According to volcanologist Terry Gerlach, these natural eruptions, “range from 0.13 to 0.44 billion metric tons [of carbon dioxide] per year” (201). Additionally, during the 9-hour periods of the Mt. St Helens and Pinatubo eruptions, 0.001 and 0.006 gigatonnes were released into the atmosphere every hour. Anthropogenic activity releases on average 0.004 gigatonnes per hour, so during these eruptions, carbon release seems to be equal to that of humans. However, as Gerlach states, “volcanic paroxysms are ephemeral, while anthropogenic CO2 is emitted relentlessly from ubiquitous sources” (202). Ergo, volcanic eruptions can and do release a sizable amount of carbon into the atmosphere, but their occurrence is so infrequent as to be relatively ineffectual in a modern climate. Anthropogenic emissions seem instead a large factor in the modern climate. Humans release a great deal of carbon into the atmosphere each year. This trend of release does not appear to be cyclical in nature, such as Milankovitch cycles are. This is displayed by the steady rise in CO2 in the atmosphere, from ~315ppm (parts per million) in 1960 all the way to surpassing 400ppm in 2015 (Tans). Nor does the increase seem to be slowing down, instead ppm increase has gone from 0.8ppm/yr. between 1960 …show more content…
However, natural influences- Milankovitch cycles and volcanic emissions, for example- are dwarfed by the anthropogenic release of carbon, which has caused an imbalance in the release and reabsorption of carbon dioxide and therefore a steady climb of carbon in the Earth’s atmosphere. It is clearly true that both humans and the planet itself alter the climate and cause it to fluctuate, however, human impact is much less stable and much more apparent than natural impact, which has historically displayed itself to be overall