I. Physical Principles: The foundation & the tools Newton's laws: forces, pressure, motion II. Atmospheric & Ocean Physics: First element of climate and environmental science Atmospheric structure (T, P in "4- D") Winds, Weather, General Circulation, Climate III. Atmospheric & Ocean Biogeochemistry: Second element of climate and environmental science Atmospheric and ocean composition, past and present Human impact, global change IV. Intersection: what we know, would like to know, will never know, and what can we contribute to the debate.
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I. Physical Principles : The foundation & the tools Newton's laws: forces, pressure, motion
IV. Intersection : what we know, would like to know, will never know, and what can we contribute to the debate. III. Atmospheric & Ocean Biogeochemistry : Second element of climate and environmental science Atmospheric and ocean composition, past and present Human impact, global change. - PowerPoint PPT Presentation
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I. Physical Principles: The foundation & the toolsNewton's laws: forces, pressure, motionEnergy: Temperature, radiant energy
II. Atmospheric & Ocean Physics: First element of climate and environmental science
Atmospheric structure (T, P in "4-D") Winds, Weather, General Circulation, Climate
III. Atmospheric & Ocean Biogeochemistry: Second element of climate and environmental science
Atmospheric and ocean composition, past and present
Human impact, global change
IV. Intersection: what we know, would like to know, will never know, and what can we contribute to the debate.
BioGEOCHEMICAL CYCLESBioGEOCHEMICAL CYCLES
• Most abundant elements: oxygen (in solid earth!), iron (core), silicon (mantle), hydrogen (oceans), nitrogen, carbon, sulfur…
• The elemental composition of the Earth has remained essentially unchanged over its 4.5 Gyr history
– Extraterrestrial inputs (e.g., from meteorites, cometary material) have been relatively unimportant
– Escape to space has been restricted by gravity
• Biogeochemical cycling of these elements between the different reservoirs of the Earth system determines the composition of the Earth’s atmosphere and oceans, and the evolution of life
THE EARTH: ASSEMBLAGE OF ATOMS OF THE 92 NATURAL ELEMENTSTHE EARTH: ASSEMBLAGE OF ATOMS OF THE 92 NATURAL ELEMENTS
BIOGEOCHEMICAL CYCLING OF ELEMENTS:BIOGEOCHEMICAL CYCLING OF ELEMENTS:examples of major processesexamples of major processes
Physical exchange, redox chemistry, biochemistry are involved
Surfacereservoirs
HISTORY OF EARTH’S ATMOSPHEREHISTORY OF EARTH’S ATMOSPHERE
Outgassing
N2
CO2
H2Ooceans form
CO2
dissolves
Life forms in oceans
Onset ofphotosynthesis
O2 O2 reaches current levels; life invades continents
red = increased by red = increased by human activityhuman activity
¶ Ozone has increased in the troposphere, but decreased in the stratosphere.
Arrows indicate El Nino events
Notice:• atmospheric increase is ~50% of fossil fuel emissions• significant interannual variability
NOAA Greenhouse Gas records
Ultra-simplified ("toy") model for atmospheric concentrations of CO2, CH4 and other gases:
A) mass balance B) Inputs or Production ("P"), controlled by biogeochemical processesC) Removal or Loss ("L"), at a rate proportional to the amount that is present in the atmosphere (1st order or linear process, for example: dissolving CO2 in the ocean, reacting CH4 with atmospheric hydroxyl radical. 1/L = "Lifetime").
Quantity: C gas concentration in the atmosphere (Gtons C, or ppm; 1 ppm = 2.1 Gtons C globally)
Ultra-simplified ("toy") model for atmospheric concentrations of CO2, CH4 and other gases:
A) mass balance B) Inputs or Production ("P"), controlled by biogeochemical processesC) Removal or Loss ("L"), at a rate proportional to the amount that is present in the atmosphere (1st order or linear process, for example: dissolving CO2 in the ocean, reacting CH4 with atmospheric hydroxyl radical). 1/L = "Lifetime".
Quantity: C gas concentration in the atmosphere (Gtons C, or ppm; 1 ppm = 2.1 Gtons C globally)
The mass balance equation:
Rate of change in the atmosphere = P - L C (units: Gtons/yr)
dC
dt=P −LC
Impulse Approach Steady State
Accumulation Airborne Fraction
Results from a "Toy Model" of human-caused CO2 change
How is the composition of Earth's atmosphere controlled by geochemical and biological processes ?
FAST OXYGEN CYCLE: ATMOSPHERE-BIOSPHEREFAST OXYGEN CYCLE: ATMOSPHERE-BIOSPHERE
……however, abundance of organic carbon in however, abundance of organic carbon in biosphere/soil/ocean reservoirs is too small to control biosphere/soil/ocean reservoirs is too small to control
atmospheric Oatmospheric O2 2 levels levels 2.1 Pg C in CO2 = 1 ppm in atm.
The heavier temperature lines 160,000 BP to present reflect more data points, not necessarily greater variability.
Source: Climate and Atmospheric History of the past 420,000 years from the Vostok Ice Core, Antarctica , by Petit J.R., Jouzel J., Raynaud D., Barkov N.I., Barnola J.M., Basile I., Bender M., Chappellaz J., Davis J. Delaygue G., Delmotte M. Kotlyakov V.M., Legrand M., Lipenkov V.M., Lorius C., Pépin L., Ritz C., Saltzman E., Stievenard M., Nature, 3 June 1999.
Antarctic Ice Core Data
CO2 varies over geologic time, within the range 190 – 280 ppm for the last 420,000 years. The variations correlate with climate: cold low CO2 . Is CO2 driving climate or vice versa?
GLOBAL PREINDUSTRIAL CARBON CYCLEGLOBAL PREINDUSTRIAL CARBON CYCLE
The carbon cycle can be viewed as a set of "reservoirs" or compartments, each characterizing a form of C (e.g. trees; rocks containing calcium carbonate [limestone]).
The cycle of C globally is then represented as a set of transfer rates between compartments.
The total amount of carbon in the atmosphere + ocean + rocks that exchange with the atmosphere/ocean is fixed by very long-term geophysical processes.
Human intervention may be regarded as manipulation of the rates of transfer between important reservoirs.
Inventories in Pg C
Flows in Pg C a-1
1950
1960
1970
1980
1990
Year
History of consumption of fossil fuels.
Emissions have increased by more than 2X since 1970. There rise in the last 5 years has been really dramatic.
But there has not been a corresponding rise in the annual increment of CO2.
In 1970 ~75% of the emitted CO2 stayed in the atmosphere, but only ~40% in 2000.
3800
6500
Global Fuel UseGlobal Fuel Use
7800 in 2005!
8200 in 2007!
Carbon Cycle on Land, Organisms in ocean•Photosynthesis:
CO2 + H2O + light => "H2CO" + O2
•Respiration:
"H2CO" + O2 => CO2 + H2O + energy
Very small fraction of organic matter is stored, on average.
Inorganic Carbon Cycle in the ocean•Dissolution/evasion
CO2 + H2O+CO32− ⇔ 2⋅HCO3
−
Composition of Sea WaterComposition of Sea Water
"alkalinity" defines Σ' Zi [i] : response of H+ and OH- to addition of CO2
Uptake by oceanic mixed layer only (VOC= 3.6x1016 m3) would give f = 0.94 (94% of added CO2 remains in atmosphere)
Global CO2 cycle
compare to ~300 moles CO3=
Observed uptake of fossil fuel CO2 by the oceans
Global CO2 cycle
NET UPTAKE OF CONET UPTAKE OF CO22 BY TERRESTRIAL BIOSPHERE BY TERRESTRIAL BIOSPHERE
(1.4 Pg C yr(1.4 Pg C yr-1-1 in the 1990s; IPCC [2001]) in the 1990s; IPCC [2001])is a small residual of large atm-bio exchangeis a small residual of large atm-bio exchange
• Gross primary production (GPP):
GPP = CO2 uptake by photosynthesis = 120 PgC yr-1
• Net primary production (NPP):
NPP = GPP – “autotrophic” respiration by green plants = 60 PgC yr-1
• Net ecosystem production (NEP):
NEP = NPP – “heterotrophic” respiration by decomposers = 10 PgC yr-1
• Net biome production (NBP)
NBP = NEP – fires/erosion/harvesting = 1.4 PgC yr-1
Atmospheric CO2 observations show that the net uptake is at northern midlatitudes but cannot resolve American vs. Eurasian contributions
CO2 + H2O "H2CO" + O2 Photosynthesis and Respiration
CYCLING OF CARBON WITH TERRESTRIAL BIOSPHERECYCLING OF CARBON WITH TERRESTRIAL BIOSPHERE
Inventories in PgCFlows in PgC yr-1
Relatively small reservoirs Short time scales net uptake from reforestation is transitory...unless resources are managed to preserve
organic matter
6.3 - 7.3Total
1-2Deforestation
5.3Fossil Fuel+ cement
Global CO2 budget (PgC yr-1 ) 1980 – 1990 1990 –2000
Sources
1-2"Missing Sink"
6.3 - 7.3Total
2.1Ocean uptake
3.2Atmospheric accumulation
Sinks
2.1 Pg C = 1 ppm atmospheric CO2 [source: Cias et al., Science 269, 1098, (1995)]
6.5
.5-1
7-7.5
3.2
1.5-2
1.8-2.8
7-7.5
EVIDENCE FOR LAND UPTAKE EVIDENCE FOR LAND UPTAKE OF COOF CO22 FROM TRENDS IN O FROM TRENDS IN O22,,
1990-20001990-2000
Carbon-Climate FuturesCarbon-Climate Futures
Carbon Flux: Ocean to Air
-10-8-6-4-202468
10
1850 1900 1950 2000 2050 2100
Pg
C/y
r
Cox et al (2000)
Friedlingstein et al (2001)
Carbon Flux: Land to Air
-10-8-6-4-202468
10
1850 1900 1950 2000 2050 2100
Pg
C/y
r
Atmospheric CO2
200300400500600700800900
1000
1850 1900 1950 2000 2050 2100
pp
m
1850 1900 1950 2000 2050 210013
14
15
16
17
18
19
20
Global Mean Temperature
Ce
lsiu
s
Vegetation matters! Different models project dramatically different futures using different ecosystem models.
~ 2º Kin 2100
Coupled simulations of climate and the carbon cycle
1950
1960
1970
1980
1990
Year
History of consumption of fossil fuels.
Emissions have increased by more than 2X since 1970. There rise in the last 5 years has been really dramatic.
But there has not been a corresponding rise in the annual increment of CO2.
In 1970 ~75% of the emitted CO2 stayed in the atmosphere, but only ~40% in 2000.
3800
6500
Global Fuel UseGlobal Fuel Use
7800 in 2005!
8200 in 2007!
2007
1
09 m
etr
ic t
on
s o
f C
/ yr
0
.5
1.
1
.5
(source: CDIAC –Trends –updated)
US fossil fuel use
US per capita fossil fuel use
Metric tons C per person
US and World Per Capita Fossil Fuel Use since 1950
Why don't we see a big upswing due to the emergence of economies in China and India ?
China is projected to have exceed US emissions in 2009.
PROJECTIONS OF FUTURE COPROJECTIONS OF FUTURE CO2 2 CONCENTRATIONSCONCENTRATIONS
[IPCC, 2001][IPCC, 2001]
PROJECTED FUTURE TRENDS IN COPROJECTED FUTURE TRENDS IN CO22 UPTAKE UPTAKE
BY OCEANS AND TERRESTRIAL BIOSPHEREBY OCEANS AND TERRESTRIAL BIOSPHERE
IPCC [2001]
C4MIP:coupled climate-biosphere model comparison
(used in IPCC 2007)
US and World Per Capita Fossil Fuel Use since 1950
Japan and Europe…
HIPPO completed the 1st of 5 global surveys in January, 2009
Ne
t E
xc
ha
ng
e (m
ol
CO
2/m
2/s
)
Time (days)3471 3471.5 3472 3472.5 3473
--
-
2001
NEE
R
GEE
-30
-
20
-
10
0
YR
R,
(-1)
*GE
E M
gC/h
a/yr
1992 1996 2000 2004
1012
1416
18
R- GEE
1998
uptake
emission
A
B
C
NE
E M
gC/h
a/yr
1992 1996 2000 2004
-5-4
-3-2
-10
NEEHarvard Forest
1998
A. Eleven years of hourly data for Net Ecosystem Exchange. B. Two days of hourly data. C. 13 years of respiration (R), GEE, and D. 13 years of NEENEE annual sums.
D
Harvard Forest, Petersham, MA. A "typical" New England forest…an artifact!
YR
R,
(-1)
*GE
E M
gC/h
a/yr
1992 1996 2000 2004
1012
1416
18
R- GEE
1998
AG
WB
MgC
/ha
1994 1996 1998 2000 2002 2004
102
106
110
93-798 99 00 01 02 03 04
0.0
0.5
1.0
1.5
AG
WI M
gC
/ha
/yr
Year
GE
E 1
200-
1500
1992 1996 2000 2004
-28
-26
-24
-22
More Efficient
1998
uptake
emission
“LUE”1200-1500
Live Biomass
NE
E M
gC/h
a/yr
1992 1996 2000 2004
-5-4
-3-2
-10
NEEHarvard Forest
1998
Long-term changes at Harvard Forest
NH
% o
f lan
d ar
ea in
fore
sts
20
4
0
6
0
8
0
1
00
Year
1700 1800 1900 2000
MA
Fitzjarrald et al., 2001
A legacy: land use change in New England
-5
-4
-3
-2
-1
0 NEE = -1.28 - 0.146 x (yr-1990); R2 = 0.337
Year
1992 1994 1996 1998 2000 2002 2004
10
12
14
16
-1 x GEE
Resp
GEE = 11.1 + 0.363 x (yr-1990); R2 = 0.732
R = 9.82 + 0.217 x (yr-1990); R2 = 0.626
NEE
(Mg-
Cha-1
yr-1)
Mg-
C ha
-1yr
-1
0
20
40
60
80
100
120
Abo
vegr
ound
woo
dy b
iom
ass
(MgC
ha-1)
93 94 95 96 97 98 99 00 01 02 03 04 05
oak
other spp
Year
Rates for growth and for carbon uptake are accelerating in this 80-year-old New England Forest…why is that? Will that continue? How big do North American trees grow?
Non-CO2 Greenhouse Gases
• CH4 – dominated by fossil emissions over USA and much of Canada
• N2O – mostly agricultural emissions
• CO – a mix of combustion and hydrocarbon sources
WRF/STILT/EDGAR model vs data, with gray and green.
Errors used in fitting are + 38 ppbv for the model, and + 23 ppbv for the measurements
Slope = 0.9
σslope = 0.1
EDGAR—2000 confirmed ±10% for CH4 !
This result pertains to urban-industrial sources, which dominate the flight region
OXIDATION STATES OF NITROGENOXIDATION STATES OF NITROGENN has 5 electrons in valence shell N has 5 electrons in valence shell 9 oxidation states from –3 to +59 oxidation states from –3 to +5
HNO3
Nitric acid
NO3-
Nitrate
+5
NO2
Nitrogen dioxide
+4
HONO
Nitrous acid
NO2-
Nitrite
NO
Nitric oxide
N2O
Nitrous
oxide
N2NH3
Ammonia
NH4+
Ammonium
R1N(R2)R3
Organic N
+3+2+10-3
Decreasing oxidation number (reduction reactions)
Increasing oxidation number (oxidation reactions)
Nitrogen: Nitrogen is a major component of the atmosphere, but an essential nutrient in short supply to living organisms. Why is "fixed" nitrogen in short supply? Why does it stay
in the atmosphere at all?
free radical free radical
THE THE NITROGEN CYCLENITROGEN CYCLE: MAJOR PROCESSES: MAJOR PROCESSES