Water Environment Partnership in Asia

Policy Brief

Series7

March 2014

Wa t e r E nv i r o n m e n t a n d C l i m a t e
C h a n g e – S u m m a r y f r o m W E PA
Discussions and Surveys
Climate change is one of the drivers ofchange in water resources and poseschallenges to existing water management
practices (Connor 2009). In the Fourth
Assessment Report of the Intergovernmental
Panel for Climate Change (IPCC), Working
Group II which contributed on impacts,
adaptation and vulnerability, concluded
that “higher water temperatures, increased
precipitation intensity, and longer periods oflow flows exacerbate many forms of waterpollution, with impacts on ecosystems, humanhealth, water system reliability and operating
costs (high confidence)” (Kundzewicz et al.
2007).
In the Asia-Pacific region, events assumed
to be influenced by climate change havealready occurred, and climate change may
render a deep, multi-pronged impact on

Impact of Climate Change on Water
Quality and Aquatic Ecosystems
The impacts of climate change include
higher water temperatures, which reduce theamount of dissolved oxygen (DO) in waterand thus its ability to self-purify. The potential
increase of water use for cooling purposesdue to atmospheric warming in the energy
sector is also considered another cause ofhigher water temperatures. Furthermore,changes in patterns, intensity and durationof precipitation also affect water quality.
Intense rainfall over short periods increases
the amount of sediment, nutrients and othertoxins in water bodies due to heavy runoff.
Changes in patterns can lead to sporadic
supplies of surface water, raising our relianceand possibly exhausting supplies of potableg r o u n d w a t e r, a n d a l s o c r e a t i n g h e a l t hhazards due to arsenic and fluorine in the
groundwater. Rising sea levels are anotherthreat, as these lead to salt water infiltrating1

the water environment. However, there is
not necessarily enough policy response toaddress these changes. In recognition of this,WEPA selected “climate change and the water
environment and possible adaptation options”
as one of its priority topics in the second
phase (April 2009 – March 2013) . Specifically,
WEPA initiated information exchange anddiscussions on the potential impacts ofclimate change on water environments (water
quality and aquatic ecosystems) through
WEPA workshops; it also conducted literature
reviews, fact-finding and surveys on the topic,
all of which are publically available on the
WEPA database’s archive – climate change
and the water environment. This brief outlined
the discussion on the topic under WEPA in its
second phase.

surface and ground freshwater systems. The
impact on human health and water quality due
to flooding of polluted water is also identified
as a potential risk. Aquatic ecosystems do
not escape either; for example, warmer
climates may threaten wetlands, one of the
key habitats for a variety of species, and also
lead to blooms of exotic aquatic species atthe expense of indigenous species. Figure
1 shows examples of changes in water
environments anticipated to result from or
be escalated by climate change, taken fromliterature and news items. Although not all
have been scientifically verified, we havealready witnessed some changes. Studies
covering Lake Biwa (Japan) and Lake Fuxian(China) imply that an increase in wintertemperature may have a higher impact on
the water environment. As reported in thestudies, high winter temperatures reduce theextent of winter mixing, causing DO depletionin the bottom layer of water bodies (Kumagai
et al. 2003), which leads to an anaerobic

state under which the release of pollutantsfrom bottom sediments may be accelerated.
Another study conducted for Lake Biwa
shows the difficulty to identify whether theobserved changes were caused by humaninduced impacts or climate change impacts(Box. 1). High levels of Total Suspended
Solids (TSS) in the Mekong River and
Brantas River (Indonesia) in the rainyseasons were reported and attributed to theincreased intensity of precipitation. Increased
runoff due to heavier precipitation carries
more pollutants from the land to surface

water bodies, resulting in assimilation of
biodegradable organic matter by aerobic
microorganisms using DO. The expansionof human activities in Asian countries places
more pressure on aquatic ecosystems andexacerbates climate change. We are also
likely to witness the extinction of a number of
species in tropical areas and semi-enclosed
seas by 2050 (McMullen 2009).

Figure1

Changes in water environments anticipated to result from or be escalated by climate change,
taken from literature and news items

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Figure2

Box.1 Impacts of climate change on the water environment of Lake Biwa
Time series data on water temperature monitored at 46
points over the past 30 years were analysed as part ofa study of potential impacts on the water environment
Lake Biwa
and possible adaptation actions, conducted by the
Ministry of the Environment of Japan from 2009 to
2011. Results showed that the yearly increasing rateof water temperature in Lake Biwa was 0.5 to 3.3°C(yearly average: 1.6°C) and 0.1 to 1.7°C (yearly average:
Water Temp Change
0.9°C) in summer and winter, respectively over the
0-1℃
last thirty years. Atmospheric temperature data (19601-2℃＞2℃
2008) at the Hikone local meteorological observatory
and water temperature at the centre of Minami Hira
offshore showed that the annual average increase rate
Water temperature change trend overof water temperature during summer was 1.73°C, which
the past 30 years in Lake Biwa
is greater than that of atmospheric temperature (1.23°C).
In winter, water temperature and atmospheric temperature
showed a different trend - the annual average increase rate of water temperature was
0.84°C and that of atmospheric temperature was 1.48°C. Distinct changes in watertemperature as compared to atmospheric temperature in summer revealed that the watertemperature of the lake is influenced by increasing atmospheric temparatures as well asother external factors. On the contrary, in winter, vertical mixing of cold water from thelower layers and warm water from the upper layers might attenuate the effect of external
factors on water temperatures of the largest lake (with 27,500 million m3) in Japan.
This study could not find significant collation between water temperature change in the lakeand other external factors such as population density and industrial activities in the lakebasin. However, heat emission from wastewater treatment is seen as another important factor
impacting water temperature. A huge volume of high temperature (25- 28°C in summer and17-19°C in winter) treated wastewater drains into Lake Biwa, which has a lower temperatureof 20- 25°C in summer and about 10°C in winter. It was estimated that about 135 million cubic
meters of treated wastewater was drained into Lake Biwa in 2005. About 80 percent of thetreated wastewater came from the southern basin and the rest from the northern basin. The
ratio of wastewater to lake volume in the southern basin was 0.53, which revealed that heatemission from treated wastewater may greatly influence the water temperature of the largest
lake of Japan.
(Source: Yuasa et al. 2011)

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Challenges in addressing climate change
impacts
In the international WEPA workshops heldin 2010 and 2011, participants exchanged
information on their concerns about the
impact of climate change on water quality.
At these workshops, participants argued that
insufficient data and information, especiallythe lack of time-series data, presents a barrier
to incorporating climate change concerns into
water environment policies.
To understand the scientific knowledgeof climate change impacts on the water
environment, WEPA conducted a survey on
Table1the state of long term data for atmospheric/water temperature and water quality, which
are key to studying climate change impacts
on the water environment. This survey was
conducted through WEPA focal points.
The survey asked them: 1) the number ofmonitoring points which have recorded data on
atmospheric temperature for over 10 years; 2)
the number of monitoring points which haverecorded data on either water temperature
and water quality for over 10 years, and 3) thetypes of parameters used for water quality at
the monitoring points concerned. The results
are summarised in Table 1.

Number of monitoring points where data has been accumulated for more than 10 years*1

The results of this survey show that many
WEPA partner countries have insufficient(i.e. less than 10 years) long-term dataon water temperature and water quality,
which is needed to understand trends andcorrelations in changes. There is also little
data especially on lakes/reservoirs andestuaries/coastal areas. Moreover, thesurvey found that water temperature/quality
monitoring is not conducted regularly in some
WEPA partner countries, and many of thepartner countries do not implement regularwater quality monitoring for basic quality
parameters such as DO, BOD and COD. In
addition to these findings, the survey reveals
that different data regarding water quality is4held in different ministries and organisations
in some countries, which is an obstacle tosystematic data management. Systems tomonitor water quality regularly should also beestablished, not only to assist in formulating
countermeasures to climate change, but also
to comprehend the state of water quality forcurrent and future policy responses to water
quality problems.
From the results of the survey we can seethat WEPA partner countries have attempted
to strengthen water quality monitoring inrecent years; however, the data collected
is insufficient for evaluation of climatechange impacts on water temperature andwater quality. Both water quality monitoringand data management are insufficiently
i m p l e m e n t e d i n s o m e W E PA p a r t n e r
countries. Therefore, comprehensive water
quality monitoring must be ensured so thatdata can be used for forming policy related towater quality improvements and adaptations
to the impacts of climate change. In Japan,
for example, Ministry of the Environment
initiated a study to investigate the impact ofclimate change on the water environment

and possible adaptation options. As a partof the project, the relationships among
atmospheric temperature, water temperatureand organic water parameters were analysedbased on 30 years of monitoring data. It is
often difficult to determine to what extent
climate change contributes to the observed
environmental changes since other stressors(e.g., population growth, urbanisation andeconomic growth) also significantly affect theregion’s water environment.

Policy Responses: Adaptation policies/
strategies of WEPA partner countrie

water shortage and natural ecosystems,
including coastal and marine ecosystems,
are often addressed in national climatechange adaptation policies, strategies, andother related government documents, but
the aspect of water quality is often lacking
in policy documents. The potential impactsof climate change and adaptation actions
are also not included, while climate change
per se is sometime included, in policy
documents related to management of thewater environment. The fact that insufficientknowledge and scientific data acts as abarrier to developing adaptation policies inwater environmental management was also
pointed out by several water experts at a
WEPA international workshop.

Policy responses to the potential impactsof climate change vary from country tocountry. To determine how each partnercountry has prepared or is preparing for the
potential impacts on the water environment
in both climate change adaptation andwater resource/management policies,
the WEPA Secretariat surveyed relevant
p o l i c y d o c u m e n t s i n W E PA p a r t n e r
countries in 2009 through WEPA focal
point organisations. The WEPA Secretariat
also reviewed policy documents covering
climate change adaptation and the water
environment available on the Internet. The
results of this survey and review show that

Message from WEPA for
Future Discussion on Climate
Change and Water Environment
The above discussion has revealed thatWEPA countries have very limited scientificknowledge of climate change impacts on thewater environment (water quality and aquatic
ecosystems). Since developing countries
generally lack time-series data of water
quantity, quality and temperature, required
research facilities and human resources, it isvery important that each country establishes
or strengthens their systems to collect andaccumulate data via monitoring.
For future actions, methods or schemes bywhich the data can be shared or utilised
between relevant parties and countries alsoneed to be considered. It is predicted that
overall, water resources will be subject toa continued negative, rather than positive
impact at the global level, and that this will
have a knock-on effect on other sustainable

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agenda, such as food security and poverty(Bates et al. (ed.) 2008). Therefore, it is
crucial to continue efforts to promote studies
and actions by both the scientific community
as well as policy makers. Such actions willcontribute to the formulation of national
adaptation action plans in each country.
In addition, in view of the increasingly serious
impacts of natural disasters – such as the2011 floods in Bangkok and Hurricane Haiyan
in the Philippines in 2013 – it is imperative todeliberate on how to enhance preparedness
and resilience against such extreme events.
This includes measures to minimise the risks
of water pollution which could easily result
from increases in sediments and suspended
solids due to heavy precipitation, as wellas health risks arising from overflows of
untreated wastewater and compromised
wastewater/water treatment facilities due todisasters.

Note
Authors:
KATAOKA Yatsuka
Senior Coordinator(Networking and Outreach);Principal Policy Researcher

This brief was the summary of Chapter 2.2 Climate Change and the Water Environment – Summaryof findings based on WEPA discussions and surveys in “WEPA Outlook on Water Environment
Management in Asia 2012”.

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