geoscience exam 1

14 questions: 5 multiple choice, 9 short answer; blank page of geologic timescale; block diagram

What is a climate proxy?

An object that indirectly records climate by ANNUALLY adding mass. Must PRESERVE something physical that is measurable. Used in substitute for weather recording instruments.

4 main drivers of climate change in order of how fast they occur (slowest to quickest)

Solar output, plate tectonics, Milankovitch cycle, anthropogenic

Solar output (as a driver of climate change)

solar flares and sunspots correspond to changes in solar radiation. more solar radiation warms the planet; less radiation leads to cooling periods;; magnitude of change: 50degrees Celsius in billions of years

Plate tectonics (as a driver of climate change)

as continents move, they change ocean currents and wind patterns. also massive volcanic activity during tectonic shift releases co2.;; magnitude of change 20 degrees Celsius in millions of years

Milankovitch cycle (as a driver of climate change)

• 3 variables relating to the position of the earth relative to the sun

• If the orthern atmosphere receives less energy from the sun in the summer the ice in North Pole will not melt and causes an ice age

• The earth orbits sun in ellipse where sun is not centered. (Eccentricity) point where earth is closest to sun is at beginning Jan. In July earth is far making it summer in northern hemisphere. Because of the distance the earth receives less energy from the sun, the ice in north melts less quickly = ice age. When the earth orbits circularly the n hemisphere is closer to sun in July and receives more energy so ice melts. This changes every 100,000 yrs.

• The tilt of earths axis relative to sun is obliquity. Tilt of 22-24.5 degrees. The wider the angle the. Orr the northern hemisphere turns toward the sun in summer and the more ice melts. The smaller the tilt the less ice melts. Changes every 41,000 yrs

• Toll movement / wiggles around earths aixis precession. Changes every 21,000yrs.

Anthropogenic (as a driver of climate cycle)

humans burning fossil fuels releases greenhouse gases like co2 and methane into the atmosphere. exacerbates greenhouse effect

What is albedo?

• The amount of light reflected back from a surface ( given in a value between 0 and 1)

• dark surfaces reflect little and absorb more

• Sea ice or snow reflect lots of light so they’re brighter. (high)

The albedo effect

• the degree of reflection of solar radiation from an object

• Snow reflects 90% of suns energy—> has a cooling effect on earth. When it gets warmer more snow melts. So less warmth of the snow is reflected back so it gets warmer so more snow melts.

• If the soil on earth is cooler (bc of smth like milankpvitch cycles) there is more snow so less warmth staying in atmosphere leading to potential ice age

• Cloud albedo effect: high temps. = more evaporation. Creates more clouds. Some clouds reflect a lot of sunlight. Due to global warming there is more evaporation so more cloud formation which means more solar radiation is reflected so it can be cooler. Other clouds block little sunlight but retain earths warmth ( similar to ghg). Result of global warming.

Order of reflectivity of albedo high to low

snow/ice, clouds, sand, grass, ocean, asphalt

What is the greenhouse effect?

The natural warming of the earth that results when gases in the atmosphere (greenhouse gases: cardio dioxide, nitrous oxide, methane, water vapor ) trap heat from the sun that would otherwise escape into space.

How does the Greenhouse Effect work?

occurs as ghgs in the atmosphere absorbed and re-emit longwave, infrared radiation emitted from the Earth’s surface, preventing it from escaping into space. this process keeps the planet significantly warmer than it would otherwise be by acting similarly to a blanket around the earth.

What is the wavelength coming in (greenhouse gas effect)?

what happens after it gets absorbed?

what wavelength leaves?

why is the problem exacerbated?

wavelength coming in: short-wavelength radiation (visible light)

after it gets absorbed, the surface warms up (re-radiated the energy back upward as heat)
sent back out to space as long-wavelength (infrared) radiation

this is exacerbated by the increased concentration of the greenhouse gases because of humans which make it harder for the wavelengths to leave

what is uniformitarianism?

Fundamental laws of nature never change. Past climate change is used to predict future climate change.

Spheres ranked in least to most dense

atmosphere, hydrosphere, biosphere, geosphere

atmosphere definition

the envelope of gases surrounding the earth, held in place by gravity. it is the least dense because the molecules are spread very far apart

hydrosphere definition

encompasses all the water on the planet, including liquid water, ice, and water vapor

biosphere

all living organisms (plants, animals, fungi, bacteria)

geosphere

includes all rocks, minerals, and landforms on earth. densest of the spheres because it is composed of heavy elements like iron, magnesium, and silicon

reasons for solar energy variation on earth’s surface and why

1) angle of incidence

2) albedo

3) distance

4) reflection angle

angle of incidence definition (in relation to why solar energy varies hitting earth)

The angle of incidence is higher at the equator because it is hitting the equator and lower at the poles (decreases with increasing latitude)

albedo definition (in relation to why solar energy varies hitting earth)

higher albedo at higher latitudes because higher latitudes have more ice

distance definition (in relation to why solar energy varies hitting earth)

at the poles, light has to travel further distances because of the earth’s shape as a sphere

reflection angle (in relation to why solar energy varies hitting earth)

solar energy is reflected more in a lower angle rather than it hitting perpendicularly (at equator)

Heat capacity / thermal inertia

how long something takes to cool of / heat up or how easy or hard does a substance change temp. High heat capacity: ammonia/fire; low: metal frying pan.

relevance: explains climate patterns, such as why coastal areas (high water heat capacity) have milder temperatures than inland regions (lower rock/soil heat capacity).

Milankovitch 3 cycles

Climate precession, eccentricity, obliquity

Climate precession - 21,000yrs

21,000yrs;

eccentricity - 100,000yrs

shape of earth’s orbit around the sun; 100,000yrs; orbit is elliptical, shao of ellipse changes over time due to changes in gravitational attraction of other planets. affects the ammount of summer ice melting.

obliquity - changes every 41,000yrs

tilt of rotational axis; 41,000yrs; 21.5-24.5 degrees; affects the amount of summer melting

Maritime climate

area near water or ocean, less seasonal variations due to higher heat capacity

geologic time scale: eons in order of youngest to oldest:

phanerozoic (0-538.8MA), proterozoic (538.8-2500MA), archean (2500-4031MA), hadean (4031-4567MA)

geologic time scale: era in order of youngest to oldest: BOLDED

Cenozoic (0-66MA), Mesozoic (66-251.902), Paleozoic (251.902-538.8MA)

geologic time scale: period in order of youngest to oldest: BOLDED

cenozoic: (quaternary, neogene, paleogene); mesozoic: (cretaceous, jurassicm triassic); paleozoic: (permian, carboniferous, evonian, silurian, ordovician, cambrian)

geologic time scale: epoch in order of youngest to oldest: BOLDED

anthropocene, holocene, pleistocene, pliocene, miocene, oligocene, eocene, paleocene