1. Global Change

2. Global Change
Is the change of any physical, chemical, or biological properties of the Earth
Can include climate change
Change in average weather patterns
Can include global warming
Warming of land, water and atmosphere

3. Sun-Earth Heating System
Solar (ultraviolet) radiation either bounces off the stratosphere or enters the troposphere
Solar radiation heats the planet’s surface and that heat is re-emitted (infrared)
Infrared is either absorbed by greenhouse gases or is lost to space

5. Greenhouse Effect
Is caused by gases in the atmosphere that absorb heat and re-emit it
Traps heat in the troposphere and increases the planet’s surface temperature
Gases can be measured in greenhouse warming potential
How much a molecule can contribute to global warming over 100 years

6. Major Greenhouse Gases
Water Vapor
Most abundant natural greenhouse gas
Carbon dioxide
Methane
Nitrous oxide (N2O)
Chlorofluorocarbons (CFCs)
Solely manmade
Particulates are not a gas, but they do contribute to the greenhouse effect

8. Natural Greenhouse Gas Sources
Volcanic eruptions produce CO2 and particulates
Decomposition of organic matter produces methane and/or CO2
Denitrification (part of nitrogen cycle) produces nitrous oxide (N2O)
Evaporation of water into the air produces water vapor

9. Anthropogenic Greenhouse Gas Sources
Fossil Fuels
Production and burning release CO2
Can also produce methane and particulates
Agriculture
Fertilizers add nitrogen to make N2O
Decomposition of organics releases methane
Landfills
Chemicals
CFCs deplete ozone and retain heat
Deforestation
Removes trees that absorb CO2

11. CO2 and Temperature are Linked
This can be shown by determining historical gas concentrations and temperature and charting them together
Intergovernmental Panel on Climate Change (IPCC) was formed to track these changes
Scientists from UN and World Meteorological Organization

12. CO2 Varies Seasonally
Discovered when atmospheric CO2 concentration monitoring began in 1958 on Mauna Kea
Drops in spring when photosynthesis increases and increases in fall when leaves die
Has shown an overall increase since monitoring began

13. Do the Math p. 526 Projecting future increases in CO2
From 1960 to 2010 CO2 has increased from 320 to 390 ppm
Average annual increase over 40 years?
390 ppm – 320 ppm = 70 ppm
70 ppm CO2/40 years = 1.75 ppm CO2/year
If rate of CO2 increase is 1.4 ppm/year, what will CO2 concentration be in 2100?
1.4 ppm/year x 90 years = 126 ppm
126 ppm ppm = 516 ppm CO2

14. Do the Math p. 526
What will the CO2 concentration be in 2100 at a faster rate of 1.9 ppm/year?
1.9 ppm/year x 90 years = 171 ppm
171 ppm ppm = 561 ppm CO2

15. CO2 Emissions Around the World
Vary greatly among nations
Developed nations produce the most CO2
Should be examined on a nationwide and per-capita basis
Are changing rapidly as populous nations like China and India develop industry and infrastructure

17. Global Temperatures Have been directly measured since the 1880s
Have increased since these measurements began
were 9 of the 10 hottest years on record

19. Determining Ancient CO2 Concentrations and Temperature
Indirect measurements include species composition and chemical analysis of ice cores
Species composition of foraminifera changes as the water temperature changes
When they die their skeletons become part of ocean sediments

20. Ice Cores Air bubbles are trapped in ice in glaciers and ice shelves
These tiny samples provide information about atmospheric gases and temperature
Oxygen isotopes appear more frequently in warmer temperatures
A single core can show 500,000 years of data

25. How do we know temperature change is anthropogenic?
Increased solar radiation would increase heat when the sun shines
Increased greenhouse gases would increase heat when the sun isn’t shining
Patterns of heating show increases that are not correlated to the sun shining

27. Climate Change Models Global warming is a confirmed phenomenon
What remains to be seen is exactly how much the temperature will rise
Models can help us predict what will happen

29. Feedback Loops and Climate Change
Positive feedback
Faster decomposition from warmer temperatures adds more CO2
Melting ice exposes darker soil which retains heat and increases melting

30. Feedback Loops and Climate Change
Negative feedback
Increase in CO2 causes more plant growth, and more plants reduce CO2
Increase in cloud cover causes more solar reflection, and temperatures drop

31. Consequences of Global Warming
Melting polar ice caps and glaciers
Adds large amounts of fresh water to the oceans
Could expose new sources of fossil fuels
Thawing permafrost
Releases methane and CO2
Could make land usable in new ways
Change in precipitation patterns
More water vapor is added to the atmosphere
Some areas get more, others get less

36. Consequences of Global Warming
Rising sea levels
Endanger low-lying human settlements through flooding and polluting groundwater
Increase in heat waves
Can cause drought and increased energy use for cooling
Can increase forest fires
Decrease in cold spells
Increase in tropical pests
Could be good for agriculture

41. Consequences of Global Warming
Increased storm intensity
Warm air holds more water
Change in ocean currents
Influx of fresh water could affect how heat is distributed
Change in distribution and extinction of organisms
Range of cold-tolerant organisms will decrease and heat-tolerant organisms will expand
Reproduction could be affected

42. Consequences of Global Warming
Increase in tropical diseases and other health problems
Mosquito range and population could increase, carrying West Nile and malaria further
Increased heat stroke, asthma, and allergies
Change in agriculture and recreation
Increased land for agriculture
Change in winter tourism

46. The Kyoto Protocol Addresses climate change at the international level
Asked nations to reduce greenhouse gas emissions to 5.2% below 1990 levels by 2012
US 7%, EU 8%, Russia 0%, developing countries 0%

48. Carbon Sequestration Involves taking CO2 out of the atmosphere
Storing carbon in soil or deep underground
Absorption by plants