Global Changes Exam 1

change in 1.0C

equals change in 1.8F

short wavelengths

high frequency

long wavelengths

low frequency

Percent IR energy which reaches the Earths surface

50%

Percent visible energy which reaches the Earth’s surface

40%

Percent UV energy which reaches the Earth’s surface

10%

Flux

the amount of energy in an electromagnetic wave that passes perpendicularly through a unit surface area per unit time

Stefan-Boltzmann Law

The amount of energy radiated is proportional to the temperature of the object raised to the fourth power

Wien’s Law

The hotter the object, the shorter the wavelength of the emitted energy

Inverse Square Law

When distance from an energy source doubles, the intensity decreases by a factor of 1/4

Earth’s current albedo

0.3

Temperature of the Earth without greenhouse gases

-18C 

Observed temperature of Earth with greenhouse gases

15C

Units out of 100 solar radiation reflected by atmosphere

30

Units out of 100 of solar radiation absorbed by atmosphere

25

Units out of 100 solar radiation absorbed by Earth

45

Total units out of 100 emitted back to space by Earth

70

Negative feedback loop

Stable system which resists change following a perturbation

Positive feedback loop

Unstable system which changes further following a perturbation

Forcing

Persistent disturbance of a system

Perturbation

Temporary disturbance of a system

Time delays

Cause negative feedback loops to take too long and a tipping point is reached

Unstable Equilibrium State

Shifts to a new stable state when pushed by a perturbation

Stable equilibrium state

Returns to the original state when pushed by a perturbation

CO2, CH4, H2O

Greenhouse gases abundant on early Earth

Volcanoes

Supplied CO2 to early Earth

Produced by volcanoes and biological processes

CH4 on the early Earth

H2O

Greenhouse gas which is self regulating

The uplift of the Himalayas

Triggered the Cenozoic cooling period by exposing rock which consumed atmospheric CO2 when weathered

Carbonate Silicate cycle

Moves atmospheric CO2 by subducting precipitated carbonates in the ocean over 100-200 million years

Methane had a longer lifetime in the early Earth atmosphere

Due to lower oxygen levels

Anti-Greenhouse Effect

When organic haze caused by an overabundance of methane leads to cooling by blocking sunlight from reaching the surface.

Decreased atmospheric methane and triggered the Paleoproterozoic glaciations after 2.4 BY

Oxygen levels rising

Suess Effect

Global atmospheric levels of 14C and 13C declining due to the burning of fossil fuels

The atmospheric CO2 level before the industrial revolution

280 ppm

The atmospheric CO2 level today

428 ppm

Photosynthesis

Drives the biological pump in surface waters

Respiration

Drives the biological pump in deep waters

Apheloin

Earth is furthest from the sun in orbit

Perihelion

Earth is closest to the sun in orbit

The pull of other planets

Makes eccentricity vary

Eccentricity

Orbit shape

Obliquity

Tilt

Precession

wobble

Present North Star

Polaris

North Star 13,000 year ago, on the other side of precession

Vega

Conditions for glaciation

Low obliquity or seasonal contrast, high eccentricity or long winters, and cold Northern hemisphere summers

Conditions for deglaciation

High obliquity or seasonal contrast, low eccentricity or short winters, and hot Northern hemisphere summers

Causes wind

uneven heating of the earth’s surface

ITCZ

Intertropical Convergence Zone

Direction wind is deflected in the Northern Hemisphere

left, counterclockwise

Direction wind is deflected in the Southern Hemisphere

right, clockwise

Coriolis Effect is caused by

rotation of the Earth

Easterlies or trade winds

Name of winds in the tropics

Westerlies

Name of winds in the midlatitudes

Continentality

Higher variation of climate extremes over land than over oceans