Volcanoes Effect on Climate Change

Earth's climate has continued to change throughout its history. In the beginning, when Earth was first created, volcanic eruptions contributed to the creation of the early atmosphere. Supervolcanoes have had the largest impact on Earth's past climate, causing global changes that last for several years. Recent volcanic eruptions continue to alter Earth's climate and atmosphere. However, humans have had a much larger impact on climate change. Their large emissions of carbon dioxide have had much more serious impacts on climate change than volcanic eruptions have. Although volcanoes have largely contributed to past and current climate change, human emission of CO2 has caused much more drastic and long lasting effects.

Effects of Past Volcanic Activity

Volcanoes have been extremely important since the early history of Earth when, through outgassing, they helped create Earth's early atmosphere. Volcanic eruptions occur when magma travels up to Earth's surface through faults and fissures in the mantle and erupts as lava through summit or flank vents. These eruptions release lava, pyroclastic debris, and gases into the atmosphere. During the Hadean period, volcanic outgassing was the main source that contributed to the gases in Earth's early atmosphere, which consisted mainly of water vapor, carbon dioxide, nitrogen, methane, and ammonia (OSU, 2018). Once the Earth had cooled enough, water vapor began to accumulate and came down as rain, forming the first bodies of water. During this period, the atmosphere contained no free oxygen. The amount of oxygen did not increase until the first forms of life appeared and began converting carbon dioxide that had been released by volcanoes into oxygen (OSU, 2018).

There were many large eruptions in the history of our planet that had large impacts on the climate and life on Earth. Supervolcanoes, which eject huge amounts of lava and ash much larger than other types of common volcanoes, have been one of the leading causes of climate change in Earth's past. Supervolcano eruptions such as Yellowstone, Toba, and Taupo have caused more drastic and long-lasting effects to Earth's climate compared to smaller volcanic eruptions (Jones et al., 2007). The ash erupted into the air spreads out radially with the finer particles spreading far across countries and even continents. Nearer the volcano, larger ash and rocks fall to the ground, covering plants and causing large amounts of deforestation. This affects different cycles such as the carbon and water cycle in the nearby areas. The aerosols remaining in the atmosphere can also cause acid rain, bringing the chemicals in the air back down to the earth (Jones et al., 2007). Past supervolcanic eruptions have also released H2SO4 aerosols into the atmosphere which blocked the sun's radiation from reaching Earth. This caused both the atmosphere and Earth's surface to cool significantly in the nearby area and for slight cooling at a global level. Many of the effects of these large volcanic eruptions lasted for a couple years (Jones, 2007).

Effects of Recent Volcanic Activity

Several more recent eruptions have continued to add elements into our atmosphere, affecting the current climate. One example of a recent volcanic eruption that had a large impact on the climate was the eruption of Mount Pinatubo in the Philippines in 1991. This eruption was so large that the volcanic plume reached the stratosphere, where strong winds spread the ash far across the Earth. The aerosols blocked the radiation from the sun by absorbing and reflecting sunlight. This caused global cooling that lasted for around two years (NASA, 2001). Several other eruptions have occured in the recent past that have similarly affected the climate many at much lower scales. Although volcanoes can affect the climate at a global scale, their effects are usually only short lived (Kappelle et al., 1999).

CO2 From Volcanoes and Humans

Volcanoes have introduced many gases into the atmosphere during eruptions with one of the most common being CO2. Carbon dioxide is released by volcanoes both through eruptions and from underground magma rising through rocks, soil, and water. (Scott, 2016). Large volcanic eruptions can inject millions of tons of CO2 into the atmosphere. An example is the eruption of Mt. St. Helens in 1980, where around 10 million tons of CO2 was released. Even with similar amounts of carbon dioxide being released by other volcanoes, the amount released has not been enough to show clear signs of contributing to global warming (USGS, 2018). This large amount of carbon dioxide being released by volcanoes is small compared to the amount humans continuously emit each year.

In the short period that humans have inhabited earth, they have had a much larger impact on the release of carbon dioxide than volcanoes have. In 2010, humans released close to 35 billion tons of CO2 into the atmosphere, which is more than several volcanic eruptions put together. Also, large volcanic eruptions only happen once every few years while humans constantly burn fossil fuels that release large amounts of carbon dioxide into the atmosphere (USGS, 2018). The amount of carbon dioxide released into the atmosphere has continued to increase since the Industrial Revolution with the creation of large factories and the increase of automobiles. Around 2000 billion metric tons of carbon dioxide have been released into the atmosphere from industrial activities since then (Scott, 2016). Many studies have been done to show how the doubling or quadrupling of carbon dioxide would affect the atmosphere and climate. By creating circulation models, these scientists have found that the large amounts of CO2 being released have caused general warming and increased moisture in the atmosphere (Manabe and Wetherald, 1980). Other studies comparing the amount of carbon dioxide released by volcanoes to the amount released by humans have shown that, on average, humans produce around 90 times more global emissions (Scott, 2016). This shows how humans are having a much larger impact than volcanoes on climate change.

The increase of carbon dioxide being released into our atmosphere by both humans and volcanoes has been contributing to the greenhouse effect. The greenhouse effect, which traps heat in the atmosphere by preventing it from leaving Earth, is caused mainly by four different elements. These elements include water vapor, nitrous oxide, methane, and carbon dioxide. Carbon dioxide has been the element that has increased the most in the atmosphere and is the main cause of climate change (NASA, 2018). Although both humans and volcanoes have released carbon dioxide into the atmosphere, humans have done it a much larger and more dangerous scale. Human emissions of CO2 are constant and are caused mainly by the burning of fossil fuels, deforestation, and other industrial activities. (NASA, 2018). These emissions have had a much greater effect on global warming and the greenhouse effect than all volcanic eruption from the same time period put together.

Conclusion

Overall, human activities are the leading cause of climate change. Volcanoes may have caused changes to Earth's atmosphere and caused global cooling that lasted several years, but the effects humans have had last much longer and are at a much larger scale. Ever since the Industrial Revolution, the amount of carbon dioxide in the atmosphere has increased. Volcanic eruptions have contributed slightly to this, but the majority comes from human activity. On a geologic time scale, this increase in carbon dioxide has occurred very suddenly. Volcanic eruptions over Earth's history have released carbon dioxide and other elements, but at a much smaller scale than is currently being done by humans. Many of the effects of climate change are irreversible and if humans want to prevent the greenhouse effect from worsening in the future, then they should decrease the huge amounts of deforestation and the large use of fossil fuels that occurs each year.

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