Anthropogenic factors are the only culprits for causing the rise in earth’s global temperature.” How far do you agree with this statement? Support your answer using evidence. [8]
Anthropogenic Factors (Human)
• Burning fossil fuels - Fossil fuel is used to power 80% of the world’s energy. Large consumers of fossil fuels include China, the United States of America (USA), Canada and the United Kingdom (UK). Energy is produced for industries, transportation and domestic and commercial activities. Due to their high carbon content, fossil fuels contribute to the increase in greenhouse gases by producing large amounts of carbon dioxide.With more greenhouse gases, it is able to trap more heat, thus increasing world’s temperature (enhanced greenhouse effect)
• Deforestation - With deforestation, there are fewer trees and other plants to absorb carbon dioxide, leading to an increase in carbon dioxide levels in the atmosphere. Deforestation exposes soil to sunlight. This increases the soil temperature and the rate of carbon oxidation in the soil. As such, deforestation increases the rate at which carbon dioxide is released from the soil into the atmosphere. For example, 52 000 km2 of forest was lost every year between 2000 and 2010. Greatest loss of forest occurs in South America, followed by Southeast Asia.Australia and Africa also suffered great losses in forest. With more greenhouse gases, it is able to trap more heat, thus increasing world’s temperature (enhanced greenhouse effect)
• Agriculture - Rice cultivation and padi fields contribute to the increase of greenhouse gases in the atmosphere. For example, tractors run on fossil fuels which release carbon dioxide. The use of inorganic fertilizers increases the amount of nitrous oxide in soil. Organic matter such as dead leaves and manure releases methane during decomposition. Cattle farming contribute to greenhouse gas emissions because cattle release millions of tonnes of methane annually as a waste gas. The slow digestive system of cows makes them a key producer of methane. With more greenhouse gases, it is able to trap more heat, thus increasing world’s temperature (enhanced greenhouse effect)
• Industries - Secondary industries, which are industrial economic activities such as manufacturing, involve the burning of fossil fuels that result in greenhouse gas emissions. Greenhouse gases are also released as by-products when goods are produced. Largest carbon emissions from industrial processes are from North and Central America, Europe and Asia (China and India due to rapid industrialization) o With more greenhouse gases, it is able to trap more heat, thus increasing world’s temperature (enhanced greenhouse effect)
• Urbanization - Large amounts of fossil fuels are burnt to provide energy for household activities in urban areas. These activities include heating, cooking and lighting. The high concentrate of cars, buses and other forms of transportation in urban areas also contribute to the amount of greenhouse gases emitted in these areas. Constructing infrastructure and producing construction materials also release greenhouse gases into the atmosphere
Natural Factors
• Solar Variation from the Sun – Other than human causes, there are also natural causes that can affect global climate. The solar radiation emitted by the sun varies over the years. During peak periods, the sun could emit more solar radiation due to its own dynamic activities. When the sun emit more solar radiation, the extra sun rays reaching the earth will also be converted to heat energy thus causing global temperature to rise. Conversely, when sun activities are down, less solar radiation reaches the earth causing lower global temperatures.
• Volcanic Eruption – Another natural factor that causes global climate change is huge volcanic eruptions that occurs over the years and centuries. When there is huge volcanic eruptions, large amount of ash is thrown up high into the atmosphere. This ash cloud can than spread and cover huge areas of the earth’s surface. The huge ash cloud cover function as a clouds preventing solar radiation from reaching the earth’s surface. This in terms leads to less solar radiation being converted to heat energy. In such instances, the earth’s temperature actually drops causing global dimming. For instance, when Krakatoa erupted in 1883-84, the huge volcanic ash cloud produced reduced global temperature by about o.4 degrees.
In conclusion, there is no denying that global climate change has happened more quickly over the last 250 years due to significant increase in human activities like industrialization, deforestation and burning of fossil fuel. Although the earth’s climate has changed in term due to variation in solar outputs and volcanic activities, the latest rise in global temperature is the result of increased human activities over the last few decades. Such increase was unprecedented and will continue if human activities are not controlled.
Comments