Lecture 5 - Lecture 5 Climate change in the past and today...

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Lecture 5: Climate change in the past and today
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Reading for this week Reading Chapter 3 of UN Global Outlook for Ice and Snow For Friday: Read P. 687-699 of Chapter 20 of the National Climate Assessment Report (downloadable from the class website) describes the changes we are likely to experience in the Southwest. Make note of the 5 key messages how many of these relate to the cryosphere in some way?
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Outline How do we know about Earth’s past climate How and why climate has changed in the past How and why climate is changing today
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“The Climate System” Characterized by CHANGE
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Past Climate: how do we know? 1. Instrumental Record (recent, ~1800s to present) 2. Geologic Record - fossils - landscape features (sand dunes, dry lakes/rivers, glacial valleys etc) 3. Proxy Records “records of natural events that are controlled by, and closely mimic, climate”
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3. Proxy records Natural “layered” records e.g. - Tree rings Past Climate: Proxy Records Bristlecone Pine from the Sierra Nevada Mountains
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3. Proxy records Natural “layered” records e.g. - Tree rings - Lake/ocean sediment (temperature and/or rainfall from pollen, sediment type, fossil plankton etc) Past Climate: Proxy Records
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3. Proxy records Natural “layered” records e.g. - Tree rings - Lake/ocean sediment - Ice cores (CO 2 and temperature records) Past Climate: Proxy Records
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3. Proxy records Natural “layered” records e.g. - Tree rings - Lake/ocean sediment - Ice cores - Cave speleothems (rainfall and temp) Past Climate: Proxy Records
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3. Proxy records Natural “layered” records e.g. - Tree rings - Lake/ocean sediment - Ice cores - Cave speleothems - Corals (SST and salinity) Past Climate: Proxy Records - farming/2007/05/31/1180205427882.html - 480.jpg
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