The impact of volcanism on the landscape appears to be underestimated. At first glance, it may seem relatively low, as it has direct influence only on the areas of volcanic activity. Volcanos exert a significant impact on the climate of the planet, but at the same time, they are not the only cause of the climate change.
Nowadays, over 80% of the Earth’s surface is of volcanic origin (United States Geological Survey, 2012, para. 1). The consequences of volcanic eruptions affect other areas far beyond the spots. Volcanic dust erupts on big heights and spreads for long distances by wind streams, dispersing among the troposphere and, consequently, preventing sun radiation rays from falling on the Earth surface. For example, the massive eruption of the Mount Tambora in 1815 in Indonesia resulted in abnormally low temperatures in Europe in 1816, which in scientific thought is called a Year Without Summer (Tully, 2006).
Over last 160 years, the climate was changed due to volcanic eruptions: for instance, global temperature decreased by 0.5-10C because of losses in sun heat. Radiation slackening caused by volcanic dust reaches the indices of 57-66% of the heat, which the area would have gained under normal circumstances. Moreover, volcanic dust is accumulated in the areas that are hundreds and thousands of miles from the eruption spot, which results into swarms of flora on mass areas (Rodo & Comin, 2003).
Considering the earlier examples of volcanism, one should note that tectonic activity formed Vaalbara, a supposed super-continent. The following seismic activity together with significant volcanic activity defined the landscape of the Earth. Cenozoic and the Quaternary periods are most notable for their considerable volcanic activity, which made a direct influence on the landscape, mineral resources and climate we face today (Kock, Evans, & Beukes, 2009). There are more than 10 thousands of volcanic islands only in the Pacific Ocean. Most known islands, which mainly or fully consist of the eruptive rock, are the Hawaii (the Pacific Ocean), the Ascension Island (Atlantic Ocean), the abovementioned Krakatau, Stromboli (the Tyrrhenian Sea) and others (Monroe & Wicander, 2001).
Different types of eruption cause unequal effects on the landscape. For instance, Icelandic eruption type volcanoes also help smooth landscapes: erupted lava flows into clefts and fissures, valleys and glades, filling them with hot magma. Other types, such as Strombolian, Vulcanian and Pelean eruptions reinforce uneven terrain; high accumulative cones formed in some cases (for example, on the east coast of Kamchatka) even ranges of mountains, consisting entirely of volcanic peaks. A volcano does not only build a cone but may also destroy it in subsequent eruptions. Volcanic mountains are a natural phenomenon, and their height can also change dramatically in a short time (Handbook of volcanic risk management, 2012).
In 1883, there was a catastrophic eruption of Krakatau in Indonesia, it destroyed a half of the island. Its area decreased from 13 square miles to nearly six square miles (Eruption of Krakatoa in 1883, 2005). New islands appear and disappear due to volcanic activity in many regions of the world, such as on the Aleutian Islands, the Azores and elsewhere; lava sometimes flows by block rivers, resulting in a formation of impounded lakes (Savino & Jones, 2007).
Thus, volcanic activity has an undeniable influence on the meteorological phenomena, the nature of the hydrographic network, on living organisms, not to mention the fact that, for example, the eruption of lava in Iceland leads to the melting of huge masses of ice and devastating floods, since many volcanoes in Iceland are in the same areas where the Icelandic glaciers. Powdery products of the eruptions, especially ashes, bury cities, fields, cover valleys, changing the entire look of the geographical landscape. No one should doubt that the greatest effect is observed in the areas of an immediate eruption.
In 1902, Mont Pele performed a dramatic eruption and destroyed the whole population of Saint Pierre and its neighborhood in several seconds. Before the Katmai volcano eruption in 1912 there was a broad wooded valley with a rather dissected landscape to the north-west to it. After the eruption, it was completely buried under volcanic sand and turned into a sloping plain with many fumaroles in it (Carazzo, Tait, Kaminski, & Gardner, 2012)
Volcanoes not only exert a significant impact on the landscape but also on other environmental aspects such as climate change. Scientists analyzed the past 2500 years and came to some very interesting conclusions. The first peculiar observation was that many cold periods were caused by high content of Sulfates in the atmosphere. These cause such effects as were observed during the Year Without Summer, referred to earlier in this paper: heat rays could not reach Earth, and so it lacked heat, which caused considerable lowering of the temperature. In the years of 526, 626 and 939 cold periods were recorded, caused by eruptions of tropical volcanoes, as well as by volcanoes in North America and Iceland (Volcanic eruptions that changed human history, 2015, para. 7). It should also be mentioned that volcanoes can also make a truly positive impact on the environment. There are many unique lakes, which were formed in the craters of former volcanoes, distinguishing by clear water and unique fauna
Volcanoes spew huge amounts of gases. Among others, such components prevail in the erupted gas: water vapor, carbon dioxide, and sometimes also hydrogen, nitrogen, hydrogen chloride, and, after eruption allocated sulfur gases (SO2, H2S). Furthermore, sometimes methane, ammonia and argon are present. Gases also transfer little parts of iron, copper, molybdenum, tin, nickel, zinc and other elements (Savino & Jones, 2007).At the same time, the produced carbon dioxide is extremely important for natural life. Some authors (Matthews, 2011) believe that life on the planet exists exceedingly owing to volcanic activity.
Even if it is false, its role is still considerable. Although statistical data differs a little, overall trend seems quite clear: the amount of CO2 increases drastically from year to year. Over the past 500 years, the volcanoes on Earth emitted over 70 cubic miles of powdery products and about 12 cubic miles of lava. Volcanoes emit from 65 to 319 million of metric tons per a year, whereas human activity causes a 29-30 billion tons per a year emission. This number is not final and is constantly growing (Volcanic gases and climate change overview, 2011).
To understand the scope of these disturbing figures one should refer to the nature of the greenhouse effect. The greenhouse effect is defined as “a natural phenomenon through which gases present in the atmosphere absorb heat, which lessens the amount of radiating heat that exists the earth’s atmosphere heating the Earth’s surface” (Rehkopf, 2011, p. 798). In other words, this phenomenon concludes in the temperature rise on the surface of the Earth to heating gases; some gases make atmosphere act as a glass of a greenhouse. Most often, the greenhouse effect is associated with global warming, neglecting other serious drawbacks of this phenomenon.
The most dangerous consequence of the greenhouse effect is the global warming, which leads to disruption of the thermal balance of the planet as a whole. This results in droughts, acid rains, winds, tornadoes, hurricanes and other natural disasters. It is most appropriate to speak, in this regard, about the intensification of tropical storms, expansion of arid areas and deserts, rapid glaciers melting, and others. Yields will drop drastically, inhabited areas will be flooded with water, many animals will not be able to adapt to rapidly changing conditions, sea level rise and change the overall water-salt balance (Rapp, 2014).
However, it is unreasonable to accuse volcanoes of causing the greenhouse effect. If we look at the chart provided by the US Environmental Protection Agency, it is clear, that humans are the primary driver for it, being responsible for at least 65% of all CO2 emission (The United States Environmental Protection Agency, n.d.).
Volcanos are, thus, not the source of a considerable harm to the environment. This is primarily a man. To stop environmental destruction the humanity should reconsider and reduce consumption of fossil fuels, especially coal, oil and natural gas, use special filters and catalysts to remove all of the carbon dioxide emissions in the atmosphere, increase the energy efficiency of the thermal power plants due to the use of environmentally friendly hidden reserves, increase the use of the renewables, as well as stop the felling of green space and establish a purposeful planting and stop the overall pollution of the planet.
Works Cited
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