Transcript Global Change and a Sustainable Future

Global Change and a Sustainable
Future
Chapter 19
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
• 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)
• 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
The Sun-Earth Heating System
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
Sources of Greenhouse Gases
* natural sources
Source
Gas
Volcanic eruptions
CO2, ash (absorbing sunlight)
Decomposition and digestion
CH4 (wetlands, termites)
Denitrification
N2O in low oxygen situations
Evaporation
H2O (land)
Evapotranspiration
H2O (plants)
• Anthropogenic
Source
Gas
Fossil Fuels
CO2
Agricultural practices
CH4 and N2O
Deforestation
CO2
Landfills
CH4
Industrial production of
chemicals
CFCs
-phased out by Montreal
Protocol
- HCFCS introduced but still
have high Greenhouse
Warming Potential
• Ranking of Anthropogenic Sources
Gas
Top Sources
CH4
Digestive processes of
livestock, landfills, production
of natural gas and petroleum
N2 O
Soil receiving synthetic
fertilizers, manure, nitrogenfixing crops (alfalfa)
CO2
Burning of fossil fuels (94%)
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)
• 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
2. U.S.
3. Canada
• 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)
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
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 (4C7C)
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)
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