What Are Volcanoes Influence Climate Change?

With each eruption, volcanoes have the potential to eject large amounts of ash, gases, and sulfuric aerosols into the upper troposphere and stratosphere (Allen, 2015). Volcanism helped form Earth’s ancient climate and influences climate change in today’s world (Kasting, 1993). A recent example of a volcano influencing climate include the 1982 El Chichon eruption in Mexico, which is regarded as the largest volcanic disaster in modern Mexican history (Mass, 1989). Ancient examples of climate-changing eruptions include the Huaynaputina volcano in Peru in 1600 C.E. (Costa, et al. 2003) and a volcano called Tambora in Indonesia which exploded in 1815 (Harpp, 2005). All three volcanoes had direct and indirect influences on humans, livestock and plant-life because of the global climate change outcome.
The primary gas emitted by volcanoes, carbon dioxide, is a greenhouse gas that contributes to climate change by trapping infrared heat energy, resulting in global warming (Gerlach, 2011). However, compared to anthropogenic outputs, volcanic outputs of carbon dioxide is very minimal, therefore having a small overall impact on climate change (Gerlach, 2011). Emitted volcanic aerosols, on the
other hand, have the opposite effect, for they cover the Earth, reflect sunlight and cool the planet down (Mass, 1989). Therefore, volcanoes have a contradictory influence on climate. There are two models for the origin of the atmosphere, outgassing and accretion (Kasting, 1993). Outgassing focuses on the releases of gases by volcanoes (Kasting, 1993). Although there are uncertainties about how our early atmosphere evolved, it is generally agreed that the atmosphere was composed of water vapor, carbon monoxide, carbon dioxide, hydrochloric acid, methane and ammonia (Kasting, 1993). This is due to the Earth’s interior being heated by radioactive decay, and trapped gases being ejected out by volcanic outgassing more than 540 million years ago (Kasting, 1993).
The ratio of carbon dioxide and oxygen in the atmosphere didn’t change until the Precambrian Era, when sea creatures such as ammonites and photosynthetic algae evolved (Kasting, 1993). Photosynthesis by early moss, algae and plants decreased carbon dioxide and increased the concentration of oxygen (Kasting, 1993). Today, the atmosphere consists of 78% nitrogen, 21% oxygen, 1% argon, and 0.03% carbon dioxide (Kasting, 1993). However, the overall percentage of carbon dioxide in our atmosphere is increasing, due to inputs by anthropogenic sources and natural processes such as volcanism (Kasting, 1993). Human emissions of carbon dioxide dwarves that of volcanic emissions (Gerlach, 2011).
Volcanoes around the globe, including those that are on-land and underwater, ventilate approximately 0.26 billion metric tons of carbon dioxide per year (Gerlach, 2011). Alternatively, anthropogenic outputs of carbon dioxide in 2010 was estimated to be 35 billion metric tons, due to multiple sources such as transportational, industrial and agricultural emissions (Gerlach, 2011). It can be concluded that volcanic eruptions enhance global warming by adding carbon dioxide into our atmosphere, however that change is marginal compared to anthropogenic inputs (Gerlach, 2011). It has been projected that the total volcanic outgassing of carbon dioxide make up less than 1% of the total input (Gerlach,
2011). The more substantial impact lies with aerosols, which are mainly particles of sulfur dioxide gas that float in our stratosphere (Mass, 1989). Once ejected, the winds carry the aerosols until they spread and cover the stratosphere around the entire globe, where they stay for approximately two years (Allen, 2015). The sulfur dioxide then reacts with the water vapor in our atmosphere, forming sulfuric acid droplets, which reflects sunlight and prevents rays from reaching Earth’s surface and cools the overall temperature of the planet (Harpp, 2005). Thus, the effects of volcanic aerosols consists of a brief but widespread drop in temperature (Harpp, 2005). Aerosols also have an effect on precipitation, and it is theorized that they contribute to the formation of acid rain (Mass, 1989). In the upper atmosphere, water needs something to aggregate on before forming a raindrop (Mass, 1989). Thus, it is thought that water vapor aggregates on sulfuric volcanic aerosols after an eruption (Mass, 1989). This makes the atmosphere and the surface of the Earth more acidic for a short period of time (Mass, 1989). The global cooling effects of aerosols are often minimal, however there are examples of catastrophic cooling in Earth’s history. In 1600 C.E., a volcano called Huaynaputina in Peru erupted and injected a large amount of sulfur in our atmosphere (Costa, et al. 2003). Tree ring records showed that the year 1601 was cold, for trees grow less in colder years which result in thinner tree rings (Costa, et al. 2003). With information gathered from tree ring records, ice core data, geological data, atmospheric measurements and visual observations, geologists have enough evidence to support a temperature drop between the years of 1601 to 1604 due to Huaynaputina (Costa, et al. 2003). These recorded cold temperatures were severe enough to cause global famine and late harvests (Costa, et al. 2003). It has been documented that Russia suffered from famine between the years 1601 to 1603, France had a late wine harvest in 1601, China’s peach tree’s bloomed late in the year, and Japan’s Lake Suwa froze at its earliest point in 500 years (Costa, et al. 2003). Although brief, the planet suffered direct and indirect effects of world-wide cooling from the explosion of Huaynaputina (Costa et al. 2003). A second example of global cooling is the explosion of Tambora, a volcano in Indonesia (Harpp, 2005). In 1815, Tambora released more ash and volcanic aerosols into the atmosphere than any other eruption in Earth’s history, which resulted in substantial atmospheric cooling (Harpp, 2005).The Tambora explosion can be closely compared to the Huaynaputina explosion in Peru, in regards to the resulted widespread famine and late harvests that affected thousands of people, livestock and plant life around the world (Harpp, 2005). Tambora killed over 100,000 people and has been nicknamed “The Pompeii of Indonesia” for that reason (Harpp, 2005). A recent example of volcanism influencing climate is the 1982 El Chichon eruption in Mexico (Mass, 1989). This volcanic explosion is regarded as the most hazardous in Mexican history (Mass, 1989). Pyroclastic flows radiated outwards of 8 km around the volcano, destroying acres of coffee, cocoa, banana crops and cattle ranches (Mass, 1989). El Chicon ejected 7 million tons of sulfur dioxide into the atmosphere that circulated the Earth within three weeks (Mass, 1989). The eruption also took place during El Nino, so the climate suffered impacts from both (Robock, 2002).
Generally, the El Chichon eruption should have cause global cooling, but it was instead counteracted by the global warming of El Nino (Robock, 2002) This made it difficult to distinguish the effects of both on temperature (Robock, 2002). This type of climate resulted in warm winter months in the Northern Hemisphere between the years 1982 and 1983, and increased temperatures in North America and Europe (Robock, 2002). In contrast, other areas of the world such as Alaska, Greenland, and China were experiencing colder winters than usual (Robock, 2002). This fluctuation of temperatures is said to be the result of the volcanic aerosol’s influence on the atmospheric wind patterns (Robock, 2002). Volcanism has a contrasting influence on climate, seemingly to both warm and cool the climate in different processes; warming from the release of carbon dioxide, and cooling from the release of volcanic aerosols (Allen, 2015). Initial photosynthesis that evolved during the Precambrian era, such as moss, algae and plants, contributed oxygen towards Earth’s early atmosphere, evolving the atmosphere we have today (Kasting, 1993). Although the central gas released by volcanoes is carbon dioxide, it is dwarfed by anthropogenic carbon dioxide outputs from multiple sources (Gerlach, 2011). Volcanoes therefore contribute minimally on global warming (Gerlach, 2011). The more important impact lies with volcanic aerosols, which can cover and spread around the Earth within a few weeks, reflecting sunlight to cool the Earth down (Mass, 1989). Volcanoes such as Huaynaputina in Peru (Costa, et al. 2003) and Tambora in Indonesia (Harpp, 2005) are prime examples of global cooling. The eruption of El Chichon in Mexico is an example of volcanic cooling conflicting with other natural processes that can affect climate, such as El Nino (Robock, 2002).