How are we affected by our atmosphere? How is our atmosphere affected by us?

Questions to explore today:

How are we affected by our atmosphere?

How is our atmosphere affected by us?

Absorption of electromagnetic radiation

Why do energies get absorbed at different heights?

Layers of the Atmosphere

Layer heights are NOT TO SCALE

Where the AIR is, and relative pressures...

Composition of Dry Air - ?

Composition of Dry Air

Where our stuff is…

Thinking deeper: Why do you freeze in space if the exosphere is 1700 ͦC?

So what does our atmosphere do for us?

So what does our atmosphere do for us?

Maintains a stable temperature

So what does our atmosphere do for us?

Maintains a stable temperature

Maintains moisture

So what does our atmosphere do for us?

Maintains a stable temperature

Maintains moistureProvides oxygen (and carbon

and nitrogen)

So what does our atmosphere do for us?

Maintains a stable temperature

Maintains moistureProvides oxygen (and carbon

and nitrogen)Blocks harmful

electromagnetic radiation

So what does our atmosphere do for us?

Maintains a stable temperature

Maintains moistureProvides oxygen (and carbon

and nitrogen)Blocks harmful

electromagnetic radiationAnd makes

PROBLEMS IN THE ATMOSPHERE

Problem #1: the Greenhouse effect

Certain gases trap heat energy from the sun in earth’s atmosphere They act like a

greenhouse, keeping earth warm

Natural greenhouse effect keeps earth warm and habitable

Major natural greenhouse gases: carbon dioxide, methane, water vapor, nitric oxide

World population: 7 billionUS population: 300 million , or ~4%, but we emit 20% of C)

Personal footprints in the US

Personal footprints in the US

YOUR TASKS:

1. Examine the effect of our carbon dioxide output on global climate change with computer models

Complete a “carbon footprint” profile with your own family compared to others Graph with Excel Common task!

Add title, too of course

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Problem #2: holes in the ozone layer

The Earth's ozone layer protects all life from the sun's harmful radiation – UVB - but human activities have damaged this shield

Ozone – O3 - is blue and has a strong odor

Normal oxygen - O2 - is colorless and odorless

Human impact: CFCs (found in

refrigerants, solvents, foam blowing agents) damage ozone layer

CFCs banned in in US in 1970s

Jet exhaust produces nitric oxide, which also breaks down ozone

The good news: Natural ozone

production process will heal the ozone layer in about 50 years