GHC Ch 12: Climate Flashcards
Earth’s atmosphere had a radical change from (…)-rich to (…)-poor.
CO2
Changes in Earth’s atmosphere caused by (…).
life processes
Plants remove (…) from atmosphere by (…).
CO2, photosynthesis
Atmospheric CO2 dissolves in (…), is absorbed by (…).
water, marine life
CO2 is chemically tied up in (…)
limestone
animals (…) of CaCO3 which further reduced atmospheric CO2.
made skeletons
Lessening of CO2 did what to the climate?
lowered temperatures
Before life, the atmosphere was full of CO2 and the surface temperature was about…?
290ºC
In the greenhouse effect, incoming visible light admitted at (…) wavelengths
warms up the atmosphere, and heat is given off as (…), (…) wavelength, radiation.
short, infrared, long,
Most important greenhouse gas is (…)
CO2
Outgoing energy is (…), in the greenhouse effect.
trapped
The greenhouse effect has weakened or strengthened since early earth?
strengthened
CO2 was what percent of the atmosphere around early earth?
0.04%
How are humans now changing atmospheric CO2 concentration?
Burning tremendous volumes of living plants (trees and shrubs) and dead plants (coal, oil, natural gas)
Humans now changing atmospheric CO2 concentration may be enough to trigger…?
climate shifts
Warm climate history is indicated by what three things?
Fossil reefs/limestone
Aluminum ore bauxite (tropical soils)
Evaporite minerals
Cold climate history indicated by…?
Erosion by glaciers (distinctive marks and debris deposition)
What is a major source of carbon dioxide to the atmosphere?
Volcanism
During (…) more carbon dioxide enters the atmosphere.
tectonically active periods
(…) building resulting from the tectonic activity leads to more (…) which removes carbon dioxide from the atmosphere. The result is a (…) feedback that helps to maintain an equilibrium of climate.
Mountain, rock weathering, negative
Climate depends on balance between incoming and outgoing…?
heat
Earth divided into what three belts by latitude?
frigid, temperate and torrid
During an Ice Age, a frigid zone expands or shrinks?
expands.
During an Torrid Age, a torrid zone expands or shrinks?
expands
Ice Age may have ended because…?
Pangaea broke apart
Water must first evaporate from (…) for clouds to form and precipitate snow (to build ice sheets)
ocean
(Warm/Cold) water evaporates more easily than (warm/cold) water.
warm, cold
If continents divert warm ocean currents to flow north and south to the poles…?
more water will evaporate to form clouds, to drop more snow
Factors to create Torrid Age
At equatorial zones were oceans, allowing more absorption of solar radiation by water. Huge volumes of gases to atmosphere. Dense, salty, oxygen-poor tropical water. Melted methane hydrates.
Oxygen may be…? (3)
16O, 17O or 18O
Atmospheric water becomes depleted in…?
18O
When 18O-depleted water is trapped on land as (…) during Ice Age, Oceans become 18O-enriched
snow or ice
Measurement of 18O/16O ratio in CaCO3 fossils is indicator of (…) organism lived in.
climate
High 18O/16O -> (warmer or colder?) climate
Low 18O/16O -> (warmer or colder?) climate
colder, warmer
Glacial advance and retreat caused by…?
cycles in Earth’s orbit around Sun affecting amount of solar energy received by Earth.
Milankovitch defined changes in…?
Earth’s orbit, tilt and wobble
Amount of solar radiation at high latitudes during summers determines…?
how much snow remains from winter to next winter, allowing glaciers to grow?
Eccentricity of orbit around Sun: varies every (…) years
100,000
Laurentide Ice Sheet existed around how many years ago?
20,000
20,000 years ago, glaciers at maximum extent covered how much of today’s land?
27%
What percent of continents are still buried under ice?
10%
If ice melts, sea level would rise…?
65 m
Cause of sudden drops or jumps in temperature could be caused by…?
Melting of continental ice sheets left behind huge cold lakes with ice dams, Failure of ice dams released enormous amounts of fresh, cold water into surface layers of ocean, disrupting oceanic circulation pattern, Constant rise in sea level from melting of glaciers.
What is climatic optimum?
Warmer global temperatures, higher rainfall totals
Average global temperatures have fallen how much?
2ºC
Factors in volcanism’s effect on climate?
Size, rate of eruptions
Height of eruption columns
Types of gases, atmospheric level of placement
Low latitude vs. high latitude (weather patterns spread debris)
Possible effects of a Flood basalt eruption…?
Increase in atmospheric CO2 -> temperature increase of 10ºC
More acidic ocean waters
Depleted ozone layer
Combined effects of eccentricity, tilt, wobble, caused (…), with numerous variations.
cooling trend
Variations within cooling trend:
Medieval Maximum: warm period from 1000 to 1300 C.E.
Little Ice Age: cold period from 1400 to 1900 C.E. – “epoch of renewed but moderate glaciation”
Smaller scale coolings and warmings within Little Ice Age
Maunder Minimum: cooler period from 1645 to 1715 C.E.
Minimal sunspot activity Sun possibly .25% weaker
Processes in climate changes of last thousand years:
Changes in Earth’s orbital patterns caused cooling
Lessened solar-energy production caused cooling
Volcanism caused changes
Interactions between ocean, atmosphere, ice sheets
Average global surface temperatures rose (…)ºC in 20th century, from 1910-1944 and since 1977
0.6
1910-1944 warming was caused by…?
hotter Sun, lack of volcanism
Warming since 1977 twice that of 1910-1944: likely mostly due to…?
greenhouse gases in atmosphere
Human activities (…)ºC increase
0.4
Nature causes (…)ºC increase
0.2
Stimuli for the late Paleozoic ice age?
large continental masses near the poles, poor ocean-water circulation
Stimuli for the late Paleocene torrid age?
warming: equatorial zones covered in water, snow and ice melted showing more land,outpourings of lavas from opening of the north atlantic ocean released a lot of gas into the air, oceans changed density
Stimuli for the late Cenozoic ice age?
cooling: breakup of Pangaea, change in ocean circulation, continental masses in polar regions, more snow and ice to reflect sunlight, circulation around equator restricted, area of shallow oceans reduced, uplifts of the Tibetan Plateau and Himalaya mountains
