Atmospheric Chemistry

1
Atmospheric Chemistry
Atmospheric Chemistry
2
Objectives

• Know the components of the atmosphere.
• Discuss the different forms of electromagnetic
  radiation emitted by the sun.
• Understand how solar radiation interacts with the
  atmosphere (energy budget).

3
Atmospheric Gases

• 78 N2
• 21 O2
• 1 Ar
• varies H2O
• lt1 CO2
• lt1 CH4
• lt1 ozone, O3 (block UV)

greenhouse gases trap heat
4
Solar Radiation

• Sunlight is mostly
• ultraviolet, UV
• visible light, VL
• infrared, IR

UV
5
Absorption of UV and IR
Ozone absorbs UV
CO2 and H2O absorb IR
6
Energy Budget
IR VL UV

• IR heats air emits to space as IR
• VL reflects back to space or heats surface and
  IR emits to space
• ozone converts UV to IR, emits to space
• energy in energy out
• global temperature stays fairly constant

7
Objectives

• Understand how CO2 affects global temperature.
• Understand how ice core samples show a
  relationship between CO2 and temperature.
• Be familiar with modern data regarding changing
  atmospheric conditions.
• Know which countries/regions produce the greatest
  quantities of CO2.

8
Global Warming

• fossil fuels coal, oil, natural gas
• fossil fuel O2 ? H2O CO2
• greenhouse effect gases such as CO2 or CH4
  absorb IR, act like a blanket, and keep the
  atmosphere warm
• global warming too many greenhouse gases result
  in a warming effect (like adding more blankets)
• global dimming more clouds (from heating and
  smog) reflect VL, result in a cooling effect
• warming gt cooling
• 97 of climatologists say humans play a role in
  global warming. U of Illinois-Chicago Survey

9
Ice Core Data source IPCC

• Trapped air in ice cores reveal CO2 levels.
• Low levels of oxygen-18 in ice lower
  temperatures.
• CO2 and temperature are closely related.

10
Ice core samples taken from two locations 650 km
apart show data is credible
11
Increasing CO2 Levels
CO2 levels up from 315 to 397 ppm (up 26)
1 kg of gasoline makes 3 kg of CO2
US Dept of Energy
12
Global Temperatures
13
Temperature Change

• average up about 0.8o C
• most warming in polar regions

14
Objectives

• Be familiar with the United Nations IPCC
  projections for future global surface temperature
  and sea-level values.
• Understand the affects of sea-level increases on
  coastal regions.
• Be familiar with environmental changes that are
  currently occurring in polar regions.

15
CO2 Level
16
Observations and Projections
17
Temperature Rise
2100 2 3.5 oC warmer (3 5 oF)
18
Observations and Projections
19
Sea-Level Rise
1 m
2100 0.3 1.0 m higher
20
Greenland
Greenlands ice is melting five times faster than
1990s rate. (Science, 2012)
21
Arctic Perennial Ice

• perennial arctic ice cap is 50 smaller than 1980
  
• less ice less reflection more absorption
  more warming

22
A Warmer Montana

• According to Montana DEQ
• reduced snow packless water for irrigation and
  hydroelectric power reduced water quality ski
  industry will be affected
• milder winters!
• changes in crop yields (some up, some down)
• longer/drier forest-fire seasons
• changes in wildlife habitatmay affect hunting
  and fishing, tourism
• Climate Change Montana