1. Climate and Climate Change
So how do weather and climate differ?
How are they the same?

2. It’s time for a foldable!
Make a vertical fold that leaves about 1 inch along one long edge
Make a horizontal fold down the middle, then fold again horizontally into thirds.
Then label it as shown.
Yes, you can borrow the scissors.
Factors That Affect Climate
LATITUDE
ELEVATION
TOPOGRAPHY
BODIES of WATER
GLOBAL WIND
VEGETATION

3. Copy this diagram (and leave an inch or so for other notes)

4. Latitude
The most intense heating is where the sun’s rays strike most directly, at the equator. As solar elevation angle (SEA) decreases, the sun’s energy is spread over a larger area and is therefore less intense, meaning less heating near the poles!

5. Latitude (cont.) POLAR ZONE TEMPERATE ZONE TROPICS TROPICS

6. Elevation
Air temperature decreases with elevation about 6.5°C with every 1000 meters.
The HIGHER the elevation, the COLDER the climate.
Compare Phoenix and Flagstaff

7. Topography
Topographic features such as mountains affect the amount of precipitation that falls over an area.

8. Bodies of Water
Large bodies of water such as OCEANS and LAKES affect the temperature of an area because the water moderates the temperatures of land areas downwind.
The more constant temperature of the water causes the air passing over it to have less temperature change throughout a year than air over land.

9. So for the same latitude, a place downwind from a large body of water has warmer winters and cooler summers than a more inland place.
Compare the average annual temperature ranges of Seattle and Spokane, WA.

10. Global Winds
Atmospheric circulation distributes heat and moisture around the globe. Winds constantly move warm air toward the poles and cool air toward the equator.
Areas of low pressure at the equator and the subpolar regions have cloudiness and associated precipitation.
Areas of high pressure (subtropical highs) at 30 degrees north and south latitude are deserts and dry regions.

11. Vegetation
You know that the kind of vegetation depends on the climate.
But did you know that the vegetation can affect the climate?? Vegetation can affect both the temperature and the moisture patterns for an area.

12. Vegetation influences how much of the sun’s energy is absorbed and how quickly it is released.

13. Water vapor is released into the atmosphere through TRANSPIRATION from plants’ leaves. This influences moisture in the atmosphere.
Stoma in tomato leaf taken with scanning electron microscope (colorized)

14. Transpiration
Different kinds of plants transpire different amounts of water vapor.
An acre of corn gives off about 3,000-4,000 gallons (11,400-15,100 liters) of water each day, and a large oak tree can transpire 40,000 gallons (151,000 liters) per year (that’s 110 gallons each day).

15. Some scientific studies have shown that vegetation releases particles that act as nucleation sites for cloud formation. Such clouds could influence precipitation patterns in a region.
“Terrestrial vegetation and atmospheric photochemistry produce large amounts of fine particles in the atmosphere, thereby cooling Earth's climate.”
reporting on research published in Nature, October 2010

16. “Next to methane, deciduous plants and trees such as oak and maple, are known to be the largest source of hydrocarbons in the atmosphere; an important factor in climate-change.”
In 2009, scientists found a new, tree-released hydrocarbon called isoprene that appears to form aerosols which are an important part of cloud formation. “ ‘Clouds can retain as well as block the heat of the sun, so, if we don't understand what drives the formation of clouds, our climate-models are bound to be less than exact’.”

17. Natural Processes that Change Climate
21.3 Climate Changes
Natural Processes that Change Climate
Set up your notes for three columns like this:
Natural Process
Cause
Effect

18. Volcanic Eruptions
Puts aerosols (volcanic ash, dust, sulfur-based aerosols) into the troposphere
More solar radiation is reflected back into space, so Earth’s lower atmosphere cools for days to years

19. Ocean Circulation
Remember you learned about the El Niño Southern Oscillation pattern in the Pacific.
Can result in short-term climate fluctuations such as increases in precipitation or decreases in precipitation

20. Solar Activity
Cycles in solar activity, such as the 11-year sunspot cycle, correspond to short-term climate changes.
Solar irradiance increases by 0.1% at solar maxima
Warm periods in North America and Europe correspond to the maxima in the sunspot cycle, when the sun is most active

21. Earth Motions
Long term changes in the locations of Earth’s tectonic plates
Result in ocean basins opening and closing and the locations of land masses

22. More Earth Motions
There is a 41,000 year cycle in the tilt of Earth’s axis of 2.4 degrees.
The smaller the tilt, the smaller the temperature differences between summer and winter

23. More Earth Motions
There is a 100,000 year cycle in how elliptical Earth’s orbit is, due mostly to gravitational interactions with Jupiter and Saturn.
However, there is another 100,000 year cycle, the inclination of Earth's orbit up and down relative to its present orbit.
Changes in the shape of Earth’s orbit result in different season lengths.

24. Even More Earth Motions
Scientists don’t understand yet if either or both of these cycles is the cause of the 100,000 cycle in ice ages which has major effects on Earth’s very long-term climate

25. (Put these notes in the bottom row of your table.)
The Greenhouse Effect
(Put these notes in the bottom row of your table.)
What is it? The greenhouse effect is a natural warming of both Earth’s lower atmosphere and Earth’s surface. The major gases involved are carbon dioxide and water vapor which are transparent to incoming solar radiation.
When this energy is absorbed by Earth’s surface and lower atmosphere, it is changed to infrared radiation. The IR is then absorbed by these gases as it is radiated toward space, warming the surface and lower atmosphere.

26. Scientists believe that without the greenhouse effect, it’s unlikely Earth would be warm enough for complex life to have developed here.

27. Human Impacts on Climate
Impact on Greenhouse Effect
Global Warming is
Climate change
Cause
Effect

28. Human Impacts on the Greenhouse Effect
Many scientific studies indicate that human activities for the past 200 years have had a huge impact on the greenhouse effect.
Much of the carbon dioxide added to the atmosphere is due to the burning of fossil fuels, such as petroleum, coal, and natural gas.
The clearing of forests also contributes to the increase of CO2 because this gas is released when vegetation is burned or when it decays.

31. Global Warming
Is Global Warming the same thing as the Greenhouse Effect?
NO! Global warming is the increase of global temperatures as a result of increases in carbon dioxide and other greenhouse gases (such as water vapor and methane) in the atmosphere.
During the 20th Century, Earth’s average surface temperature increased about 0.6°C, and by 2100 scientists predict temperatures will increase by 1.4°C to 5.8°C.

33. The Earth has experienced many shifts and changes in climate over its 4.6 billion year lifespan due to both the natural causes we already learned about and catastrophes such as asteroid impacts and megavolcano eruptions.
There have been many ‘extinction events’ in Earth’s history where many forms of life died off. There have been many ‘ice ages’.
Compared to these events, how could humans cause much difference to Earth’s climate?

34. Human Impact on Climate Change
Humans have contributed to climate change long before our modern industrial period (last 200 years), by using fire to clear lands, agricultural practices, and overgrazing of marginal lands by domestic animals.
Since the Industrial Revolution, levels of CO2 have risen markedly.
What is controversial is whether human activities are the cause of climate change, and, if so, what we can do about preventing further change that will negatively affect our environment and society.

35. Is There Scientific Consensus on Global Warming?
Yes, 97% of climate scientists agree that humans are causing climate change
Scientific research includes computer models that successfully reproduce temperature data, which means the models are based on a correct understanding of the physical and chemical mechanisms involved.
Statement from 18 science organizations
American Association for the Advancement of Science (127,000 members)
American Chemical Society (160,000 members)
American Geophysical Union (60,000 members)
American Physical Society (48,000 members)

36. What will be the effects of global warming?
Warmer surface temperatures increase evaporation rates increasing the amount of water vapor in the atmosphere. Water vapor is an even better greenhouse gas than carbon dioxide is, magnifying the effect of more CO2.
Sea ice and ice sheets will melt, reducing Earth’s albedo (and increasing the absorption of solar energy at the surface) and raising global sea levels (leading to coastal flooding and shoreline erosion).

37. More effects of global warming
Changes in weather patterns, such as more intense heat waves and droughts in some regions and more intense hurricanes.
Other predicted effects include: warming of the oceans leading to coral reef die off, acidification of the oceans, more frequent and intense wildfires, changes in global ocean circulation, and thawing of permafrost in the polar regions (releasing methane, a powerful greenhouse gas, leading to even more warming).