Geoscience Reference
In-Depth Information
system in global changes requires a study of its dynamics with consideration of
various kinds of information for a long historical period. Of course, it is important
here to reasonably use the respective models and data from the paleocenographic
record. This is only possible with coordination of various programs on study of the
atmosphere-ocean system.
An assessment of the greenhouse effect requires a complex consideration of the
interaction of all processes of energy transformation on Earth. However, in the
diversity of processes (from astronomical to biological) that affect the climate
system on various time scales, there exists a hierarchy in their signi
cance. But this
hierarchy cannot be constant, since the role of some processes can vary in a wide
range of their signi
cance for climatic variations. Consideration of one factor
separately simpli
es an analysis of its impact on climate. In fact, the impact of the
greenhouse effect is determined by an exceeding of surface temperature T
L
over the
effective temperature T
e
. The Earth
'
is surface temperature T
L
is a function of surface
emissivity
κ
. The effective temperature T
e
is a function of emissivity
α
of the
atmosphere-land-ocean system. In general, the parameters
depend on many
factors, in particular, on the CO
2
concentration in the atmosphere. There are a lot of
simple and complicated numerical models where attempts have been made to
parameterize these dependences. Unfortunately, there is not a single model that can
meet the requirements of adequacy and reliably describe the prehistory of the
climatic trends on Earth. Nevertheless, one can state that the greenhouse effect
depends non-linearly on the difference T
L
−
T
e
, that is, on atmospheric turbidity,
especially in the long-wave region. The more CO
2
is in the atmosphere, the stronger
is the atmospheric turbidity. The strongest effect of CO
2
on the atmospheric tur-
bidity is in the long-wave region 12
κ
and
α
18
ʼ
m. This effect is weaker in the wavelength
-
intervals 7
m. It is clear that with the increasing partial
pressure of CO
2
in the atmosphere the role of various bands of CO
2
will grow, and
it means that with the intensi
8, 9
10, 2.0, 2.7, and 4.3
ʼ
-
-
ed CO
2
absorption bands the upward long-wave
radiation
fl
flux will decrease. At the same time, the downward long-wave radiation
fl
flux on the Earth surface will increase. From the available estimates, a reduction of
the upward and increase of the downward
fl
fluxes are estimated at 2.5 and
1.3 W m
−
2
, respectively.
Thus, to estimate the level of the greenhouse effect due to CO
2
and other GHGs
(Table
1.8
), it is necessary to know how to predict their concentration in the
atmosphere, with all feedbacks in their global biogeochemical cycle taken into
account (Watson et al. 2000; Krapivin and Potapov 2007). This problem touches
upon several spheres of science
biogeochemistry, geochemistry, soil science,
ecology, agrochemistry, geology, oceanology, physiology, and radiochemistry. The
present methods of the global ecoinformatics enable one to combine knowledge
accumulated in these
—
fields.
Of course, the global cycle of chemical elements should be studied not only to be
able to assess the climatic consequences of the anthropogenic activity but also to
understand the prospects of the environmental dynamics from the viewpoint of its
quality and possibility of life. Since the cycles of chemical elements in nature are
closely connected with living substance activity, one can single out the geological,
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