What are trends
Global temperature change over a period of time
What are rythms
Repeating cycle of climate
Persistent glaciers
Ice age
Glacial period
Glaciers growing
What’s called global glaciation?
Snowball Earth
Hot house Earth
No persistent glaciers present
Tipping point
Physical/ecological state of an area crossing an irreversible (human time scale) treshold (seuil) of climate forcings
Sun radiation
Helium atoms in the sun forced together as a result of gravity pressure releasing energy, it doesn’t impact intensely the change in temperature (planet warming)
First life involved….
Many methanogens
Cyanobacteria are (first photosynthesizers)
Producing a lot of O2 as a waste product
Where can methanogens live
In oxygen free environment
If O2 replaces CO2 & CH4
It lowers temperature
Huronian glaciation
Cycle of glacial intergalcial period = possible snow ball Earth
Ice Albedo effect
Positive feedback between ice formation and albedo increasing lowering temperature
Earth = tectonically active planet so,
= continental drift and new landmasses formed (their location influence temperature) can cretate new surface rocks
Higher latitude
Less energy per area of the Earth’s surface
Lower latitude
Greater concentration of solar thermal energy per area of the Earth’s surface
Does equatorial regions have generally more rainfalls than higher latitudes?
Yes
Tectonic plates can
Mountain-building events:
* Formation of new elevated regions of rock
* Can form from volcanic activity
* Flow of lava resulting in a new mountain formation
* Completely new minerals form from cooling lava
* New rock exposed to the surface for chemical weathering
Cenozoic period
Several mountain building event (antartic circumpolar event)
Orbital processes
Earth’s movement varying over time
Types of movement change
1- Eccentricity-changing distance between the sun & the earth
2- Obliquity-tilt angle creating difference in solar insolation seasonally
3- Precession-tilt direction
Milankovic cycles
Acted as a major climate forcing during the pleistocene (high insolation during interglacial period)
Pleistocene
Major period of glacial and interglacial moment
