Presentation on theme: "Greenhouse effect Sources, Causes & Impacts. Interpretation of global warming Global warming is a long-term climate change which raises the temperature."— Presentation transcript:
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.
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
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
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
Impacts of global warming Physical environment – Rise in sea-level - melting of ice caps and glaciers - flooding of low-lying coastal areas - expansion of sea water under high temperature
Impacts of global warming Physical environment – Soil - Increase in soil moisture deficit - Lower water-holding capacity - more soil erosion - Lower productivity of the land
Impacts of global warming Physical environment – Plants / Animals - disturbance to the food chain - coral bleaching in tropical seas & oceans - Major threat to biodiversity
Impacts of global warming Socio-economic – Agriculture - longer growing season in high-latitude regions - more pests to lower crop yield - dry summers give low production of cereal crops - salinization destroys coastal farmland
Impacts of global warming Socio-economic – Forestry - reduction of coniferous forests in high-latitudes - longer growing season for lumbering
Impacts of global warming Socio-economic – Transport - navgation on high-latitudes year-round - extreme weather to hinder navigation e.g. storm & coastal flooding
Impacts of global warming Socio-economic – Recreation - shortened winter hinders sports activities - extended summer favours qauatic sports
Impacts of global warming Socio-economic – Energy - more demand in summers: air-conditioning* - less demand in winters: less heating
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
Other impacts? Besides the physical environment and the socio-economic concerns
Impacts of global warming Political – international cooperation? - Who gains? - Who loses?