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deforestation cannot be estimated uniquely. Clearly, a single correct way to solve
the principal problem and the respective partial problems is to make a detailed
inventory of the forest ranges and to use the obtained data in the global model. The
speci
c features of this inventory should be determined in an adaptive regime of
using the model, gradually changing the spatial-temporal scales, starting from the
known model with a mean-annual time step and the one of geographical grids
4
°×
5
°
,1
°×
1
°
or 0.5
°×
0.5
°
.
5.4.3 Observational Data
Analysis of observational data is reduced, as a rule, to the consideration of two
categories of information:
(1) SAT changes for the last 1.5 century (and especially during the last 20
-
30 years, when an increase of the global mean annual mean SAT was at a
maximum).
(2) Paleoclimatic changes. They attract attention from the viewpoint of their
comparison with present climatic trends and, to some extent, as an analog to
possible climate change in the future (such attempts are being continued,
though inadequacy of paleoanalogs for future climate forecast has been
repeatedly and convincingly argumented).
nition, climate is characterized by values of meteorological parameters
averaged over 30 years (so, for instance, climate anomalies in 2010 are determined
as deviations from averages over the period 1981
By de
2010). An analysis of the spatial-
temporal climate variability for individual years is also widely practiced. In par-
ticular, the World Meteorological Organization (WMO) publishes annual surveys
of global climate. In these reports attempts are being made to answer the most
important questions:
-
Does a climate warming take place?
Is the moisture cycle intensity changing?
Is the general circulation of the atmosphere and ocean changing?
Do extreme climate changes (storms, droughts,
fl
floods) intensify?
Is a reliable estimate of the anthropogenic contribution to climate change
possible?
The decade of the 1990s, on the whole, was the warmest over the whole period
of meteorological observations (beginning from 1860), and the year 1999 was the
fifth year by the level of anomalies of the global mean annual mean SAT (+0.33
°
C)
for the period 1860
C)
in the Northern Hemisphere, but in the Southern Hemisphere it was only the tenth
(+0.20
-
1999 (also the
fifth was the average SAT anomaly (+0.45
°
°
C)).
The band of maximum annual mean SAT extended from the continent of North
America eastward across the Atlantic Ocean and the Eurasian continent to the
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