Information on Solar Changes - Essay Example

?SOLAR VARIABILITY, VOLCANIC ERUPTIONS AND GREEN-HOUSE GASES Solar variability, Volcanic Eruptions and Green-house Gases Introduction Climate is the prevailing weather condition of a given geographical region over a given period of time (Korte and Constable, 2005). It is measured using atmospheric elements such as humidity, temperature, atmospheric pressure, water vapor concentration and other valuable atmospheric elements. Weather is the atmospheric condition of a location at a given time, these conditions include cloud, rain, sunshine and wind intensity (Korte and Constable, 2005).The climate system generates the climatic pattern of a given place which is determined by the five major components of a given climatic system, these include: hydrosphere, atmosphere, land, cryosphere and biosphere. Climate change is brought about by many factors. These include circulation of the oceanic processes, solar variations, volcanic eruptions, plate tectonic activities and human factors. Studies to determine the level of climate change is done using observation and theorems. Factors that affect climate are called climate forcings (Yang et al,2000) .They are internal and external climate forcings; these forcings affect some parts of the environment faster or slower depending on the position of the given atmospheric location. The ocean is known to respond slowly to climate forcings. Forcings are either internal or external depending on the genesis of the process (Valet, 2003). Internal forcings include natural processes within the atmosphere like volcanic eruptions, tectonic plate movements, variations in solar radiations and concentration of greenhouse gas effects (Geel et al., 1999). External forcings are human activities that lead to the emission of dangerous gases into the atmosphere. There also are climate change feedbacks which are elements that act in three ways to climatic forcings (Orr, 1999). It can be sudden, where there occurs a sudden cooling effect occasioned by a high presence of volcanic ash in the atmosphere which will reflect sunlight and heat. It can be gradual, in this case, the water bodies become warm slowly; and then overflow. The third possibility is a combination of both fast and slow reactions, in such a situation a sudden cooling of ice is experienced in the Arctic Ocean followed by a sudden meltdown of the ocean ice (Grootes and Stuiver, 1997). Currently, we are in a period between two ice ages, and if there are no other influences, another ice age will occur in a time scale of thousands of years. The rate of global temperature change linked to astronomical forcing is approximated to be in the order of a few tenths of a degree Celsius per thousand years (Washington et al., 2001). Solar Variations Information on solar changes is obtained from cosmogenic radionuclide records. The variables used in this study illustrate how changes over periods of time have influenced the climatic conditions of given geographical regulates and the production of carbon dioxide. (Svensmark and Friis-Christensen, 1997). High powered galactic cosmic rays induce a reactivity series of nuclear reactions that produce cosmogenic radionuclide in the atmosphere. When elements carrying high energy hit oxygen and nitrogen in the atmosphere, Be (beryllium) is formed. Further reactions of this element with nitrogen form slow neutrons. The sun regulates the intensity of the galactic cosmic rays (GCR) that reaches the earth’s surface and in this way, affects the production of radionuclides in the atmosphere. After Be is formed, it combines with aerosols and hangs in the atmosphere for one to two years (Mc Hargue and Damon, 1997). Disparities in 10Be records between Antarctica and Greenland during 1950 AD have led to differing conclusions regarding solar activity in this period (Lean, 1991). According to Greenland records, there was low 10 Be production after 1950 AD but in the Antarctic records, the trend is opposite. These 11-year averages of sunspot data and the neutron monitor show a relative stable solar activity in the second part of the 20th century (Muscheler et al. 2007). Carbon transforms into CO2 after production and stays in the gaseous state for a period of about five years; this long period of residence gives it ample time to mix with other gases in all the five parts of the earth’s components. The CO2 mingles freely in the atmosphere, causing a uniform distribution within the atmospheric spheres. This indicates that the production of C14 directly affects the amount of radioactive carbon in the atmosphere (Siegenthaler et al, 1980).Of interest is the Suess effect. Studies established that the use of radio- carbon free fossil fuel during industrial revolution in Europe led to the reduction of C14 and C12, thereby greatly influencing the atmospheric radio-carbon record of that period (Lean, 1991). A study was carried out to determine the level of change in solar variation for the past 1000 years in Greenland and the Antarctica (Yang et al, 2000). The results reflect that circulation of atmospheric gases has an effect on the solar variations of a given place. Cosmogenic radio nucleic records affirm that the solar variation is relatively high in this century compared to the period before 1959 AD (Bard et al, 2000). Dynamic and chemical processes in the middle atmosphere amplify the solar impact on climate. Changes in the heliosphere arising from fluctuations in the Sun's magnetic field mean that GCRs are less able to reach the Earth when the Sun is more active, so the cosmic-ray flux is inversely related to solar activity, although, again, there are subtle differences between this and radiometric indices (Haigh, 2002). In the recent past, solar activity has varied; this is evidenced by the existence of several sunspots. Of interest is the relationship between the cosmic rays and the clouds (Friis-Christensen and Lassen, 1991). There is scanty information on this fact, but scientific research shows that clouds have a very strong radioactive property that directly affects the cosmic stability of a region (Alley et al., 1997). The properties include the altitude of a cloud, its reflective ability and how much visible IR it can absorb as well as its emission to the earth and into the outer space (Caballero-Lopez and Moraal, 2004). It has been established that a change in the absorption of UV alters the wind circulation in the upper stratosphere; this has direct effect on the planetary wind intensity. However, it has a small effect on the surface wind unless there was a large solar variation. One study showed that when ozone changes and realistic solar radiance are incorporated, the response to solar radiance increases (Shindell et al., 1999). Overall, there is no proof on the role of solar activity in climate changes such as the present global warming and quaternary glaciations. There is need for more evidence but data that has been generated to date suggests that solar changes have led to small climate oscillations that occur on time scales of a few centuries similar to the fluctuations exhibited in the last millennium right from the Medieval Warm Period (900–1400 A.D.) followed on by the Little Ice Age (1500–1800 A.D.) (Bard and Frank, 2006). The suborbital millennial to decennial climate variability observed in the Holocene climate reconstructions is postulated to be a combined effect of intense volcanic eruptions, solar variability and internal feedback mechanisms in the climate system of the earth (Nesje, 2005; Raisberk and Yiou, 2004). Volcanic Eruptions Volcanic activities affect the environment in case of a volcanic eruption (Korte and Contable, 2005). Volcanic ashes release poisonous gases into the atmosphere. Sulfur dioxide is one of the gases produced and it leads to a cooling effect. Carbon dioxide is also released during such eruptions. This gas is highly harmful and it has a greenhouse effect, which subsequently leads to global warming. In volcanic eruptions, the released sulfur dioxide is converted into sulfuric acid in a process where sulfur condenses into sulfate aerosols. The aerosols block the sun’s penetration into the earth by reflecting sunrays back into space. In this way, the earth’s surface experiences a cooling effect. This trend therefore shows how increased eruptions heighten the cooling effect on the earth’s surface. Critiques have however refuted this claim and argue that the greenhouse gases that absorb the outgoing gases neutralize the effects of sulfur dioxide during its conversion into sulfuric acid in the atmosphere. The presence of dust particles and aerosols in the atmosphere intensify the effects of volcanic eruptions to the climate. Studies on the effects of the recent volcanic eruptions to the climate (Kelly and Sear,1984) suggest that a single eruption may cause a global cooling of about 0.3° C and the effects can last up to one or two years. Documented effects of volcanic eruptions include the eruption of Mt Etna in 44B.C which is believed to have deemed the sun for a number of days. The ensuing cooling effect led to shrinking of crops and a severe famine raged in Egypt and Rome during the epoch (Forsyth, 1988).Scientists have in the recent past attributed the heavy presence of sulfur related aerosols to meteorites, comets and nuclear winters. Calculating the radioactive effect of the nuclear forcings emitted during an eruption clearly reflects the damage that a volcanic eruption causes to the environment. A larger eruption is observed to be followed by a warm winter in the northern hemisphere (Forsyth, 1988).This is attributed to nonlinear effects that arise out of atmospheric dynamics. After the Mt Helena in 1980 in the USA, there was a heavy loading of the troposphere with volcanic ash (Mass and Robock, 1982).Darkness followed such that the streetlights automatically went on in the daytime. This was occasioned by the separation of the earth’s layer from the atmosphere by the thick aerosol. This condition brought a cooling effect such that the temperature of Yakima town, which is 135 Km west of Washington DC, recorded a temperature of 15° C for the next fifteen hours. The Mt. Helena eruption however had no recorded long term effect on the climate. Summer cooling and stratospheric heating are the other documented effects of volcanic eruption in the atmosphere; however, observations place these volcanic effects to a minimal percentage and they are partially limited to a particular area. A debate has therefore developed on the applicability of volcanic activities to climate change studies. Mass and Robock(1982), tend to agree with this school of thought by suggesting that volcanic activities have reduced tremendously over the past century and furthermore, it is such a natural activity that nature is always in a position to neutralize its effects albeit over a long period of time. A volcanic dust veil index (DVI) was designed by Lamb to analyze the effect of volcanoes on surface weather, on both upper and lower atmospheric temperatures, and on large scale wind circulation (Robock, 2000). Lamb and various researchers analyzed data and suggested that volcanism was very instrumental in causing climate change in the past 500 years. In addition, they used lamb’s index to stimulate an energy-balance model simulation of the Little Ice Age. They demonstrated that volcanic aerosols played a crucial part in producing the cooling during this Little Ice Age period. The techniques used to construct the DVI incorporated optical phenomena, historical reports of eruptions, temperature information, radiation measurements (from the 1883 period onward), as well as volume estimates of ejecta. Winter warming in Russia is attributed to volcanic eruptions. Surface air temperature from stations in North America and Europe was averaged for 2-3 years after the volcanic years of 1815, 1822, 1831, 1835, 1872, 1883, 1902, 1912, and 1963 (Robock, 2000). A significant warming was shown in Russia but insignificant changes were not noted in other regions. For instance, cooling was observed in north-eastern North America. In a separate study by Groisman in 1992, he closely examined the winter patterns after 1982 El Chichon and 1991 Pinatubo eruptions and warming was established in Russia and over north-eastern North America (Robock, 2000). Greenhouse Gases Greenhouse gas concentration is a condition that arises out of the presence of gases in the atmosphere. These gases interfere with the natural balance of gases to and from the earth’s surface. Naturally, a balance should exist in such a way that the atmosphere filters the amount of sunrays that enter the earth and then freely expels unwanted gases into space. The green house gases are produced via spontaneous natural processes or industrial processes. Natural greenhouse gases are water vapor, carbon dioxide, methane and nitrous oxide (Yang et al, 2000). Greenhouse gases trap gases that should be expelled into the space within the earth’s space. This way, heat is trapped within the earth’s atmosphere. With time, the heat trapped in the atmosphere causes a warming effect. Carbon dioxide is the most common greenhouse gas; it is produced by both natural and human processes. These are the plant and animal respiration processes, emissions during volcanic eruptions and the exchange of gases between the ocean and the atmosphere. Human processes that increase the concentration of carbon dioxide gas into the atmosphere include burning of fossil fuels and excessive use of chemicals on land that emit carbon into the atmosphere. In 1958, Charles David Keeling initiated an accurate measurement of carbon concentration in the atmosphere. The method uses master timing formula that indicates the changes in atmospheric composition. The results clearly showed the effect of human activities on the composition of the atmosphere at any given time in the study. The Kyoto Protocol lists hydroflorocarbons, and sulfur hexafluorides as forcings that are emitted in the atmosphere through human activities. Economic factors are the major contributors to the human related gaseous emissions into the atmosphere. For the past 1000 years, drastic changes have occurred and most notable is the industrial revolution. Industries use energy to drive machines. Over time, the major sources of industrial energy have evolved from coal to less harmful sources of energy in the recent past, but the fact remains that the harmful gases that were already emitted during this period still circulate. Nuclear stations have been established by almost every nation in the new industrial world and arms race is evidenced by each nation, boasting more efficient technological and military acquisitions. What the nations fail to consider is the threat that these nuclear power stations pose for the whole world (Mc Hargue and Damon, 1997). Industries emit poisonous gases that become greenhouse gases in the atmosphere and only few industrialists concern themselves with the task of purifying the gases before emitting into the atmosphere, as many deem such as an expensive undertaking would reduce company profits. Transport fuel also emits very poisonous gases. For the past 1000 years, vehicles have emerged the most commonly used mode of transportation. This indicates that the increasing standards of human life call for the acquisition of motor vehicles for efficiency of movement of people (Masarik, 1999). Vehicles use organic fuel; some are even laced with lead - the non-decomposing substance responsible for the widespread atmospheric pollution in the world. The advancement in the agricultural field brought about extensive use of fertilizers and other compounds. The decomposition of fertilizers leads to the formation of nitrogen which mixes with oxygen in the atmosphere and becomes a forcing as it traps gases that should be expelled into space. Enteric acid brings about the gas methane. Water vapor occurs naturally but has profound effect as a greenhouse gas, its lifespan in the atmosphere is shorter compared to other gases (Siegenthaler et al, 1980). Some human activities may influence the concentration of water vapor within a locality, though there is no documented proof that directly links the production and retention of water vapor within a geographical region to human activities. Water vapor levels are also naturally neutralized in the climatic change over the past 1000 years to aerosols. These are small droplets that trap gases in the atmosphere (Magny, 1993). Aerosol production is attributed to intensive burning of biomass. The top element in this category is deforestation that leads to the formation of black carbon. Other processes include: industrial combustion which leads to the emission of soot; and other harmful compounds like ammonium, and dust which is produced by intense effects of irresponsible land use. For the past 1000 years, human activities have contributed to the production of greenhouse gases that trap heat within the hemisphere. This has led to an increase in global temperatures which is commonly known as global warming. For the past 1000 years, it has been recorded at 0.65 °C increase at the earth’s surface. Recent studies indicate that carbon dioxide is the key contributing factor to the increasing warming level for the past centuries (Valet, 2003). The last three decades recorded the warmest average temperatures of the millennium, about 0.2 °C warmer than the warm periods of the 11th and 12th centuries. The 20th century exhibited the strongest warming trend of the millennium at approximately 0.6 °C per century (Jones et al., 2001). Conclusion Climate change is an emerging issue in the twenty first century and a major concern for both political bodies and international corporations (Mc Hague and Damon, 1997). This paper focuses on the role of solar variation, greenhouse gas emissions and volcanic eruptions in the climate change issue. Effects of the sun on the climate are rather obvious and natural. The sun is a natural phenomena, no human activity can dictate its intensity or radiance. This shows that nature has its own modalities for regulating the effect of the sun’s activity on earth (Yang et al, 2000). This is a fact that has generated a debate on the ability of sun variability to regulate climate change. It remains an issue that calls for extensive research for pale climatologists and future climatic forecast. The debaters argue that if the effect of solar variations was big, then it may have not been possible for scientists to extract the anthropogens from records of studies carried out over the past 1000 years. Recent research shows that greenhouse gases have contributed a larger extent to the varied climatic conditions that are experienced in the present time. Analyses from glass core records show that greenhouse gases have a direct correlation between the atmospheric greenhouse concentration and global warming (Valet, 2003). This is attributed to the gases acting as feedback mechanism during the major transition period in the interglacial era. This and the results of recent studies indicate that the future climate will be affected by the intensity of the ever increasing greenhouse gases that is aggravated by the increased eruptions that have increasingly reduced over the past 1000 years. This may be attributed to the decreasing amounts of sulfur into the atmosphere (Kelly and Sear, 1984). The warming signal has been observed along lines of natural climate variation, a clear indication that human activity, as opposed to other factors is the major forcing in climate change (Beer, 2000) trend in the warming of the earth and ocean surface, this is worrying as it poses a threat to the coastline. References Alley, R. B., Mayewski, P. A., Sowers, T., Stuiver, M., Taylor, K. C., & Clark, P. U. (1997). Holocene climatic instability in a prominent widespread event 8200 years ago. Geology. 25: 483-486. Bard,E. and Frank, M. (2006). Climate change and solar variability: What's new under the sun? 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Yang, S., Otah, H. and Shaw, J.(2000).Variations In the Geomatic Dipole Moment Over The Past 12000 Years. Geophysical Journal International. 1: 158-162. Read More