The Sun and The Earth’s Climate System

The Global Climate System Consists of: 1. W ater 2. A ir (Atmosphere) 3. L and 4. L iving Things

How the Sun Affects Global Climate System Solar Energy:  the Earth's climate is powered by energy from the sun.  different regions on Earth receive different amounts of solar energy Factors that affect the amount of solar radiation:  Latitude - closer to the equator receives direct solar energy and as you move toward the poles the solar energy becomes more spread out  Earth's tilt - on an angle such that part of one hemisphere is a further distance from the sun than another at one time

Latitude & Solar Energy Since the Sun hits higher latitudes at an angle, the radiation must pass through more of the atmosphere. Thus, more energy is absorbed and reflected by the atmosphere, and less will reach the ground. = lower temperatures

Solar Energy: Absorbed & Reflected  When solar radiation enters our atmosphere three things can happen, it can be absorbed, reflected or transmitted  What happens to the solar energy?  30% reflected back to space by clouds and particles in the atmosphere  70% transmitted and absorbed by the Earth's surface and clouds  the energy that is absorbed is either used by plants for photosynthesis or absorbed by rocks, soil and water causing them to heat up and heat the air around them

Energy absorbed by Earth and atmosphere Energy radiated back again by Earth and atmosphere = As a result of this balance of energy, Earth’s global temperature stays fairly constant.

The Climate System Balance is maintained by: 4 Main Components 1. Water (Hydrosphere) 2. Air (Atmosphere) 3. Land (Lithosphere) 4. Living Things (Biosphere)

Atmosphere   The layers of gases surrounding Earth   Near Earth’s surface, the atmosphere consists mainly of nitrogen (78%), oxygen (21%), and small amounts of other gases, such as argon, carbon dioxide, and water vapour.   Acts like a blanket conserving thermal energy   Also protects Earth from dangerous radiation   The atmosphere consists of several layers, each with distinct properties:

Layers of the Atmosphere Troposphere contains 75% of all the air in the atmosphere, and almost all of the water vapour (which forms clouds and rain). - Weather occurs in this layer 2. Stratosphere referred to as the “ozone layer”. Ozone protects us by absorbing the harmful ultraviolet (UV) radiation from the Sun. 3. M esosphere, the middle layer. This layer contains the lowest density of gases and temperature. 4. Thermosphere is the hottest layer Produces a beautiful light called the aurora – more commonly referred to as the Northern and Southern Lights. 5. Exosphere is the beginning of “space”.

Ozone in the Stratosphere   Ozone prevents most of the harmful energy from reaching us   It absorbs high-energy UV radiation from the sun   UV radiation damages plants and causes cancer in animals and people   In 1970’s the ozone layer was thinning over Antarctica   In 1990’s an ‘hole’ began to form over the Arctic region   Ozone depletion is causes by man-made chlorofluorocarbons (CFCs) which were used in pressurized spray cans, refrigerators and air conditioners.   When released, they can travel up to the stratosphere, react with the ozone and destroy it   In 1987, the use and production of CFCs was banned (Montreal Protocol)   Ozone layer is starting to recover, but will take about 50 years to get back to its original thickness

Ozone in the Troposphere   UV radiation from Sun and exhaust from cars combine to produce ground level ozone   This toxic mixture of gases and particles is called photochemical smog   Photochemical smog harms human health, damages buildings and affects plants and animals   Ontario has introduced the Drive Clean program to reduce smog-causing emissions produced by cars

The Hydrosphere   The hydrosphere includes all of Earth’s water, both fresh and salt, liquid and ice. It makes up around 70% of Earth’s surface. THE WATER CYCLE   Our weather systems depend greatly on water in its three states: solid, liquid, and gas or vapour.  Evaporation absorbs energy and cools the surroundings; condensation gives off energy and warms the surroundings.

Water & Climate Zones   Water absorbs and stores more thermal energy than land   Water heats up and cools down more slowly than land   Regions near large bodies of water tend to be cooler in summer and warmer in winter than inland regions   Regions downwind tend to get more snowfall, because air passing over the water absorbs more water vapour, which condenses to form snow when it reaches the colder land

Ice & Climate System   2% of Earth’s water is frozen, most located at the poles   Sea ice (pack ice) is relatively thin ice formed from frozen sea water, floats in the water   Ice sheets are areas of permanent ice spread out overland and are several kilometres thick   Permanent ice is also found in glaciers, on mountaintops and the permafrost   Icebergs are large pieces of glaciers that have broken off and float in the ocean   Ice and snow reflect more radiant energy than rocks and vegetation

Ice - Albedo Affect Albedo is a measure of the reflectivity of a surface. The albedo effect when applied to the Earth is a measure of how much of the Sun's energy is reflected back into space. Overall, the Earth's albedo has a cooling effect.

Albedo Affect -Altered

Low level clouds are often thick and reflect much of the incoming shortwave radiation. Because of their low altitude they emit large amounts of longwave radiation into space. High clouds tend to have a net warming effect as they because of their high altitude and resulting low temperature only emit little longwave radiation towards space and reflect little of the incoming shortwave radiation.

Lithosphere   Is the earth’s crust   Includes solid rock, soil and minerals on land under the oceans   It absorbs higher-energy radiation from the Sun and converts it into thermal energy, then emits the energy back as lower-energy (Infrared radiation)

Land Formations & Climate Zones   Mountains force air to rise up on the windward side resulting in precipitation as it rises, then on the leeward side there is little rain   This process is called the rain shadow effect   At high altitudes, atmospheric pressure is lower because there is less air pushing down   Air is cooler at higher altitudes forming an ‘alpine climate’, which greatly affects the ecosystems located there

Living Things - Biosphere   Plants and animals are involved in change of gases in the atmosphere   Plants undergo photosynthesis   Plants and animals undergo cellular respiration   Some animals (cows, sheep) and termites produce methane gas   Carbon dioxide and methane absorb infrared radiation emitted by Earth, the amount of these gases will affect the amount of radiation the atmosphere can absorb; which can affect the Earth’s climate