Climate Change Flashcards
climate change=
give an example
long-term variations of the average weather conditions experienced in a particular region
example: Edmonton has milder winters than 30yrs ago
global warming=
increase over time in the average temp across the entire planet
example: the planet as a whole is on average 1C warmer than it was in 1880
explain the positive feedback loop of ice melting
ice melts –> albedo decreases because more land is exposed –> more solar radiation is absorbed –> warming –> more ice melts
list 5 factors/ events that can cause climatic shifts
- variations in solar output
- variations in earth’s orbit
- volcanic events
- meteorite events
- anthropogenic greenhouse gas emissions
dust, smoke, and fog in the atmosphere are called ___
They absorb ____ _____
aerosols
shortwave radiation
Clouds alter the amount of sun that makes it to the surface. How?
they reflect shortwave radiation back out
the amount of _____ ____ we receive from the sun varies on a daily, yearly, decadal, centennial, and millennial basis
solar radiation
Changes in ___ ____ _____ (TSI) are caused by changes in activity of ___ and ___
total solar irradiance
sunspots
faculae
sunspots=
dark spots on the surface of the sun in which magnetic forces are very strong and block the hot solar plasma; they are cooler and darker than their surroundings (so absorb more heat)
more sunspots = ___(more/less) faculae = ___ (increased/ decreased) TSI
more
increased (solar output)
what is the average TSI? (total solar radiance)
1368 W/m2
When was the little ice age? Why did it occur?
16th to mid-19th century
- caused by increased volcanic activity and fewer sunspots
Eccentricity=
our orbit around the sun is eccentric (it changes over time)
Regarding Eccentricity;
There is currently a 3% (5million km) difference between perihelion and aphelion
Perihelion=
Aphelion=
This difference equates to a __% difference in the solar radiation reaching the Earth in perihelion vs aphelion
perihelion= closest to the sun
aphelion= furthest from the sun
6%
Earth’s orbit cycles between circular and elliptical about every ___ yrs, from __ (circular) to ___ (slightly elliptical)
100,000yrs
0-0.07
Is the sun ever right in the middle of earth’s orbit?
When is the difference between perihelion and aphelion larger?
no it’s not
The difference b/w perihelion and aphelion increases as eccentricity increases
The obliquity is:
does it change? If so, by how much?
the tilt of the earth
yes
cycles every 40,000 years between 24.5 degrees to 22.1 degrees
What obliquity are we currently at?
high angle=
low angle=
23.5 degrees
high= more extreme seasons (cold winters, hot summers)
low= mild seasons (cool summers, warm winters- ice sheets form here because snow can accumulate during the cool summers)
precession is:
cycle spans___ yrs
changes in the orientation of the Earth’s axis
25,000yrs
precession can alter:
1.
2.
1, the position of the earth with respect to perihelion and aphelion
2. which hemisphere is facing the sun at each point