Environmental Engineering Reference
In-Depth Information
101
Atmosphere
750
7
100
V
e
g
e
tatio
n
Vegetation
Detritus
& Soils
egetation
Det
Fossil
ossil
Fuels
Fos
sil
Fuels
&
Cement
P
roduction
90
Det
ritus
itus
& Soils
Fuels
&
C
e
m
ent
93
& Soils
Cement
Production
Ocean
40 000
2200
2200
Production
fig. 3.2
Global carbon cycle. Fluxes (approximate) and amounts
stored in the three carbon reservoirs in gigatonnes of carbon.
greenhouse modelers. The rest is absorbed by the land
and oceans. Even the part absorbed by the ocean may
cause serious problems. The upper layers of the ocean are
becoming more acid, with uncertain consequences.
Plants take carbon dioxide out of the atmosphere when
they grow, mostly in the spring and summer, and return
most of it to the atmosphere when they decay, mostly in
the fall and winter. Roughly
Gt go back and forth
each year. The ocean dissolves carbon dioxide near the
surface, and transports it slowly into the deep oceans
through the slow natural circulation process. There is also
a biological transport in the oceans through the birth of
plankton which absorb CO
from the air and their death
when the CO
incorporated in their structure sinks into
the depths. Natural evaporation of water vapor at the
ocean surface brings dissolved gases including CO
back
into the atmosphere. Roughly
Gt more carbon goes
into the ocean than comes out, absorbing part of the
increased emissions from human activity.
The CO
that stays in the atmosphere increases the
greenhouse effect. The temperature will increase until a
.
