[C7] Chapter 7: Climate Change
[C7] Chapter 7: Climate Change
Radiation Activities
Short-wave radiation reaches Earth surface → earth surface absorbs short-wave radiation → some long-wave radiation transmitted from cloud / atmosphere as counter-radiation → more long-wave radiation absorbed in atmosphere → CO2 does not absorb short-wave radiation and absorbs long-wave radiation / counter-radiation → more heat is trapped in atmosphere → intensify greenhouse effect → rise in global mean temperature
Factors Leading to Global Warming
Human Activity | Greenhouse Gas | Explanation | Mechanism |
Deforestation | CO2 | - Reduction in global forest cover - Increase in lumbering - Decrease in amount of CO2 absorbed by plants / carbon sink - Increase in amount of CO2 released from burning of forests | Increase in greenhouse gases emission |
Urbanization | CO2 | - Population growth - Rising living standard - Global market and production - Increase in movement of goods - Increasing use of vehicles / electrical appliances - Fossil fuel combustion | |
Increase in industrial activities | CO2 | - Fossil fuel combustion - Increase in fossil fuel consumption - Increase in electricity consumption for industrial use | Absorb more long-wave radiation |
N2O | Production of nylon // synthetic fibres | ||
CFCs + HFCs | Production of foams // refrigerants // solvents | ||
PFCs + SF6 | - Aluminium smelting - Production of magnesium | ||
Increase in agricultural activities | N2O | Increasing use of chemical fertilizers | Intensify greenhouse effect |
CH4 | - Wet rice farming - Digestive process of livestock | ||
CO2 | - Farming machines - Organic waste combustion | ||
Disposal and treatment of garbage and human waste | CH4 | Garbage decomposes in landfill | |
CO2 + N2O | Garbage combustion in incinerators |
Impacts of Global Warming
Location | Function | Aspect | Explanation |
Australia | Negative | Ecosystem | - Rise in seawater temperature - Rise of seawater acidity - Coral bleaching - Marine life losing habitats - Disrupting food chain |
Economy | - Decreasing catches in fishery industry - Hindering development of tourism | ||
Arctic regions | Positive | - Shorter sea transport route - Reducing transport time and cost - Easier to exploit natural resources (oil) - Favors fishing industry | |
Negative | - More melting of sea ice - Reducing habitats of polar bears - Reducing hunting ground for natives - Drafting ice blocks affect shipping safety - Disrupting transportation on ice surface | ||
Switzerland / High-latitude | Positive | Short-term | - Longer frost-free period - Longer growing season - Providing freshwater for irrigation / drinking |
Long-term | Increasing farmland area / pasture / farming productivity | ||
Negative | - Continuous retreat of glaciers - Reducing water supply in long term - Increasing resources for non-farming activities (fishing / tourism) → farmers may lose jobs | ||
Tuvalu / Low-latitude | Negative | - More salinization - Rainfall decreases - More coral bleaching - More crop failure - Increasing frequencies of tropical cyclones - More drowning of land - More climate refugee / mitigate to neighbouring countries - More heat waves - More infectious diseases | |
Hong Kong | Negative | - More coastal flooding - Stronger tropical cyclones - More severe storm surges - Rise in sea level (Mai Po Natural Reserve flooded) - Higher seawater temperature (coral bleaching in Sai Kung) - Increasing energy consumption (increase use of air-conditioners) - Increasing health risks (heat strokes) | |
Urban Heat Island Effect in Hong Kong
Reason | Explanation | Effect on Microclimate | |
High-density and tall buildings | - Retain heat - Reduce outgoing long-wave radiation | Lower wind speed | |
Lack of plants | Less evaporation to transfer heat | Lower relative humidity | |
Lack of water bodies | Less cooling effect | Higher air temperature | |
Impervious concrete and asphalt surface | Absorb heat | ||
Use of air conditioners / vehicles | - Various waste heat resources in urban areas - More particulates to absorb heat - Produce man-made heat | - Reduced visibility - More cloud cover - Smaller amount of sunshine received on the ground - Higher rainfall | |
Adaptation Measures
Measure | Effective | Ineffective | |
Renewable solar energy | - Clean - Safe | - Price of electricity generated is larger than other means - Cannot harness powers during storms / cloudy days / at night → vulnerable to weather | |
Renewable wind power | - Clean - Price of electricity generated is low | - High installation costs → huge capital investment is needed - Stable wind speed over a long period of time is necessary - Visual and noise pollution | |
Renewable HEP | - Clean - Safe - Low operating costs | - Huge construction costs - Cannot harness power when drought - Disrupts natural river environments and aquatic ecosystems → few specific locations suitable | |
Renewable geothermal power | - Clean - Low maintenance costs - Occupies a smaller area than fossil fuel plants | - Only a few sites have the potential to develop this kind of energy (advanced tech is needed) - High construction costs | |
Renewable tidal and wind power | - Clean - Reliable and predictable | - High construction and maintenance costs - Only a few locations have the potential to develop this kind of energy - Spinning turbines may kill animals and fish → operated on a small scale only | |
Biofuels | - Reduce reliance on oil - Reduce emission of CO2 - More bio-degradable - Cause less groundwater contamination - Lower price | - Growing of biofuel crops occupies a large amount of farmland - Causes price increase in certain types of food - Less stable food supply → food shortage - Speeding up rate of deforestation - Upset ecological balance - Higher CO2 emission rate than conventional fuels in process of production | |
Passive solar design | - Reduce energy consumption for heating / air-conditioning - Reduce greenhouse gas emissions - Good insulation and ventilation | - Unreliable → depends entirely on weather - Not all regions have sufficient sunlight - High cost of design and installation - Improper design can lead to an increase in energy consumption in heating and cooling | |
Capturing and storing CO2 | Reduce amount of CO2 in air | - Small amount of captured and stored CO2 → small scale - Huge investment - Not mature technology yet | |
Afforestation | - Increase in CO2 stored / absorbed - Cut down the amount of CO2 emitted into atmosphere | - Huge investment - Takes time for trees to grow - Local people would rather earn living from deforestation than growing trees | |
Coastal protection measures | Protect coastal areas from flooding | - Expensive to conduct and maintain - Require advanced technology - Continuous coastal erosion may wear away structures - May be destroyed by large storm surges | |
Better farming practices | - Reduce use of nitrogen fertilizers - Increase soil fertility - Reduce CH4 emissions | - Huge capital input - Require advanced technology - Increasing pest problem may offset efforts of soil and water conservation | |
International Cooperation
Method | Concerns | Practical Constraints | |
International carbon trade | Level of econ development | No agreement was reached among nations in terms of fairness and standpoints | |
International tech transfer | Use of energy resources | Some nations are worried about the huge costs incurred | |
Financial assistance | - Existence of fossil fuel reserves - Political consideration - Tech level | Problems may arise in supervision and control | |
Countries | Reason to Help | Reason not to Help |
MDC | - Possess capital to help LDCs develop renewable energy - Possess more tech to increase energy efficiency - Long history of emissions | - Both total and per capita emissions of CO2 from LDCs have increased - Cutting GHG emissions incurs extra cost → slow down econ growth / living standard |
LDC | - Increasing industrial activities with increasing carbon emissions - Rapid econ growth leads to higher energy consumption on electricity - Combustion of coal because it is a cheaper energy resource | - Build-up of GHGs in atmosphere is mainly caused by MDCs - Per capita emissions of LDCs are still lower - Cutting GHG emissions ignores the rights of LDCs to develop their economy |
Countries | Limitations |
MDC | - Incur extra costs to slow down econ growth and living standards |
LDC | - Lack of money and tech to deal with - World factories are concentrated in LDC → reducing emissions may hinder econ development |
