanic events marked on the graph from left to right are Mount St Helens (1980), El Chichón (1982) and Mount Pinatubo (1991). I’ve placed a six month span on the volcanic event but this of course may have been much longer for Pinatubo. Looking at the graph there is no doubt about the obvious effect that Pinatubo had on global temperature, but it’s not obvious with the other two. I’ve tried drawing a left, right and a centre aligned 12 month moving average, and none of them synchronize well with any fall in global temperature, in fact the 1982 event almost appears to have caused a spike in global anomalies. Interestingly, although Wikipedia claims the Puyehue-Cordón Caulle event was a VEI 5 event in June 2011, the NOAA database lists it as a VEI 4. I suppose in reality even events with a VEI of less than 5 still emit a lot of dust, ash and gas into the atmosphere so they all must have some effect, looking at the graph there was a decrease in anomalies in 2011 which possibly had something to do with the 2011 eruption. I’ll have another think about the eruption data and maybe come up with some kind of annual index to overlay rather than specific events. It’s now been almost twenty-five years since we’ve had a type 5 VEI event on the planet, I wonder if 2017 will continue in the same vein?