Long-Term and Short-Term Changes in Climate

•The Earth is 4.54 billion years old

•In it’s history, there have been many natural variations to it’s climate

•These change have occurred due to changes in how energy is absorbed and trapped by the Earth

For example…•Ice Ages

▫a period in Earth’s history where the Earth is colder and much of the planet is covered in ice

Long-Term Changes are due to:Continental Drift•According to plate tectonics, all of the continents have been moving and are continuing to shift their position on the Earth’s surface

•How it impacts climate?▫Changes ocean currents and wind

patterns▫Changes how land masses are

distributed which reduces the effect of local bodies of water on climate

▫Creates mountains which affect climate

Video

Cycles in Climate•Long term cycles (over tens and hundreds of thousands of years) occur alternating between ice ages and warmer interglacial periods

•Theories on why the climate changes:▫Shape of the orbit changes over time▫Earth’s tilt changes and wobbles

Short-Term Changes are caused by:Volcanic Eruptions•When an eruption occurs, rocks, dust and

gas are shot high into the atmosphere•These particles reflect the suns rays and

lower the energy transmitted to the Earth

Changing Ocean Currents•El Nino – a recurring change in the Pacific

winds and ocean currents that brings warm, moist air and water toward South America instead of Africa

Changes in the Sun’s Radiation•If the amount of radiation from the Sun drops, the Earth receives less energy and cools

•Scientist’s are constantly monitoring the Sun’s energy output

Homework•Pg 353 # 2, 4, 5, 7