1. The Earth’s Climate System

2. Is climate change new? Climate change is a natural part of Earth’s history. For example, thousands of years ago, thick ice sheets covered most of Canada and a large portion of the United States.

3. Key Terms Weather refers to the condition of the atmosphere at a specific place and time. It describes factors such as wind, temperature and humidity. Climate refers to the condition of the atmosphere over a large area, averaged over many years.

5. Temperature and Climate The Earth is surrounded by an envelope of gases called the atmosphere.The Earth is surrounded by an envelope of gases called the atmosphere. Without this envelop, the days would be too hot and the nights would be too cold!Without this envelop, the days would be too hot and the nights would be too cold! So how is heat energy transferred?So how is heat energy transferred?

6. How is Heat Transferred? Heat is always transferred from the hotter object to the colder object. There are three types of heat transfer:

7. Conduction The transfer of heat between substances that are in direct contact with one another The better the conductor the more rapidly the heat will transfer.

8. Convection The up and down movement of gases and liquids caused by heat transfer. As a gas/liquid is heated it expands and rises because it is less dense. As it rises and expands, it cools and falls. This creates convection currents.

9. Radiation Electromagnetic waves moving through space. These waves come in contact with an object and transfer the heat to the object.

10. Earth’s Climate System A complex framework of interactions between various factors that influence the Earth’s climate.

11. Earth’s Climate Systems What does it involve? Atmosphere Lithosphere These components interact with one another and with aspects of Earth’s biosphere to determine not only day-to-day weather, but also long term averages, climate. The Hydrosphere

12. 1. The Sun 2. The Earth 3. The Atmosphere 4. The Hydrosphere 5. Human Activity Factors Affecting Climate Change

13. 1. The Sun 2. The Earth 3. The Atmosphere 4. The Hydrosphere 5. Human Activity Factors Affecting Climate Change

14. Solar Energy The most important factor that affects climate is the sun Earth’s climate systems are driven by radiation energy received from the sun. The intensity of the energy that reaches Earth’s surface affects the temperature of air, water and land Heat produces winds, rain and other features of climate.

15. Changes in Solar Activity The Sun produces a variable amount of energy. When the number of sunspots is high, the Sun emits higher amounts of solar radiation. Some scientists believe that changes in solar output are the main cause of climate change in the past.

16. 1. The Sun 2. The Earth 3. The Atmosphere 4. The Hydrosphere 5. Human Activity Factors Affecting Climate Change

17. Factors on Earth that Affect Climate 1.Rotation 2.Revolution 3.Tilt 4.Latitude

18. Solar Energy and the Earth The amount of solar energy that reaches Earth depends on solar activity, the shape of the Earth and the tilt of the Earth.

19. Rotation vs. Revolution a Review Earth rotates once every 24 hours (1 day) around its axis, an imaginary line that goes from the North Pole to the South Pole through the center of the Earth. The Earth also revolves (orbits) around the Sun every 365 and a half days (1 year). Another important detail is that the Earth’s axis of rotation is tilted at an angle of about 23.5 ˚

20. The seasons are created by Earth’s revolution and its tilted axis. Earth’s Seasons

21. Latitude Energy coming from the sun is not distributed uniformly across the surface of the Earth. Due to the shape of the Earth, the energy is most intense at the equator and weakest at the poles.

22. Temperatures Around the World This non-uniform energy distribution leads to temperature differences.

23. Land Surfaces Earth’s outer layer is made of massive pieces of solid rock, called tectonic plates. Earth has about 12 major plates that move at a rate of a few centimeters per year. The plates carry the continents with them as they move. This means that the shape of the oceans and continents is always changing.

24. The Movement of the Continental Plates Patterns of air and water circulation are affected which in turn affects the thermal energy around the world. The formation of mountain chains also affects the patterns of wind and precipitation around the globe.

25. Volcanoes Most volcanoes are located at the boundaries of tectonic plates. Plate movement affects climate by producing volcanic activity. In these areas, molten rock and gases from below the Earth’s crust rise up through cracks in the rock and spew into the air as volcanic eruptions.

26. Volcanic Eruptions During a volcanic eruption, particles called aerosols (such as ash) are released into the atmosphere. Aerosols reflect solar radiation, having a cooling effect on the global climate, and scatter light Some volcanic eruptions can raise global temperatures by releasing greenhouse gases.

27. 1. The Sun 2. The Earth 3. The Atmosphere 4. The Hydrosphere 5. Human Activity Factors Affecting Climate Change

28. Atmospheric Factors that Affect Climate 1.Greenhouse Effect 2.Wind

29. The Atmosphere… Earth’s Warm, Snuggly Blanket The Earth’s atmosphere is like a big blanket that surrounds the globe keeping humans warm. If it was suddenly stripped off, the Earth’s average temperature would plummet and everything would freeze. Like a blanket that could be made from a mix of cotton and wool, the Earth’s atmosphere is made from a mixture of gases.

30. The Earth’s Atmosphere The atmosphere starts at Earth’s surface and goes up to about 560 km into space. It is mostly made of nitrogen (N 2 ) and oxygen (O 2 ) gases as well as water vapour, very low concentrations of other gases and particles of solids.

32. The Greenhouse Effect A natural process that keeps Earth’s temperatures within a certain range. Without it Earth’s average temperature would be colder (approximately 34˚C lower) and most of the solar energy reaching Earth would radiate out back into space. The atmosphere contains greenhouse gases and solar radiation passes through them. Solar radiation warms the surface of the Earth and heat rises from the surface Some heat is able to pass back through the gases and some cannot. The heat that is trapped adds to overall global temperatures.

34. Wind Wind is caused by uneven heating of Earth’s surface. The air moves as wind transfers thermal energy around the world from warm areas to cooler areas. It is the movement of air from an area of high pressure to an area of lower pressure.

35. Prevailing Winds Winds blow in fairly constant directions around the world. These are known as prevailing winds.

36. Wind Winds disperse energy throughout the atmosphere. The movement of air affects: –precipitation patterns –ocean currents

37. Precipitation As air masses of different densities move across the Earth’s surface, they interact. When air masses meet (called a front), one air mass usually rises over the other. The rising air cools and any water vapour in the air condenses to form precipitation.

38. Ocean Currents The difference in atmospheric temperature cause the ocean to react and create convection currents. These currents transport heat from the warm tropics to the cold Polar Regions and back again.

39. 1. The Sun 2. The Earth 3. The Atmosphere 4. The Hydrosphere 5. Human Activity Factors Affecting Climate Change

40. The Hydrosphere Two thirds of the Earth is covered by oceans. The hydrosphere includes all of the water on the planet in its different forms.

41. On Earth water is found in many forms: –vapour and clouds of water droplets in the atmosphere –liquid in the oceans, seas, and smaller bodies of water –ice and snow in temperate and colder regions GasLiquidSolid The Hydrosphere

43. Specific Heat Capacity Oceans and lakes act as heat reservoirs. They buffer temperatures in the atmosphere. Large bodies of water influence climate because water has a large specific heat capacity compared with other substances.

44. Specific Heat Capacity Specific heat capacity is the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius. Water has a large specific heat capacity. This means it takes more heat to raise the temperature of 1 g of water by 1 o C than it does to do the same to many other substances.

45. Specific Heat Capacity… So what? The higher the heat capacity, the longer it takes to warm the substance up and the slower the substance loses its heat. Water’s high specific heat capacity means that a land mass near a large body of water will have its temperature “moderated” by the water – it will warm up more slowly in summer and cool down slowly in winter than will a land mass further from water. The water will warm and cool more slowly than the beach 20 degrees 25 degrees

46. Specific Heat Capacity Some Common Specific Heat Capacity Values Substance Specific Heat Capacity in “The number of joules of heat energy needed to raise the temperature of 1 g of the substance by 1 o C.” Pure Water4.18 Sea Water3.89 Dry Air1.00 Wet mud2.51 Sandy soil0.92

47. Snow and Ice Ice and snow reflect heat The light colour of ice and snow allow them to reflect solar radiation. Because as we know, light-coloured surfaces reflect energy, and dark surfaces absorb energy.

48. Ice and Snow Reflect Heat The light colour of ice and snow allow them to reflect solar radiation. The amount of energy that is reflected by a surface is known as albedo. Light-coloured surfaces reflect energy, and dark surfaces absorb energy. Exampl e: Because of their large differences in albedo, the distribution of water, ice and land on Earth’s surface greatly affects the average global temperature.

49. 1. The Sun 2. The Earth 3. The Atmosphere 4. The Hydrosphere 5. Human Activity Factors Affecting Climate Change

50. Burning of Fossil Fuels

54. Climate Systems Recap What are 3 ways that heat is transferred? Povide a diagram. Compare and contrast weather and climate. What are the 5 main influencing factors on Earth’s climate system?