Volcanism and its Effects on Climate Change



Volcanism and its Effects on Climate Change

Introduction

There is much debate in today's world about the role of humans in the changing global climate due to the burning of fossil fuels and the release of CFC gases into the atmosphere. However, there are many who point out that natural processes cause as much, if not more, harm to the atmosphere, for example, volcanic eruptions. There are certain compositional changes within our atmosphere which have the following three effects - the ozone effect, the greenhouse effect and the haze effect. Volcanic eruptions amplify all three of the above mentioned effects to varying degrees as volcanoes can have an enormous impact on climate change. These eruptions seem to directly impact cooling and warming of the atmosphere and the depleting ozone layer (Reiter, 2008).

When major eruptions come to pass, massive amounts of ash, aerosol droplets and volcanic gas are injected or mix in with the stratosphere. Regardless, the ash which was injected in the stratosphere rapidly falls with little or no impact on climate change. However, volcanic gases including sulfur dioxide can lead to global cooling whereas carbon dioxide which is actually a greenhouse gas, can potentially lead to global warming (Gore, 2006).

Discussion

The Influence of Volcanic Eruptions and Its Effects on Greenhouse Gases

As stated above, volcanic injections in to the stratosphere cause significant impact on the climate. This is due to the fact that sulfur dioxide converts into sulfuric acid, which then condenses in the stratosphere and forms fine sulfate aerosols. Due to these aerosols, radiation from the sun is increasingly reflected back in space which causes the Earth's troposphere (or lower atmosphere) to cool. Many famous eruptions during the last 100 years or so have caused average temperature of the Earth's surface to decline by almost half a degree on the Fahrenheit scale for up to three years. For example, a climatic eruption in the summer of 1991, of Mount Pinatubo injected almost twenty million metric ton of sulfur cloud in the stratosphere at an altitude of twenty miles. This is counted as one of the most massive eruptions of last century (Reiter, 2008).

The cloud, named as the Pinatubo cloud, was also one of the largest clouds made of sulfur dioxide in the atmosphere since the advent of satellite observation in the year 1978. This cloud is believed to have caused one of the biggest aerosol disturbances in the stratosphere in the 1900s. However, eruptions in the eighteenth and nineteenth century, for example, Tambora in 1815 and Krakatau in 1883 caused more damage to the atmosphere in comparison. The Laki fissure eruption from 1783 to 1784 also caused considerable regional cooling in North Americana and Europe by almost 1.3 degrees (Gore, 2006).

The Pinatubo cloud caused a similar cooling impact on the Earth's surface for almost three years. Data from the satellite showed a considerable amount of loss in the ozone layer after the Pinatubo eruption regardless. This demonstrated the lethal albeit indirect, effect and ...