Vol. XXVI, 1st Quarter
In the continuing debates over the imminent cataclysm brought about by Global Climate Change, some popularly known scientific theories about the present condition of the earth is contradicted by recent development. Contrary to popular knowledge, volcanic activities, scientists confirmed, have little effects in the rising global temperature but actually help ease the brunt of global warming.
In a 2005 article in The Sydney Morning Herald, CSIRO climate scientist John Church says that, “if it had not been for the eruptions, sea levels today would be six or seven millimeters higher.” According to the article, a key indicator of climate change is the rising of global sea levels due to the melting of Polar ice caps.
He stressed that “since the mid-1950s the seas have been rising by an average of 1.8 millimeters a year. Scientists have blamed global warming for both sea water’s volume expanding and ice melting.” Church added that, “From 1915 to 1963 the world was relatively free of major volcanic eruptions. Then, in 1963, Indonesia’s Mount Agung exploded. It was followed in 1982 by Mexico’s El Chichon and, in 1991, by Mount Pinatubo in the Philippines.” These volcanic eruptions in the past 44 years have emitted sulfate aerosol, (salts that contain a charged group of sulfur and oxygen atoms: SO42-, the basic constituent of sulfuric acid, www.washington.edu) which acted as a mirror that reflected sunlight, consequently cooling down the world temperature by about 0.4 degrees for a few years.
This view is shared by Phivolcs Director, Renato U. Solidum. In a recent press conference on Global Warming at the Sulo Hotel, he cited that volcanic eruptions particularly Mt. Pinatubo in 1991, resulted in the decrease in global mean temperature by <1 °C. He stated that the eruption produced the largest sulfate aerosol clouds, about 25-30 megatons. A fete never been duplicated since Mt. Krakatau in Indonesia erupted in 1883.
He explained that, emitted sulfur dioxide into the atmosphere during a volcanic eruption turns into sulfate aerosol which absorbs the sun’s heat and beaming it back into space, in effect, warms the stratosphere and cools down the troposphere, the lowest layer of the atmosphere.
It is also important to note that not all volcanic eruptions reduce global temperature. Volcanic debris emitted from an eruption that formed as a cloud and have reached the stratosphere or about 50 kilometers high above the earth’s surface affects world temperature while volcanic emissions within 18 kilometers are washed away by air and rain. In addition to this, an article on www.geology.sdsu.edu says that sulfuric gases are importantly considered as a factor in determining the effects of volcanic eruptions in global warming.
Dr. Solidum also added that human activities such as the burning of fossil fuel plays a major role in enhancing greenhouse effect by producing 10 B tons/year of carbon dioxide (CO2), a green house gas (GHG) compared to volcanic eruptions, which was previously believed as a great contributor to global warming, produce 110 M tons/year of CO2.
However, he pointed out the negative effects of volcanic activities that should not be discounted since health hazards and economic losses, range from simple to life threatening especially those people living near the volcanoes.
Some findings faulted volcanic emissions in the depletion of the ozone layer. In a separate report, Dr. Solidum cited 15-25% of the ozone was lost at high latitudes and 50% ozone depletion over the Antarctic due to hydrogen chloride (HCI) spewed was reported by www.geology.sdsu.edu.
Large volcanic eruptions releases water vapor (H2O), carbon dioxide (CO2), sulfur dioxide (SO2), hydrogen chloride (HCl), hydrogen fluoride (HF) and ash (pulverized rock and pumice). Sulfur dioxide is then converted into sulfuric acid (H2SO4), which when it condenses, it forms the sulfate aerosol. This process creates complex chemical reactions that alter chlorine and nitrogen chemical species in the stratosphere. With human made chlorofluorocarbon pollution mixed up with the stratospheric chlorine, chlorine monoxide (CIO) is then produced which is to be blamed for the ozone depletion.
Aside from the depletion of the ozone layer, volcanic eruptions similar to the magnitude of Mt. Pinatubo resulted in the loss of 11.10 billion pesos in crops, infrastructure, and personal property in 1991 to 1992 while a total of 491 million pesos of business was lost in the years 1991 to 1992.
Although this phenomenon according to scientific data, eases global warming but only for a period of time, by which scientists predict that in a decade or more, global temperature will gradually return to its previous state. However, majority of the earth’s denizens would prefer a quick, firm and lasting solution to global climate change. But, will the answer to this colossal problem comes before the projected time table set by experts? Or is the world praying for another major volcanic eruptions that will stall time in coming up with a solution?