1. Chapter 22: Climate and Climate Change
What is Climate?

2. Chapter 21: Climate and Climate Change
What is Climate?
Climate is the long-term state of Earth’s atmosphere.

3. Climate Characteristics
What are the two main characteristics of an area’s climate?

4. Climate Characteristics
The two main characteristics of an area’s climate are temperature and precipitation.

5. Climate Characteristics
What are three other characteristics of an area’s climate?

6. Climate Characteristics
Number of days and hours of sunlight
Direction, speed, and steadiness of the wind
Occurrence of severe weather conditions

7. Controls on Climate
Temperature
Precipitation

8. Temperatures are generally colder towards the poles
Controls on Climate
Temperature
Precipitation
Latitude
Temperatures are generally colder towards the poles
Areas near the equator and 60 N/S latitude are wet. Areas near 30 N/S and the poles are dry

9. Controls on Climate Temperature Precipitation Latitude
Temperatures are generally colder towards the poles
Areas near the equator and 60 N/S latitude are wet. Areas near 30 N/S and the poles are dry
Elevation
Temperatures colder at higher elevation
Air at higher elevations has less moisture

10. Controls on Climate Temperature Precipitation Latitude
Temperatures are generally colder towards the poles
Areas near the equator and 60 N/S latitude are wet. Areas near 30 N/S and the poles are dry
Elevation
Temperatures colder at higher elevation
Air at higher elevations has less moisture
Nearby Water
Coastal areas have mild climates due to WATER!!!
More precipitation near large water bodies

11. Controls on Climate Temperature Precipitation Latitude
Temperatures are generally colder towards the poles
Areas near the equator and 60 N/S latitude are wet. Areas near 30 N/S and the poles are dry
Elevation
Temperatures colder at higher elevation
Air at higher elevations has less moisture
Nearby Water
Coastal areas have mild climates due to WATER!!!
More precipitation near large water bodies
Ocean Currents
Warm ocean currents warm nearby coast. Cold ocean currents cool nearby coast.
Ocean currents can produce fog.

12. Controls on Climate Temperature Precipitation Latitude
Temperatures are generally colder towards the poles
Areas near the equator and 60 N/S latitude are wet. Areas near 30 N/S and the poles are dry
Elevation
Temperatures colder at higher elevation
Air at higher elevations has less moisture
Nearby Water
Coastal areas have mild climates due to WATER!!!
More precipitation near large water bodies
Ocean Currents
Warm ocean currents warm nearby coast. Cold ocean currents cool nearby coast.
Ocean currents can produce fog.
Topography
Leeward side of mountains warmer than windward side
Windward side of mountains are wetter than leeward side

13. Controls on Climate Temperature Precipitation Latitude
Temperatures are generally colder towards the poles
Areas near the equator and 60 N/S latitude are wet. Areas near 30 N/S and the poles are dry
Elevation
Temperatures colder at higher elevation
Air at higher elevations has less moisture
Nearby Water
Coastal areas have mild climates due to WATER!!!
More precipitation near large water bodies
Ocean Currents
Warm ocean currents warm nearby coast. Cold ocean currents cool nearby coast.
Ocean currents can produce fog.
Topography
Leeward side of mountains warmer than windward side
Windward side of mountains are wetter than leeward side
Prevailing Winds
Air masses delivered from hot or cold regions determine temperature
Air masses delivered from wet or dry regions determine precipitation

14. Controls on Climate Temperature Precipitation Latitude
Temperatures are generally colder towards the poles
Areas near the equator and 60 N/S latitude are wet. Areas near 30 N/S and the poles are dry
Elevation
Temperatures colder at higher elevation
Air at higher elevations has less moisture
Nearby Water
Coastal areas have mild climates due to WATER!!!
More precipitation near large water bodies
Ocean Currents
Warm ocean currents warm nearby coast. Cold ocean currents cool nearby coast.
Ocean currents can produce fog.
Topography
Leeward side of mountains warmer than windward side
Windward side of mountains are wetter than leeward side
Prevailing Winds
Air masses delivered from hot or cold regions determine temperature
Air masses delivered from wet or dry regions determine precipitation
Vegetation
Vegetation affects rate at which Earth heats/cools
Vegetation releases water vapor

15. What are the major climate controls here in La Cañada?

16. Controls on Climate in La Cañada
Temperature
Precipitation
Latitude
Temperatures are moderate
Most precipitation occurs in winter
Elevation
Cooler temperatures up Angeles Crest
More rain falls at higher elevations due to orographic lifting
Nearby Water
Temperatures moderated by nearby ocean
Precipitation comes from Pacific Ocean
Ocean Currents
Our cold California Current keeps temperatures moderate.
Cold ocean current can produce fog and low clouds.
Topography
Prevailing Winds
Winds blow from Southwest off of ocean keeps LC cool. Northeast Santa Ana winds keep LC warm.
Southwest winds bring precipitation. Northeast winds bring clear, dry weather.
Vegetation
Chaparral in hills keeps LC cool at night. Asphalt keeps us hot.
Vegetation releases water vapor

17. What is El Niño?
Warm ocean water makes its way across the Pacific Ocean and reaches our coast around Christmas time. This produces more rainfall in La Cañada.

18. Climate Zones around the World
Subclimate
Description
Polar
Tundra
Icecap
Always cold & dry with short, cool summers
Freezing all year

19. Climate Zones around the World
Subclimate
Description
Dry
Desert: Arid
Semiarid
Very Dry: Evaporation > Precipitation
Dry: Evaporation > Precipitation

20. Climate Zones around the World
Subclimate
Description
Humid Tropical
Tropical Wet
Tropical Wet & Dry
Hot & Rainy most of year
Hot all year with wet & dry seasons

21. Moist mid-latitude with mild winters Humid Subtropical
Climate Zones around the World
Climate Zone
Subclimate
Description
Moist mid-latitude with mild winters
Humid Subtropical
Marine West Coast
Mediterranean
Hot, humid summers & mild winters
Mild and rainy all year
Hot, dry summers. Mild, rainy winters

22. Moist mid-latitude with severe winters Humid Continental Subarctic
Climate Zones around the World
Climate Zone
Subclimate
Description
Moist mid-latitude with severe winters
Humid Continental
Subarctic
Warm summers & cold, snowy winters
Short summers & long, cold, snowy winters

23. Temperature & Precipitation vary greatly with latitude & elevation
Climate Zones around the World
Climate Zone
Subclimate
Description
Highland
None
Temperature & Precipitation vary greatly with latitude & elevation

24. Earth’s Climate Over the Past 400,000 years
Climate Change
Earth’s Climate Over the Past 400,000 years

25. How does Earth’s energy budget affect climate?
Climate Change
How does Earth’s energy budget affect climate?

26. Causes of Climate Change
Earth’s Motions and Milankovitch Cycles: Eccentricity
The shape of Earth’s orbit changes with a period of 100,000 years.

27. Causes of Climate Change
Earth’s Motions and Milankovitch Cycles: Axial Tilt
The tilt of Earth’s axis goes between 22.1 and 24.5 every 41,000 years. The tilt right now is 23.5.

28. Causes of Climate Change
Earth’s Motions and Milankovitch Cycles: Precession (Wobble)
You can think of the Earth as a top that wobbles back and forth. Earth’s axis wobbles with a period of 23,000 years.

29. Causes of Climate Change
Plate Tectonics
Large landmasses near the poles cause temperature differences between the poles and the equator to increase. This usually contributes to global cooling because glaciers on land reflect light. Global warming occurs when there are no large landmasses near the poles.

30. Causes of Climate Change
Sunspot Cycles:
Sunspot cycles occur on 11 year cycles.

31. Causes of Climate Change
Sunspot Cycles:
More sunspots on the face of the sun means that the sun gives off more energy. This translates to global warming.
Fewer sunspots means that the sun gives off less energy. This translates to global cooling and the Maunder Minimum.

32. Causes of Climate Change
Sunspot Cycles:
Sunspot cycles occur on 11 year cycles.

33. Causes of Climate Change
Sunspot Cycles:
Sunspot number prediction through the year 2015.

34. Causes of Climate Change
Volcanic Eruptions:
Dust and sulfur dioxide gas are sent into the stratosphere when volcanoes erupt. Sulfur dioxide reacts with water to form sulfuric acid droplets that remain suspended in the stratosphere for many years. This reflects sunlight and causes global cooling.

35. Causes of Climate Change
Volcanic Eruptions:
Very large volcanic eruptions can cause large amounts of carbon dioxide to be ejected into the atmosphere. Carbon dioxide, as you know, is a greenhouse gas. This can cause global warming. Go here for an LA Times story about volcanic eruptions that caused warming.

36. Causes of Climate Change
Human Effects:
We spoke of these during our viewing of Inconvenient Truth.

37. Causes of Climate Change
Human Effects:
Mr. Gore spoke of the relationship between carbon dioxide emissions and global temperatures.

38. Causes of Climate Change
Human Effects:
Mr. Gore spoke of the effects of human-induced global warming, such as sea level rise.

39. Causes of Climate Change
Human Effects:
The effects of human-induced global warming, such as species extinction

40. Causes of Climate Change
Human Effects:
Mr. Gore spoke of the effects of human-induced global warming, such as storm intensities.

41. Methods for Measuring Climate Change
Sea floor Sediments:
Scientists can use the ratio of Heavy Oxygen 18 to Lighter Oxygen 16 to tell what climate was like in the past. More Oxygen 18 in sea floor sediments means that more glaciers existed when the shells in the sediments formed.

42. Methods for Measuring Climate Change
Glacier Ice Core Samples:
Bubbles of ancient air in samples can be analyzed for carbon dioxide content. Snow that fell on a glacier during a warm period has more heavy Oxygen 18.

43. Methods for Measuring Climate Change
Tree Growth Rings: Scientists can study a tree’s growth rings to determine past climate. Thicker growth rings signify a wetter, cooler period. Thinner growth rings signify a dryer, warmer period.