 What is your view on climate change? Write down either: What you believe about climate change What you have heard someone say about climate change  Add your view to the Venn diagram on the board

 Atmosphere: thin layer of gases that surround Earth  Weather: condition of the atmosphere at a specific time (describes wind, temperature, amount of moisture, etc.)  Climate: characteristic pattern of weather conditions in a region including: temperature, wind, precipitation, etc. over a long period of time

 Climates have changed many times over the billions of years of Earth’s history

 In 1988 an international scientific panel was organized to study the evidence & advise governments about the effects of climate change  ry/2011/12/05/environment-co2- emissions-record.html ry/2011/12/05/environment-co2- emissions-record.html

1. The Sun (most important) 2. The Atmosphere 3. The Hydrosphere 4. Moving Continents 5. Human Activity

 Energy from the Sun is the MOST important factor that affects climate on Earth Changes in Solar Activity:

Movements of Earth in Space  Seasons are caused by a combination of Earth’s tilt (23.5 °) & Earth’s annual orbit around the Sun

Changes in Earth’s Rotation, Orbit & Tilt (Milankovic – early 1900s)  Eccentricity: due to gravitational attraction of other planets, the orbit of Earth fluctuates slightly over years (elliptical) Changes length & intensity of seasons

 Tilt: angle the Earth’s tilt on its axis changes 2.4° over years Greater the tilt, greater the temperature differences between summer & winter  Wobble: Earth is not a perfect sphere, so wobbles slightly as it rotates on its axis Amount & intensity of solar energy received in different hemispheres is affected

 orbit.html orbit.html

Effect of Latitude on Climate & Seasons  Curved shape of the Earth affects the amount of sunlight reaching surface Rays that hit Earth more directly have a higher intensity than those hitting at an angle  Equator = highest intensity  45° = moderate intensity  Poles = lowest intensity

 Earth’s atmosphere can absorb and reflect solar radiation It can also prevent radiation from escaping into space.

Greenhouse Effect:  Natural part of Earth’s climate system  Caused by gases in Earth’s atmosphere that absorb energy that is radiated by the Sun & Earth

 Wind: movement of air from an area of high pressure to low pressure (convection) Warm air rises Cold air sinks

 Winds disperse heat energy through the atmosphere  Affects global ocean currents & precipitation patterns

 Hydrosphere: all water in its different forms on Earth (liquid water, ice & water vapour)  Oceans & lakes act like heat reservoirs Water has a large specific heat capacity (lots of energy is required to raise one gram by 1° C in temperature vs. other substances)  Ice and snow reflect heat Albedo: amount of light reflected by the surface of the object

 Turn on the lamp and record the temperature of soil, sand and water each minute for 10 minutes  Turn off the lamp and record the temperature of soil, sand and water each minute for 10 minutes

 Earth’s 12 tectonic plates change the shape of oceans and continents  Affects: Heat transfer Wind patterns Precipitation Ocean currents

Volcanic Eruptions  Volcanoes are located at the boundary of tectonic plates  Volcanic eruptions spew ash & particles into the atmosphere (aerosols) which reflect solar radiation, cooling the Earth  Volcanic eruptions also add large amounts of greenhouse gases (CO 2 ) to the atmosphere which might cause global temperatures to rise

 Warming trend since the 1970s caused partially by humans (anthropogenic)

 Burning of fossil fuels (since the Industrial Revolution – 1700s) has increased concentration of gases in the atmosphere  These gases produce the greenhouse effect

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