Ice Ages What is an Ice Age? Interglacial Interval Long Term Decrease In Global Temperatures Ice Age = Glacial Sheets Advance http://www.museum.state.il.us/exhibits/ice_ages/ Interglacial Interval Time between ice ages We are in one now!

Volcanic Activity When volcanoes erupt they release large amounts of dirt and dust into the air. This can block incoming solar radiation, sunlight, from reaching Earth This causes climates to be cooler then normal Short Term Lasts 2-7 yrs

Do You Remember…. Why do we have summer and winter? Seasons Vocabulary Review Why do we have summer and winter? The Earth’s Tilt As It Rotates Around The Sun What is a solstice? **One hemisphere of the Earth is tilted towards or away from the Sun. *Northern Hemisphere Tilted towards = Summer *Northern Hemisphere Tilted Away = Winter What is an equinox? **Neither Hemisphere is tilted towards or away from the Sun. *Fall and Spring

Solar Activity The amount of sunspots present on the Sun can also affect Earth’s climate. More Sunspots = Warmer Global Climates Less Sunspots = Cooler Global Climates The last time the Sun had minimal sunspots we experienced a mini ice age. Rivers were frozen in June. Least amount of Sunspots = Called the Maunder Minimum

Earth’s Orbit Earth’s Orbit switches between a circle and an ellipse every 100,000 years. Circular Orbit Seasons are determined by the tilt of the Earth on its axis. Elliptical Orbit Seasons would be more intense Seasons would be determined by physical distance between the Earth and the Sun

Earth’s Wobble Every 26,000 yrs the Earth slowly changes which star it is tilted towards Polaris or Vega Polaris = We are currently facing In another 12,000yrs we will be facing Vega This will reverse our seasons We will have summer in December and winter in June We are tilted away or towards the Sun differently