1. Earth and its Climate System

2. Starting Point: What is the difference between weather and climate?

3. Weather: Set of environmental and atmospheric conditions encountered at a specific place on a day- to-day basis (Short- Term) Climate: Set of environmental and atmospheric conditions for a large area averaged over many years (Long-Term)

4. Temperature and Climate The Earth is surrounded by an envelope of gases called the atmosphere. Without an atmosphere, the days would be too hot and the nights would be too cold. So how is heat energy transferred? – Always move from hotter object to colder object

5. Heat Energy Transfer 1.Radiation: Heat transfer by electromagnetic waves through space and can transfer its heat to an object. 2.Convection: Heat transfer through movements of particles in a liquid or gas. – 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. 3.Conduction: Heat transfer through collision of particles (direct contact with one another)

6. Earth’s Climate System The biosphere is the global sum of all biological components. Made up of three spheres: 1.Atmosphere – air 2.Hydrosphere – water 3.Lithosphere – rocks, soils, minerals What powers this system? The sun! The interaction of these components and the sun produces climate zones!

7. Factors that Affect Climate What are some factors that cause different climates in different areas? Sun Latitude & axial tilt of Earth Large bodies of water Air and ocean currents Land formations (eg. mountains, volcanoes) Altitude

8. 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. Heat produces winds, rain & other features of climate. The intensity of the energy that reaches Earth’s surface affects the temperature of air, water and land. – Earth absorbs different wavelengths from the sun, heats up and gains thermal energy. It then emits this as infrared radiation which returns to the atmosphere and back into space. – Earth’s global temperature stays constant (for the most part).

10. Changes in Solar Activity 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. But many argue that the phenomenon is too weak of a correlation with climate change.

11. The Atmosphere Layers of gases surrounding the Earth. It acts as a blanket, conserving thermal energy to keep Earth warm. Reflects, absorbs and radiates or transfers energy. Also shields Earth from dangerous radiation. 78% nitrogen, 21% oxygen Other gases: argon, CO 2, helium, hydrogen, ozone

12. Ozone (O 3 ) In the stratosphere (50 km up), ozone absorbs dangerous UV radiation. In the last few decades, a hole in the ozone layer has been apparent (Antarctica), allowing radiation and heat to get through. Causes? – Human-made chlorofluorocarbons (CFCs) thins the ozone layer (found in spray cans, refrigerators, A/C). It was banned in 1987. – Montreal Protocol in 1989 (treaty for protection) Is the ozone recovering? – New NASA research: Maybe not until 2070! http://www.ryot.org/full-recovery- ozone-layer-wont-happen- 2070/499477

13. Wind Atmospheric factor that affects climate = movement of air from areas of high pressure to areas of low pressure Caused by uneven heating of the Earth’s surface – Air moves as wind transfers thermal energy around the world from warm areas to cooler areas – Movement of air affects precipitation patterns and ocean currents. Winds blow in fairly constant directions around the world (prevailing winds) More on this later!

14. Hydrosphere Consists of liquid water, water vapour and ice Reflects, absorb and emit, or transmits energy from the sun Water Cycle (driven primarily by the Sun) – Energy is absorbed when water evaporates → cools surroundings – Energy is released when water vapour condenses into clouds → warms surroundings

16. Large Bodies of Water Water absorbs and stores more thermal energy than land. It also heats up and cools down more slowly than land. Temperatures of regions near oceans or a large lake: – Summer: Cooler – Winter: Warmer Regions downwind from large bodies of water have more snow (“lake-snow effect”) such as the Great Lakes area.

17. Specific Heat Capacity Water acts as a “heat reservoir” and influences climate due to this. Therefore, water has a large specific heat capacity compared to other substances. – Specific heat capacity: The amount of heat required to raise the temperature of 1 g of a substance by 1°C. – In other words, for 1 g of water, it takes more heat to raise its temperature by 1°C compared to other substances.

18. The higher the heat capacity, the longer it take to warm the substance up and the slower the substance loses its heat. Water’s high specific heat capacity means a land mass near a large body of water will have its temperature “moderated” by the water – it will warm up more slowly in the summer and cool down more slowly in the winter compared to a land mass further from the water. – Eg. Vancouver versus Ottawa climates The water will warm and cool more slowly than the beach 20 degrees 25 degrees

19. Ice 2% of the Earth’s water is frozen. Most ice is located at the two poles. Sea ice: thins and floats on the ocean. Ice sheets: enormous areas of permanent ice stretching over land. Surfaces covered in ice and snow reflect more radiant energy than land (explains why the poles are so cold).

20. Albedo Effect Albedo: Measurement (%) of how much light an object reflects The higher the %, the more light that is reflected by the object. Contributes to the maintenance of global temperature but with the disappearance of the ice caps, what will happen?

21. Revolution & Axial Tilt of Earth Earth revolves around the sun and completes its orbit every 365 days. The Earth is tilted at 23.5° so a different hemisphere is pointed towards the sun throughout the year. This explains the changes in seasons. When Northern Hemisphere is tilted towards the sun = SUMMER but Southern Hemisphere experiences WINTER during same time and vice versa. Contributes to distribution of heat around Earth

22. Latitude Sunlight striking the earth perpendicular to the surface is very concentrated. Sunlight striking an angled surface is more dispersed and less effective. Thus higher latitudes tend to be cooler than those closer to the equator. This creates temperature differences around the world.

23. Mountain Climate & Altitude Mountain chains (due to movement of continental plates) affects the patterns of wind & precipitation around the world. Mountains receive more rainfall than low-lying areas because the temp. on the top of the mountains is lower. – As altitude ↑, air is less dense (less pressure) so it expands and cools. – Warm air from water body evaporates & rises, cools and condenses. This moisture falls as rain on the windward side of mountain. The other side of the mountain gets less rain. This effect is called the rain shadow. The higher the mountain peak, the more pronounced this effect becomes.

24. Volcanic Eruptions Related to continental plate movement as well. 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. Forest fires have a similar effect as well.

25. https://www.youtube.com/watch?v=lrPS2HiY Vp8 https://www.youtube.com/watch?v=lrPS2HiY Vp8