North america in the global carbon cycle
This presentation is the property of its rightful owner.
Sponsored Links
1 / 18

North America in the Global Carbon Cycle PowerPoint PPT Presentation


  • 48 Views
  • Uploaded on
  • Presentation posted in: General

North America in the Global Carbon Cycle. What is the role of North America in the emissions of fossil fuel CO 2 ? What will future trends be?

Download Presentation

North America in the Global Carbon Cycle

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


North america in the global carbon cycle

North America in the Global Carbon Cycle

  • What is the role of North America in the emissions of fossil fuel CO2? What will future trends be?

  • What is the role of North American vegetation in the global carbon cycle? Why do we think there is a vegetation sink, and what may the course be in the future?

  • How can we understand and monitor North American sources and sinks of CO2 and CH4?


North america in the global carbon cycle

Antarctic Ice Core Data

The heavier temperature lines 160,000 BP to present reflect more data points for this time period, not necessarily greater temperature variability.

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.


North america in the global carbon cycle

Global CO2 cycle


Global fuel use

Global Fuel Use

7800 in 2005!

6500

1990

1980

1970

3800

Historical consumption of fossil fuels.

Emissions have increased by 2X since 1970, 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.

1960

1950

Year


Recent growth in atmospheric co 2 concentrations

RECENT GROWTH IN ATMOSPHERIC CO2 CONCENTRATIONS

Year-to-year change in CO2 (ppm)

(SPO+MLO)/2

3.0

2.5

2.0

1.5

1.0

0.5

0.0

60

62

64

66

68

70

72

74

76

78

80

82

84

86

88

90

92

94

96

98

00

02

The average annual increase did not change much between 1970 and 2000, despite significant increases in fossil fuel emissions.

Starting year

0.8

0.6

CO2 Airborne Fraction

Average rate of increase per year, 1.5 ppm = 3.25 x 109 tons/yr—little change (some variations) since 1975, but possibly starting to rise by 2005.

0.4

0.2

0.0

60

62

64

66

68

70

72

74

76

78

80

82

84

86

88

90

92

94

96

98

00

Starting year


North america in the global carbon cycle

Changes in oxygen track the role of the land vegetation vs. ocean uptake ofanthropogenic CO2.

Land uptake may have decreased at the end of the 1990s, after having increased in the early 1990s.

(Manning and Keeling et al., 2006)


North america in the global carbon cycle

Global CO2 budget (PgC yr-1 ) 1980 – 1990 1990 – 2000

6.5

.5-1

7-7.5

Sources

3.2

1.5-2

1.8-2.8

7-7.5

Sinks

2.1 Pg C = 1 ppm atmospheric CO2[source: Cias et al., Science 269, 1098, (1995)]

  • Is this budget accurate? What is the scientific basis for these numbers?

  • Why should mid-latitude terrestrial plants absorb anthropogenic CO2? When did this uptake begin, can/will it continue?

  • What are the implications of terrestrial uptake for

     Future CO2?  US policy?  Climate change?


North america in the global carbon cycle

Atmospheric release of CO2 from burning of fossil fuels will likely give rise to a marked increase in ocean acidity, as shown in this figure. (upper) Atmospheric CO2 emissions and concentrations, historical (—) and predicted (---), together with changes in ocean pH based on mean chemistry. The emission scenario is based on the mid-range IS92a emission scenario assuming that emissions continue until fossil fuel reserves decline.

10 0.1=25% 100.7 = 5 (!) increase in [H+].

The ocean’s capacity to take up CO2 will diminish with time, as the pH of the ocean declines due to uptake of CO2. The ocean becomes acidified.

Uptake of CO2 by chemical dissolution is limited by the rate for exchange between deep ocean water and surface water, and eventually, by acidification of the oceans. Acidification of the ocean is likely to lead to major shifts in marine ecosystems.


North america in the global carbon cycle

Regional ocean- and land-atmosphere CO2 fluxes, 1992–1996.

Orange:Bottom-up land-atm. flux[Pacala, et al., 2001; Kurz and Apps, 1999 N. America; Janssens, et al., 2003, Europe; (Shvidenko and Nilsson, 2003; Fang, et al., 2001, for North Asia];

Cyan:Bottom-up oceanfluxes(Takahashi, et al., 2002),

Blue = ocean-atmosphere fluxes, inverse models,

Green = land-atmosphere fluxes, inverse models,

Magenta = land plus ocean inversion fluxes,

Red: fossil fuel emissions, subtracted from net.

Source: P. Ciais, 2006


North america in the global carbon cycle

Uptake of CO2 in the US (PgC yr-1) [Pacala et al., 2001]

US "forests": Net sink: 0.3-0.6 PgC yr-1

Emissions (1996): US 1.44

Mexico 0.09

Canada 0.11

Forests in the US – and many other places – are in middle to young age classes (25-75 years), due to changes in agriculture (intensification) and forest management (intensification).


North america in the global carbon cycle

A legacy: land use change in New England

MA

NH

% of land area in forests

20 40 60 80 100

Year

1700 1800 1900 2000

Fitzjarrald et al., 2001


North america in the global carbon cycle

NEE = -1.28 - 0.146 x (yr-1990); R2 = 0.337

0

-1

-2

NEE (Mg-Cha-1yr-1)

-3

-4

-1 x GEE

-5

GEE = 11.1 + 0.363 x (yr-1990); R2 = 0.732

Resp

16

R = 9.82 + 0.217 x (yr-1990); R2 = 0.626

120

oak

other spp

14

Mg-C ha-1yr-1

100

12

10

80

1992

1994

1996

1998

2000

2002

2004

Aboveground woody biomass (MgCha-1)

60

Year

40

20

0

93

94

95

96

97

98

99

00

01

02

03

04

05

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?


North america in the global carbon cycle

20 30 50 cm

Changing climate and C: an example from NOBS flux site, Thompson, MB

PEAT

45% cover

Snow cover

Temperature


North america in the global carbon cycle

Thompson, MB

60

40

20

NEE (kgC/ha/yr)

0

-20

-40

85

90

95

100

105

110

115

P2 (mm/2yr)

(gC m-2 yr-1)

Uptake | emission

r2=.72 p<.0035 slope=-3.5

Precipitation (mm in 2 yr)

Net CO2 echange

Annual NEP, 1994-2004

-15 0 15 -2 0 2 -50 0 50

T : warmer

Annual T anomaly (oC)

Water table depth and hydrology are key factors controlling the accumulation or ablation of peat.

Precip: wetter

Annual Precip Anom (mm)

95 96 97 98 99 00 01 02 03

Year

Deviation from the 9-year means of annual Net Ecosystem Exchange (upper, g C m-2 ), temperature (middle, C), and two-year precipitation sums (lower, cm), illustrating the critical role hydrology plays in determining the annual carbon balance at a mature black spruce forest.


North america in the global carbon cycle

Daily respiration, g C m-2

Water table depth, cm

Figure 2: interaction of WT depth and CO2 Flux from the boreal peatland in Manitoba, summer 2002


North america in the global carbon cycle

[base yrs: 1951-1980]

But wasn't the weather unusually cold in 2002-2003? Not over the globe….


Correlation d t d soil moisture index ccsm1 carbon control simulation

Positive correlation  warmer-wetter; or cooler-drier

Correlation: {DT, D soil moisture index}CCSM1-Carbon Control Simulation

DJF

JJA

Negative correlation  warmer-drier; or cooler-wetter

slide courtesy Inez Fung [I. Fung, S. Doney, et al.]]


North america in the global carbon cycle

  • Summary

  • The North American Carbon Program will:

  • measure the large sink for fossil fuel CO2 that appears to be operating in the region

  • determine why this sink exists, and define the controlling factors (temperature, precipitation, legacies, CO2, nutrients, …) quantitatively.

  • enable projections of future trajectories

  • support decision makers in dealing with key global change issues through management and policy options.


  • Login