Evaluating Climate Change Impacts on Species - Literature review Example

Essay on Quaternary period

The human activities of deforestation and industrialization have led to noticeable global warming evident in the arctic zones. Additionally, natural causes such as changes in the earth’s orbit, the number of sunspots and volcanic eruptions also contribute to changing the earth’s radiation balance. Scientists, however, report not to understand fully the recent climatic anomalies surrounding the medieval period (MWP) and the little ice age (LIA). The scientists argue that volcanism and variations in sunspots might have contributed to the phenomena. Besides, land cover and vegetation play a significant role in regional climatic. The vegetation and land cover determine the balance between the reflected and absorbed solar radiation (Campioli et al., 2012, p. 5). For instance, areas with an inadequate land cover such as snow and desert reflect more radiation back into the atmosphere than the forests that absorb heat thus contribute to warm temperatures. Vegetation additionally influences the water balance where the forest covers such as the Amazon generates its rainfall through the process of evapo- transpiration through the leaves (Steffen et al., 2011, p. 739). The previous warmer periods give an insight into the impacts of changes in precipitation, warmer climates and how the effects of landscape and vegetation cover contribute to climatic variations.

The Antarctica contains over 90 percent of the world’s ice (Carey et al., 2012, p. 3). Scientists and other research bodies have examined the Antarctica ice cores to identify the effects of past climatic changes on the current climatic conditions. The scientists have gained a much deeper understanding of the past variations in climate than was understood previously. According to the timescales, the quaternary Antarctica was distinctively different from the present Antarctica. The recent Antarctica was warmer and had trees and other vegetation indicated by the fossils found in the continent (Hicks, 2014, p. 94). The pattern of oceanic circulation and different tectonic configurations are a result of the warm times experienced in the Antarctica continent millions of years ago. Ice has, however, covered the continent for the last 6 million years ago. Further geological evidence reveals that the Antarctica ice record extends from the present time to about 800000 years ago. The time span’s distribution of sea and land across the globe has been steady over the period. Thus, the deviations recorded in the Antarctic ice provide relevant information concerning climatic variations depending on the tectonic configurations and how the climate may change in the future (Carroll et al., 2015, p. 9).

The scientists obtain the ice cores by drilling into a sheet of ice or glacier to extract a cylindrical section of the ice. The sections of the ice represent many thousands of years of snow buildup. Each layer of snow provides an idea of how the atmosphere was at the time the snow was deposited. The scientists then extract the air temperature values through the stable isotopes of oxygen and hydrogen (Carroll et al., 2015, p. 2; Wohl et al., 2014, p. 6). However, some of the climatic change skeptics argue that the present warm conditions are a natural phenomenon and, therefore, global warming could as well be natural. On the contrary, the onset of the industrial revolution contributed to a significant increase in the atmospheric temperatures (Dooling, 2015, p. 100). Scientists have simulated climatic models to disapprove of the effects of sunspot variations and volcanism on climatic conditions. The models support the claim that the present increasingly warm atmospheric temperatures are a result of human activities.

(Retrieved from: http://discoveringantarctica.org.uk/oceans-atmosphere-landscape/atmosphere-weather-and-climate/climate-change-past-and-future/)

The Antarctic temperature variations attribute to natural climatic variations of glacial retreat and expansion during the Quaternary ice age. The cold glacial phases lasted considerably longer periods than the warm interglacial conditions (Gillson, 2015, p.1; Hudson, 2014, p. 946). Moreover, significant changes in sea level contributed to the change in the climatic conditions. The carbon dioxide concentration and greenhouse gases led to the temperature changes because of the changes in the earth’s orbit. The rising levels of greenhouse gases amplified the change in atmospheric temperature (Campioli et al., 2012, p. 15). Simply stated, the levels of greenhouse gases magnified the variations in temperature instead of responding to the orbitally-induced temperature changes. The claim supports the suggestion that the current changes in greenhouse gases concentration will affect the global climate. The above table indicates that the current levels of methane and carbon dioxide concentration are beyond the sustainability of the natural variation in the present geological time (Gillson, 2015, p. 4).

Understanding the past climatic and landscape changes makes people appreciate that the climatic systems are complex and different regions respond uniquely to climatic effects of greenhouse gases. It also enables people’s understanding that it takes a considerable time for the changes in atmospheric gas concentration to begin to affect t the weather and hence the climate. Scientists, therefore, need to analyze many years of data before establishing a meaningful climate trend. The results obtained from studying the past climatic conditions and their cause and effect on human existence can help the present global population plan the agricultural activities so that they can sustain the survival of future generations. For instance, Lake Titicaca is the highest great lake in the world at an altitude of 3500 above the sea level. The lake covers an area of 58000 square kilometers. The lake has modified the climatic conditions of the area since the lake water evaporates to add moisture to the atmosphere in addition to buffering the extremes of temperature and warming the local environment by about 4-5 °C (Gillson, 2015, p. 6). The modified climatic conditions favored agriculture in the area about 3500 years ago. At the time, the conditions became wet enough to sustain crop cultivation. The region remains to be the world’s highest agricultural region globally supporting the livelihood of about 2 million people (Gillson, 2015, p. 6). The region, however, has limiting factors of short rainy season, a low water-holding capacity of the soils and high evapo- transpiration that limits the cultivation of crops. Therefore, future changes in aridity and temperature are a major concern for food security in the area.

Studies on the vegetation around Lake Titicaca show an adaptation of the vegetation to an arid-adapted community after the people in the surrounding villages had been moving with their animals uphill and downhill in search of pasture. The phenomenon occurred in the past interglacial about 370000 years ago. The falling levels of the lake have also decreased the buffering effects on the temperature of the region that caused significant aridification and regional cooling (Rowland, Davison & Graumlich, 2011, p. 325; Stein et al., 2013, p. 528). Therefore, the warm climate had twofold effects including local cooling and aridification that countered the global trends of rising temperatures.

The study revealed a substantial impact of the regional and local process in modifying the climatic conditions and further suggesting that the tipping point may occur again. An increase in temperature within the range of 1 to 2 °C could lead to cool and arid conditions with serious effects on the future of agriculture in the region since the region is extremely sensitive to changes in climatic conditions (Gillson, 2015, p. 8). Research studies into the past climatic conditions of the region around Lake Titicaca indicate that any climatic change resulting in a prolonged dry period may cause conditions beyond the adaptive capacity of the farmers and vegetation. However, the farmers in the region have previously applied adaptive management to manage it through the periods of drought through adjusting planting seasons to match the changing conditions each planting season (Lawler et al., 2015, p. 619). The people have used clues from nature such as flowering and stars (The Pleiades appearing in June) to predict years of drought to prevent or reduce crop failure. The observation is analogous to the scientific observation and association of dry periods with El Nino rains (Smithson, Addison and Atkinson, 2013, p. 212). Scientists have found that the drought brings the westerly winds and the high altitude clouds thus blocking the movement of the moisture-laden air from the east and consequently resulting in low and short rainfall.

The farmers additionally make informed choice of irrigation, species, and varieties of crops to improve the adaptation processes. The present day eucalyptus demands a large amount of water thus depleting the underground water resources and increasing a region's vulnerability to drought and risk of fire. Consequently, the plant species endangers the surrounding indigenous vegetation. Similar adaptations such as agro forestry and fire control to conserve water and buffer the aridification effects can help sustain livelihoods (Gillson et al., 2013, p. 134). Furthermore, a return to the previous traditional agricultural techniques could enhance the resilience and sustainability agriculture in warming climates as evidenced in the past periods. For instance, the use of manure increases the soil nutrient and improves the water holding capacity of the particular soil thus buffering against drought and frost. Planting a variety of crops in a similar field also enhances the range of crop maturity and climate tolerances thus improving crop resilience to changing climatic conditions.

A study concerning the Sahara desert indicates that lakes and oases dotted the desert about 9000 to 5000 years ago. Neolithic communities also flourished the area about 10000 to 4000 years ago supported by the benign vegetation and climatic conditions present at the time (Gillson, 2015, p. 10). The effects of diminished orbital effects caused the lakes and waterholes to dry up. The tropical trees were the first to disappear in 6500 years ago followed by inputs of wind-borne dust. The vegetation also shifted over a variety of changes with each utilizing unique photosynthetic means to survive. The shift resulted in population redistribution, migrations, and socio- ecological adaptations to best use the unreliable resources through innovations. The green Sahara eventually ended in 3200 years ago and replaced by the desert plants typical of the ones present today in 2700 years ago (Gillson, 2015, p. 12). Scientists have simulated the orbital effects on greening the Sahara region with considerable precision. However, the simulations also reveal the effects of desert retreat evidenced by the fossil pollen record as major factors contributing to the emergence of a green Sahara. The process began by the expansion of the vegetation growth and the surface waters that significantly modified the climate, consequently enhancing the monsoon rainfall through condensation of evaporated water. Evapo- transpiration released moisture to the atmosphere resulting in rainfall in the Sahara. Additionally, the vegetation contributed to less solar irradiation compared to the bare ground thus further enhancing precipitation through an increase in the temperature contrast between land and ocean. The land cover change contributed to a climatic change that resulted in the present Sahara desert.

The palaeoecological records provide the relationship between vegetation and climatic conditions in predicting a future green Sahara. The data enables scientists to quantify the effects of land cover on the climate thus leading to the development of a realistic vegetation-climate simulation that enables the prediction of the effects of future climatic change. The models indicate a non-linear response of the Sahara region to changing climate. However, models that are more complex reveal how the abrupt changes in vegetations can occur even in increasing cases of orbital insolation. The vegetation thus tips abruptly into a green state with gradual changes in orbit. The green vegetation remained resilient for thousands of years even in diminishing orbital factors. The tipping point between the green stables and the desert conditions provide important information about the vulnerability of the North Atlantic monsoon to the Sahara region. Predictions show that Sahara could become green again if warmer climatic conditions exist in the area (Gillson, 2015, p. 12). The simulation models have indicated that the green Sahara might resurface with an increase in carbon dioxide and rainfall levels.