HUMAN CAUSES OF GREENHOUSE EFFECT

HUMAN CAUSES OF GREENHOUSE EFFECT

1) DEFORESTATION

Point – Define ‘deforestation’	Elaborate – How does it contribute to greenhouse gases	Example – Provide specific country with data to support	Limitation – Explain why Deforestation may not be the main cause of global warming.
Deforestation is the loss of forests due to the clearance of trees in forested areas. It contributes carbon dioxide which is a greenhouse gas.	Deforestation results in fewer trees absorbing the carbon dioxide in the atmosphere when trees photosynthesize. The burning of trees also generates smoke in which releases carbon dioxide into the atmosphere. Therefore Deforestation contributes to the large amount of carbon dioxide in the atmosphere.	The greatest loss of forests occurs in South America followed by Southeast Asia. Australia lost more than 2,500,000 hectares of forests between 2005 and 2010.	Deforestation is being strictly regulated by the government now and does not have such an extensive impact today. Carbon dioxide is also being produced largely in the burning of fossil fuels in manufacturing industries.

2) BURNING FOSSIL FUEL

Point – Define ‘burning fossil fuel’.	Elaborate – How does it contribute to greenhouse gases	Example – Provide specific country with data to support	Limitation – Explain why burning fossil fuel may not be the main cause of global warming.
Fossil fuels such as petrol, coal and natural gas are being burnt to generate energy.	When fossil fuels are burnt, they releases huge amount of carbon dioxide. This is especially so after Industrialization period in 1980s for the production of goods and services.	Large consumers of fossil fuels include China, USA and UK. In 2010, global carbon dioxide emissions totaled 30.6 billion tonnes.	There are alternative sources of energy being used such as solar and wind to generate electricity. Therefore the usage of fossil fuels may be reduced. Deforestation also contributes to a large amount of carbon dioxide in the atmosphere.

3) AGRICULTURE

Point	Elaborate	Example	Limitation
Agriculture is the practice of cultivation of land to produce crops and raise livestock.	In Agriculture, carbon dioxide are released from the tractors that run on fossil fuel. The use of inorganic fertilizers increase the amount of nitrous oxide in the soil, and this will be released into the atmosphere when it rains or during ploughing. Methane is also released during decomposition of organic matter and also from cattle’s digestive systems.	Millions of tonnes of methane are released each year from cattle farming. Every cow produces between 1000 and 8000 litres of methane emission everyday.	Methane and Nitrous oxide made up a small portion of greenhouse gas in the atmosphere (15%). The amount of carbon dioxide released from machineries in agriculture is insignificant compared with those in Industrialization and urban development.

4) URBANIZATION

Point	Elaborate	Example	Limitation
Urbanization is the process which people live in urban cities with daily activities that contributes to greenhouse gases.	Modes of transport such as cars burns fossil fuels and release carbon dioxide, nitrous oxide and methane to the atmosphere.  Domestic usage of energy such as electrical appliances at home contributes to a large amount of greenhouse gases released too.	Large amount of fossil fuels are used in transport, constructing infrastructure and producing construction materials.	There are many green cities today that advocates energy saving products to save electricity and consumption of energy. Agriculture in developing countries also produces greenhouse gases such as carbon dioxide, methane and nitrous oxide.

In conclusion: The combination of human activities contributes to the production of greenhouse gases in the atmosphere. The government and international organizations must work hand in hand to control the release of greenhouse gases, and look for alternative sources of energy to fuel our consumption.

Resource pack

	‘Deforestation is the main cause of global warming.’ How far do you agree with this statement? Support your answer using evidence.                                                                                                                                                          [6]
	Deforestation is the loss of forests due to the removal or clearance of trees in forested areas. Deforestation takes place as wood is required to make products such as paper, building materials and space is needed for mining and farming. Between 2000 to 2010, 52,000 square kilometres of forest were lost every year. The greatest loss was in South America followed by Southeast Asia. With deforestation, there are fewer trees and plants to take in carbon dioxide, leading to an increase in carbon dioxide in the atmosphere. Carbon in the soil accumulates through the decay of organic matter like dead leaves and animals. Deforestation increases carbon oxidation in the soil to produce carbon dioxide that traps heat. Burning of fossil fuels like coal, oil and natural gases which are formed from dead organic matter that has decomposed over many millions of years will produce large amount of energy for man’s daily use and release large amount of carbon dioxide which is a greenhouse gas. Large consumers of fossil fuels include China, the United States of America, Canada and the United Kingdom. In 2010, global carbon dioxide emissions totalled 30.6 billion tonnes, which was 5.6 per cent increase from 2009. Agriculture which is the practice of cultivating land, producing crops and raising livestock also contribute to greenhouse gases. In rice producing countries such as China and India, organic matter such as dead leaves and manure releases huge amount of methane during rapid decomposition in the rice fields due to the high level of moisture in the soil. The use of inorganic fertilisers increases the amount nitrous oxide in soil and it is released when soil is ploughed or when rain flows through the soil. Cattle raising such as cow produce a lot of methane as a waste gas too. Variation in solar output is another factor causing global warming. The sun emits varying amount of solar radiation due to changes in its magnetic field. Occurrence of sunspots may cause an increase in the global temperature. Sunspots are cooler regions on the sun’s surface that appear as dark spots. The areas surrounding the sunspots will radiate more energy, which compensates for the lower temperature of the sunspot areas. For example, a peak in the number of sunspots in 2000 coincided with higher solar activity.
1		Using specific examples, explain two anthropogenic factors that have led to enhanced greenhouse effect.
		·        The enhanced greenhouse effect refers to an increase in the concentration of greenhouse gases in the atmosphere leading to a rise in global temperatures ·        It occurs when human activity causes greenhouse gases to be released at a far greater rate than that of natural emissions of greenhouse gases ·        Anthropogenic factors are factors caused by human activities such as the burning of fossil fuels, deforestation and changing land use Anthropogenic factors: Burning fossil fuels ·        the major fossil fuels are oil, coal and natural gas. The burning of these fossil fuels produces large amount of energy that is important for human activities ·        The energy produced is used for industries, transportation, other commercial activities ·        Fossil fuels are estimated to produce more than 80% of global energy ·        Large consumers of fossil fuels include China, the US, Canada and UK ·        Due to the high carbon content, fossil fuels contribute to the increase in greenhouse gases by producing large amounts of carbon dioxide when burnt ·        The world’s usage of fossil fuels has increased in recent years, releasing billions of tonnes of carbon dioxide into the atmosphere each year. For e.g., in 2010, global carbon dioxide emissions totalled 30.6 b tonnes which was a 5.6% increase from 2009 Deforestation ·        Refers to the loss of forests due to the removal /clearance of trees in forested areas ·        2nd largest contributor of greenhouse gases in the atmosphere ·        Trees are felled for wood to make products such as paper and building materials. ·        Trees are also removed to clear the area for mining, grazing of animals, plantations, construction of infrastructure ·        With fewer trees to absorb carbon dioxide, which leads to an increase in the carbon dioxide levels in the atmosphere ·        Deforestation also increases carbon oxidation as soil is exposed to sunlight, thereby increasing the soil temperature ·        When soil temperature increases, the rate of carbon oxidation also increases ·        Carbon oxidation is the process by which carbon in the soil reacts with oxygen in the atmosphere to produce carbon dioxide ·        The greatest loss of forests occurs in South America, followed by Southeast Asia Changing landuse i)       Agriculture: ·        Rice cultivation contributes to an increase in greenhouse gases in the atmosphere ·        For e.g. tractors run on fossil fuels release carbon oxide; the use of chemical fertilisers increases the amount of nitrous oxide in soil. Nitrous oxide is released when soil is ploughed or when rain flows through the soil ·        Cattle farming contributes to greenhouse gas emissions because cattle release methane as a waste gas. Millions of tonnes of methane are released each year from cattle farming ii)      industries: ·        industrial activities involve the burning of fossil fuels that result in greenhouse gas emissions ·        Greenhouse gases are also released as by-products when goods are produced. ·        Some processes or products result in greater emissions than others ·        The largest carbon dioxide emissions from industrial processes are found in North and Central America, Europe and Asia ·        In recent years, countries such as China and India are also contributing more to global carbon dioxide emission due to their rapid industrialization Urbanisation ·        Large amounts of fossil fuels are burnt to provide energy for household activities in urban areas ·        These activities include heating, cooling, cooking, lighting ·        The high concentration of cars, buses and other forms of transportation in urban areas also contribute to the amount of greenhouse gases emitted in these areas ·        In addition, construction of infrastructure and producing construction materials also release greenhouse gases into the atmosphere HOW MUCH IS ONE HECTARE? Most sports fields are one hectare in size. The Apple Bowl in Kelowna for instance is a 400 m running track and the grassy area inside is 1.12 hectares. The international rugby field pictured above is very close to one hectare in size, it is actually 1.0008 hectares. A perfect square is 100 meters by 100 meters is a hectare.