Environmental Engineering Reference
In-Depth Information
decade, with summer decreases of 7.4 % (5.0-9.8 %) per decade (IPCC
2007a
).
The maximum surface of seasonally frozen ground has decreased by about 7 % in
the Northern Hemisphere since 1900. There have been decreases in spring of up to
15 % (IPCC
2007a
). (iii) Increase in soil temperature that subsequently enhances
the soil respiration (Lloyd and Taylor
1994
; Petersen and Klug
1994
; Arnold
et al.
1999
; Feng and Simpson
2008
,
2009
; Frey et al.
2008
). (iv) Weather modi-
fications that can enhance natural disasters such as tornadoes, typhoons, storms,
thunderstorms, and floods (Khalilov
2010
). (v) Variations in water temperature
profiles that cause changes in the euphotic zone, induce a longer summer stratifi-
cation period and high photoinduced degradation of DOM and OM, make harm-
ful algal blooms more likely, induce alteration of DOM dynamics, and change the
seasonal patterns of chlorophyll or primary production and the nutrient concentra-
tions. These effects induce as a consequence changes in species composition and
in the seasonality of the water column, and finally modify food webs among phy-
toplankton, zooplankton, fish and birds in the aquatic environment (Huisman et al.
2006
; Baulch et al.
2005
; Castle and Rodgers
2009
; Davis et al.
2009
; Kitaysky
and Golubova
2000
; Hobson and McQuoid
2001
; Mudie et al.
2002
; Morrison
et al.
2002
; Johannessen and Macdonald
2009
). (vi) Increases in sea level. They
are consistent with warming and the global average sea level has risen at an aver-
age rate of 1.8 mm (1.3-2.3 mm) per year from 1961 to 2003. However, in the dec-
ade 1993-2003 the average rate has been of about 3.1 mm (2.4-3.8 mm) per year
(IPCC
2007a
). An increase of the global average temperature of about 2 ºC may
cause a warming of about 2.7 ºC in the area around Greenland, possibly triggering
the loss of the Greenland ice-sheet. Such a process may cause a global sea-level
rise of 7 m over the next 1,000 years or more (Huybrechts et al.
1991
; Gregory
et al.
2004a
,
b
). The rise of the sea level introduces vulnerability issues for agri-
culture, food, water resources, coral reefs, low-lying estuaries, intertidal zones,
mudflats, mangrove forests, ecosystems and biodiversity (IPCC
2007a
; Smith
et al.
2001
; Johannessen and Macdonald
2009
; Doney et al.
2009
; Masson and
Cummins
2007
; Burd et al.
2008a
,
b
). The impacts on the coastal environments
may lead to changes in the food web and affect the diversity of higher trophic lev-
els such as marine mammals, fish and birds. (vii) A total ozone reduction of 2.5 %
per decade during summer time causes a 5 % increase in UV irradiance (Varotsos
and Kondratiev
1995
), with a direct impact on terrestrial and aquatic environments.
3 Environmental Processes of GHGs Emission Affecting
Global Warming
The key environmental processes of GHGs emission that may affect global
warming can be categorized as follows: (i) soil respiration; (ii) agricultural activi-
ties in soil; (iii) anthropogenic sources of atmospheric greenhouse gases; (iv)
deforestation; (v) photoinduced degradation of DOM and OM by natural sun-
light; (vi) photoinduced degradation of OM in plants and soil environments.
