GEOG 203 1nd Edition Lecture 12 Outline of Last Lecture I Review for quiz II Distribution of climates on an idealized climate Outline of Current Lecture I Intro to the dynamic earth changing climates and shifting continents II Changing Climates a Louis Agassiz the theory of a great ice age in the past and some types of evidence for climate change b Reconstructing climate history c What causes climate change Current Lecture These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Are the earth s climates changing 15th century reconstruction of Ptolemy s world map ancient Greeks proposed frigid zone uninhabitable temperate zone and torrid zone uninhabitable Changing climates Louis Agassiz the theory of a great ice age in the past and some types of evidence for climate change o Found evidence for past glaciation o In 1837 Louis Agassiz proposed glaciation from the north all the way to Mediterranean Sea o Also did a lot of study on glacial movement Instrumental records deal with data gathered using instruments Proxy records things that can stand in place of instrumental records to be used as proof Reconstructing climate history o One measure of glaciers includes exit glacier terminus positions recording the ages of trees to see the rate at which the glacier was melting and new trees were growing in o Ice cores are used to reveal annual temperature variations o Can look at the ratio of the isotopes Oxygen 16 vs Oxygen 18 for example in order to replicate past temperatures o The Holocene time period most recent wholly new in history approximately the last 11 000 years o Interglacials periods of warmth between glaciations o Glacials periods of cold glaciations o The Pleistocene most new approximately the 2 million years preceding Holocene o Marine sediment cores an even longer record using sediment from Northern Atlantic ocean floor What causes climate change o The current tilt of the earth causes the seasonality without this tilt seasons would be nonexistent