Greenhouse effect

1. Greenhouse effect Sources, Causes & Impacts

2. Interpretation of global warming • Global warming is a long-term climate change which raises the temperature of the atmosphere • It is the result of intensification of the greenhouse effect. • Global warming is caused by a layer of greenhouse gases in the atmosphere. • The more the greenhouse gases emitted, the more the heat will be trapped.

3. Sources Where come the GHGs?

4. Sources of greenhouse gases (GHGs) • Carbon dioxide (CO2) : - combustion of fossil fuels - deforestation - incinerators - industrial production

5. Sources of greenhouse gases (GHGs) • Methane (CH4) : - cattle rearing - rice growing - landfill sites - sewage disposal

6. Sources of greenhouse gases (GHGs) • Nitrous oxide (N2O) : - biomass burning - plants powered by fossil fuel - industrial production

7. Sources of greenhouse gases (GHGs) • Chlorofluorocarbons (CFCs) : - refrigerants - aerosol sprays - plastic foams - solvents

8. Causes Of the Intensified Greenhouse Effect

9. Causes of intensified greenhouse effect • Natural factors - variation in the Earth’s orbit e.g. at the perihelion - variation in polar axis e.g. warmer season with a larger angle and more tilted axis - variation in Solar activity e.g. lower temperature when sunspots appear dark - variation in aerosols e.g. their size and reflectivity may cool or warm the air

10. Causes of intensified greenhouse effect • Human activties - burning of fossil fuels e.g. coal & oil - deforestation e.g. burning of forests & shrinking of the carbon sink - agricultural activity e.g. cattle ranching & rice cultivation release methane - landfill sites e.g. decomposition releases methane

11. Impacts

12. Impacts of global warming • Physical environment - Climate change - drier tropical areas - decrease in freshwater storages - more temperate conditions in high latitudes - increased evaporation & changing rainfall pattern - Increased energy level in the atmosphere, more extreme weather & climate conditions

13. Impacts of global warming • Physical environment – Rise in sea-level - melting of ice capsand glaciers - floodingoflow-lyingcoastal areas - expansion of sea water under high temperature

14. Impacts of global warming • Physical environment – Soil - Increase in soil moisture deficit - Lower water-holding capacity - more soil erosion - Lower productivity of the land

15. Impacts of global warming • Physical environment – Plants / Animals - disturbance to the food chain - coral bleaching in tropical seas & oceans - Major threat to biodiversity

16. Impacts of global warming • Socio-economic – Agriculture - longer growing seasonin high-latitude regions - more pests to lower crop yield - dry summersgive low production of cereal crops - salinization destroys coastal farmland

17. Impacts of global warming • Socio-economic – Forestry - reduction of coniferous forests in high-latitudes - longer growing season for lumbering

18. Impacts of global warming • Socio-economic – Transport - navgation on high-latitudes year-round • extreme weather to hinder navigation e.g. storm & coastal flooding

19. Impacts of global warming • Socio-economic – Recreation - shortened winter hinders sports activities - extended summer favours qauatic sports

20. Impacts of global warming • Socio-economic – Energy - more demand in summers: air-conditioning* - less demand in winters: less heating

21. Impacts of global warming • Socio-economic – Health risks - more heat waves: more heart attacks, heat stroke - less freshwater supply: lack of fresh & safe drinking water

22. Other impacts? Besides the physical environment and the socio-economic concerns

23. Impacts of global warming • Political – international cooperation? • Who gains? • Who loses?

24. Impacts of global warming

25. Impacts of global warming Maldives cabinet held underwater meeting in 2009

26. Impacts of global warming