exam 4 Milankovitch Cycles & The Ozone Story

define Milankovitch Cycles

Periodic and consistent variations in Earth's orbit
around the sun (eccentricity) and around its axis
(obliquity & precession), affecting the distribution of
solar radiation reaching Earth causing climatic changes

what temp during peak ice age

46F

what temp of current global average

57F global average

is there a hole in the Ozone

NO. What we actually observe is a thinning of the Ozone
layer in the Stratosphere. Refer to this as Ozone Thinning!

what is the Ozone creation. in science

German chemist, Christian Schonbein
(1839), identified a form of Oxygen gas
(O3) in the atmosphere. He named this gas
Ozone, which in Greek means “to smell’

production of the Ozone in stratosphere

production of Ozone Troposphere

Ozone is created by interaction with UV light, but also the
high energy of lightening can break apart O2 and free oxygen
atoms to become ozone.

production of ground level Ozone

1. also known as bad ozone is not emitted directly into the air, but is created by chemicall reaction between Nix and VOCs in the presence of heat and sunlight

2. Emissions from industrial facilities and electric utilities motor vehicle exhaust gasoline vapors and chemicals solvents are some of the major sources of oxides of nitrogen and volatile organic compounds

Good and BadOzone depend s on what

on
where in the atmosphere it
is located and what is does

Good O3 or ozone does what

absorbs
UV light &
destroys air
pollutants

bad ozone does what

Traps
heat &
contributes to
smog pollution

what are the benefits of a good ozone

sun emits Ultra Violet light and the ozone absorbs about
95% of the harmful UV rays (UV-C, UV-B).

UV-C – Cancer
• UV-B – Cancer
• UV-A – Skin aging,
eye damage, immune
suppression, and can
lead to cancer

what do tanning beds release

emit ≈ 95% UV-A and ≈ 5% UV-B.
They do not emit UV-C.

Harmful Effects of Increased UV Light
Humans

Damages DNA (causes cell mutations)
• Skin Cancer
• Cataracts

Harmful Effects of Increased UV Light
Other organisms

Damages DNA (causes cell mutations)
• Single-celled Organisms?
• Ecosystem Effects?

what are some natural ways ozone thins out

Fluctuations in Sunlight & Temperature
o Sunlight needed to produce Ozone (why?)
o Heat holds Ozone together better than col

human causes of the Ozone thinning

The manufacturing and release of Ozone
Depleting Chemicals (ODC’s)
• CFCs – Chlorofluorocarbons
• HFC’s - Hydrofluorocarbons
• Bromine Gases

Chloroflourocarbons were first
created in

1928 as non-toxic, non-
flamable refrigerants, and were first
produced commercially in the 1930's
by DuPont.

CFS are are in what

Freon
– Coolants
– Refrigerants
– Aerosol Spray Cans
– Cleaners
– Foam Packaging

Role of CFS in Ozone thinning

1 CFC can break
apart 100,000
molecules of ozone.
• Takes up to 20
years to rise up to
Stratosphere.
• CFC’s can last 75 –
111 years.

What is required to create Ozone?

ChatGPT

Requirements to Create Ozone:

1. Sunlight: Ozone is created through the interaction with ultraviolet (UV) light from the Sun.

2. Oxygen Molecules (O2): Ozone formation involves the interaction of oxygen molecules.

What leads to the destruction of Ozone?

1. Ozone-Depleting Chemicals (ODCs):

   • Chlorofluorocarbons (CFCs)

   • Hydrochlorofluorocarbons (HCFCs)

   • Halons

   • Methyl Chloroform

   • Carbon Tetrachloride

   • Hydrobromofluorocarbons (HBFCs)

   • Methyl Bromide

2. Natural Causes:

   • Fluctuations in sunlight and temperature can influence ozone levels.

   • Natural variations may lead to temporary thinning or destruction of ozone.

why Ozone thinning is more pronounced at poles

Sunlight needed to create O3 (no sun, no new
Ozone will be created)
• Destruction is enhanced by colder temperatures
• Wind currents concentrate CFC’s at poles

what is the largest depeletion ever recorded is where and what year

South Pole September 2006

what is the 1978 Montreal protocol

banned production of ozone depleting
substances, particularly CFC’s
• Mostly impacted industrialized countries
• Ozone depletion has declined 20% over
Antarctica since 2005
• Widely viewed as a major environmental
success story