Tuesday, May 6, 2008

The Chaiten Volcano, Chile---A Factor In Climate Change?

If this recent volcanic eruption in Chile causes significant global cooling, we may want all the CO2 in the atmosphere (that allegedly causes warming) that we can get. The links in this article and the linked satellite photo are excellent.

May 06, 2008
The Chaiten Volcano - Could it Be a Factor?
By Joseph D’Aleo, CCM
The news is reporting a relatively large and long lasting volcanic eruption in Chile. According to the AP, the Chaiten volcano spewed lava and blasted ash more than 12 miles (60,000 feeet) into the sky on Tuesday, prompting a total evacuation of the provincial capital and other settlements. The volcano’s five-day eruption has sent a thick column of ash into the stratosphere, streaming across Patagonia to the Atlantic.

In earlier stories, we noted that there are usually 8 to 12 volcanic eruptions on-going at almost all times. Most are the small guys which emit just lava or if eruptive have their ash and gas clouds only reaching thousands to a few tens of thousands of feet in the air, remaining within the troposphere where the ash and gases quickly falls or gets rained out within a few days or weeks.
It is the bigger eruptions that reach above this tropospheric layer into the more stable stratosphere that can have long lasting (up to several years) and extent effects (global).

Pinatubo in 1991 reached over 110,000 feet and El Chichon 105,000 feet in 1982. Both Mt. St. Helens in 1980 and Cerro Hudson in 1991 reached around or just over 60,000 feet. Chaiten may fall into that category of a St Helens or Cerro Hudson and have some effect on the climate. the activity has not ceased and it is still possible a larger eruption will follow. The long lasting (5 days plus) nature of this eruption adds to the likelihood of an effect. It’s higher latitude means a a lower stratosphere and increases the chances of material being injected into that stable layer.

See larger image here

Note how much a major eruption can reduce incoming solar energy. This would add to the global cooling from the ocean flips and the a super long cycle 23 and possibly quiet solar cycle 24.
See larger graph here.

We have written on volcanic potenital effects here and here.

One other note, back over a decade ago, there was some speculation that volcanic activity led to El Nino development as the ash reduced the thermal and thus pressure gradients and through them the equatorial easterlies, reducing cold water upwelliing in the eastern Pacific and favoring the sloshing east of warm water from the western Pacific. Anecdotally the super El Nino of 1982/83 followed El Chichon and the El Ninos of 1991/92 and 1992/93 followed Pinatubo and Cerro Hudson. Stay tuned as better assessments are made of how much Chaiten may play a role on what’s ahead.

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