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THE EFFECT OF GLOBAL WARMING TO OUR WATER RESOURCES
1.1 Introduction
Many water supply sources (rivers, lakes, groundwater basins, etc.) are already over
allocated, suffer degraded water quality, and are often not in sufficient condition to
support endangered species. Climate change will exacerbate these water challenges,
leading to insufficient water for people and the environment and making it increasingly
difficult to meet the needs of both.
Implementing actions now to improve water quality and supplies, protect aquatic
ecosystems, and improve flood management not only makes sense, but early action will
also help reduce future impacts related to climate change. Even if greenhouse gas
emissions are reduced today, there is already warming “in the pipeline” that will create
additional impacts. Adaptation is not a solution to climate change, but given the
importance of our water resources, immediate action is needed to avert significant
societal impacts.
Global warming occurs because of climate change, also known as climate disruption.
Climate is a fundamental driver of the water cycle. It determines how much water is
available (supply) and how much water we need (demand) in the short and long term.
The United Nations Framework Convention on Climate Change (UNFCCC) defines
climate change as, “a change of climate which is attributed directly or indirectly to
human activity that alters the composition of the global atmosphere and which is in
addition to natural climate variability observed over comparable time periods”.
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Climate change has an impact on weather and changes in weather patterns determine
variability in water supply and demand on a day-to-day and season-to-season basis –
the weather one year may be drier or wetter than the last. Changes in temperature and
precipitation patterns have affected the water cycle by changing its availability,
quantity and its quality. With raising atmospheric temperature and increase rate of
evapotranspiration the demand for water from human beings and the agriculture sector
will also increase. Without adaptation and mitigation measures, climate change may
threaten the sustainability of water systems, irrigation systems and farming systems.
Climate change is primarily caused by the growing concentration of heat-trapping gases
in the atmosphere, often referred as greenhouse gases. The increase of carbon dioxide,
methane, and other greenhouse gases has may many causes, but most of the increase
result from human activities, such as deforestation, pollution and burning fossil fuels.
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1.2 The Effects of Global Warming to Water Resources
Global Warming will have changes in the availability, quantity and quality of our water
resources, which will have impacts on the whole cycle of water supply, i.e. from water
demand, water resources and the water infrastructures.
The effects of global warming are vast and cover every sphere of one’s life. Both the
nature and the living beings are suffering from the effects of global warming. If we do
not take note of the alarming rate of growing global warming then our earth might
cease to exist someday. The water resources have been heavily affected by the global
warming phenomenon. Sea levels have risen, glaciers retreats are taking place often
and the most harmful affect is the shrinking of the Arctic Circle. This phenomenon has
caused concerns among all the sectors and geo-engineering is considered to be a way of
mitigation.
If we put it simply then the water bodies would be affected during the long and
scorching summers since the rate of evaporation would increases with hotter summers.
Water cycle is important for any kind of human activity and global warming would
adversely affect this cycle causing a topsy turvy in the human activities as well as the
climactic changes. Global warming might also lead to floods. The water levels in many
regions would lower due to excessive evaporation and this would cause in torrential
downpours increasing the chance of deluge.
The acceleration in the phenomenon of global warming has caused the ice sheets in the
West Antarctic Circle and Greenland to shrink. Carbon sediments have been released in
the air and due to the increase of carbon emission the reduction in the ice sheets has
taken place. This reduction might cause a huge flood around the world. By the end of
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twenty first century the water in the sea is expected to rise by 7.1- 23.2 inches. Due to
the augmentation of global warming effects the Thermohaline circulation might as well
get disrupted. The fresh water from the Polar Regions would interrupt the Gulf Stream
causing this distress. The implication of a change of course of the gulf stream would
have worldwide effect that would drastically accelerate climate change and extremes.
The imbalance created in the water cycle by global warming has far reaching effects.
Some places on the earth would face extreme temperatures along with torrential rainfall
while others would face scarcity of water and drought. In fact, according to the
scientists this phenomenon of global warming might even cause desertification in the
extreme Tropical areas like Africa.
The glacier rich areas like Western North America, Asia, Alps, Indonesia and Africa
are suffering badly due to global warming. The melting of glaciers in these regions has
raised concerns regarding the increase in water levels. Ocean circulation also suffers
due to global warming. The oceans act as the absorber of carbon dioxide and when it
reaches the saturation point it fails to absorb any more carbon dioxide. As a result the
ocean surface becomes warm.
Acidification of oceans is caused due to the concentration of carbon dioxide in the
atmosphere. This is an indirect effect of global warming causing distress to people
worldwide. The rise in sea level would cause infiltration of the saline water into the
groundwater. This will pose as a potential danger for the health of the living organisms.
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1.3 Change in Water Demand Pattern
During dry spells, the consumers will tend to consume more water either by watering
the garden or bathing more frequently. To ensure the existing water infrastructures
could cope with the water demand, contingency measures such as banning of car
washing and watering the garden has to be implemented during extreme drought, if
needed.
1.4 Impact on Water Resources
The climate change will affect water yield from the reservoirs, surface water and
ground water. With the change of rainfall patterns whereby a reservoir catchment area
may receive higher rainfall within a shorter duration but the reservoir storage capacity
was not designed to contain such high rainfall and the excess water could not be
harvested and will be ended up in the ocean. At the same time, the reservoir catchment
area may also experience a dry season with lower rainfall, higher evaporation rate and
extended dry period. This phenomenon will reduce the capacity of the reservoir to
supply reliable yield to water treatment plant.
Likewise, for raw water intakes rely on rivers extractions will see less runoff during
longer dry season, which may cause the raw water intakes to operate at with under
capacity condition more frequently.
As for water supply system, extracting ground water, the ground water dynamics are
expected to change due to climate change. During the extended droughts, recharge of
the ground water will be slower and the water extraction rate may have to be reduced in
tandem with lower recharge to avoid detrimental effects on the ecosystem.
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The effects of climate change are already being felt, for example:
1) Water
Rising global temperatures will lead to an intensification of the hydrology
cycle, resulting in dryer dry seasons and wetter rainy seasons, and subsequently
heightened risks of more extreme and frequent floods and drought. Changing
climate will also have significant impacts on the availability of water, as well as
the quality and quantity of water that is available and accessible; and
2) Coastlines
Melting ice and thermal expansion of the oceans are the key factors driving sea
level rise. In addition to exposing coastlines, where the majority of the human
population lives, to greater erosion and flooding pressures, rising sea levels will
also lead to salt water contamination of groundwater supplies, threatening the
quality and quantity of water resources access to large percentages of the
population.
Figure 0.1: Temperature change affects many natural processes that in turn affect the quality and quantity of our water resources.
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1.4.1 Availability & Quantity – Drought and Flood
Malaysian Climate Projection from NAHRIM Study in Peninsular Malaysia for future
annual rainfalls there will be a 10% increase for Kelantan, Terengganu and Pahang, and
5% decrease for Selangor and Johor. There will be more droughts i.e. dry years
anticipated (2028, 2029, 2034, 2042 and 2044) and higher maximum and lower
minimum rainfall will be observed in the future in many sub regions. Climate change
could play havoc with our water resources by changing our weather pattern, expected
dry months has changed to a wet months while expected dry months has changed to
wet month. Prolong drought was experienced in Kluang, Johor from Feb-March 2010
when the production of Sembrong Timur Water Treatment Plant almost fell to almost
zero due to decrease in river yield. In the 2009 & 2010 droughts in the Federal
Territory Labuan, extensive water rationing exercise was implemented and some
company such as Petronas Methanol had to close some of their operations - losing
millions of economic returns. As for the long term planning, the government launched a
project to extend the water treatment plant in Beaufort (Phase 2) which will increase
the supply of treated water to Labuan with an additional of 38.8 MLD. The total cost of
the project is RM 383 million and it involves huge CAPEX.
One of the well remembered, but localised incidence was the 1991 drought in Malacca
that caused the drying up of Durian Tunggal Dam and resulted in prolonged water
rationing in most parts of the state. The extreme droughts disrupted supply services,
especially in urban areas and frequent drought problems will further decrease the river
flow. Emergency measures were then followed to transfer raw water from the adjacent
Muar River as well as hundreds of water tankers were ferried around with drinking
water to relieve the distressed water shortage problem.
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The beneficial impacts of increased annual runoff in other areas are likely to be
tempered in some areas by the negative effects of increased precipitation variability and
seasonal runoff shifts on water supply, water quality and flood risks. Extreme flood
events had occurred in Kedah, Malacca and Johor. The state of Johor experience
extreme flood event early this year whereby road communications and water supply to
several districts were cut-off. Food, water, medical, and other humanitarian aids were
dispatched from neighboring states. At the end of 2010, the state of Kedah was hit by
flood – Bukit Pinang Treatment Plant in township of Alor Setar was submerged with
flood water leaving thousands of consumers without water supply. Flooding at river
intake will cause plant shut down because raw water pumps were submerged by flood
water and intake clogged with debris and sand. Water supply operator has to endure
high cost of cleaning, rebuilding damaged plants and equipments while consumers may
have to endure long duration of water supply disruption due to ongoing
maintenance/repair works.
1.4.2 Change in River Yield
Due to changing weather pattern, the safe yield of rivers may decrease and due to
decreasing yield, treatment plants could not produce to their design production. As an
adaptation and mitigation measures, river intake has to be relocated further downstream
where yield is higher or a barrage/weir has to be constructed across river to increase
water depth. To ensure there are enough raw water for plants to operate, dams and off-
river-storages have to be constructed to supplement this reduction. In the recently
reviewed Malaysia National Water Resources Study, RM 1.7 billion worth of source
works will be expected to be developed in the next 4 decades.
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1.5 Impact on Raw Water Quality
With higher water temperature, algae blooms in the storage reservoir could be expected
to increase and additional cost will have to be spent to remove it from the system.
Lower river runoffs during extended droughts are normally associated with a decreased
dilution capacity of the river on the pollutants, resulting in higher concentrations of
contaminants in the raw water. Higher rainfall intensity will cause water to overflow
the bank more extensively and erosion of the river bank will occur in the process, this
situation has led to an increase in water turbidity. It is often to find that the existing
water treatment plant may not be equipped with the facilities to deal with these
deteriorated raw water quality.
Raw water intakes or wells located near the coastal area will face the threat of saline
intrusion due to rising sea level compounded by lower surface runoff or lower ground
water recharge rate, limiting the use of these facilities for water supply. More capital
may have to be invested for building engineering structure such as barrage to prevent
saline intrusion into river intake.
The Initial National Communication (INC) prepared Peramu T/Plant intake (due to
saline intrusion). In the Ninth Malaysia Development Plan, the state of Terengganu
constructed Kemaman Barrage to raise river level and stop intrusion of saline water
into intake of Bukit Sah Water Treatment Plant.
Climate change causes prolong drought and with the reduced riverflow, deterioration of
river water quality due to pollution enhances. In the past this had lead to closing down
of treatment plants such as Cheras and Labu treatment plants. As the consequences, the
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affected river sources is either be abandoned or the water treatment plant be upgraded
by adding the advanced treatment such as membrane technology which requires high
capital outlay and would definitely increase the financial burden of the water operators.
In addition, the water operators also found that operating cost of the water treatment
plant is higher in tandem with the higher chemical dosage to treat the highly polluted
water sources. The situation is further compounded by higher residual produced and
cost of disposal the residual as the consequences of higher chemical dosage.
1.6 Development of Water Resources
The following recommendations are intended to guide the development of water
resources response measures:
a. Implement water use efficiency first.
Maximizing water use efficiency is one of the most cost-effective measures
communities can quickly implement to protect water supplies while also
reducing energy use and global warming pollution.
b. Use climate-smart water management tools.
Tools such as groundwater banking and water recycling may perform better in
a warmer future, while those that rely on historical hydrology (e.g., river
diversions and surface storage) are likely to perform less effectively in the
future.
c. Prioritize multi-beneficial approaches.
Adaptation measures that address multiple impacts, such as source water
protection, smart growth, and low impact development can benefit not only
water supply, but also interrelated issues including water quality, fish and
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wildlife habitat, flood management, reduced energy consumption, and reduced
global warming pollution.
d. Integrated regional water management.
Employing a regional planning approach can capitalize on solutions that benefit
a broad range of issues, stakeholders, and agencies and therefore will probably
have wide support and the ability to broadly distribute implementation costs.
e. Factor in energy use.
Each component of water use, from transport and treatment through
distribution, can require energy. Energy consumption and efficiency need to be
considered in response planning to ensure solutions are not exacerbating the
basic problem of carbon emissions.
f. Water system reoperation.
Regional water supply systems are often interconnected by tributary rivers and
canals. Reoperating water supply systems for improved flood control and
stormwater management can buffer climate-related impacts by distributing the
effect of changes in hydrology over a wider area.
g. Factor climate change into feasibility analyses and project design.
Evaluations of potential surface storage and other facilities should take into
account the effects of climate change on likely future hydrology, demand,
economic analyses of alternatives, and potential environmental impacts.
h. Incorporate the need for flood management.
Because most dams serve both water supply and flood management roles,
increasing downstream flood protection can enable existing dams to be operated
for increased water supply. Improved flood management should be incorporated
as a multi-beneficial tool for water supply management.
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Figure 0.2: Performance of Water Management Strategies After ConsideringGlobal Warming Effects
1.7 Conclusion
The impact of climate change will increase over the years, it will gain momentum and
if unattended, will cause havoc to our life. For millions of years human beings have
been able to survive in this planet because they are able to adapt and mitigate changes
that surround them. With the change in climate, we have to respond to it by changing
our lifestyle, not to stress the environment, be more protective and not to pollute it,
going for technologies, industries and crops that are water efficient.
There is a need to improve our understanding of long-term climate variability and
change. Where and which part of the water supply infrastructure are affected by climate
change. Are the effects localized or across state boundaries, a better understanding will
facilitate in policy response, going for appropriate water resource options, planning,
designing robust water supply systems or in short what are the adaptation and
mitigation measures to be implemented.
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To achieve efficient water demand management may take years and need resources but
it is an option we have to take. Sustainable water management with realistic pricing is
one way to curb wastage. A Tariff Policy, which discourages excessive and inefficient
use of water, should be in-place. Consumers can be the source and also solution to
unsustainable consumption of natural resources. Consumer education cannot be
sidelined if we want to achieve sustainable urban development in an ever-changing
environment. The expected changes in the hyrdologic regime of Malaysia due to the
impact of climate changes may require significant planning of the Malaysia‟s water
resources to accomodate aforesaid changes into the future water balances over the
Malaysia.
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