Natural Forcing Flashcards
Eccentricity - impact of more elliptical vs more circular
More elliptical - further away during N Hem summer - colder/glacials
More circular - closer during summer - hotter - melting - interglacials
Obliquity - range of Earth’s tilit
22-24.5 degrees
Obliquity - impact of increased/decreased tilt
Increased - N Hem more exposed to sun in summer to more heat energy - more melting - interglacials
Decreased - N Hem less exposed to sun in Summer - less melting - glacials
Length of Eccentricity cycle
100,000 years
Length of Obliquity cycle
41,000 years
Length of precession cycle
26,000 years - around
Impact of precession
Can increase/decrease impact of Eccentricity
When N Hem closer towards sun during circular - increased impact
When N Hem closer towards sun during more elliptical - decreased impact
Makes seasonal contrast more extreme in 1 hemisphere and less in the other
What would the average temp be without GHGs
-18 degrees
What do GHGs absorb and re-emmit
Long wave solar energy/IR waves that have been re-radiated from the Earth’s surface
How much can increased sun spots increase the temperature
0.1 degrees
Length of solar activity cycle
11 years
What is it called when sun activity decreases for a sustained period of time
Grand Minimum
How long do Grand Minimums last
10s-100s of years
When was the last Grand Minimum
During the ‘Little Ice Age’ - Maunder Minimum
What gas is produced by volcanic eruptions that decreases the global temperature
Sulfur Dioxide (SO2)
Impact of volcanic ash
Blocks out sunlight - so decreased solar energy - global cooling
Very short term - weeks/months
Impact of volcanoes in the long term
CO2 and increased GHG effect
What recent volcanic eruption was significant + what was the impact
Mount Pinatubo 1991 - caused a 1 degree temp decreased in a year
Due to 20 mil tons of SO2 released
Another volcanic eruption and its impact
Tambora 1815 - 1816 called ‘year without summer’ - cooling
Impact of continental drift
Split from Pangea - so increased land at higher latitudes so decreased temps - increased by albedo
Impact of formation of isthmus of Panama
Cut off ocean circulation between Atlantic and Pacific - forming the Gulf Stream - increased temps in Europe
LT - as a result increased evap so increased precip - this decreased salinity of Arctic and Atlanitc - so decreased downwelling and weakened gulf stream and deep ocean currents changed - triggered Quaternary Ice Age
