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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(Source: Accuweather 2008)
Completely off topic - but it is actually pouring at my house! Yea - it was so dry the dust was having problems.
What? Imagine that! j/k, zoo - God forbid we should talk about the weather! Thanks for that little bit of gravity!
134. Orcasystems
I believe you just did, Orca...BTW, how have you been?
Everything is going good up here in Victoria BC.. mind you.. still waiting for summer or even spring to start. We have finally started to get some nice weather lately.
Really enjoyed the Vacation in January to Cancun.. and for the people on here who said it was nicer the PV, they are right.. the water and beaches were perfect.
Storm W, gave us a 14 day weather forecast before we left.. and beat the local Met people on every forecast.
Now its back to watching the blog to find out where we are going this year.
These waves are rather impressive early in the tropical wave season
well ok we all know the GFS has convective feedback issues, what I meant is lets see if the moisture increases in the area like the GFS says it will, that can be an early indication as to how well the GFS is initializing
I wonder if the scheduled changes to the GFS model will reduce that feedback?
Wish we could recast all of the candiates. Then again, all politicians are crooked one way or another. It's just a matter of whose message you are more gullible too.
Oh yeah, Michelle Obama really should keep her mouth shut.
There have been plenty of things to be proud of as an American since she was given birth to. It was just a highly ignorant statement of her to make. Period. It was not well thought out.
Just imagine if these tropical waves were further north at around 10N to 15N. Then we would really have to become concerned, 456.
we will kno soon as the AEJ + ITCZ shifts to 10N in the next month....still not seeing any reason (s) to change my mind from an active CV season ahead.
Seems like that could actually help us in the US down the line by developing storms further out in the East Atlantic. Increasing the chance for a recurve. Only fly in the ointment is the cooler MDR waters may make the storms wax and wane across the CATL and put them back into striking distance.
i have been hinting some form of cyclogenesis i off the coast of Panama for the past few days. the gfs has been hinting of some low presure developing in the sw caribbean the next few days. conditions in the general area near Panama is conducive for tropical storm development. the ball of convection is indicative that some of the conditions are ripe for cyclogenisis.we will wait and see what pans out as this area is climatologically favourable for development this time ofyear
That is very possible...makes alot of sense.
Those changes have been officially withdrawn. GFS apparently had some real issues and poor performance, synoptically, during parallel testing.
From email:
"-------- Original Message --------
375
NOUS41 KWBC 141442
PNSWSH
TECHNICAL IMPLEMENTATION NOTICE 08-31 AMENDED
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
1041 AM EDT WED MAY 14 2008
TO: SUBSCRIBERS:
-FAMILY OF SERVICES
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
OTHER NWS PARTNERS...USERS AND EMPLOYEES
FROM: JASON TUELL
SCIENCE PLANS BRANCH CHIEF
OFFICE OF SCIENCE AND TECHNOLOGY
SUBJECT: PLANNED IMPLEMENTATION OF GLOBAL FORECAST
SYSTEM /GFS/ MODEL CHANGES IS WITHDRAWN:
EFFECTIVE MAY 14 2008
REFER TO: 1. TECHNICAL IMPLEMENTATION NOTICE /TIN/ 08-31
TRANSMITTED ON APRIL 2 2008
2. TECHNICAL IMPLEMENTATION NOTICE /TIN/ 08-31:
AMENDED TRANSMITTED ON MAY 8 2008
AMENDED TO WITHDRAW THE IMPLEMENTATION DUE TO UNACCEPTABLE
SYNOPTIC BEHAVIOR OF THE GFS DURING THE FINAL EVALUATION
PERIOD. A NEW TIN WILL BE ISSUED IF A DECISION IS MADE TO
REATTEMPT THE IMPLEMENTATION.
"
Do you have your 2008 predictions ready Jp?
For some reason, I continue to see two circulations associated with the Panamanian convection: (1) Overland in Panama and (2) north of Panama over the extreme Southwestern Caribbean just in the northern extent of the convection. It may just be my eyes playing tricks on me, but that is what I see.
not ur eyes but the visible image..I'm seeing it too
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