1. Understanding Earth Chapter 15: THE CLIMATE SYSTEM Grotzinger • Jordan
Sixth Edition
Chapter 15:
THE CLIMATE SYSTEM
© 2011 by W. H. Freeman and Company

2. Chapter 15
The Climate System

3. About the Climate System
The study of Earth’s climate system is crucial to the well-being of life on Earth.
Consequences of climate system change include global warming, sea-level rise, and unfavorable changes in weather patterns.
There are five main components of the climate system of Earth.

4. Lecture Outline Components of the climate system
2. The greenhouse effect
3. Climate variation
4. The carbon cycle
5. Twentieth century warming: fingerprints of anthropogenic global change

5. ● Climate describes the average surface conditions and their
1. Components of the Climate System
● Climate describes the average
surface conditions and their
variation during daily, yearly, and
long-term cycles of solar heating.
● Climate system includes all parts of
the Earth system and all of the
interactions in space and time.

6. 1. Components of the Climate System

7. ● Atmospheric zones ● troposphere ● stratosphere ● outer atmosphere
1. Components of the Climate System
● Atmospheric zones
● troposphere
● stratosphere
● outer atmosphere

8. Components of the Climate System: Atmospheric Zones

9. ● Atmospheric composition ● molecular nitrogen (78 vol %)
1. Components of the Climate System
● Atmospheric composition
● molecular nitrogen (78 vol %)
● oxygen (21 vol %)
● other gasses (argon, carbon
dioxide, water vapor, ozone,
methane, etc.)

10. ● global ocean (circulates by two major current systems)
1. Components of the Climate System
● Hydrosphere
● global ocean (circulates by two
major current systems)
● continental water (lakes, rivers,
and groundwater)

11. Components of the Climate System: Surface Ocean Currents

12. Components of the Climate System: Thermohaline Ocean Currents

13. ● floating ice, sea ice, and frozen lakes and rivers
1. Components of the Climate System
● Cryosphere
● ice caps and glaciers
● floating ice, sea ice, and frozen
lakes and rivers

14. Components
of the Climate
System:
Sea Ice in the
Bering Strait
(May 2002)

15. ● land surface absorbs and returns solar energy
1. Components of the Climate System
● Lithosphere
● land surface absorbs and returns
solar energy
● topography affects wind and rain
patterns
● volcanism affects atmospheric
dust level

16. ● all organisms living near Earth’s surface ● plants and animals
1. Components of the Climate System
● Biosphere
● all organisms living near Earth’s
surface
● plants and animals
● microbes, marine and
terrestrial

17. Components of the Climate System: Global Distribution of Plant Life

18. ● about 50% as visible light ● infra-red radiation
2. The Greenhouse Effect
● Solar energy output
● about 50% as visible light
● infra-red radiation
● ultra-violet radiation

19. ● Solar radiation energy balance ● annual energy = 342 W / m2
2. The Greenhouse Effect
● Solar radiation energy balance
● annual energy = 342 W / m2
● planet absorbs and radiates
exactly this amount to
maintain this balance

20. Earth’s energy balance

21. ● What if Earth had no greenhouse gasses? ● greenhouse gasses (water
2. The Greenhouse Effect
● What if Earth had no greenhouse
gasses?
● greenhouse gasses (water
vapor and carbon dioxide) trap solar energy
● without these gasses, solar
energy goes back into space

22. ● Earth’s greenhouse atmosphere ● solar energy passes through
2. The Greenhouse Effect
● Earth’s greenhouse atmosphere
● solar energy passes through
● some solar energy is
trapped making our planet’s
atmosphere at least 33ºC
warmer than it would be

23. ● Balancing the system through feedbacks ● positive feedback
2. The Greenhouse Effect
● Balancing the system through
feedbacks
● positive feedback
● negative feedback

24. ● Feedbacks that can significantly affect the temperatures achieved
2. The Greenhouse Effect
● Feedbacks that can significantly
affect the temperatures achieved
by the radiation balance:
● water vapor feedback
● albedo feedback
● radiation feedback
● plant growth feedback

25. 2. The Greenhouse Effect: Feedbacks

26. ● Climate models and their limitations ● general circulation model
2. The Greenhouse Effect
● Climate models and their limitations
● general circulation model
● complex and subject to errors

27. General
circulation
model

28. Thought questions for this chapter
Give an example not discussed in this chapter of a positive feedback and a negative feedback in the climate system.

29. ● Short-term regional variations ● El Niño-Southern Oscillation
3. Climate Variation
● Short-term regional variations
● El Niño-Southern Oscillation
● La Niña

31. ● Climate changes of the past ● long periods of global warmth
3. Climate Variation
● Climate changes of the past
● long periods of global warmth
● intervening cold epochs – the
ice ages

32. ● Wisconsin glaciation ● three other glaciations and
3. Climate Variation
● Pleistocene ice ages
● Wisconsin glaciation
● three other glaciations and
intervening interglacial warm
intervals

33. Changes in global climate – last 1.8 m.y.

34. Vostok
ice core:
data and
its meaning
for climate
history

35. ● Milankovitch cycle theory ● Pleistocene alternation between
3. Climate Variation
● Milankovitch cycle theory
● Pleistocene alternation between
glacial and interglacial is best
explained by this theory
● three other glaciations and
intervening interglacial warm
intervals

36. ● eccentricity (100,000 years) ● tilt (41,000 years)
3. Climate Variation
● Milankovitch cycles
● eccentricity (100,000 years)
● tilt (41,000 years)
● precession (23,000 years)

37. 3. Climate Variation: Milankovitch Cycles

40. ● Permian-Pennsylvanian ● Ordovician ● Proterozoic (twice)
3. Climate Variation
● Ancient ice ages
● Permian-Pennsylvanian
● Ordovician
● Proterozoic (twice)

41. ● Short-term variations ● 1000-year cycles imposed on longer cycles
3. Climate Variation
● Short-term variations
● 1000-year cycles imposed
on longer cycles
● 30 to 50 year global changes

42. Thought questions for this chapter
Do Milankovitch cycles fully explain the warming and cooling of global climate during Pleistocene glacial cycles?

43. ● Carbon dioxide levels in atmosphere
4. The Carbon Cycle
● Carbon dioxide levels in atmosphere
● 280 parts per million before the
industrial revolution
● 370 parts per million in 2000
● Should be higher – something is
removing some of the carbon

44. ● Geochemical cycles – how they work ● Geochemical reservoirs
4. The Carbon Cycle
● Geochemical cycles – how they work
● Geochemical reservoirs
● Residence time
● Chemical reactions
● Transport across interfaces

45. Transport processes between components of the climate system

46. ● Example – the calcium cycle ● calcium enters reservoir through
4. The Carbon Cycle
● Example – the calcium cycle
● calcium enters reservoir through
rivers of the world + dust
● sedimentation of calcium
carbonate
● calcium residence time is long
(600,000 yr)

47. The calcium cycle, showing fluxes into and out of the ocean

48. ● Earth’s carbon budget ● Air-sea gas exchange
4. The Carbon Cycle
● Earth’s carbon budget
● Air-sea gas exchange
● Photosynthesis and respiration
in the terrestrial biosphere
● Dissolved organic carbon
● Carbonate weathering and
precipitation

49. 4. The Carbon Cycle

50. ● Human perturbations of the carbon cycle ● humans add carbon to
atmosphere
● plants and air-sea gas
exchange removes some of it
● there is a net annual increase

51. Human perturbations of the carbon cycle

52. ● Human fingerprints of global change ● Twentieth-century warming
4. The Carbon Cycle
● Human fingerprints of global change
● Twentieth-century warming
● fossil fuel burning
● deforestation
● Enhanced greenhouse effect

53. Thought questions for this chapter
Draw a simple diagram of the geochemical cycle for the element sodium, which is found in marine evaporites (like halite) and clay minerals as well as dissolved in sea water.
What would the carbon cycle have looked like after life had originated but before photosynthesis had evolved?
How would the calcium cycle be affected by a global increase in chemical weathering?

54. 5. Twentieth-Century Warming

57. Thought questions for this chapter
If human activities keep pumping carbon dioxide into the atmosphere at a steadily increasing rate and Earth warms significantly in the next 100 years, how might this affect the global carbon cycle?
Why are scientists reasonably sure that most of the twentieth-century warming was due to changes in the climate system caused by human activities?

58. Key terms and concepts Carbon cycle Climate model Climate system
Albedo
Carbon cycle
Climate model
Climate system
El Niño
ENSO
Geochemical cycle
Geochemical reservoir
Glacial cycle
Greenhouse effect
Greenhouse gas
Ice age
Interglacial period
Milankovitch cycle
Negative feedback

59. Key terms and concepts Positive feedback Residence time Solar forcing
Ocean acidification
Positive feedback
Residence time
Solar forcing
Stratosphere
Thermohaline circulation
Troposphere
Twentieth-century warming