Where has all the Carbon Gone Atmospheric oxygen

Where has all the Carbon Gone? Atmospheric oxygen, carbon fluxes and the implications for climate change. Mark Battle (Bowdoin College) Michael Bender (Princeton) Ralph Keeling (Scripps Institute of Oceanography) Pieter Tans (NOAA/CMDL) Jesse Bastide, Carrie Simonds, Blake Sturtevant, Becca Perry Bates College, 12/3/2004 Funding from: NSF, EPA, NOAA GCRP, BP-Amoco, Bowdoin College

Organizing Principle: 1 topic superficially

Organizing Principle: 1 topic superficially Several topics with vanishing content

Outline: • Context: – Climate Change – CO 2 as an agent of change • Where does the CO 2 go? • How does O 2 tell us this? • The basic answer • A more refined answer • Related work in progress

Why should we care about climate change? “An increasing body of observations gives a collective picture of a warming world…” “…most of the warming observed over the last 50 years is attributable to human activities. ” “ Anthropogenic climate change will persist for many centuries. ” “Emissions of greenhouse gases… continue to alter the atmosphere in ways that are expected to affect the climate. ” IPCC, 2001

Why CO 2? IPCC, 2001

Why CO 2? “ The atmospheric concentration of CO 2 has increased by 31% since 1750. The present CO 2 concentration has not been exceeded during the past 420, 000 years and likely not during the past 20 million years. The current rate of increase is unprecedented during at least the past 20, 000 years. ” IPCC, 2001

Where does anthropogenic CO 2 end up?

Recap: • • The planet is warming Human activities are to blame CO 2 is the primary culprit Future buildup depends on Atm vs. Land vs. Ocean • Land/Ocean partition is tough to measure

The link between O 2 and CO 2 = Land biota + Industry + Ocean O 2 = Land biota + Industry

O 2/N 2 changes are small O 2/N 2 per meg (O 2/N 2 sa – O 2/N 2 st)/(O 2/N 2 st) x 106 1 per meg = 0. 0001% 1 Gt. C = 109 metric tons C = 1015 g C 1 Gt. C from FF 3. 2 per meg O 2/N 2

Graphically…

The Princeton cooperative flask sampling network

Ships of opportunity

Research Vessels

Automatic Air Recovery Device Version ARK-5 In use at: Cape Grim Ka’imimoana Samoa Barrow Sable Macquarie Princeton

Our measurement technique: • IRMS (Finnigan Delta+XL) 32/28 and 40/28 (as well as 44/28 and 29/28) • Custom dual-inlet system • Indirect comparison with standards For more details: Bender et al. , In review

Battle et al. , Science 2000

1991 – 1997 Land sink = 1. 4 ± 0. 8 Gt. C/yr Ocean sink = 2. 0 ± 0. 6 Gt. C/yr Battle et al. Science 2000 (2467 -2470)

Is it really that simple? Heat Biology O 2 = Land biota + Industry + Ocean CO 2 = Land biota + Industry + Ocean

Longer records from more sites…

Longer records from more sites + Solubility correction + Stratification correction Ocean uptake = 1. 7 ± 0. 5 Net Land uptake = 1. 0 ± 0. 6 (1994 – 2002) Bender et al. In review

Summary • • • The climate is changing Anthropogenic CO 2 is to blame O 2 can tell us about the fate of CO 2 The O 2 -CO 2 linkage isn’t trivial We find a substantial terrestrial sink (volatile? ) But the story doesn’t end here…