PALEOCLIMATES Ancient climates 11/22/2018
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Earth’s climate history Has always been changing
Earth’s climate has always been changing 11/22/2018
How do we study past climates??? 11/22/2018
Fossils Certain critters only live in WARM climates Trilobites Corals (Petoskey stones) dinosaurs 11/22/2018
Glacial evidence Indicates COLD climate Grooves Erratics Misplaced boulders 11/22/2018
Ice cores Ancient air bubbles are trapped in the ice Can analyze ancient air! 11/22/2018
18O/ 16O 18O is heavier- harder to evaporate More 18O when climate is hotter Seen in ice cores 11/22/2018
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Tree rings Wider rings represent warm wet climate 11/22/2018
Coral reefs Corals add layers every year Like tree rings Bigger layer= warmer 11/22/2018
NATURAL CAUSES OF CLIMATE CHANGE
VOLCANOES Lava type= Emit CO2; warms- long term (need a lot!) Ash type= emit SO2- blocks heat- cools- short term
Impact events (space rocks) 1) Stirs up dust= colder
Milankovitch cycles Earth tilt changes Less tilt= less seasons Cooler in mid latitudes Ice age! OR Earth’s orbit becomes More oval= colder
Variation in Solar output Sunspots Cause solar storms Make earth hotter
Land vs. sea ice Melting of sea ice (icebergs) will NOT effect sea level Melting of land ice will effect sea level Antarctica/ Greenland Could also cause global cooling (Day After Tomorrow)
Global warming can cause global cooling?
Rising sea level by 2080 (projected)
Current state of glaciers
Glacier national Park, Montana 1938 vs. 2005
Alaska 1917 vs. 2005
Greenland notice 2002-3
Carbon footprint Your impact on GHGs. Extra credit!!