A reminder: our prodigious CO2 production

Global Carbon Cycle
•Ocean sequester
~30% of fossil
fuel CO2
•Human
perturbations
overlay large
natural background
C cycle
•Climate responses
and feedbacks of
ocean C sink not
well known
Sabine et al. (2004) SCOPE
Feb 2004 Chemical Oceanography Seminar
3
4
Under IPCC
“Business as
Usual”the pH of
surface sea water
drops by 0.4 pH units
by 2100. CO3= in
surface water drops
by 54% from preindustrial values.
 = [Ca2+][CO32-]
Ksp'
a > 1 ~ Supersaturated
Average Surface Water DIC Increase in 2000 ~ 1.2 µmol kg-1 yr-1
2004 Hatfield Seminar
Air Increase = 1.48 ± 0.05 µatm yr-1; Seawater Increase = 2.48 ± 0.28 µatm yr-1
Dore et al., (2003)
WOCE/JGOFS/OACES Global CO2 Survey
~72,000 sample locations collected in the 1990s
DIC ± 2 µmol kg-1
TA ± 4 µmol kg-1
Sabine et al (2004).
Global
Anthropogenic
CO2 Inventory =
118±19 Pg C
Because the ocean
mixes slowly, half of
the anthropogenic
CO2 stored in the
oceans is found in the
upper 10% of the
ocean.
Sabine et al.
Science (2004)
Column inventory of anthropogenic CO2 that has accumulated in
the ocean between 1800 and 1994 (mol m-2)
Mapped Inventory 106±17 Pg C
+ marginal seas 6± 6 Pg C
+ Arctic Ocean 6± 6 Pg C
Total Inventory 118±19 Pg
C
Sabine et al. Science (2004)
Carbon Changes Between 1800 and 1994
Over the past
200 years, the
ocean has been
the only reservoir
to consistently
take up
anthropogenic
CO2 from the
atmosphere.
Sabine et al.
Science (2004)
Aragonite and Calcite Saturation Depths in the Global Oceans
Scanning electron micrographs of Emiliania huxleyi (left) and
Geophyrocapsa oceanica (right) under conditions of 300 (top) and 780 850 ppm (bottom) pCO2 showing malformed coccospheres at the higher
CO2 levels.
From Riebesell et al. Nature (2001)
2004 Hatfield Seminar
Coccolithophores
Forams
Calcareous algae
Corals
2004 Hatfield Seminar
Pteropods
aragonite
R. W. Gilmer and G. R. Harbison
The effects of increased levels of CO2 on
the dissolution of Clio pyramidata
shells after 4 and 48 hours of exposure.
2004 Hatfield Seminar
From: R. Buddemeier
From: R. Buddemeier
From: R. Buddemeier

Download Report