Discuss the impact of volcano-induced climate change in Earth's history - Term Paper Example

This paper discusses how volcanic activities have caused climate change, and the resulting impact on earth’s history. How Volcanoes induce climate change Although large scale volcanic eruptions last only a few days, the effect of these eruptions on climate on the Earth can last for several years. At first, scientists believed that the dust emitted from volcanic eruptions blocked the solar radiation from reaching earth thereby leading to cooling of the earth. However, measurements later indicated that most of this ejected dust returns back to earth within six months of the volcanic eruption.

The stratospheric data suggests that during large explosive volcanic eruptions, large quantities of greenhouse gases (CO2) and sulfur dioxide (SO2) gas are also expunged into the atmosphere. SO2 reacts with the water vapor in the stratosphere and converts to sulfate aerosols, which are sub-micron droplets containing 75% sulfuric acid. These aerosols form a dense optically bright haze layer. Typically, they stay in the stratosphere for 2-4 years. Now, the large quantities of greenhouse gases released by volcanoes trap the heat radiated off the surface of the earth and form a sort of insulation around the planet.

Further, the volcanic aerosol clouds scatter a significant amount of incoming Sun’s radiation back to space. This effect is known as “radiative forcing” that can last for up to 2-3 years following a volcanic eruption. Due to these two combined effects, the Earth experiences a change in climate pattern (NASA, 2011). Evidence of climate change due to volcanic eruptions Observational evidence has also shown that volcanic eruptions and lowering of global temperatures are correlated. Four of the largest eruptions in the recent past have been associated with significant lowering of average global/regional temperatures (DGSDU, 2011) - the eruptions of Laki, Iceland in 1783, Mt Tambora, Indonesia in 1815, Krakatu, Indonesia in 1883, and two large volcanic eruptions occurred within a gap of one month in 1991 – one in Philippines (Pinatubo) and Chile (Mt Hudson) in 1991.

Over the next two years, the mean world temperature was observed to have dropped by about 1°C. Research on the recent eruption of Eyjafjallajokull, Iceland in 2010 showed that the effect of volcanoes on climate change could have been previously underestimated by 7 to 8 orders of magnitude (Boulon, Sellegri, Hervo, & Laj, 2011). This leads us to believe that there could have been a significant effect of volcano-induced climate change that significantly impacted the earth history. Impact on earth history The volcanic activity as we see today is only a small proportion of the level of volcanic activity of the historical past when large scale volcanic eruptions were much more common, long lasting, and frequent.

Thus, the volcano induced climate change could possibly even have led to major changes in earth’s history. For example, approximately 70,000 years ago, a large scale volcanic eruption of Mt Toba, Sumatra may have caused a terribly cold winter leading to the coldest 1000 years of the Last Ice Age (Michigan Tech, 2011). Sev Kender conducted research on the middle Miocene period (16 to 11.5 million years ago) and found that super-volcanic eruptions may have caused terribly cold win