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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people fearing foreclosure may also want the cat 5 that will flatten their house..
Take the money and run........
Oil and Politics
I agree that headline is misleading to the actual content of the story. However I find the study and its source very interesting. I wonder what Doc M. is brewing up for his climate change : hurricane strength article. perhaps he has a different perspective?
As for the Government and its dissapointing governace....we all knew it a long time ago "absolute power corrupts absolutely" - Socrates.
I'm more diappointed in the Americans that kept GW in office a second term. (and Fla is still on notice in my book for allowing him to get there in the first place) Although many Floridians' votes were stolen...geez where was the rioting in the streets when they took their votes away???? Take my vote and see what happens! thank GOD my state is blue!!!!
alright..no more politics from me.
*steps down from soapbox*
If you're rich...no problem. If you're middle to lower income...you're suffering.
what is that blob is the sw caribbean??? I can;t find any one talking about it.
Big blow-up of thunderstorms...interesting feature.
1021. surfmom 8:59 AM EDT on May 20,
Hiexpress - those boxes look like they'll pass above Myakka???? bummer --cause the park needs rain big time.
How's that working out ?
viking, that makes me wonder what's going to happen if we have a cat 5 bearing down on a large city with mass evacuations and no one able to afford gas..
That would be a terrible situation...even a cat 5 cruising through the GOM would be awful.
Link
Don't worry about convection; worry about conditions. You want an area with warm waters, not too close to the equator, with moist air on the water vapor loop, and either circulation (even if not closed) on the QuikSCAT or cyclonic turning in the lower-level clouds. If you don't see that, there's nothing to really focus on, convection or not. Right now, the only place that makes sens to look is the southern Carribean, since the waters near Africa warm enough are too close to the equator, the waters near South America warm enough are a narrow strip close to the coast, and shear picks up the further north you go in the Carribean (and covers the whole Gulf).
No visible cyclonic turning in the lower level clouds. Nothing on the QuikSCAT. Hence, nothing to see here for at least half a day.
A CAT 5 in the GOM would mean large spikes in fuel prices...most of the petro industry (including inbound ports for refineries) are located in the GOM; does anyone remember the fuel prioe spikes in '05?
History teaches that a lack of hurricane awareness and preparation are common threads among all major hurricane disasters. By knowing your vulnerability and what actions you should take, you can reduce the effects of a hurricane disaster. Hurricane Preparedness Week during 2008 will be held May 25th through May 31st.
The goal of this Hurricane Preparedness Web site is to inform the public about the hurricane hazards and provide knowledge which can be used to take ACTION. This information can be used to save lives at work, home, while on the road, or on the water.
(If you got back sooner, my apologies; I haven't had a chance to go through all the earlier pages from this morning yet. This place is really picking up!)
or rehashing the Past,..or comparing calamities..or hypeing gloom and doom.
One would be Putting words into Action.
Do this today.
Buy and Store 5,5 gal cans of Fuel and add some stable mix to it.
With a Fill up and that.
You'll have a jump on evacuation.
And saving money too.
cchweather man.... thanks that's waht I was looking for.... how about a link to that info.
See IKE's post 1119 for the link to the model.
Gas prices are high due to the weak dollar, rampant speculation, and tight supplies, not the oil companies deciding to take revenge on the populace.
While OPEC is a cartel, the independent supermajors and non-OPEC nationals are in fierce competition with each other. They can't just set prices that way. And anyways, with tight supplies, OPEC's power to set prices is greatly diminished.
BBL
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