Global Warming
Q:What is global warming?
A:Global warming means a progressive rise in
the mean annual temperature in the whole
world.
Q:What causes global warming?
A:It’s mainly due to the greenhouse effect.
Greenhouse effect
Natural greenhouse effect
Enhanced greenhouse effect
Types of greenhouse gases
carbon dioxide (CO2)
methane (CH4)
nitrous oxide (N2O)
chlorofluorocarbons (CFCs)
ozone (O3)
water vapour (H2O)
Carbon dioxide
Methane
Nitrous Oxide
Chlorofluorocarbons
Chlorofluorocarbons
Greenhouse gas
Carbon Dioxide (CO2)
Methane (CH4)
Nitrous Oxide (N2O)
Ozone (O3)
Chlorofluorocarbons (CFCs)
Sources
1) Burning of fossil fuel
2) Land-use change (deforestation)
1) Biomass burning
2) sewage disposal, landfill sites
3) Rice paddies
1) Biomass burning
2) Fossil-fuel combustion
3) Fertilizers
4) vehicle exhausts, power stations
Photochemical reactions involving O2
Industrial production, e.g.refrigerators,
aerosol sprays, solvents, foams
Consequences of greenhouse effect
Rise in sea level
Disease to human e.g. skin cancer
Dying forests
Change in climate
Impact on human life
Economic Impact:impact on low-lying coastal
areas and islands
Agricultural Impact:changing the soil moisture
contents
Effects on Aquatic systems:reduce fish
populations, and the abundance of freshwater
species