2. The Hydrosphere WATER • liquid water, water vapour & clouds absorb energy from warm air and the Sun, and then release it back. • also reflects some of the Sun’s energy. The Water Cycle evaporates from lakes/oceans or transpiration from plants sends water into atmosphere cools and condenses into clouds falls as precipitation runs off or gets into groundwater then goes back to bodies of water Large Bodies of Water water absorbs more energy than land lg bodies of water affect climate of a region take longer to warm up or cool down, so region cooler in summer and warmer in fall air passing over cold water in winter picks up vapour, condenses into snow over land, so nearby regions have more snowfall (lake effect snow) Ocean Currents • sea ice freezes at poles (fresh water) • remaining water is salty • dense salt water sinks to the ocean floor. • Warmer surface water from the equator then flows to the poles to take its place. • This process is called the thermohaline circulation of the oceans. • Ocean currents around the globe slowly move water (and the thermal energy it carries) from the equator to the poles. • warm currents warm air above them, over land it warms the land and produces rain (warm wet climate) • why northwest Europe is warmer and wetter than here even though it is further north (Gulf Stream) Thermohaline Circulation Ice 2% of all earth’s water is frozen, most at poles, some in mtns Arctic – sea ice, only a few metres thick Antarctic & Greenland - permanent ice caps many km thick Glaciers – permanent ice in mountains together reflect back 75% of sun’s energy major role in climate 3. The Lithosphere the earth’s crust all rock, soil and minerals on earth (including under oceans) absorbs higher-energy UV radiation from the Sun, converts it into thermal energy, and emits it back as lower-energy infrared radiation. Land Formations, Altitude, and Climate Zones mtns and other landforms affect how air moves over an area clouds blown up mtns, lose moisture on windward side leeward side is dry (rain shadow effect) as air rises it expands and cools, so air cooler at higher altitudes 4. Living Things • Plants and animals change the relative amounts of gases in the atmosphere: • photosynthesis - plants take in CO2 and release O2 • cellular respiration - organisms take in O2 and release CO2 • Cows and sheep produce CH4 as they digest food. • Termites and some bacteria produce CH4 • Some gases in the atmosphere (for example, CO2 and CH4) absorb lowerenergy radiation emitted by Earth. • If the amounts of CO2 and CH4 change, it affects how much radiation the atmosphere can absorb.