- Feb 23, 2005
- 22,902
- 2,359
- 126
This is really interesting to me. I found this while researching vacation plans and hadnt heard of anything like it. I was aware of the volcano, as I started travelling to SE Asia just after this, and it caused travel concerns. Im sure other events have contributed to temp changes, but this one seems pretty big. 1 degree is ALOT globally for one event. The article also states "At the same time, the temperature in the stratosphere rose to several degrees higher than normal, due to absorption of radiation by the aerosols." Very interesting indeed.
My intent is NOT to create yet another "how much do humans affect GW" thread, but rather to show natural events really do have a BIG effect on the planet, maybe cumulatively larger than man's. It seems most threads that are started in this subject talk about yet some other story of mankind's influence on the planets eco-system. It would be interesting to get a thread of natural events thazt cause significant changes for a change instead of people-related threads.
Wiki entry here.
Mount Pinatubo is an active stratovolcano located on the island of Luzon in the Philippines, at the intersection of the borders of the provinces of Zambales, Tarlac, and Pampanga. Ancestral Pinatubo was a stratovolcano made of andesite and dacite. Before 1991, the mountain was inconspicuous and heavily eroded. It was covered in dense forest which supported a population of several thousand indigenous people, the Aeta, who had fled to the mountains from the lowlands when the Spanish conquered the Philippines in 1565.
The volcano's eruption in June 1991 produced the second largest terrestrial eruption of the 20th century. The 1991 eruption had a Volcanic Explosivity Index (VEI) of 6, and came some 450-500 years after the volcano's last known eruptive activity (estimated as VEI 5, the level of the 1980 eruption of Mount St. Helens), and some 500-1000 years after previous VEI 6 eruptive activity. Successful predictions of the onset of the climactic eruption led to the evacuation of tens of thousands of people from the surrounding areas, saving many lives, but as the surrounding areas were severely damaged by pyroclastic flows, ash deposits, and later, lahars caused by rainwater remobilizing earlier volcanic deposits, thousands of houses and other buildings were destroyed.
The effects of the eruption were felt worldwide. It ejected roughly 10 billion metric tons of magma, and 20 million tons of SO2, bringing vast quantities of minerals and metals to the surface environment. It injected large amounts of aerosols into the stratosphere?more than any eruption since that of Krakatoa in 1883. Over the following months, the aerosols formed a global layer of sulfuric acid haze. Global temperatures dropped by about 0.5 °C (0.9 °F), and ozone destruction increased substantially.
The powerful eruption of such an enormous volume of lava and ash injected significant quantities of aerosols and dust into the stratosphere. Sulfur dioxide oxidised in the atmosphere to produce a haze of sulfuric acid droplets, which gradually spread throughout the stratosphere over the year following the eruption. The injection of aerosols into the stratosphere is thought to have been the largest since the eruption of Krakatoa in 1883, with a total mass of SO2 of about 17 million tons being injected?the largest volume ever recorded by modern instruments.
This very large stratospheric injection resulted in a reduction in the normal amount of sunlight reaching the earth's surface by roughly 10%. This led to a decrease in northern hemisphere average temperatures of 0.5?0.6 °C (0.9?1.1 °F), and a global fall of about 0.4 °C (0.7 °F). At the same time, the temperature in the stratosphere rose to several degrees higher than normal, due to absorption of radiation by the aerosols. The stratospheric cloud from the eruption persisted in the atmosphere for three years after the eruption.
Satellite measurements of ash and aerosol emissions from Mount Pinatubo.The eruption had a significant effect on ozone levels in the atmosphere, causing a large increase in the destruction rate of ozone. Ozone levels at mid-latitudes reached their lowest recorded levels, while in the southern hemisphere winter of 1992, the ozone hole over Antarctica reached its largest ever size until then, with the fastest recorded ozone depletion rates. The eruption of Mount Hudson in Chile in August 1991 also contributed to southern hemisphere ozone destruction, with measurements showing a sharp decrease in ozone levels at the tropopause when the aerosol clouds from Pinatubo and Hudson arrived.
Another noticeable effect of the dust in the atmosphere was the appearance of lunar eclipses. Normally even at mid-eclipse, the moon is still visible although much dimmed, but in the year following the Pinatubo eruption, the moon was hardly visible at all during eclipses, due to much greater absorption of sunlight by dust in the atmosphere.
My intent is NOT to create yet another "how much do humans affect GW" thread, but rather to show natural events really do have a BIG effect on the planet, maybe cumulatively larger than man's. It seems most threads that are started in this subject talk about yet some other story of mankind's influence on the planets eco-system. It would be interesting to get a thread of natural events thazt cause significant changes for a change instead of people-related threads.
Wiki entry here.
Mount Pinatubo is an active stratovolcano located on the island of Luzon in the Philippines, at the intersection of the borders of the provinces of Zambales, Tarlac, and Pampanga. Ancestral Pinatubo was a stratovolcano made of andesite and dacite. Before 1991, the mountain was inconspicuous and heavily eroded. It was covered in dense forest which supported a population of several thousand indigenous people, the Aeta, who had fled to the mountains from the lowlands when the Spanish conquered the Philippines in 1565.
The volcano's eruption in June 1991 produced the second largest terrestrial eruption of the 20th century. The 1991 eruption had a Volcanic Explosivity Index (VEI) of 6, and came some 450-500 years after the volcano's last known eruptive activity (estimated as VEI 5, the level of the 1980 eruption of Mount St. Helens), and some 500-1000 years after previous VEI 6 eruptive activity. Successful predictions of the onset of the climactic eruption led to the evacuation of tens of thousands of people from the surrounding areas, saving many lives, but as the surrounding areas were severely damaged by pyroclastic flows, ash deposits, and later, lahars caused by rainwater remobilizing earlier volcanic deposits, thousands of houses and other buildings were destroyed.
The effects of the eruption were felt worldwide. It ejected roughly 10 billion metric tons of magma, and 20 million tons of SO2, bringing vast quantities of minerals and metals to the surface environment. It injected large amounts of aerosols into the stratosphere?more than any eruption since that of Krakatoa in 1883. Over the following months, the aerosols formed a global layer of sulfuric acid haze. Global temperatures dropped by about 0.5 °C (0.9 °F), and ozone destruction increased substantially.
The powerful eruption of such an enormous volume of lava and ash injected significant quantities of aerosols and dust into the stratosphere. Sulfur dioxide oxidised in the atmosphere to produce a haze of sulfuric acid droplets, which gradually spread throughout the stratosphere over the year following the eruption. The injection of aerosols into the stratosphere is thought to have been the largest since the eruption of Krakatoa in 1883, with a total mass of SO2 of about 17 million tons being injected?the largest volume ever recorded by modern instruments.
This very large stratospheric injection resulted in a reduction in the normal amount of sunlight reaching the earth's surface by roughly 10%. This led to a decrease in northern hemisphere average temperatures of 0.5?0.6 °C (0.9?1.1 °F), and a global fall of about 0.4 °C (0.7 °F). At the same time, the temperature in the stratosphere rose to several degrees higher than normal, due to absorption of radiation by the aerosols. The stratospheric cloud from the eruption persisted in the atmosphere for three years after the eruption.
Satellite measurements of ash and aerosol emissions from Mount Pinatubo.The eruption had a significant effect on ozone levels in the atmosphere, causing a large increase in the destruction rate of ozone. Ozone levels at mid-latitudes reached their lowest recorded levels, while in the southern hemisphere winter of 1992, the ozone hole over Antarctica reached its largest ever size until then, with the fastest recorded ozone depletion rates. The eruption of Mount Hudson in Chile in August 1991 also contributed to southern hemisphere ozone destruction, with measurements showing a sharp decrease in ozone levels at the tropopause when the aerosol clouds from Pinatubo and Hudson arrived.
Another noticeable effect of the dust in the atmosphere was the appearance of lunar eclipses. Normally even at mid-eclipse, the moon is still visible although much dimmed, but in the year following the Pinatubo eruption, the moon was hardly visible at all during eclipses, due to much greater absorption of sunlight by dust in the atmosphere.
Facebook
Twitter