The Independent today has an article entitled ‘Scientists find what they think is largest volcanic region on Earth hidden in Antarctica after student’s idea’ (fig 1). I can’t believe for one moment that this work hasn’t been previously done before by the Americans or the Russians, but apparently it was all the idea of a third-year student at the University of Edinburgh, Max Van Wyk de Vries, that would be a great collective name for the 91 volcanoes that they discovered – the Van Wyk de Vries volcanoes. They found 91 volcanoes which range in height from 100 m to 3,850 m in a massive region known as the West Antarctic Rift System.
I had to take exception with the bit that Paul Ward has written, because with a story like this there just has to be a link to AGW no matter how weak:
Previous studies have suggested that volcanic activity may have occurred in the region during warmer periods and could increase if Antarctica’s ice thins in a warming climate.
I don’t know about the reference to a previous study he carelessly throws into the article, but what it (or he) is suggesting is that if the ice cap begins to thin a little, this could encourage the dormant volcanoes to reawaken. I am no geologist, or volcanologist come to that, but I find it hard to believe that these volcanoes were effectively plugged by an icecap that formed on top of them, and that they’ll suddenly spring back into life if ever the icecap starts to thin. Surely it’s got more to do with what’s going on under the mantle, and the tectonic forces that are at play, rather than waiting for the icecap to thin? I imagine that volcanoes would have no problem finding the ir way to the surface, despite being sat under an icecap which is 4 km thick in places, isn’t that what recently happened in Iceland with the Vatnajökull volcano.
That just leaves one important question as far as I’m concerned, and that is, what are all the scientists in the many Antarctic ice stations that the nations who have staked a claim to their piece of Antarctica actually doing with their time?
The coldest August since 1910 was that of 1912. It was both wet, cold and dull. At many coastal stations around the UK the sea temperature was higher than the air temperature. In the monthly weather report for 1912 the review of the month concludes by saying
Observers in various parts of the United Kingdom noticed in the rare intervals of fine weather the sky seldom assumed its ordinary blue tint, but appeared to be covered with a hazy film “producing grey whiteness of the unclouded sky, and extreme weakness of all sunshine”. A similar appearance was noted by several continental observers.
The mean temperature for the UK was just 11.7°C which is 3.26°C below the 1981-2010 long-term average. The mean maximum anomaly for the month was even lower at 3.94°C below average. Looking at the regional temperature anomalies (fig 2), the cold was across the board.
As well as being very cold, it was also very wet, especially in more southern regions, and particularly in East Anglia which saw over three times the monthly average rainfall (fig 3).
In fact August 1912 was and still is the wettest August in the entire EWP rainfall series that started in 1766 (fig 4).
As you probably noticed in the daily charts for the month (fig 1), August 1912 was a very cyclonic month as you can see in the Lamb Circulation types for the month (fig 5).
As regards the CET for the month, I can’t remember ever seeing a summer month as cold as this one (fig 6). August 1912 was, and still is the coldest August on record back to 1659, beating even the cold year of 1695 into second place.
Not only was it the coldest August on record, it was also ushered in the start of a three-month cold spell in central England, with a cold September (mean anomaly -2.5°C) and October (mean anomaly -2.4°C) to follow (fig 7).
At this point I would like to produce some statistics to show that August 1912 was also the dullest on record, but I can’t, the Met Office maintain that they only began measuring sunshine from 1929. The MWR comes to the rescue though, because it says about sunshine:
Sunshine was very deficient, a large number of stations situated in nearly all parts of the kingdom recording considerably less than half the average amount. In the Channel Isles and at a few places in the extreme southeast of England the mean daily duration ranged between 4 and 4½ hours, and was equal to about 30 percent of the possible. Over Central and Southern Scotland and at a few places in the northeast of England the daily duration was less than 2 hours; at Crathes, Glasgow and Eskdalemuir it amounted to only 1o percent of the possible.
What caused it?
Here’ a graph of 12 month rolling CET values for around that time, forget the date in the subtitle, another bug for the programmer to fix. I’ve overlaid the volcanic dust index events that were greater, or equal to 4, on the VEI on top of the line series, and as you can see the Novarupta event (VEI 6) looks like it may well have been responsible for global cooling that also affected our own CET series back in 1912 across, and fits well with the reports of a greyish white haze from the Monthly Weather Report for August 1912.
I had never heard of the Novarupta eruption until I started researching this article today. I never even realised it was the most powerful volcanic eruption of the 20th century, here’s what the Wikipedia article had to say about it:
The eruption of Novarupta in the Aleutian Range began on June 6, 1912, and culminated in a series of violent eruptions. Rated a 6 on the Volcanic Explosivity Index, the 60-hour-long eruption expelled 13 to 15 cubic kilometers (3.1 to 3.6 cu mi) of ash, 30 times as much as the 1980 eruption of Mount St. Helens. The erupted magma of Rhyolite, Dacite, and Andesite resulted in more than 17 cubic kilometers (4.1 cu mi) of air fall tuff and approximately 11 cubic kilometers (2.6 cu mi) of pyroclastic ash-flow tuff. During the 20th century, only the 1991 eruption of Mt. Pinatubo in the Philippines were of a similar magnitude; Pinatubo ejected 11 cubic kilometers (2.6 cu mi) of tephra. At least two larger eruptions occurred in the 19th century: the 1815 eruption of Tambora (150 km3 (36.0 cu mi) of tephra), and the 1883 eruption of Indonesia’s Krakatoa (20 km3 (4.8 cu mi) of tephra).
The latitude of the Novarupta eruption was just about perfect at 58° north for maximum effect across the northern hemisphere, as was the timing of the 6th of June to coincide with the cold months of August, September and October of 1912 in the CET series. I should imagine that the ash from the eruption would have taken at least a month or so to completely encircle the northern hemisphere and reduce the amount of sunlight. I am of course completely guessing that this was the cause of the cold August of 1912, I’ll have to spend some more time looking at NCEP reanalysis surface temperature data for 1912 to see just what affect it had on other countries across the northern hemisphere to completely be sure of my assertion.
Finally here are the daily CET values for the Summer of 1912 (fig 11), which I think says it all. This is one of the better articles that I’ve put together for my blog, I found little evidence of any link between the cold August of 1912 and Novarupta in any of my climate and weather books, and even though Philip Eden does mention the poor summer of 1912 in his book ‘Great British Weather Disasters’, he doesn’t make the link with the volcanic ash of Novarupta. August 1912 does get a short mention as the worst on record in the book ‘The Wrong Kind Of Snow’, but again no mention of why. So if you thought that August 2017 has been cool in its first ten 10 days, the mean temperature for the first 10 days of August 1912 was 2.5°C colder still.
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.
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.
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?