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What is a climate proxy and why do we need to use them?

• something that closely tracks something else we cannot measure

• provides a baseline for our current climate

Examples of proxies

isotopes, fossils, rock types, ice cores, pollen, tree rings, animal forms

What is the limit of a proxy and why do we need more than one?

• proxy is not the direct signal and can never fully prove anything (only gives us confidence)

• a single proxy could lead us to the wrong conclusion

Parts of the geologic time scale

eons, eras, periods, epochs

What is the age of the Earth and the current time we are in now?`

• 4.5 billion years old

• cenozoic era, quaternary period

Why is the geologic time scale broken up the way it is?

It is based on changes in the fossil record, which provides us with environment indicators

How does studying the earth's past climate help us understand current climate change?

constraints the uncertainty of climate models looking into the future and it can help us prepare for impacts today

What is the first snowball earth?

• global glaciation: ice reached within 5 degrees of the equator

• the earth is covered in glacial ice and became more reflective (higher albedo and lower temp)

What geologic evidence was present in the first snowball earth?

glacial till: a type of sedimentary rock

What is the faint young sun hypothesis?

when the Sun was billions of years younger it was not as bright and we did not get as much solar energy

How did CO2 levels come back up after the first snowball Earth?

• there was no rain or chemical weathering

• volcanoes were erupting and adding CO2 to the atmosphere deposits of carbonates were deposited and ice was pure which allowed sun to penetrate it and life to continue

What is a mass extinction?

the rate of extinction is very high

Permian Triassic Extinction

• caused by the eruption of Siberian Traps (during of coal and limestone released CO2 into the atmosphere)

• earth's temp increased and water became more acidic bc of more CO2 being released

• conditions lasted for millions of years

How do climate extremes cause mass extinctions?

If the climate is warming or cooling at a degree that organisms cannot handle they will simply die

What is an isotope?

an atoms that has a different number of neutrons making the element heavier or lighter

Evaporation and isotopes

• easier for lighter isotopes to escape and easier for heavier isotopes to be captured

• the warming it is the more energy there is for evaporation and the more of the heavier isotope evaporates

What is eustatic sea level and what controls it?

• global sea level changes related to changes in the volume of water in the ocean

• tectonic shrinking or growing in the ocean, rise in temps causing expansion of water, ice sheets melting

How did the formation of Rodinia affect the climate?

plate tectonics, determines the size of ocean basins, determines erosion (how much carbon is going back into the ocean), and ocean currents

How did the formation of Pangea affect the climate?

plates were colliding, erosion of mountains was a good environment for plants to flourish, thriving plants were extracting large amounts of CO2

How did the breakup of Pangea affect climate change?

carbon was moved out of the atmosphere and more CO2 was moving out of the atmosphere and into plants

Ocean currents in relation to the Isolation of Antartica

• continents were in a circus polar current and warm water was prevented from reaching Antartica

• temps dropped, glaciers formed, the ice albedo feedback cooled the globe

Ocean currents in relation to the formation of Panama

warm water from the Caribbean and the Gulf was brought to the Northern Atlantic

How does salinity affect ocean circulation?

colder water = higher salinity = more dense water and more of it sinks to the bottom of the ocean

How does evaporation/precipitation play a role in ocean currents?

High rates of evaporation leaves behind salt and when it rains, it dilutes the water

How did the North and South poles accumulate ice?

uneven distribution of temps throughout the water so both began to freeze

How does population growth affect our planet?

if population rises, the total GHG will still rise

What is the difference between total emissions and per capita emissions?

Per capita emissions: emissions divided by total population (per person average emissions) Total emissions: GHG emissions per country

Carrying capacity

• maximum population and environment can support

• we cannot determine the carrying capacity of humans because we can manipulate it

Ecosystem services

• an essential service an ecosystem provides that supports life and makes economic activity possible

• ex: air purification, water cycling, nutrient cycling, pollination, soil

Relationship between GHG emissions and wealth

people with more money tend to own more gadgets, travel more, eat more carbon intensive foods, have less home grown gardens, have a larger house to heat and own more cars

What role does soil play in the carbon cycle and GHG emissions?

soil takes carbon out of the atmosphere and can convert it to organic matter keeping it from being released

What are the different types of agriculture techniques?

only using land that is suitable for agriculture, no till, planting over crops, contour plowing, terracing, preserving wetlands, decreased deforestation

Sources of methane emissions

• agriculture

• fossil fuel production

• leaky infrastructure

• landfills and rotting trash

How did coal form?

layers of dirt and rock covered plants and resulted in pressure and heat turning the plants into coal

How did salt form?

weathering and volcanic activity

How did Marcellus shale form?

biological matter and organisms dropping into the sea floor and mixing with sediments