climates of the distant past Flashcards
what is a climate trend?
global temperature change over a set period of time
what is a climate rhythm?
repeating cycles of climate over a shorter geological time scale
what is an ice age?
persistent glaciers present
what is a glacial period?
glaciers are growing
what is an interglacial period?
glaciers are receding
what is a Hot House Earth?
no persistent glaciers present
how does Earth’s climate move between extremes?
- climate forcing
- feedbacks
- tipping points
what were the notable features of the early atmosphere?
- lack of oxygen
- high level of methane
- high level of carbon dioxide
what has happened within the Cenozoic period?
- several mountain building events (increased chemical weathering)
- formation of Antarctic circumpolar current (formation of Antarctic glaciers)
- ithmus of Panama (creation of gulf stream -> more snowfall in North Europe + America)
what are the three types of orbital processes?
- eccentricity
- obliquity (tilt angle)
- precession (tilt direction)
what is eccentricity?
change in the distance between the sun and Earth as the Earth orbits the sun
- influences length of seasons + solar radiation on Earth
what is obliquity?
varying angle of the Earth
- creates differences in seasonal solar insolation
- greater tilt = greater extremes between seasons
what is precession?
direction of the Earth’s tilt
- makes seasonal contrasts more extreme in one hemisphere and less in the other -> why winter extreme is milder in Northern Hemisphere than summer extreme in southern hemisphere
what are the Milankovic cycles?
changes in Earth’s movement influence climate on predictable short geological time scales
