consequences of climate warming: evidence
historical record
fossil record
rock types ( reefs,glaciers, sand dunes...)
assessing global warming
if global equivalent of CO2 levels increase, global temperature should increase
we can predict how much do temperatures increase
compare our predictions with observations
can we make policy ( about fossil fuels) based on this science?

Final Review

• ocean floor - age magnetic stripes 
• types of seismic waves 
• body waves - passes through the interior of the earth 
• yosemite- land lock hot spot 
• hawaii- ocean hot spot 
• goelogic structure anticline and sincline 
• anticline - up 
• sincline - down 
• anticline- flows away from the axis 
• sincline- flows towards the axis 
• japan - subduction zone ( bumpy trenches) 
• an important characteristic of an index fossil is the organism existed for a relatively short period of geologic time 
•  andesite is not a type of sedimentary rock 
• short term climate cycles include volcanoes, anthropogenic, albedo 
• A water table aquifer is also known as a 
• when maximum tilt occurs weather is more severe
• albedo is also known as the reflection coefficient 
• the goemetry of the water table tend to follow the topography 
• a normal fault is when the hanging wall block moves down with respect to the footwall block 
• felsic refers to rocks that have a higher percentage of light colored minerals and silica (sio2) 
• the rock breccia always contains which of the following: angular gravel-sized fragments '
• metamorphic textures include - foliated, non-foliated 
• which of the following minerals is most likely to be abundant in a mafic igneous rock - audite ( pyroxene) 
• the parent rock or protolith of slate is shale 
• which of the following describes the configuration of an unconfined water table around a pumping well- cone of depression 
• a common strategy to clean up groundwater involces determining the water table because contaminents flow with the direction of groundwater flow 
• climate- long periods of time 
• weather- short period of time 

Global Warming and the Greenhouse effect

• causes natural and anthropocentric ( human caused ) 
• the atmosphere is the gaseous envelope that surrounds the earth
• atmosphere composition 
• dust 
• major gasses : N (78%) and O (21%) 
• Minor gases: Ar (0.93%), CO2, CH$, etc. 
• ozone (O3) 
• water vapor  
• increase in "greenhouse" gases, which in turn traps heat 
• more greenhouse gases = more warming 
• greenhouse gases are: carbon dioxide (co2), nitrous oxide ( n2o), methane (ch4), cfc's water vapor ( clouds) 
• anthropogenic enhancement 
• industrialization and consumerism; burning of fossil fuels 
• greenhouse gasses in the Earth's atmosphere absorb thermal energy ( infra-red) radiated from Earth's surface
• how it works 
• co2 occurs naturally in low concentrations but has a big effect 
• how co2 is added to the atmosphere 
• exchange between atmosphere and seawater 
• biological respiration 
• burning of fossil fuels 
• volcanism (volcanoes ie mammoth mountain)  
• fires ( burning tress) 
• how co2 is removed form atmosphere 
• exchange between atmosphere and seawater 
• photosynthesis 
• formation of carbonate rocks ( limestone) in oceans 
• fossil fuels and fires are instantaneous greenhouse gasses 
• consequences of climate warming 
• glaciers/ sea ice 
• sea level 
• species migration 
• catastrophic weather events 
• shut-down of the ocean conveyor belt ( worst possible thing to happen) 
•  what factors effect sea level 
• increase in glaciers = fall in sea level 
• less glaciers - rise in sea level 
• slower seafloor spreading - drop in sea level 
• faster spreading - rise in sea level 
• ocean cools, water contracts - drop in sea level 
• warming oceans - rise in sea level 

Orbital Eccentricity

The shape of the Earth's orbit ( viewed from above)
Cycles every 400,000 and 100,000 years

• Is it more circular-shaped or more egg- shaped? 
• circular: low eccentricity 
• oval shaped: HIGH ECCENTRICITY 
• obliquity or axial tilt 
• changes from 21 degrees to 24.5 degrees 
• cycles every 41000 years 
• greater tilt, the greater the seasonality 
• minimum tilt develops more glaciers 
• maximum tilt : warmer summers near poles and less glaciation 
• orbital procession 
• earth wobbles like a spinning top 
• the spin axis sweeps out an imaginary cone 
• cycles every 19-23 thousand years 
• how do orbital changes show up in the geological record? 
• example: changes in tilt 
• More tilt = more severe the season 
• less tilt = less severe of the season 
• effects 
• slightly warmer winters 
• but cooler summer 
• snow from winter doesn't melt 
• past glaciation interpreted extended of ice sheets 20,000 years ago 
• interpretation temperature variations over the last 100,000 years 
• milankovitch cycles with paleoclimate records for the pas million years 
• periods of low eccentricity and glacial periods 
• showed that procession along with eccentricity and tilt, affects the total amount of insolation 
• insolation = exposure to suns rays 
• lighter composition absorbs lighter isotopes 
• correlation in inferred temperature an co2 concentration