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erosion in lowland areas, thawing of permafrost accompanied by hydrological and
climatic changes. Climate change will affect terrestrial ecological systems through
changes in permafrost as well as direct climatic changes, including changes in
precipitation, snow cover, and temperature. Terrestrial ecosystems are likely to
change from tundra to boreal forests, although vegetative changes are likely to lag
behind climatic change. Major shifts in biomass will be associated with changes in
microbiological (bacteria, algae, etc.) and insect communities (some of them may
diminish while others prosper).
It has been pointed out (Everett and Fitzharris 2001) that in the recent geologic
past, the tundra was a carbon sink, but recent climate warming in the Arctic,
coupled with the concomitant drying of the active layer and the lowering of the
water table, has shifted areas of the Arctic from sinks to sources of CO
2
(this
problem is, however, far from being solved). An important potential consequence
of permafrost thawing is emissions of methane
a greenhouse gas. As for tropo-
spheric ozone, another greenhouse gas, changes might happen due to warming of
the troposphere (Kondratyev and Varotsos 2000; Varotsos 2005).
An interesting illustration of potential future surprises due to interactions and
feedbacks has been discussed by Stevenson et al. (2000) who obtained future
estimates of tropospheric ozone radiative forcing and methane turnover in the
context of the impact of climate change (it should be pointed out that studies of the
contribution of tropospheric ozone, O3T,
3T
, as a greenhouse gas as well as assessments
of potential impact of global warming on permafrost melting and methane emis-
sions are still at the preliminary stage of development). Interactive simulations of
climate dynamics and O3T
3T
changes during the period of 1990
—
2100, for scenarios
-
of
(B2) cases of CO
2
emissions, resulted in tropospheric
ozone radiative forcing (RF) equal to +0.27(A2) or +0.09(B2) Wm
−
2
, if climate-
ozone coupling was neglected, then relevant RF values were equal to +0.43
(+0.22) Wm
−
2
. When climate change was included, CH
4
lifetime fell by 0
“
high
”
(A2) or
“
central
”
5%.
Hence, climate warming exerts a negative feedback on itself by enhancing O3T
3T
and
CH
4
destruction.
The three principal achievements have stimulated during the recent years the
progress in studying the Arctic environment (Dickson 1999; Baker 2011; Vallis and
Thoumi 2012):
-
(1) further development of observation programs with the usage of various
observation means (including satellites and submarines);
(2) declassi
cation of the military Soviet-American archive of ocean
“
climatol-
data; and
(3) discovery of the fact that the climatic forcing in the Arctic region and northern
seas in the 1990s has increased in comparison with that observed during the
previous century [similar situation also took place with respect to climate
dynamics indicators (such as Arctic Oscillation (AO) and North-American
Oscillation (NAO))].
ogy
”
decadal differences between
the 1990s and 1980s in winter sea-level pressure and 300 hPa zonal winds have an
Overland and Adams (2001) have pointed out that
“
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