The document discusses the causes and effects of global warming. It explains that increased air pollutants like methane, nitrous oxide, carbon dioxide, and CFCs in the atmosphere are enhancing the greenhouse effect and trapping more heat, causing global temperatures to rise. Some consequences of rising temperatures include more extreme weather events, rising sea levels that could flood coastal areas, and threats to wildlife and ecosystems. Suggested measures to reduce global warming include decreasing emissions of greenhouse gases through actions by individuals, countries, and on a global scale.

1. Unit19: Global Warming By : An Jiasheng (23) Andrew Lam (24) Chong Kai Xiang (26) Class: 203

2. What is global Warming? Due to recent human activities , there is an increase in air pollutants in our atmosphere. These air pollutants are keeping excess heat within the earth’s atmosphere. These “enhanced Green house effect” caused by pollutants traps more infra-red radiation and cause Earth’s climate to heat up.

3. Extent of global warming Global Warming affects the whole world. Example ,due to global warming ,mean surface area of the world went up. Most places in the world have higher temperature than usual.

4. Causes of global warming Greenhouse gases present in the atmosphere. Methane(CH 4 ) Nitrous Oxide(N 2 O) Carbon Dioxide(CO 2 ) Chlorofluorocarbons(CFCs)

5. Methane (10% of greenhouse gases in atmosphere) Natural by-product of bacterial actions in the stomach of livestock and in the water of rice field. In keeping with the effort to increase food supply, more methane will be released into the air.

6. Nitrous oxide (5% of greenhouse gases in atmosphere) Emitted through burning of fuels and use of chemical fertilizers containing nitrogen.

7. Carbon dioxide (72% of the greenhouse gases in atmosphere. Released when any form of burning takes place. Burning of fossil fuels and large-scale destruction of forests (deforestation)are main cause of increase of carbon dioxide.

8. CFCs (13% of the greenhouse gases in atmosphere Man-made chemicals used in manufacturing of aerosols, air-con and refrigerator .

9. Consequences of global warming (the Environment) Scientists predict that average world temperature will rise by 0.5 Celsius every 10 years over the next 100 years. After the increase of more than 6 degrees, we shall die . Due to increase in evaporation More rain will likely to fall in tropical regions Temperate regions will experience longer and drier summer, shorter and wetter winter. There will be more droughts in the interior of north America and Russia and more storms in Asia .

10. Environment Polar ice caps and glaciers will melt and shrink. This may cause … Sea level to rise by 3 meters Low-lying regions will be flooded There will be more storms and land slides and increased river flooding.

11. Effects of climate change In tropical regions where floods or droughts are expected, crop yields will decline. Present arable lands in temperate regions will also suffer due to a longer and drier summer season. However, present dry places will experience more rain causing their yields to increase.

12. Effects of sea level changes by the year 2050 Islands in South Pacific Ocean could be submerged Settlements, port facilities and coastal structure might be damaged Countries like Venice and London will sink. Water supply to coastal settlements will be affected when salt water seeps into groundwater due to flooding making the water to saline. River Delta will be flooded, affecting people living there. Wildlife in salt marshes and coral reefs will be threatened. Mangrove swamps with its species will be destroyed.

13. Measures to reduce the impact of global warming Reduce CO 2 emission On the world scale Earth summit 1992, 154 countries pledge to stabilize emission by 2000 On the country scale Impose carbon tax Introduce energy substitutes like solar energy. Retain trees to absorb carbon dioxide Introduce measures to save electricity Individual scale Switch off electric appliances when not in use.

14. Continue … Reduce nitrous oxide emission World scale NIL Country scale Improve public transport Reduce use of chemical fertilizer containing nitrogen Individual scale Use public transport rather than private owned transport.

15. Continue… Reduce methane emission World scale Stop cows from farting. Reduces 10kg of methane every year  Country scale Reduce demand for meat & rice product. Individual scale Find food substitutes for meat and rice.

16. Continue… Reduce CFCs emission World scale Montreal Protocol signed by 92 countries in 1992. Country scale Ban the use of CFCs Individual scale Buy only non-CFC products

17. Adjusting to the effect of global warming Rising sea level Country scale Limit the no. of buildings built along the coast. Provide coastal protection such as dykes. Individual scale Develop right attitude and help reduce any form of heat increase to the atmosphere. Switch off any unused fans or lights. Reduce comforts of energy consuming appliances like dishwasher and air-con.

18. Continue.. More frequent drought conditions Country scale Initiate research to produce new crops which can grew in dry conditions. Introduce efficient irrigation system Individual scale Adopt right attitude towards using water Consciously save water

19. Continue…. Extinction of wildlife and plant species Country scale expand and create wildlife reserves Create a global network of corridors of natural vegetation to allow for free movement of species. Individual scale Aware of ecological problems and solutions Respect natural habitat Decision makers and profit making developers should conserve rather than recreate.

20. we hope this power point slide is helpful to your learning. Thank you! The End