Ozone & Global Warming

What’s the difference???

What is Ozone?

Ozone - A variety of Oxygen that has 3 oxygen atoms and is an odorless and colorless gas.

1. O2 + O --> O3

Why is Ozone Important?

It forms an essential layer of concentrated ozone that protects the earth from:

• Ultraviolet (UV) rays radiating from the sun.*** Without the Ozone Shield, UV light would

damage the DNA of plants and animals!!!***

• Ozone is a powerful disinfectant - kills microbes

Ozone( O3) Layer

• Ozone Layer- Is an area on the stratosphere where ozone is highly concentrated.– Over 90% of the ozone resides

here.– This is known as GOOD ozone,

versus BAD Ozone.– Bad Ozone - Ground Level

Ozone - considered a pollutant

Ozone: The Good, The Bad, and Useful

• Good - Stratospheric Ozone (20 miles above us) is helping to protect our eyes and skin from UV radiation.

• Bad - Ground level ozone is harmful to our health.

• Useful - Ozone generators are used in businesses - kills mold and odors

• Useful - Used by the city’s water treatment plant to kill bacteria and microbes in the water that we drink.

Chemicals that Destroy Ozone

• CFC’s (chlorofluorocarbons)– Used as coolants in refrigerators, air

conditioners & aerosol spray cans.– CFC’s will travel up into stratosphere to

ozone layer.– Chlorine will bond with an oxygen atom

and take it away from an ozone molecule.– All that’s left is 2 oxygens (just oxygen gas)

The Break Down (Depletion) of Ozone

• Chlorine breaks apart the ozone, and continues the cycle over and over again.

• UV -->CCl4-->Cl (UV rays break down the CFC and releases Chlorine)

• Cl +O3 --> ClO + O2 (Chlorine and Ozone Combine to release Chlorine Monoxide and Oxygen)

• ClO + O3 --> 2O2+ Cl (Chlorine Monoxide Reacts with Ozone and the process continues)

More on CFC’s

• 1 CFC molecule can destroy 100,000 ozone molecules!

Ozone Hole - Thinning of Stratospheric Ozone over the

poles in the SPRING.How does it form…1. During the dark cold winter, a cold area forms2. Temps below - 80oC, water and nitric acid form

high altitude Polar Stratospheric Clouds3. At the surface of these clouds, CFC’s break

down into Cl24. In spring, sun (UV) breaks down Cl2 into 2 Cl.

This rapidly destroys ozone.

Polar Stratospheric Clouds• High Altitude (12 miles) very cold clouds

that form over the poles. They produce active Chlorine for ozone destruction.

The Ozone Hole

• The Ozone layer above South Pole has thinned by as much as 98%.

Ozone Depletion Effects

• Humans…– UV radiation damages DNA, causes skin cancer,

weakens the immune system, and causes eye damage.

• Plants and Animals..– Plants - interferes with Photosynthesis– Amphibians - death of eggs

• Amphibians lay their eggs in shallow water, too much light destroys their eggs.

– Kills ocean’s phytoplankton• Phytoplankton is a major food source form many marine

organisms, their death causes and increase in CO2 in the atmosphere.

What have we done??• World Conferences

– Montreal Protocol (1987)• Countries would limit use of CFC’s• Copenhagen Denmark (1992)

– Developed Countries would eliminate by 1995.

– CFC production declined to almost nothing!

• But CFC’s stay active in stratosphere for 60-120 Years……

What is the greenhouse effect?

• The warming of the surface and lower atmosphere that occurs when carbon dioxide (CO2), water vapor, and other gases in the air absorb and reradiate infrared radiation.

Greenhouse Effect• Remember: Certain gases in our atmosphere

absorb and trap heat.• The Gases:Carbon Dioxide, water vapor,

methane, many others.• Why it is important: Without the

Greenhouse Effect, the Earth would be too cold for life to exist.

This is what happens to Earth!

Carbon Dioxide Levels

• Levels of CO2 rise and fall throughout year– Low in the summer

(more plants to take up CO2)

– High in winter (many plants die or leaves fall - not able to take in CO2)

Rising CO2 Levels?

• Scientists noticed that CO2 levels were getting higher every year– Winter levels

were getting higher that usual

– Summer Levels didn’t go as low

Could this be bad?

More Greenhouse gases

• The more greenhouse gases in atmosphere, the more heat is trapped.

• This might cause an increase in global temperature.

****Millions of tons of carbon dioxide are released into the atmosphere each year from power plants that burn coal or oil, and cars that burn gasoline. Millions of trees are burned in tropical rainforest to clear the land for farming.

Other greenhouse gases that we are releasing into the atmosphere!

How certain is Global Warming?

A gradual increase of Earth’s temperature.

Many scientists believe it will continue to rise into the 21st century!!

Opposition

• Some scientists believe that the warming is a natural trend that happens often in Earth’s history.

Consequences of Warming Earth

• Melting Ice/Rising Sea Levels

• Change in Global Weather Patterns

• Human Health Problems• Agriculture• Plants/Animal Extinction

Melting Ice/Rising Waters

• Ice caps, Greenland, and glaciers would melt.

• Earth’s water level would rise, flooding low level lands (coasts)

Change in Weather Patterns

• Ocean may absorb more heat– Cause more hurricanes and typhoons– Flooding and droughts

Human Health

• Heat related death increase

• Increase in ground level ozone (respiratory diseases)

• Warm weather breeds mosquitoes which carry diseases

Agriculture

• If droughts occur, crops will die

• High temperatures won’t allow crops to grow.

• Increase need for irrigation, depleting freshwater sources

Plants and Animals

• Cause animals to migrate to different areas, plants to grow in different areas

• Warming ocean temps. would kill phytoplankton (major ocean food source)

• Kill algae, which feed coral reef systems.

Current Findings

• IPCC (Intergovernmental Panel on Climate Change)– During 20th century, average global

temperature increased by 0.6 degrees Celsius.

– Greenhouse gases have continued to rise and Earth’s temp will continue to rise.

What have we done?• Kyoto Protocol

– Developed countries would reduce greenhouse emissions by 2012.– US did not ratify this treaty.

Developed vs Developing

• Many developing countries don’t have technology to produce low emission products.

• Developing countries are going to release half of all greenhouse by 2035

Developed vs. Developing