1. Global Change and a Sustainable Future
Chapter 19

2. Global Change Result of human activities
a. placed increased demands on natural resources
b. emitted greater amounts of gases (CO2, N, and S)
c. agricultural methods
- fertilizers and pesticides
d. challenges of waste disposal, sanitation, and
disease

3. Global Change
a. “changes that occur in the chemical, biological,
and physical properties of the planet”
b. natural causes
ex) Global temperatures
c. anthropogenic
ex) emissions from coal-burning power plants
and incinerators (release of mercury)

4. Global Climate Change
a. “changes in global climate”
b. natural causes
ex) El Nino
- 3-7 years, alters patterns in
temperatures and precipitation
c. anthropogenic
ex) fossil fuel combustion, deforestation
 Global Warming
* warming of the oceans, landmasses,
and atmosphere

5. The Sun-Earth Heating System
Sun’s energy is very HOT – it is in the form of high energy visible ultraviolet radiation
Earth’s energy is not as hot – infrared radiation, not visible but we can feel it radiating from Earth’s surface

6. Global Warming Potential Duration in Atmosphere
Greenhouse Effect
2 most common gases in atmosphere
a. N2 and O2
b. not greenhouse gases
Global Temperature
a. with greenhouse gases (14C)
b. without greenhouse gases (-18C)
Greenhouse Gas
Global Warming Potential
Duration in Atmosphere
H2O (water vapor) **
<1
9 days
CO2 1
Highly variable
CH4 25
12 years
N2O (nitrous oxide)
300
114 years
CFCs (don’t exist naturally)
1,600 to 13,000
55 to >500 years
Global warming Potential
How much a molecule can contribute to global warming over a period of 100 years relative to a molecule of CO2
Must consider – 1)amount of infrared energy it can absorb and 2) it’s persistence

7. Sources of Greenhouse Gases * natural sources
Volcanic eruptions
CO2, ash (absorbing sunlight)
Decomposition and digestion
CH4 (wetlands, termites)
Denitrification
N2O in low oxygen situations
Evaporation
H2O (land)
Evapotranspiration
H2O (plants)
Decomposition – under high oxygen situations dead organic matter is converted into CO2, but in low oxygen situations there is not enough oxygen to create CO2 therefore CH4 is produced

8. Anthropogenic Source Gas Fossil Fuels CO2 Agricultural practices
CH4 and N2O
Deforestation
Landfills
CH4
Industrial production of chemicals
CFCs
-phased out by Montreal Protocol
- HCFCS introduced but still have high Greenhouse Warming Potential
Agriculture
Overirrigated fields create low oxygen environments similar to wetlands and produce methane and nitrouse oxide
Livestock (digesting the plant matter in their gut)

9. Ranking of Anthropogenic Sources
Gas
Top Sources
CH4
Digestive processes of livestock, landfills, production of natural gas and petroleum
N2O
Soil receiving synthetic fertilizers, manure, nitrogen-fixing crops (alfalfa)
CO2
Burning of fossil fuels (94%)

10. Changes in CO2 and Global Temperatures
Increasing CO2 Concentrations
a. Charles David Keeling
1. Mauna Loa Observatory
2. CO2 levels vary seasonally and increase
from year to year
- seasonal (photosynthesis)
- annual increase (fossil fuels and
deforestation)
Charles – first to test assumptions that CO2 has been increasing

11. Developed v. Developing
a. consumption of fossil fuel is greatest in
developed (leads to greater production of CO2)
b. Emitter of CO2
1. China
2. U.S.
c. per capita of CO2
1. Australia
3. Canada

12. Global Temperatures Since 1880 a. 1880 – 2009
- increase of 0.8C (1.4F)
Global Temperatures the past 400,000 years
a. indirect measurements used
1. species composition (foraminifera)
2. chemical analysis of ice
b. rapid increase of CO2 in past 50 years
c. CH4 and N2O in addition to CO2 rose
dramatically (Industrial Revolution)
Formaminifera
Tiny marine organisms whose hard shells resist decay afer death and they build up in sediments
Rock strata
Different species of fora. Prefer different water temperatures
Scientists can infer the dominant species in the rock strata as well as the temperature of the ocean at the time the sediment was deposited (this allows insight on the varying temperature changes over millions of years
Chemical analysis of ice
In the antartic and himalayas snowfall compresses to become ice
Ice strata
In the compressed ice are air bubbles which contain samples of the atmosphere at the time the ice was formed
Scientists can measure the concentration of greenhouse gases that are trapped in the air bubbles

13. Feedbacks Increasing or Decreasing Impact of Climate Change
Positive Feedback Loop
a. intensifies change
ex) rise in temperatures
Negative Feedback Loop
a. dampens change
ex) plants response to increases in
atmospheric carbon
Positive
Higher temperatures increase activity of decomposers in soils leading to release of additional CO2
Negative
Photosynthesis requires CO2, an increase in CO2 stimulates plant growth causing more CO2 to be removed from the atmosphere
This allows the co2 and temperature increases to be super small compared to what they could be

14. Consequences due to Global Warming
Impact of Global Warming
Effect Global Warming has it
Polar Ice Caps
Large openings in the ice
Over next 70 years, Arctic warm by (4C-7C)
Glaciers
Melting (lack of reliable water supply)
Ex) Glacier National Park
Permafrost
Melting; Tundra and Boreal Forests
Shrinks lakes, unstable surface for structures, release of CH4
Sea Levels
Increase in total volume due to melting of glaciers and ice sheets, ocean becomes warmer and expands
Potential flooding of low-lying land
Heat Waves
* Increased energy demand for cooling, risk of death, damage to crops, increases use of irrigation
Precipitation Patterns
* Warmer temperatures drive increased evaporation from Earth’s surface
Diseases
* Warmer temperatures allow for easier spread of disease geographically (ex-West Nile)
Polar ice caps
Large openings in ice
- benefit – creates new shipping lanes for ships reducing the distance they have to travel
- creates easier access to the undiscovered oil and natural gas that lies below the polar ice caps
Glaciers
Park in NW Montana used to have 150 glaciers in 1850 but now has only 25
Glaciers provide water source for communities
Thye used to melt in the spring/summer and grow back during the winter but summers are too warm now that they are melting faster than they can grow back
Permafrost
Lakes shrink due to the lake water drained deeper into the ground as the permafrost is melting
Organic matter in the tundra begins to decompose in wet soils under low-oxygen conditions therefore releasing methane
Diseases
* Diseases that are temperature limited can spread further into new areas as it gets warmer

15. Kyoto Protocol Control emissions of greenhouse gases
Countries agreed to different levels of emission restrictions
Grounded on precautionary principle
- reducing emissions
- removing CO2 from atmosphere
* carbon sequestration
U.S. has not yet ratified the agreement