1. CLIMATE

2. SOME REVIEW…
Weather is the condition in the atmosphere at a given place and time.
Climate describes the long-term pattern of weather at a given location. 
Weather and climate are key components of Earth's energy flow and cycles of matter, especially water, oxygen and carbon dioxide. 

3. CLIMATE
Generally based on
temperature
and moisture patterns

4. Energy and the atmosphere
Heat energy enters the atmosphere from heat absorbed and radiated from the earth, from friction due to winds, volcanic activity and absorption of insolation.

5. Radiation
All bodies of matter radiate electromagnetic energy. The higher the temperature of the radiating body the more energy it will emit and the shorter the wavelength.

6. Energy can be transferred three ways:
Radiation travels as electromagnetic waves and can even pass through empty space. 
Convection occurs in fluids (liquids and gases) and involves density-driven currents.  Warmer, less-dense fluids rise and cooler, more-dense fluids sink. Convection currents are most important in creating weather and moving tectonic plates.
Conduction involves heat energy moving between substances that are touching, such as your hand and a hot pot. 

8. The electromagnetic spectrum describes all of the various types of radiant energy, each of which covers a specific range of wavelengths. (ESRT p. 14)
The Sun's energy reaches Earth as incoming solar radiation (“Insolation”). Most of the insolation is visible light, with lesser amounts of infrared (heat) and ultraviolet waves.

9. INSOLATION
Incoming
solar
Radiation

10. ABSORBTION OF ENERGY:
Dark-colored objects are good absorbers and radiators of heat, and poor reflectors. 
Light-colored objects are good reflectors, but poor absorbers or radiators.
Smooth surfaces are good reflectors and rough surfaces are good absorbers.

11. Energy & Temperature:
Kinetic energy is energy of moving things. The faster they move, the more KE they use.
Temperature is the "average kinetic energy" of an object. 
Potential energy is stored energy.  It increases with mass and as the object gets higher.

12. ALBEDO
The amount of insolation reaching Earth is balanced by the amount reflected back to space (albedo) and the terrestrial re-radiation, mostly as infrared waves.
Radiative balance (equilibrium) occur when the energy emitted by an object is equal to that absorbed by the object.

15. Global and Regional Weather and Climate Systems

16. Local weather is a small part of global and regional weather patterns.
Global wind, pressure, and precipitation patterns result from differences in the amount of energy received at different latitudes and Earth's rotation.

17. Global climate patterns (ESRT p
Global climate patterns (ESRT p. 14) include: wet conditions and calm winds centered around the equator (doldrums); east-to-west winds trade winds in the tropics; zones of calm centered around 30 degrees north and south ("horse latitudes"); west-to-east winds in the mid-latitudes ("prevailing westerly"); and east-to-west winds at high latitudes ("polar easterlies").

18. Additional Climate and Weather Factors
Adiabatic Cooling: As air rises, it cools because it expands and the pressure decreases.
Adiabatic Heating: As air sinks, it warms as it contracts and the pressure increases.
Orographic effect: As air rises up the windward side of a mountain, adiabatic cooling occurs, and as it sinks down the leeward side, adiabatic warming occurs. So the windward side has greater cloud cover and precipitation, and the leeward side often has a rain-shadow desert.

20. Water & Climate:
Water has a higher specific heat value than rocks, so when the same amount of insolation strikes materials at a shoreline, the water will remain cooler and the beach will warm up more rapidly. 
These heating rate differences produce on-shore sea breezes during the day and off-shore land breezes  at night.

21. WARM AIR RISES
COOL AIR MOVES INLAND

22. COOL AIR OVER THE LAND PUSHES OUT TO SEA
WARM AIR RISES

23. Large bodies of water make cooler summers and warmer winters. 
On a regional scale, similar factors create the monsoons, with wet-seasons in summer and dry-seasons in winter. 

24. A long term perspective
Global Climate Change
A long term perspective

25. Global Warming…Truth? Fiction? Both?
CO2 levels in the atmosphere rising
Average global temperature is rising
Polar ice caps and mountain glaciers are shrinking
Sea level is rising
Deserts are expanding
Weather is getting more severe

26. Is this normal?
How can we tell if the present change in climate is normal or something produced by humans?
Is the amount of present climate change normal or is it extreme?
Is there any way to answer these questions?

27. Changing Perspectives
Our perspective: single human life.
We can expand to a few other generations based on research.
We need a longer time frame to evaluate global climate change.
So…how do we do that???

28. The Geologic Record
The evidence contained in the ROCKS of the EARTH for the past 4.6 BILLION years
Provides us with longer perspective
Contains indirect evidence of climate
Contains direct evidence of climate
Gives us a history of global climate change on a scale of millions of years to billions of years.

29. Indirect Evidence Evidence for Recorded by specific types of rocks
Aridity
Warm Climate
Cold Climate
Recorded by specific types of rocks

30. Examples: Desert sandstones

31. Examples: Reef Limestones

32. Examples: Glacial Features

33. Direct Evidence
Ice Cores – a core sample from glaciers that have trapped air bubbles from previous time periods
Can contain wind-blown dust, ash, bubbles of atmospheric gas and radioactive substances
Sediment Cores - long cylinders of sediment taken from beneath the surface of the (usually) ocean floor.

34. Ice Cores

35. Data from Ice Cores Direct Evidence for last 100,000 years
Quantities of dust in each layer
Related to wet vs. dry climate
Air bubbles trapped in each layer
Samples of ancient air
Levels of CO2

37. Sediment Cores Deep Sea Drilling Project (DSDP)
Ocean Drilling Project (ODP)
Integrated Ocean Drilling Project (IODP)
Coring in lakes and bogs
contain microscopic fossils of marine animals, volcanic glass, sands originally from land cosmic material, and other unusual materials unique to a marine environment

38. The microfossils are important as time and environmental indicators; they are very sensitive to slight changes in temperature and chemical changes in their environment.
Volcanic glass is an important "time marker" and records instantaneous geological events.
Sands can indicate the presence of ocean currents, tell of ancient shorelines, reveal a past dust storm, or record submarine slides which might indicate submarine earthquakes.
Deep-sea samples hold a permanent record of magnetic history revealing to scientists the ever-changing magnetic orientation of the poles.

39. So…What does the Geologic Record Tell Us?
The “normal” climate of the past 1.0 billion years was…
Warmer than present
More uniform than present (less fluctuation)
Past 20 million years have been highly variable and generally much colder

40. Climate History: 20 Ma to Present
20 Ma – climate was somewhat moderate
Similar to present
5 Ma – coldest climate of past 65 million years
2 Ma – Great Ice Ages begin
At least 4 episodes of glacial advance & melt back
12,000 – 10,000 Modern Climate sets in

41. Recent Climate History
BP - Warm Peak
’s – Medieval Warm Spell
1300’s – Cool and Wet
1550 – 1850 – “Little Ice Age”

42. Food For Thought
How many of the great events of recorded human history have been directly influenced by climate?

43. Recent Climate History
BP - Warm Peak – Great Ancient civilizations (e.g., Mesopotamia, Egypt)
’s – Medieval Warm Spell – Rise of “modern” European nation-states
1300’s – Cool and Wet – Bubonic Plague/Dark Ages
1550 – 1850 – “Little Ice Age”
First Settlers come to America – many deaths
Washington crosses the Delaware
Winter at Valley Forge

44. So, are we to blame?
Paleoclimatic record reveals major shifts in climate through time
Is it coincidence or causation that climate is warming as we come out of last ice age?
Is it coincidence or causation that industrial revolution falls within this same time?

45. What factors cause changes in climate?
Long term vs. short term changes
Volcanic eruptions
Ex: eruption of Krakatau in 1883
Yellowstone supervolcano – 2 MYA, 1.3 MYA, & 630,000 YA
Earth’s orbital variations