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Science provides the unambiguous answer George White October 2008 Revised July 2009 co2@palisad.com. CO2 Forcing: Fact or Fiction. Many sources of information. Ice Core Data (ppt) Atmospheric Absorption (ppt) Satellite Observations (ppt) Ground Based Observations (ppt)
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Science provides the unambiguous answer George White October 2008 Revised July 2009 co2@palisad.com CO2 Forcing: Fact or Fiction
Many sources of information • Ice Core Data(ppt) • Atmospheric Absorption(ppt) • Satellite Observations(ppt) • Ground Based Observations(ppt) • Biology(ppt) • Physics(ppt)
The Ice Cores • > 400K year history from Vostok • > 800K year history from DomeC • The climate is far from constant • CO2, CH4 and Temperature are all correlated • The data tells us far more than this • What kind of changes are expected? • Which came first, the gas or the heat? • What are the periodic influences?
Data Smoothing • Data samples are intrinsically biased • Recent samples represent short term averages • Ancient samples represent long term averages • Different variables have different sample periods • Integrate samples over N years • Matches short term data to long term data • Matches temperature to CO2 and CH4 • Isolate long and short term periodicity • Isolate long and short term dependency
Correlation Analysis • Simple correlation metric for time Δt from t • Plus 1 when t+Δt changes in the same direction as t • Minus 1 when t+Δt changes in the opposite direction • Cross correlation identifies cause and effect • Auto correlation identifies periodic components • Use smoothing to select long or short term • Variable window to match Δt to sample period
Cross Correlation Analysis • Can identify which of 2 variables changes first • Temperature and CO2 • Temperature and CH4 • CO2 and CH4 • Smoothing is required to normalize variability • Smoothing does not mask cause and effect • Smoothing makes short term dependence apparent
DomeC Cross Correlation • DomeC has finer resolution CO2 measurements • Shows apparent correlation of CO2 to future Temp • Frequently misinterpreted as a causal dependency • Also shows earlier correlation to opposite change • This is an aliasing effect which really indicates • CO2 increase -> Temp Decrease -> Temp Increase • Indicates correlation across a period of unrelated change • Indicates interference from a periodic effect • When smoothing is applied • Same results as Vostok data
Auto Correlation Analysis • Auto correlate temperature • Apparent short term periodic behavior • 200 year DomeC, 300 year Vostok • Seems to be aliasing of seasonal variability • Apply smoothing • Unambiguous 22K, 41K period (Vostok and DomeC) • Modulated peaks are evidence for other periodicity • Related to variability in Earth's orbit and axis • Related to sums and harmonics of this variability • Common to temperature, CO2 and CH4
Combined Effects • The change between 96K and 41K ice ages • Considered by some to be a mystery • When the 41K, 96K and 500K forcing are combined • One can cancel or enhance the other • 96K is weaker, 500K is weakest, 41K is dominant • The pattern is clearly an interference pattern • We are entering a new age of 41K ice ages • Evidenced by current weaker, but longer interglacial • Currently approaching 500K peak • 41K and 96K peaks are separated by about 30K years • Stretching out the current interglacial
Is This Enough Forcing? • Some say that these effects are not strong enough • The periodicity clearly aligns • Magnitudes seem unexpected • 96K is weak, but appears dominant recently • Several 41K peaks have aligned with 96K minimums • This mitigates the magnitude of the 41K effects • There is a feedback effect at work • Hemispheric asymmetry and ice amplification
Atmospheric Absorption • An objective review of atmospheric absorption is all that's required to disprove CO2 forcing • The atmospheric absorption spectrum is known • It has been measured and correlated to theory • Water vapor contributes about 2/3, CO2 is 1/3 • Relatively transparent window from 8μ to 14μ • Weak ozone absorption in the middle • 7.5μ CH4 line on one side, 15μ CO2 line on the other, water vapor continuum absorption throughout
CO2 Absorption • 15u CO2 line absorption • Highly saturated • Energy limited, not concentration limited • Double CO2 • Insignificant increase in width • Primarily decreases mean distance before absorption • Other bands are between 2u and 4.3u • Narrower lines • Significant H2O overlap • Far less energy available to be absorbed
GHG Forcing • The Energy Cycle • CO2 captures 15u surface energy • Collisions transfer energy to other gas molecules • Some energy gets back to the surface • The cycle repeats • Delays the release of surface energy • GHG flux is a circulating flux • Solar flux is an incident flux
Satellite Observations • 25 year history of detailed weather measurements • 10 km surface resolution • 3 hour time resolution • 100% surface coverage • Measurements include • Surface temperature • Cloud temperature • Cloud coverage • Reflectivities
Observed Variability • Global mean temperature varies significantly • +/- 2.1˚ C seasonal variability • +2.1˚ in June, -2.1˚ in December • Sun is closest in early January, farthest in July • Global mean temperature changes oppositely • Indicates dramatic hemispheric asymmetry • Unambiguously supports Milankovitch forcing • Data calibration error around 2001-2002 • This has been misinterpreted as 'evidence' of warming
Hemispheric Differences • Southern Hemisphere • 8˚K Degrees peak to peak variability • 276˚K mean • Northern Hemisphere • 24˚K Degrees peak to peak variability • 280˚K Mean • Equatorial • Small 6 month periodic variability • Clearly illustrates 2001/2002 calibration error
Surface Reflectivity • Northern Hemisphere • Higher mean • More land, less water • More variability • Greater range in surface ice • More time spent during higher reflectivity • More persistent ice coverage • Consequences • Sun closer in Northern summer -> cooler climate • Sun closer in Southern summer -> warmer climate
Where is the Sun Now? • Sun is closest in early January • 3.4% more incident energy than average • Sun is farthest away in early July • 3.4% less incident solar energy than average • Nearly 7% total solar variability over a year • Corresponds to a 4˚C difference in temperature • Peak aphelion/perihelion differences are > 20%