Climate and Weather

Climate vs. Weather Climate and weather are NOT the same Weather – the condition of the atmosphere in one place during a limited period of time Climate – the weather patterns that an area typically experiences over a long period of time. Example: What is the weather today? vs. What is the climate of Kentucky?

Earth’s Tilt and Rotation The Earth is tilted on its axis – an imaginary line running from the North to South pole through the middle of the earth The tilt of the earth affects the temperature – the measure of how hot or cold a place is Areas that are tilted toward the sun have warmer temperatures while areas tilted away from the sun have colder temperatures The earth rotates. The area facing toward the sun has daylight. The area facing away from the sun has night time.

Earth’s Revolution The earth not only rotates, but also revolves. One revolution around the sun takes 365 days. The earth’s revolution and tilt cause changes in the amount of sunlight that reach different locations on the planet. This is why we have seasons When our area is faced more directly to the sun we experience summer. When our area is faced away from the sun we experience winter.

Equinox The seasons of the world are reversed north and south of the equator Around March 21 the sun’s rays fall directly on the equator, meaning the amount of daylight and sunlight is equal Around September 23 it happens again

The Tropic of Cancer and Tropic of Capricorn Tropic of Cancer – a line of latitude at 23.5 degrees north. The northernmost point at which sunlight directly hits the earth. The suns rays reach the Tropic of Cancer around June 21 (the summer solstice), marking the beginning of summer in the Northern Hemisphere Tropic of Capricorn – a line of latitude at 23.5 degrees south. The southernmost point at which sunlight directly hits the earth The suns rays reach the Tropic of Capricorn around December 22 (the winter solstice), marking the beginning of winter in the Northern Hemisphere

The Poles The amount of sunlight at the Poles varies most dramatically during the year At the North Pole the sun never sets from March 20 to September 23. This happens at the South Pole from September 23 to March 20. The tilt of the earth’s axis causes this phenomenon. Since people don’t live on the poles it goes mostly unnoticed, but some living near the Arctic experience the “lands of the midnight sun”

The Greenhouse Effect Only about half of the sun’s radiation passes through the earth’s atmosphere. Some radiation is reflected back into space, and just enough passes through to warm the air, land, and water. Earth’s atmosphere acts like a greenhouse in that it traps heat even during cold weather

Global Warming Carbon dioxide (CO2) helps to absorb the heat that is reflected off the earth and send it back to the surface. Too much CO2 could cause overheating on the earth’s surface Global warming – a rise in atmospheric CO2 levels due to the burning of fossil fuels Scientists do not agree on the extent of global warming but it is possible that global warming could spark climate change across the earth.