1. CHAPTER 19
Global Change

2. Is this evidence of global warming?

3. Climate Change Debate?
“The major scientific agencies of the United States — including the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA) — agree that climate change is occurring and that humans are contributing to it.” - EPA

4. Questions Still Up For Debate
Scientists are still researching a number of important questions:
Exactly how much will Earth warm?
How quickly will it warm?
What will the consequences of the warming be in specific regions of the world?

5. Global Change
Global change: any chemical, biological, or physical property change of the planet (ex: cold temperatures causing ice ages)
Global climate change: changes in the climate of the Earth
Global warming: one aspect of climate change, the warming of the oceans, landmasses, and atmosphere of the Earth

7. Greenhouse Effect
When radiation from the sun hits the atmosphere, 1/3 is reflected back
Some UV radiation is absorbed by the ozone layer
Some strikes the Earth and is converted into low-energy infrared radiation
Infrared radiation then goes back toward the atmosphere, where it’s absorbed by greenhouse gases that radiate most of it back to the Earth

9. Greenhouse Gases Water vapor (H2O) Carbon dioxide (CO2) Methane (CH4)
Nitrous oxide (N2O)
Chlorofluorocarbons (CFCs)
Ozone (O3)

10. Global Warming Potential
Certain GHGs are more effective at warming the Earth than others
2 most important factors:
How well the gas absorbs energy
How long the gas stays in the atmosphere
Global Warming Potential (GWP) is a measure of the total energy that a gas absorbs over a particular period of time (usually 100 years), compared to CO2

12. U.S. Greenhouse Gas Emissions in 2010

14. Natural Sources of Greenhouse Gases
Carbon dioxide from volcanic eruptions
Methane from decomposition
Nitrous oxide from denitrification
Water vapor

15. Anthropogenic Sources of Greenhouse Gases
Burning of fossil fuels
Agricultural practices
Deforestation
Landfills
Industrial production (ex: CFCs)

18. U.S. Carbon Dioxide Emissions, By Source

19. Particulate Matter
Aerosols are a subset of air pollution that refers to the tiny particles suspended in our atmosphere
Particles can be both solid and liquid
Light-colored aerosol particles can reflect incoming solar energy
Dark particles can absorb solar energy

20. Greenhouse Effect

21. Radiative Forcing
Energy is constantly flowing into the atmosphere and being absorbed by Earth
Some energy is always radiating back out into space (infrared light)
If:
Energy flowing out > energy flowing in = cooling
Energy flowing out < energy flowing in = warming
Energy flowing out = energy flowing in = no change

22. Radiative Forcing
Energy is constantly flowing into the atmosphere and being absorbed by Earth
Some energy is always radiating back out into space (infrared light)
If:
Energy flowing out > energy flowing in = cooling
Energy flowing out < energy flowing in = warming
Energy flowing out = energy flowing in = no change

23. Radiative Forcing
Energy is constantly flowing into the atmosphere and being absorbed by Earth
Some energy is always radiating back out into space (infrared light)
If:
Energy flowing out > energy flowing in = cooling
Energy flowing out < energy flowing in = warming
Energy flowing out = energy flowing in = no change

24. Radiative Forcing
Radiative forcing is a direct measure of the impact that human activities are having on changing the planet’s climate
Measured in watts per square meter (W/m2) of surface

26. IPCC
The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for the assessment of climate change
Established in 1988 by two United Nations organizations: the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP)
Its mission is to provide the world with a clear scientific view on the current state of knowledge in climate change and its potential environmental and socio-economic impacts
Thousands of scientists and other experts contribute (on a voluntary basis) to writing and reviewing reports, which are reviewed by representatives from all the governments

27. Increasing CO2 Concentrations
David Keeling began measuring CO2 in 1958

28. Comparing Emissions Which country emits the most CO2?
Which country emits the most CO2 per capita?

29. Comparing Emissions

30. CO2 Emissions Per Capita

31. What do you think?
Should developing countries be held to the same CO2 emissions standards as developed countries?
Things to consider:
How did developed countries become so wealthy?
Which countries are to blame for climate change?
Will strict CO2 standards inhibit growth in developing countries?
Will developing countries be able to afford costly new technology?

32. Global Temperature Change
Since 1880, temperatures have increased 0.8°C

34. Global Temperature Change

35. Temperatures & Greenhouse Gas Concentrations in Past 400,000 Years
No one was around thousands of years ago to measure temperatures, so we must use indirect measurements
Changes in species composition
Chemical analysis of ice

36. Ice Cores
Ice cores contain an abundance of climate information – more so than any other natural recorder of climate like tree rings or sediment layers
Although their record is short (in geologic terms), it can be highly detailed and extend back hundreds of thousands of years
This record can include:
Temperature
Precipitation
Chemistry and gas composition of the lower atmosphere
Volcanic eruptions
Solar variability

38. Ice Cores

39. CO2 Concentration Throughout History

40. CO2 Heat Trapping

43. Sediment Cores
Rarely disturbed ocean sediment cores can provide records up to 180 million years ago as new layers of sediment bury and preserve those of the past
Fossilized specimens of microscopic foraminifera can provide clues to the climate conditions during their lives
Some species are only found in certain environments, so we can reconstruct the sea level, ocean, and climate conditions of that period based on our knowledge of foraminifera species

44. Oxygen Isotopes
Ocean water during warmer times has a lower 18O / 16O ratio than ocean water during colder times
Foraminifera incorporate that oxygen into their shells (CaCO3), which accumulate on the ocean floor after they die
We can estimate the water temperature by the ratio of  18O / 16O in fossilized shells

45. Climate Models
Scientists use climate data gathered from the past to help predict the future
Current models predict that average global temperatures will increase 1.8⁰ – 4.0⁰ C (3.2⁰ – 7.2⁰ F) by 2100

47. Battery Drive
Bring in your old batteries to HR and put in the canisters this week

48. Feedback Loops What is a positive feedback loop?
What is a negative feedback loop?

49. Positive Feedback Loop

50. Positive Feedback Loop
We know that an increase in CO2 in the atmosphere causes a greater capacity for warming through the greenhouse effect
Higher temperatures  warmer oceans  oceans release CO2 gas into atmosphere

51. Negative Feedback Loop

53. AP Practice Question
Which statement about feedback loops that occur with climate change is true?
All feedback loops are positive.
All feedback loops are negative.
Increased soil decomposition under warmer temperatures represents a positive feedback loop.
Increased evaporation under warmer temperatures represents a negative feedback loop.
Increased plant growth under higher CO2 concentrations represents a positive feedback loop.

54. Consequences of Global Warming
Melting of polar ice caps, Greenland, and Antarctica
Melting of glaciers around the world
Melting of permafrost
Rising sea levels
Heat waves and droughts
Fewer cold spells
Greater frequency and intensity of storms

55. Melting Ice Caps

56. Melting Arctic Ice Cap

57. Rising Sea Levels

58. Rising Sea Levels

59. Consequences to Living Organisms
Changing growing season for plants can harm animals if they can’t move to better climates
Humans may have to relocate
Diseases, like those carried by mosquitoes, could increase
Economic consequences

60. Controversy of Climate Change
The fundamental basis of climate change (that greenhouse gas concentrations are increasing and that this will lead to global warming) is not in dispute among the vast majority of scientists
What is unclear is how much world temperatures will increase for a given change in greenhouse gases, because that depends on the different feedback loops

62. Kyoto Protocol
In 1997, representatives of the nations of the world went to Kyoto, Japan to discuss how best to control the emissions contributing to global warming
The agreement was that emissions of greenhouse gases from all industrialized countries will be reduced to 5.2% below their 1990 levels by 2012
Developing nations did not have emission limits imposed by the protocol

63. Climate Change Awareness
The Nobel Peace Prize 2007 was awarded jointly to Intergovernmental Panel on Climate Change (IPCC) and Albert Arnold (Al) Gore Jr. "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change"

64. Carbon Sequestration
An approach involving taking CO2 out of the atmosphere
Some methods include storing carbon in agricultural soils or retiring agricultural land and allowing it to become pasture or forest
Researchers are looking at cost-effective ways of capturing CO2 from the air, from coal-burning power stations, and from other emission sources
This captured CO2 would be compressed and pumped into abandoned oil wells or the deep ocean

65. Carbon Sequestration

66. AP Practice Question
Which statement regarding the Kyoto Protocol is true?
Developed and developing nations all agreed to reduce their emission of greenhouse gases
All nations agreed to stop their emission of greenhouse gases
The developed nations agreed to different levels of emission reductions
Developing nations agreed to reduce their emission of greenhouse gases
Developing nations agreed to stop their emission of greenhouse gases

67. What Do You Think? What is the best way to reduce CO2 emissions?
Force people and companies to be more energy efficient and/or to use “green” technologies OR
Allow people and companies to pollute as much as they want, but tax them on how much CO2 they emit