effect of co2 slides

8/9/2019 Effect of CO2 Slides

1/19

Philip S. Lowell, P.E., Ph.D.

James L. Machin, P.E.


2/19

Some say anthropogenic CO2 will disastrouslywarm the earth.

Some say it will have little effect. Who is more likely correct? We will examine

three types of information:

Geologic Record

Radiation

Computer Simulations


3/19

Antarctic ice core (Vostok) data North American ice sheet (glacier) coverage


4/19

http://www.usgcrp.gov/usgcrp/images/Vostok.jpg
http://www.usgcrp.gov/usgcrp/images/Vostok.jpghttp://www.usgcrp.gov/usgcrp/images/Vostok.jpg


5/19

18,000 YR. AGO (GLACIERS =PALE)

14,000 YR. AGO (WATER =DARK)

http://www.museum.state.il.us/exhibits/larson/glacier_maps.html


6/19

12,000 YR. AGO 10,000 YR. AGO


7/19

8,000 YR. AGO

Warming over last18,000 years coincides

with Vostok data.

Rate of retreat ~1,400miles in 10,000 yr, or740 ft/yr.

Thickness decreasedfrom 2 mi -> 0 over10,000 yr, or ~1 ft/yr.


8/19

100,000-yr periods of rapid warming followed byslow cooling over last 400,000 years

Time increment for climate change is not years

or decades, but centuries or millennia Temperature, CO2, and methane all correlated,

with temperature leading by about 800 years CO2 levels higher now than ever Glacial retreat ~740 ft/yr Juneau Icefield Research Program: 5 glaciers

retreated an average of 60 ft/yr 1946-2005. Lessthan historical rate


9/19

What is radiation range of interest? Plancks Radiation Law: black body radiator.

Infrared (IR) is primary range radiated What is not reflected is absorbed or

transmitted CO

2

infrared (IR) spectrum Water vapor transmission spectrum Incident solar IR radiation absorbed by upper

atmosphere


10/19

05001000150020002500300035000

1 .105

2 .105

3 .105

4 .105

40 C

-25 C

Wave number, 1/cm

Radiantflux,

W/s

qmcm

flcm

wN

TKC 40 C( ),

W

m2

cm

flcm

wN

TKC 25 C( ),

W

m2

cm

wN

Effective Range: 300-3500

RadiationFlux,W

/sqmcm


11/19

These peaks fallmostly outside the300-3500 range.

Virtually 100%(none absorbed)

Virtually 0 (allabsorbed)

Inbandfrequencies

Inbandfrequencies


12/19


13/19

CO2, ppm Percent of IRAbsorbed in

Effective Range

Percent Increaseover 350 ppm

Angle from Vertical: 0o 60o 89o 0o 60o 89o

350 89.4 96.2 99.99 0 0 0

450 92.4 97.7 100.0 3.4 1.5 0.01

700 96.3 99.2 100.0 7.7 3.1 0.01


14/19


15/19

Almost all incident radiant energy will beupwelled from the earth as either heat invaporized water or IR radiation

Radiation from the oceans is emitted atfrequencies tuned to absorption by watervapor

Increasing temperature of the oceansincreases atmospheric water vaporconcentration in contact with it (positivefeedback loop)


16/19

Doubling CO2 from 350 to 700 ppm only causes3.1% increase in energy absorption from CO2,which is a small portion of the total energy

absorbed Increase in IR absorbed by CO2 decreases with

increased CO2 concentration

Water vapor is the major greenhouse gas Anything, not just CO2, that causes an increase

in water vapor by an increase in temperature willincrease GHGs (feedback loop)


17/19

Prediction of CO2-caused warming basedsolely on computer simulations

Significant uncertainties

Upwelling air convection currents Ocean currents

Clouds, and weather in general

Simulations better suited to sensitivity thanpredictions

None has been verified against the Vostokdata


18/19

Geologic data indicate natural cooling orwarming and that centuries or millennia arethe proper time scale.

Vostok cores indicate that warming precededCO2 rise by ~800 years.

Since the atmosphere is almost saturated

with respect to IR energy absorption byCO2,increases in CO2 will have a small effect.


19/19

Water vapor is the major greenhouse gas. Computer simulations, the basis of global

warming predictions, have not been verified

against the Vostok data.

effect of co2 slides

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