Ice House To Greenhouse: Climate Change Flashcards
What is carbon dating
Using radioactive testing to find the age of rocks which contained living material
What is erosion
Waering away of the landscape
What is an eon
Basic unit of geological time where a type of rock system is formed
What is an era
Subdivsion of geological time divides an eon into smaller units
What is an example of an eon
The phanerozoic eon
What era is the phanerozoic eon split into
Paleozoic
Mesozoic
Cenozoic
What is an epoch
Longer than an age and shorter than a period
What is geology
Earth science
Study of solid rock
Rocks of which its composed.
Change the rock goes through
What is glaciation
A cold period of time where glaciers expanded widley
What is strata
Horizontal layers of rock
What is a greenhouse earth
No continental icesheets on earth due ti warmer tenperatures from higher concentration of greenhouse gases in atmosphere
Normal/ most common state
What is ice house earth
Ice sheets cover a large proportion of the land due to overall temperature of earth being lower than average
How many known ice house earths ahve there been
At least 5
What is a glacial period
Cooler when ice advances
What is an interglacial period
Wamer when ice retreats
What is the name the most recent ice age
Quaternary ice age
Started 2.6million years ago to present day
What are the two epochs of the quaternary
Plesitocene lasted untill 10000 years ago
Holocene 10,000 years to present day
How many glacial and interglacial cycles happened in the Pleistocene epoch
50 cycles
What happened during the Pleistocene
Glaciers reached their maximum extent
What is the last glacial extent know as
Devensian
When did the devensian occur
18,000years ago
What was rhe last glacial advance in the uk called
Loch lomond stadial
When did the loch lomond stadial occur
12,000-10,000 yrs before present
What has been linked to the start of the quaternary ice age
Changing position of continents a result of plate tectonics
North and south american plates collided creating the panama isthmus
What is an isthmus
A thin stretch of land with oceans on both sides
How were trade winds affected (creation of Panama isthmus)
Wamr carribean waters that flowed through the gap between the americas were forced towards europe creating the gukd stream
What did the formation of the gulf stream do
Transported extra moisture into the arctic atmosphere this fell as snow triggering the build up of the greenland ice sheet
When did Antarctica seperate from SA
34 million years ago
What was created when Antarctica seperated from SA
The drake passage
Antarctica was completely surrounded by ocean
What is the circupolar current
Ocean currents isolating Antarctica from the warmth of global oceans
Why is it cooler in Antarctica
Oblique solar rays larger area receives a lesser concentration per M
Why is it warmer near the equator
Verticle rats so the solar rays are more concentrated per m
What has happened to global temperatures on average
They are increasing
What is eccentricity
Shape of earths orbit
Circular to elliptical
100,000year cycle
When is there more solar radiation exposure for eccentricity (elliptical or circular)
Elliptical
What is the furthest point in earths orbit from the sun
Aphelion
What is the closest point in earths orbit to the sun
Perihelion
What is obliquity
Tilt of earths axis during its orbit
Varies between 21.5 and 25.5
41,000yr cycle
Changes season severity
What is the procession of equinoxs
Wobble as earth spins
Season where earth experiences perihelion changes
Northern hemisphere winter at perihelion
21,000yr cycle
Affects seasonsl intensity
What volcanic eruption occurred in april 1815
Mt Toabora, indonesia
What happened to temperatures the followng year after the Italian volcanic eruption
Accounts of very cold weather documented globally
What did scientists originally cuased the cooling after volcanic eruptions
Ash emittied into the atmosphere was responsible for widespread cooling
However, measurments showed that most ash retured to surface within a few weeks/months
What is the main contributer to volcanic colling
Vast amount of sulphur dioxide gas injected into the atmosphere for upto three years
How do sulphate aerosols cause net cooling
They increase the reflection rate of solar radiation back into space cooling earths lower atmosphere
What is the name for variations in solar outputs
Sunspots
What are sunspots
Darker areas on the suns photosphere
Regions of reduced surface temperature
What causes sunspots
Cooncentrations of magnetic field flux that inhibits convection
What do sunspots indicate
The sun is more active releasing more thermal energy
What is the maunder minumum
Sun was observed to have very little solar spot activity at the end of the little ice age (1650-1750)
