Chile's volcano not likely to affect the climate
It's been a busy month for natural disasters, and I haven't found time to talk about Chile's Chaiten volcano, 760 miles (1,220 km) south of the capital Santiago. The volcano started erupting on May 2 for the first time in thousands of years, spewing ash, gas and molten rock into the air, forcing the evacuation of thousands of people. Did this mighty eruption have a cooling effect on the climate?
Figure 1. This May 5, 2008 image from NASA's Terra satellite caught Chaiten erupting. Image credit: NASA.
Many historic volcanic eruptions have had a major cooling impact on Earth's climate. However, Chaiten is very unlikely to be one of them. To see why this is, let's examine recent volcanic eruptions that have had a significant cooling effect on the climate. In the past 200 years, Mt. Pinatubo in the Phillipines (June 1991), El Chichon (Mexico, 1982), Mt. Agung (Indonesia, 1963), Santa Maria (Guatemala, 1902) Krakatoa (Indonesia, 1883), and Tambora (1815) all created noticeable cooling. As one can see from a plot of the solar radiation reaching Mauna Loa in Hawaii (Figure 2), the Mt. Pinatubo and El Chichon eruptions caused a greater than 10% drop in sunlight reaching the surface. The eruption of Tambora in 1815 had an even greater impact, triggering the famed Year Without a Summer in 1816. Killing frosts and snowstorms in May and June 1816 in Eastern Canada and New England caused widespread crop failures, and lake and river ice were observed as far south as Pennsylvania in July and August. Volcanic eruptions cause this kind of climate cooling by throwing large amounts of sulfur dioxide gas into the stratosphere. This gas reacts with water to form sulphuric acid droplets (aerosol particles), which are highly reflective, and reduce the amount of incoming sunlight.
You'll notice from the list of eruptions above that all of these climate-cooling events were from volcanoes in the tropics. Above the tropics, the stratosphere's circulation features rising air, which pulls the sulfur-containing volcanic aerosols high into the stratosphere, where the upper-level winds circulate them all around the globe. These aerosol particles take a year or two to settle back down to earth, since there is no rain in the stratosphere to help remove them. However, if a major volcanic eruption occurs in the mid-latitudes or polar regions, the circulation of the stratosphere in those regions generally features downward subsiding air, and the volcanic aerosol particles are not able to penetrate high in the stratosphere and get carried all around the globe. Chaiten is located near 40° south latitude, far from the tropics, and thus is unlikely to be able to inject significant amounts of sulfur aerosols into the stratosphere. Furthermore, the character of Chaiten's eruptions so far has been to eject a lot of silica and not much sulfur into the air. The total amount of sulfur ejected has been only about 1/10000 of what Mt. Pinatubo put into the air, according to NASA.
Figure 2. Reduced solar radiation due to volcanic aerosols as measured at Mauna Loa Observatory, Hawaii. Image credit: NOAA/ESRL.
Realclimate.org has a nice article that goes into the volcano-climate connection in greater detail. One interesting quote from the article: There can be some exceptions to the tropics-only rule, and at least one high latitude volcano appears to have had significant climate effects; Laki (Iceland, 1783-1784). The crucial factor was that the eruption was almost continuous for over 8 months which lead to significantly elevated sulphate concentrations for that whole time over much of the Atlantic and European regions, even though stratospheric concentrations were likely not particularly exceptional.
My next blog will talk about new research regarding the hurricanes/global warming connection.
Jeff Masters
Reader Comments
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And as I am always forced to reply: "It's all
Cacalacky to a Virginia boy." It's just in my DNA.
Seeing the GFS is still wanting to develope some type of low pressure system in the SW caribbean.Its a bit to long range for me but a good effort on consistency.Anything that developes in the NW or SW caribbean will probably follow june climatology and track towards florida hopefully bringing some much welcomed rain.Also noticed the CFS is forcasting even higher shear in the western atlantic.
and politics and religion will do just
that.
Whats Happening!
Plus,think of the Quick VORTEX RECON he can do.
What do yall think about the ECMWF joining the GFS in developing a Caribbean disturbance? Although its still over 200 hours out and extremely inaccurate.
ITCZ AXIS IS CENTERED ALONG 5N10W 4N23W 3N36W 4N44W 3N51W.
CLUSTERS OF MODERATE TO STRONG CONVECTION ARE FROM EQUATOR TO 8N
BETWEEN 4W-15W. PART OF THIS ACTIVITY IS AFFECTING SW AFRICA
INCLUDING LIBERIA. THIS CONVECTIVE ACTIVITY MAY BE ASSOCIATED
WITH A NEW TROPICAL WAVE. UPPER DIFFLUENCE ASSOCIATED WITH AN
UPPER HIGH LOCATED OVER W AFRICA NEAR 12N15W IS HELPING TO
INDUCE THIS ACTIVITY.
Drak didnt 2004 have neutral conditions develop in July and August?
Yes. There is strong concensus suggesting neutral conditions throughout the entire season this year.
".... whatcha think?... should we.. ..."
Excuse me please, while I poke out my mind's eye
The GFS goes into medium, higher resolution mode at 180 hours. If it's still showing a storm when it gets into that time frame and the ECMWF still shows signs of activity in the Caribbean, then i'd start thinking that the GFS may be on to something. Right now it's still in the long range and we've already seen the model drop it once, and chances are still significant that it's on to a ghost.
THE CARIBBEAN SEA...
CLUSTERS OF MODERATE TO STRONG CONVECTION HAVE DEVELOPED OVER
THE SW CARIBBEAN POSSIBLY ASSOCIATED WITH THE COLOMBIAN LOW AND
A DIFFLUENT PATTERN ALOFT. A 1011 MB LOW IS ANALYZED NEAR 9N76W.
THIS ACTIVITY IS FORECAST BY THE COMPUTER MODELS TO SPREAD OVER
PARTS OF CENTRAL AMERICA DURING THE NEXT FEW DAYS. PRES GRADIENT
BETWEEN A SFC RIDGE ALONG THE GREATER ANTILLES AND THE COLOMBIAN
LOW IS PRODUCING MODERATE TO FRESH TRADE WINDS ACROSS THE
SOUTH-CENTRAL CARIBBEAN. A QUIKSCAT PASS FROM AROUND 11Z SHOWED
ELY WINDS OF 20 TO 25 KT IN THIS AREA. THESE WINDS VEER SE OVER
THE NW WATERS IN RESPONSE TO THE TROUGH IN THE GULF OF MEXICO.
530. jphurricane2006 3:47 PM EDT on May 19, 2008
interesting Drak, this is shaping up to be an interesting season
Should be a rather interesting year for the southeast with the way things are shapeing up.
Those waves are rather impressive for mid may and the frequency on how there rolling of the coast is also interesting for this time of the year.
Is there any significance to this in terms of whats to come later in the year?
Agreed...another 2004 type season would be very interesting, in a Chinese curse sort of way, huh?
Drak....Could I talk you into elaborating a little on what that means?
Neutral conditions just as expected. Neutral years have a lot of activity. And the way things are looking we are in for an interesting season.
lol GS, well said...err I think lol
This blog today probably increased Global warming, you think.....lol
518. hurricane23 7:43 PM GMT on May 19, 2008
Those waves are rather impressive for mid may and the frequency on how there rolling of the coast is also interesting for this time of the year.
Is there any significance to this in terms of whats to come later in the year?
Thats a tough question but i suspect this year the eastern atlantic has the potential to be rather active.
sdf once it gets to 144 hrs out then we may have something
The GFS goes into medium, higher resolution mode at 180 hours. If it's still showing a storm when it gets into that time frame and the ECMWF still shows signs of activity in the Caribbean, then it'd start thinking that the GFS may be on to something. Right now it's still in the long range and we've already seen the model drop it once, and chances are still significant that it's on to a ghost.
You have a point. And I think the ECMWF has the best resolution out of all of the models.
2004 also had a negative NAO around this time, didn't it?
Is the current SOI indicating a trend towards a warm anomaly or has it balanced out at a weaker La Nina/Neutral?
Way too early to tell, but damned if the tropics aren't starting to heat up a bit...
We used to track canes with Pigeons and Quija Boards mostly before Tiros-7.
All this new fangled stuff is smoke and Mirrors.
Either its coming or its not.
Its gonna be big.
Or Just a lil one.
Then there was the Ones Like Camille..and the Keys Big un.
Shoot.If ya see the Birds have left and the wind is from the Se and the High clouds are moving in...and dat Lil Bulb of stuff is falling fast.
High tail it outta Savannah Goober and Gomer.
Time to Head to Raleigh and visit fer a spell with da Kin.
Ahh,..the good ol Days.
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