Before 1950, atm. CO 2 values come from ice cores. Scholander made first measurements of gases in icebergs in Baffin Bay in 1950’s.
The National Ice Core Laboratory in Denver, Colorado
Depth Bubble Close- Off Region Free Atmosphere Glacier Surface Issues: 1)Ice age - gas age 2)Trapped gases are ave. 3) Gravity and thermal frac.
Depth Bubble Close- Off Region Free Atmosphere Glacier Surface Convection Zone Static-Air Column Non-diffusive Zone Depth N (‰) 15 0.0 Barometric Equation: Pz = Po(e (mgz/RT))
Bubble close- off region To Waste Density (g/cc) Depth Rubber Bladder Firn Air Sampling Device To Inflate bladder To Flasks Bender Baffle
Using 15 N to assess the depth of bubble close-off in the past Bubble close off is primarily a function of temperature (colder temps -> deeper close off depths). Gravitational fractionation is also a function of temp. Pz = Po(e (mgz/RT)) Age difference between bubbles and surrounding ice is proportional to accumulation rate which is also tied to surface temperature
T=10.4±2 o C
Dry Extraction technique only Numerous labs using different techniques Numerous Antarctic ice cores drilled differently
IPCC 2007 Synthesis report
Sources of CO 2 to atmosphere Weathering reactions H 2 SO 4 + CaCO 3 → CaSO 4 + H 2 CO 3 Fossil Fuel Burning CH O 2 → CO H 2 O Respiration C 6 H 12 O 6 → 2 CO C 2 H 5 OH O Volcanoes emit CO 2 from subducted oceanic sediment
Sinks of Atmospheric CO 2 Increase C org reservoir Increase CaCO 3 reservoir (coral reefs) Store CO 2 in deep ocean Sequestration