F ACTORS A FFECTING C LIMATE C HANGE By: Aiman and Vaishnavi

W HAT I S C LIMATE C HANGE ? Change in average ‘weather’ Everything associated to weather Temperature Precipitation Referred to on a global scale

N ATURAL C AUSES Solar output Ocean variability Continental drift Earth’s tilt Comets, meteorites Orbital modifications Volcano (dust and gas) Less snow and ice cover on Earth

V OLCANOES Large volumes of sulphur dioxide, water vapour, dust, ash in the atmosphere Over the years: sulphur dioxide can reach higher levels of atmosphere Block sun rays  leads to cooling Sulphur dioxide combines with water Forms droplets of sulphuric acid Small droplets can stay in air for several years

E ARTH ’ S T ILT Causes seasons Controls severity of the seasons More tilt = warmer summers and cooler winters Less tilt = cooler summers and milder winters Earth’s axis not fixed Changes approx. half a degree a century Causes changes in climate

O CEAN C URRENTS Oceans cover approx. 71% of the Earth Absorb twice as much of sun’s radiation than land Move a lot of heat across the planet Can change direction and slow down Escaped heat  usually in the form of water vapour (most abundant greenhouse gas) Forms on clouds shading the Earth’s surface Has a cooling effect

C ONTINENTAL D RIFT N EW ICE SHEETS N EW VOLCANOES N EW OCEANS

A NTHROPIC C AUSES Increase in fossil fuel use (Industrial Revolution) Natural resources overused (construction, industries, transport, consumption) Clearing of land for houses Increases in dust and smog Changes in land use Increase in C02 emissions and other green house gases Changes since industrial era 30% increase in C % increase in CH 4 15% increase in N 2 0

G REENHOUSE E FFECT Natural system  regulates Earth’s temperature When sun rays hit Earth’s atmosphere, some reflected, others absorbed and later radiated into atmosphere Some heat radiated to atmosphere does not escape to space Absorbed and trapped by atmospheric gases (GHG’s) Certain human activities disrupt balance of the system More heat trapped in the atmosphere  increase in Earth’s temperature

G REENHOUSE G ASES Produced by combustion of fossil fuels Energy-production Transportation Industry Study of carbon flow through carbon cycle ½ of human-produced C0 2  in atmosphere

A NTHROPOGENIC S OURCES OF G REENHOUSE G ASES CO 2 (Carbon Dioxide) Methane (CH 4 ) Nitrous Oxide (N 2 O) Chlorofluorocarbons (CFCs)

C ARBON D IOXIDE Most important Burning of fossil fuels Uses of fossil fuels Energy in transportation & manufacturing Heating Electricity generation Industry Rising emissions of C02 due to Land use Deforestation Land clearing agriculture

M ETHANE Sources Rice farming Cattle ranching Decaying organic materials Sewage treatment plants Coal mining Natural gas extraction Deforestation Slow smouldering of trees  combustion reaction Released from landfills, waste dumps, oil drilling, coal mining

N ITROUS O XIDE 2/3 comes from management of livestock feed and waste Nitrogen fertilizer usage Certain industrial processes Fossil fuel use Emission partly from fertilizers, leguminous plants such as beans and pulses  nitrogen to the soil.

C HLOROFLUOROCARBONS Refrigerator agents Atmospheric levels now decreasing due to international treaties Montreal Protocol on Substances that Deplete the Ozone Layer

Sources of Greenhouse Gases in Canada

Sources of Greenhouse Gases in Agriculture

Bibliography