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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Thanks Dr.Masters...
On a sad note.
I lost a friend at 2am Sun Morn.
Charles Kimble..a Good man.
Done in by Cancer.Diagnosed on May 8th. Gone 10 days later.
What they missed at the Hospital 3 months ago,as a torn rotator Cuff..Was Stage 4 Lung Cancer that metastasized thru his Body.
He went on and didnt go Back to the doc till the Ambulance came May 8th and took him to Hospice.
Dont be tough folks. Pain is a signal.
Now ..hes just gone.
If ya smoke..Quit.
If you dont.Dont start.
I'm so sorry to hear about that. Charles must have been a vital person in your life. Hope that you and your family are doing well, all things considered. You send a great message to everyone on these blogs; no matter how strong one thinks they may be, you can never live life on your own; we all need help, even when we don't think so. Send my condolences to your family and his for me.
And welcome to the fold cchs.
"My next blog will talk about new research regarding the hurricanes/global warming connection."
O boy..Im getting my Hard Hat out for this one.
"My next blog will talk about new research regarding the hurricanes/global warming connection."
O boy..Im getting my Hard Hat out for this one.
LOL...GW...LOL...OMG.
Is there someway we can fast foward past this?
I'll have to bring my remote that day and try it
It's fact.
The cause is what has folks shorts in a Bunch.
Looking forward to the entry also.
Project Director: Nan Walker Link
Do you all think that a global warming discussion will cause problems on the blog? I can't imagine there being any disagreement at all. I have a feeling that the next blog will be the least controversial of all.
You're in for an awakening...get ready.
IKE, I know I've seen it before. I'm normally one of the ones involved in the dispute.
Enjoy!
How's about a $4 a gallon gas debate? LOL.
Don't think hard hat will do. Going to try to borrow friend back from Mideastern Oil Sands' body armor.
23. HouseofGryffindor
Sarcasm is not becoming for a gentleman. ROFLMAO
...up 65 cents bl already this morning.
Figure 1 - Current Florida Radar Loop (Source: Wunderground 2008)
38. IKE 2:39 PM GMT on May 19, 2008
cchs...I think he has GW blogs every year right around the time hurricane season starts...I just avoid the debate. There's plenty of other blogs around to discuss weather.
How's about a $4 a gallon gas debate? LOL.
We can debate $4 a gallon gas. I hope it goes higher.
Higher???? I'm in sales..using my car!
: )
Hey all - Season is starting...the Pub is back!!!
: )
Hope all has been well! And everyone had a good winter!
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