Wednesday, 3 October 2007
Geography Chapter: Global WarmingY
Global Warming
The Greenhouse Effect
-the trapping of heat from the sun's rays in the atmosphere by greenhouse gases
-e.g. carbon dioxide, methane, nitrous oxides, chlorofluoro carbons (CFCs)
-helps keep the earth warm (by warming the atmosphere) to sustain life
Global Warming
-increase in amount of greenhouse gases in the atmosphere due to industrialisation and other human activities
-hence causing enhanced greenhouse effect
-which causes the global temperatures around the world to increase
Causes
mainly because of human activities (hey, humans are dumb!)
-Carbon dioxide : burning of fossil fuels at the power stations
-Nitrous oxides : vehicles exhaust pipes, fertilisers, livestock wastes
-CFCs : aerosol cans, air-conditioners, refrigerators, plastic forms
-Methane : landfills, rice paddies, guts of cattles
Extent of Global Warming
-the Poles experience a higher temperature increase than the Equator
-because the ice are suppose to reflect about 80% to 90% of the sunlight back into space, but the ice is melting due to global warming and the darker-coloured ocean bodies are absorbing more sunlight
-thus global warming is more pronounced in the Polar regions
Consequences
Changes in weather conditions
-prolonged droughts in dry regions
-frequent heat waves
-severe flooding in wet regions
Impact on plants
-change in rainfall and temperature patterns will affect vegetation growth around the world
Impact on animals
-reduction of ice in the 2 Poles affects natural habitats of animals living in the region
-causing some of them to migrate
e.g. polar bears which tried to swim in search of new habitats, but many of them are drowning because warmer waters have widened the distance between ice floes
Impact on people
-rising temperature in the Tropics allow mosquitoes to thrive, causing the spread of diseases like dengue fever, malaria and yellow fever
-heat waves, causing people to die of dehydration and heat stroke
Rising sea levels
-low-lying coastal wetland and islands, coral reefs and part of the world's coastal cities will be subjected to flooding
e.g. Miami and Florida, along the East Coast of the US
-agricultural lowlands and deltas in some countries where most of the rice is grown will be flooded
e.g. Bangladesh, India, China
-low-lying islands in the Pacific Ocean and the Indian Ocean will be submerged under rising sea levels
e.g. Marshall Islands of the Pacific Ocean and Maldives of the Indian Ocean
-natural habitats and ecosystems along coastal areas will be at risk
e.g. French Polynesia