SLIDE 1 The Carbon Cycle: The Carbon Cycle: Ocean and Biosphere Ocean and Biosphere
EES 3310/5310 EES 3310/5310 Global Climate Change Global Climate Change Jonathan Gilligan Jonathan Gilligan
Class #10: Class #10: Wednesday, January 29 Wednesday, January 29 2020 2020
SLIDE 2
Biosphere Feedbacks Biosphere Feedbacks
SLIDE 3 Hydrological Cycle Hydrological Cycle
Transpiration in plants: Roots take water from ground Leaves emit water vapor Evaporation cools the air Can be an important source of water vapor
Image credit: NASA/JPL-Caltech https://climatekids.nasa.gov/heat-islands/
SLIDE 4 Transpiration and CO Transpiration and CO2
Transpiration occurs through “stomata” in leaves Tradeoff: stomata Allow plant to get CO2 Cause plant to lose water More CO2 in atmosphere: Fewer stomata Less transpiration
Image credit: Photo of stomata on duckweed: Micrographia . Diagram of response to CO2: University of California Museum of Paleontology’s Understanding Evolution . http://www.micrographia.com/specbiol/plan/planaq/plaq0100/lemna-01.htm http://evolution.berkeley.edu
SLIDE 5 Carbon Cycle Feedbacks Carbon Cycle Feedbacks
Dead organic matter in ground (leaves, roots, etc.) stores carbon Warming temperatures accelerate decomposition Bacterial/fungal metabolism Huge amounts of dead organic matter in arctic tundra & permafrost Concerns about accelerated greenhouse gas emissions as ground thaws & warms
Image credit: K. Schaefer et al., Environ. Res. Lett. 9, 085003 (2014). doi: 10.1088/1748-9326/9/8/085003
SLIDE 6
CO CO2 in the Atmosphere in the Atmosphere
SLIDE 7
Carbon Chemistry Carbon Chemistry
SLIDE 8 What does the oxidation state tell you about What does the oxidation state tell you about a molecule containing carbon? a molecule containing carbon?
The energy you can get from burning it. Whether the carbon came from natural or human sources. Large oxidation state large greenhouse effect. Large oxidation state small greenhouse effect.
→ →
SLIDE 9 Carbon Carbon
Oxidation states: Oxidation states:
Chemical State Oxidation Simple carbon Bound to oxygen Bound to hydrogen
+2 −1
SLIDE 10 Examples Examples
Chemical Oxidation Name methane long-chain aklane carbon dioxide carbohydrate
CH4 −4 ( )n CH2 −2 CO2 +4 ( O) CH2
n
SLIDE 11 Carbon Carbon
Category Oxidation State Examples Mineral carbon Organic carbon
Energy: Energy:
Negative oxidation greater energy Positive oxidaton lower energy Photosynthesis: Respiration:
> 0 : +4 CO2 ≤ 0 CH4 ( O) CH2
6
: −4 (methane) : (sugar)
→ → + O + energy ⇒ + CO2 H2 ( O) CH2
n
O2 + ⇒ + O + energy ( O) CH2
n
O2 CO2 H2
SLIDE 12 Carbon Carbon
Energy: Energy:
Negative oxidation greater energy Positive oxidaton lower energy Photosynthesis: Respiration:
History of oxidation on earth: History of oxidation on earth:
Buried organic carbon could suck up all the
- xygen in the atmosphere many times over.
→ → + O + energy ⇒ + CO2 H2 ( O) CH2
n
O2 + O + energy ⇐ + CO2 H2 ( O) CH2
n
O2
SLIDE 13 Where is most of the carbon on earth? Where is most of the carbon on earth?
- 1. The atmosphere.
- 2. The oceans.
- 3. Living and dead biomass at the land surface.
- 4. Deeply buried biomass.
- 5. Fossil fuels.
- 6. Carbonate rocks.
SLIDE 14
Carbon Reservoirs Carbon Reservoirs
SLIDE 15 Carbon Reservoirs Carbon Reservoirs
Image credit: D. Archer, Global Warming: Understanding the Forecast
SLIDE 16 Carbon Pathways Carbon Pathways
Image credit: D. Archer, Global Warming: Understanding the Forecast
SLIDE 17
The Planet’s Lungs The Planet’s Lungs
The land breathes 1 year The oceans breathe Hundreds to thousands of years The rocks breathe Hundreds of thousands to millions of years
SLIDE 18
More complete picture More complete picture
SLIDE 19 Complete Carbon Cycle Complete Carbon Cycle
Image credit: NASA Earth Observatory https://commons.wikimedia.org/wiki/File:Carbon_cycle.jpg
SLIDE 20
CO CO2 Over Time Over Time
SLIDE 21 Why the difference in wiggles? Why the difference in wiggles?
Image credit: D. Archer, Global Warming: Understanding the Forecast
SLIDE 22 Northern vs. Southern Hemisphere Northern vs. Southern Hemisphere
Image Credit: Pearson Education, Inc.
SLIDE 23
Fate of CO Fate of CO2 Emissions Emissions
SLIDE 24 Fate of CO Fate of CO2 Emissions Emissions
Image credit: J. Houghton, _Global Warming: The Complete Briefing, 4th ed. (Cambridge, 2009), Fig. 3.4
SLIDE 25 Fate of CO Fate of CO2 Emissions Emissions
Image credit: J. Houghton, _Global Warming: The Complete Briefing, 4th ed. (Cambridge, 2009), Fig. 3.4
SLIDE 26 Fate of CO Fate of CO2 Emissions Emissions
Image credit: J. Houghton, _Global Warming: The Complete Briefing, 4th ed. (Cambridge, 2009), Fig. 3.4
SLIDE 27 Fate of CO Fate of CO2 Emissions Emissions
Image credit: J. Houghton, _Global Warming: The Complete Briefing, 4th ed. (Cambridge, 2009), Fig. 3.4
SLIDE 28 Fate of CO Fate of CO2 Emissions Emissions
Image credit: J. Houghton, _Global Warming: The Complete Briefing, 4th ed. (Cambridge, 2009), Fig. 3.4
SLIDE 29 Fate of CO Fate of CO2 Emissions Emissions
Image credit: J. Houghton, _Global Warming: The Complete Briefing, 4th ed. (Cambridge, 2009), Fig. 3.4
SLIDE 30 Fate of CO Fate of CO2 Emissions Emissions
Image credit: J. Houghton, _Global Warming: The Complete Briefing, 4th ed. (Cambridge, 2009), Fig. 3.4
SLIDE 31
Source of CO Source of CO2
SLIDE 32 Source of CO Source of CO2: O : O2 and and 13
13C
SLIDE 33 Source of CO Source of CO2: : 13
13C and
C and 14
14C
SLIDE 34 Fossil Fuels vs. CO Fossil Fuels vs. CO2
Image credit: W. Knorr, Geophys. Res. Lett. 36, L21710 (2009) doi:
Concentrations match 46% of fossil fuel consumption
10.1029/2009GL040613
SLIDE 35 Assessing the Evidence Assessing the Evidence
Decreasing : produced by burning. Not a mineral source (volcanoes). : must have biological origin. : The fuel must be thousands of years old. Possible sources: Burning billions of tons per year of very old organic matter. Rate of rise matches fossil fuel consumption. Therefore: Dominant source must be fossil fuels.
O2 CO2 / C
13
C
12
CO2 C
14
SLIDE 36
The Oceans BreatheCenturies to Millennia The Oceans BreatheCenturies to Millennia
SLIDE 37 Studying Ancient Climates Studying Ancient Climates
Image Credit: R Mulvaney/British Antarctic Survey
SLIDE 38 Ice Cores Ice Cores
Image credits: Pete Bucktrout/British Antarctic Survey
SLIDE 39 Inside the Ice Core Inside the Ice Core
Image credit: National Ice Core Laboratory
SLIDE 40 Inside the Ice Core Inside the Ice Core
Image credit: Pete Bucktrout/British Antarctic Survey
SLIDE 41
The Oceans Breathe The Oceans Breathe
SLIDE 42
Ice Ages Ice Ages
SLIDE 43 25,000 years ago 25,000 years ago
Image credit: Ron Blakey
SLIDE 44 25,000 years ago 25,000 years ago
Image credit: Ron Blakey
SLIDE 45
Causes Causes
SLIDE 46
Insolation Insolation
SLIDE 47
Question Question
Why would the summer sunlight in the far northern hemisphere be so important?
SLIDE 48 Northern vs. Southern Hemisphere Northern vs. Southern Hemisphere
Image Credit: Pearson Education, Inc.
SLIDE 49
Timing of Ice Ages Timing of Ice Ages
SLIDE 50
Ice Age Feedbacks Ice Age Feedbacks
SLIDE 51
Ice Age Feedbacks Ice Age Feedbacks
Orbital cycles match timing of ice ages Changes in sunlight are too small to explain temperature changes There must be positive feedbacks to amplify them
SLIDE 52 Theory of Feedbacks Theory of Feedbacks
Image credit: J. Hansen et al., Phil. Trans. Royal Soc. A 371, 20120294 (2013) doi:10.1098/rsta.2012.0294
SLIDE 53 Theory vs. Observations Theory vs. Observations
Image credit: J. Hansen et al., Phil. Trans. Royal Soc. A 371, 20120294 (2013) doi:10.1098/rsta.2012.0294
SLIDE 54 Ice-Age Feedbacks: Ice-Age Feedbacks:
Temperature starts to fall Glaciers grow higher albedo drops weaker greenhouse Colder Temperature starts to rise Glaciers retreat higher albedo rises stronger greenhouse Warmer Without and ice-albedo feedbacks, ice-ages couldn’t happen Ice ages can’t happen with today’s levels.
→ CO2 → → CO2 → CO2 CO2
SLIDE 55
