Download Preliminary research of carbon-sink effect of Tianjin’s wetlands system in... context of global climate change

2011 International Conference on Environment Science and Engineering
IPCBEE vol.8 (2011) © (2011) IACSIT Press, Singapore
Preliminary research of carbon-sink effect of Tianjin’s wetlands system in the
context of global climate change
Sandra Meng Ying Leea,b
a
School of Civil Engineering, Tsinghua University
b
School of Architecture, Tsinghua University
Beijing, China
[email protected]
urban area is higher than peripheral region, which is due to
decrease number of wetlands and other territorial waters
caused by expansion of urban area.(Figure 2) This
phenomenon is called “heat island effect”, which has
exacerbated from 1998 to 2007 according to figure 2. Tianjin
wetland has long been facing the same problem such as
overpopulation, urban sprawl and most importantly the
continuation of climate change. Under this given
circumstance, Tianjin has been suffering from water shortage
and water resources problem, resulting wetlands in Tianjin
faceing more pressing crises.
Abstract—Hydrosphere environment is the most susceptible
fundamental systems subjects to current global climate change.
The unique geographical feature and developing potential of
Tianjin wetlands systems has impacted on the local water
environment severely. In this article, preliminary estimation of
restorable wetlands area and its atmosphere values has been
made. Based on assessed potential carbon sink capacity, it is
deduced that wetlands system would help restoring carbon
sink in Tianjin area. The purpose of this research is to provide
strategies aiming to improve the ecological security pattern,
whilst maintaining economic development of Tianjin area.
Keywords-wetland system; carbon sink; global Climate
Change; Tianjin
I.
INTRODUCTION
The ecological security pattern of wetlands system plays
an important role of regulating climate change, and reduces
greenhouse gases emission. A mature restoration of wetlands
system possesses carbon sink function that features in
regulating climate. Thus, the value of the wetland ecosystem
service has been stand out.
II.
CURRENT CONDITION OF TIANJIN WETLAND
Figure 1.
Tianjin wetlands have valuable historical meaning
because they were typical ancient low-lying lands ranged
from “Qi-li-Hai” to “Huang-Zhuang-Wa” swamp series
derived from Hai-He river basin. In the past century,
ecosystems in Tianjin wetlands area had changed
fundamentally. The decrease of water flow from outer region
and over exploitation of groundwater has caused river
interception in local Tianjin area. Currently, local rivers in
Tainjin area are constructed rivers that relied on water
pulling from Luan River and Yellow River. However, the
water supplies continuing decrease and slowly diminish. The
area of Natural wetlands has been decreasing from 45.9 % in
the 20th century to 3.6% by the year of 2000. Remote
sensing images from different periods illustrated in Figure
1indicate the obvious signs of construction, fragmentation,
salinization, and the decline of ecological function of
wetlands in Tianjin region.
The declining land cover of wetlands and ecological
service area would in turn diminish the ability of regulating
climate. The results of remote sensing data analysis (1998,
2007, Landsat TM6) revealed a clear sign that temperature in
Figure 2.
Analysis diagram of land use of Tian Jin City in 2000 and 2007
(“Strategy of spatial planning of Tian Jin City” 2008)
Comparison of island heat of Tian Jin City in1998 and 2007
(“Strategy of spatial planning of Tian Jin City” 2008)
Tianjin wetlands ecosystem is a degrading ecological
system shaped by human activities and nature environmental
factors. This changing pattern of wetlands and ecological
46
function indicated a negative growth relationship between
human activities and natural environment, which suggests
the importance of Tianjin wetlands conservation and
restoration management. In addition to maintaining the basic
wetland ecosystem services function, "water security", it is
more crucial to sustain its "ecological security" in order to
enhance habitat of various species; by providing migratory
birds and other valuable species an optimal habitat, Tianjin
wetland biodiversity can be improved.
Solution to the problems of Tianjin wetlands system
should be mapped out based on the perspective of managing
entire river basin. By exploring the problems in upstream,
midpoint, and downstream individually, a plan of integral
wetlands system is proposed to solve the problems of river
basin step by step. Therefore, in order to fully understand the
magnitude of this subject, it is important to tackle the
problem from the perspective of the overall watershed
management, and wetland system layout can be use in
solving practical problems faced in Tianjin.
III.
Tianjin area. Moreover, water pollution, biodiversity decline
and loss of wetlands resulted in decline of wetland
ecosystem services function. By preserving the wetland
resources in Tianjin area, not only the ecological security
patter of downstream of Haihe River would be preserved, but
also the effectiveness of ecological security patterns of
Tianjin area would be improved.
IV.
COMPOSING OF ECOLOGICAL SECURITY PATTERN IN
TIANJIN
The main target of planning Tianjin wetlands system
should be aiming to sustain and maintain wetlands’ “water
security" and "ecological security" function as the basis for
regional sustainable development. Only through the
development of an overall well-established eco-network
architecture can help adaptation and mitigation of climate
change, and further contribute to safe living environment.
THE IMPORTANCE OF PROTECTION AND RESTORATION
OF WETLANDS SYSTEM IN TIANJIN
Wetlands system is the second most important carbonsink other than forests system in lithosphere. Wetlands not
only provide safe habitat for endangered animals and plants,
but also serve as life support systems for regional ecological
security pattern. Studies have shown that 35% of the
terrestrial biosphere carbon is contained in only 6% of
Earth's land area of wetlands. The capacity of carbon storage
depends on the types of wetlands, wetland size, vegetation,
soil thickness, groundwater, nutrients, pH values, and other
factors [3].
Wetlands included approximately 770 billion tons of
global carbon, more than agro-ecosystems (150 million tons),
temperate forests (159 million tons) and the tropical rain
forest (428 million tons). [3]
“Carbon sink” would turn into “Carbon leak” if
destruction of wetlands occurs, which diminishes carbon
fixation function, and stimulates carbon oxidation process
that contributes toward global warming process.
Unrestrained land reclamation and destruction of wetlands
will increase the greenhouse gas emissions. Therefore,
prompt wetland protection management will in turn improve
carbon fixation function.
The key element in wetland protection and restoration in
the hope for achieving “net carbon sink” is wetland habitat
protection and preservation management.
Wetlands restoration helps maintaining carbon fixation in
terrestrial ecosystems, which decomposes atmospheric
greenhouse gases, and mitigates global warming process.
Consequently, preserving carbon cycling contained in
wetlands system plays a significant role of serving it’s
ecological service function in responding toward global
climate change. Furthermore, this ecological service function
improves the relationship between human and their
environment in five scales, global, regional, urbanization,
and social and architectural context. [2].
As in recent years, human over population and
exploitation of land caused the reduction of wetlands in
Figure 3. Ecological security pattern map in Tian-Jin (S.M.Y.Lee)
“Water security” implies the function of water supply,
flood control, water-logging, water purification, and
“ecological security “should take account of mapping out the
protection plan in ecologically sensitive areas for the Haihe
River Basin. Ecological security also refers to the ecological
safety toward human settlement and infrastructure
development patterns. It should be integrate through wetland
restoration from the perspective of governance in order to
improve the security situation in Tianjin eco-quality.
“Ecological security pattern” of wetlands system in
Tianjin is consisted of “Water security” and “Ecological
security”. Wetland management should use biogeography
and ecological point of view in integrating ecological
47
Biomass of Reeds(tons/hm2)=5 tons/hm2; Biomass of
Rice(tons/hm2) =19.44 tons/hm2
security pattern with regional land use. In order to regulate
urban climate change, reduce heat island effect and improve
urban ecological quality, the integration of wetland into
urban area is critically important. Based on the principle of
ecological security pattern strategic plan, wetlands work as
the media in adjusting of entire Tianjin water environment.
A complete wetland system reserve and restoration plan
from foothills wetlands system to plain wetlands system to
coastal wetlands system, and a regional ecological security
connection made by construct wetlands and river wetlands
system would increase the overall wetland area and
distribution, and helps strengthening the ecological security
pattern in Tianjin. Under this plan, the restored and reserved
wetland areas are estimated to be 3055 km² in the future.
(Figure. 4)
Under the plan of wetlands reservation and restoration,
the preliminary estimated amount of carbon dioxide fixed by
wetland reeds and rice are shown as followed. (Table1, 2)
Preliminary estimation concluded that after actual
execution of Tianjin wetlands system preserving and
restoring plan, area of wetlands would increase, which
improves the level of regulating climate. Therefore, it clearly
indicates the importance in protecting and restoring wetlands
system, ecosystem services management and stability as net
carbon sink is crucial and urgent.
TABLE 1 ESTIMATED AMOUNT OF CARBON DIOXIDE FIXED BY REEDS (T)
Year
1985
Coastal
Wetland
34858.35
River
Wetland
166050.00
Lake
Wetland
117.86
Swamp
Wetland
2879.55
Man-made
Wetland
246037.50
2000
21676.06
54414.78
88.78
2741.72
209660.50
2007
22392.23
56212.63
91.72
2832.30
216587.63
2010
24318.96
61049.41
99.61
3076.00
235223.78
(S.M.Y.Lee)
TABLE 2 ESTIMATED AMOUNT OF CARBON DIOXIDE FIXED BY RICE (T)
Figure 4. The changing pattern of Wetland areas (S.M.Y.Lee)
V.
Year
THE IMPORTANCE OF COMBINING WETLANDS
SYSTEM AND ITS CARBON-SINK FUNCTION
It is important to fully integrate Tianjin's own natural
wetland resources in the plan of restoring the local wetlands
system. Constructed wetlands and flood detention wetlands
assist in performing wetland functions. Wetlands, ponds, salt
pans, reservoirs, rivers, road networks, etc form bases,
patches, and corridor of the ecological security pattern, in
which costal mudflat, downstream riverbank are ecological
bases, reservoir wetland, flood detention wetlands, ancient
lagoon wetlands, constructed wetlands are ecological patches,
and river wetlands are ecological corridors that connect bases
to patches. To strengthen the connecting network within
wetlands system, the quality of ecological security patter and
carbon sink formation would be improved.
Reference to a number of scholars’ research results,
preliminary calculations of the wetland carbon sinks between
wetland reeds and rice fields had not fully integrated the data
of carbon sink efficiency. If taking into account and consider
the value of carbon fixation, the benefit from carbon fixation
of wetland systems in Tianjin will be tremendous. The
formula is as follows:
1985
Coastal
Wetland
81317.6
River
Wetland
387361.4
Lake
Wetland
274.9
Swamp
Wetland
6717.4
Man-made
Wetland
573956.3
2000
50565.9
126938.8
207.1
6395.9
489096.1
2007
52236.6
131132.8
213.9
6607.2
505255.6
2010
56731.3
142416.1
232.37
7175.7
548730.1
(S.M.Y.Lee)
VI.
CONCLUSIONS
The concept of global climate change integration had
becoming publicized and being educated toward the general
public. Under the influence of carbon trading, we often
overlook the innate ability of nature carbon sink forming
process, which can filter and provide cleaner water resource
and better soil nutrient. Wetlands system is one of the
systems that possesses carbon sink ecological service,
Therefore, the key to achieve net carbon sink is through
wetland restoration, preservation and development
management. In the context of global climate change, the
role of wetlands should be taken more seriously due to its
ability in regulating climate change.
In the composing plan, Tianjin wetlands system is
divided
into
bases,
patches,
and
corridors,
preservation/restoration and construction of wetlands in each
region ensures it’s ecological security function to work
systematically. Tianjin wetlands’ most important goal is to
protect "water security" and "ecological security" as the basis
for sustainable urban development, and the establishment of
Weight of fixed carbon dioxide(tons)= covering area
(hm2)X biomass( tons/hm2)X Capacity of fixing carbon
dioxide (1.62tons/tons[7] )
48
better ecological network architecture. Adaptation and
mitigation through better development and management of
wetlands can further benefit and achieve safe living
environment.
Profound knowledge about carbon sink system should be
included in the planning of straightening ecological security
pattern in wetlands system. However, existing methods and
data were insufficient; the next in-depth investigation on the
basis of such research should be strengthened.
[3]
W. H. Li et al. “Evaluation theory, method and application of the
value s of ecological system service function”.[M] BeiJing: China
Renmin University Press, 2008: p312
Article in a journal:
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[M]. BeiJing: China Architecture and Building Press, 2001: p 39.
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Article in a conference proceedings:
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system” [A]. Chen Gang Chi. “Research of swamp of San Jiang
Plain”[C]. BeiJing: Science Press, 1996:p165-168.
ACKNOWLEDGMENT
This Project was granted financial support from China
Postdoctoral Science Foundation.
China Postdoctoral Science Foundation Financial
Number: 20100480016
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