Why Has Global Warming Paused?

Argonne National Laboratory

March 22, 2013

William HapperPrinceton University

CO2 has been demonized because it allegedly causes

Catsrophic Global Warming

Der Spiegel, Jan. 2013Klimawandel: Forscher rätseln über Stillstand bei Erderwärmung

Mail Online, Monday, March 18

• After a long pause, or slight decline from the dust bowl maximimaof the 1930’s, temperatures started to rise rapidly in the 1980’s.• Temperatures have been stable since about 1998, although CO2 levels have continued to rise.

http://www.drroyspencer.com/latest-global-temperatures/

Satellite temperature measurements show little warming

El Nino

Normal

La Nina

•The earth is almost always warming or cooling.

•A strong warming phase began about 200 years ago, long before CO2 levels began to increase.

From John Muir's notes about his first visit to Glacier Bay in October, 1879.

“Glacier Bay is undoubtedly young as yet. Vancouver's chart, made only a century ago, shows no trace of it, though found admirably faithful in general. It seems probable, therefore, that even then the entire bay was occupied by a glacier of which all those described above, great though they are, were only tributaries.”

John Muir, first President ofThe Sierra Club

From “Travels in Alaska, Chapter X”

http://soundwaves.usgs.gov/2001/07/glacierbaymap.gif

Could much of the warming from1950 to 2000 have been due to natural causes and not CO2 ?

• Solar activity?• Cosmic rays?• Pacific Decadal Oscillation?• Atlantic Meridional Oscillation?• Etc., etc.

Let’s review the basic physics!

The Earth from Space

Atmospheric Circulation

A NASA Website

MODTRAN Radiation Spectrum of Earth

Examples of FTIR Data from a Satellite

Saturation of the CO2 Band

•At current CO2 levels, the radiative forcing of CO2 is not proportional to the concentration, [CO2], but is approximately proportional to ln [CO2]. This is the celebrated “logarithmic response.”

MODTRAN Calculation of T versus C02

Warming from Doubling CO2

(Climate Sensitivity)

Direct Effect of CO2: about 1 C

IPCC “Most Probable”: 3 C

Most of the large discrepancy is due to supposed positive feedback from water vapor.

Even the 1 C may be too big!

2349 cm -1

frequency too high for greenhouse warming

666 cm -1 (Satan’s number) greenhouse warming

1388 cm-1 no changing dipole moment,no absorption or emission

Attenuation Coefficient (e-foldings / length)

N is the number density of CO2 molecules, and seg is the cross section of the transition from a lower state g to an upper state e; Geg is the lineshape function.

Line strength (in cm)

neg = frequency (in cm-1) of the transition, Deg = the electric dipole matrixelement, Eg = lower-state energy, T = absolute temperature, k = Boltzmann’s constant, h = Planck’s constant, c = speed of light, T = absolute temperature.

Partition function

A Lorentzian line shape

meg = collision broadening of line; n = emission/absorption frequency

A Voigt line shape

Normalized line shapes

Hedy Lamarr Frequency-Hopping Patent(to defeat torpedo-jamming by Nazi ships)

• Lamarr-Anthiel system hopped over 88 frequencies (piano keyboard). US Patent 2,292,387

• CO2 can hop to any of several thousand vibration-rotation frequencies at each collision.

Schwartzschild equation for radiant intensity from earth.

Planck brightness

Attenuation rate

Optical depth to space

Downwelling Flux at the Surface

Planck Brightness

Optical Depth from Surface to Altitude z

390 ppm CO2

780 ppm CO2

Using Voigt Profiles IncreasesThe Radiative-Forcing IncrementFrom Doubling CO2 By A Factor

~1.4

But far wing absorption from Voigtprofiles does not exist!

Hartmann, Boulet and Robert, Collisional Effects on Molecular Spectra, Elsevier, 2008

Voigt Line Shapes Don’t Work in Far Wings!

Mail Online, Monday, March 18

Why has global warming paused?

• Qualitatively, more CO2 almost certainly causes some warming.• Complicated physics makes it difficult to quantify the warming. • Essentially all of the warming and coolings before 1900 were natural.• Much of the warming of the past century was probably natural.• The radiative forcing from more CO2 has probably been overestimated.• One possible reason, poorly modelled far-wing lineshapes, has been discussed.• Feedback from water vapor and clouds may have been over-estimated too.• Contributions from long term natural cycles have probably been underestimated:

The SunCosmic RaysPacific Decadal OscillationAtlantic Meridional Oscillationetc., etc.

• “I am in revolt against the age-old lie that the majority is always right.”

Henrik Ibsen, An Enemy of the People

Closing Thought