Climate Change Impacts
to the Water Environment-Present Approach of MOEJ-

Shu Nishi
Ministry of Environment, Japan

Contents
1. Background
2. Previous Knowledge
3. Investigation Commission
4. Philosophy of Investigation
5. Analysis of Previous Information(Macro-scale Analysis)
6. Investigation of Forecasting Method

1.Background
Hot issue in Japan:
Climate Change

Annual surface temperature
anomalies in Japan

Projected average temperature
in Japan

Regional temperature change
in Japan (℃)

Projection of Change in precipitationin Japan2. Previous Knowledge
Impacts on Water Quality
Previously-Observed Impacts
・Increase in Annual Mean Water Temperature
・Abnormal Growth of Algae in Lakes
・Expansion of Red Tide Damage by Drought
Impact Forecast in the future・Declining Water Quality in the River by Heavy Rainand Drought
・Water Temperature Rise in River, Lake and Groundwater
・Increase in Amount of Evaportranspiration
・Change of Snowmelt Runoff
・Stop of the Water Circulation in Lake・Increase in Abnormal Growth of Algae
・Change in the timing, intensity and duration of Participation
・Change in Water Use and Aquatic Ecosystem

Impacts on Aquatic Ecosystem
Previously-Observed Impacts
・Change of Ecosystem by Stopping of Water Circulation
and Decrease of Dissolved Oxygen
・Habitat Change of Cold-water Fish in Freshwater
・Increase in Southern Strain
and Decrease in Northern Strain in Coastal Area
・Coral Death and Bleaching
Impact Forecast in the Future・Expand of stopping of Water Circulation in Lake and Sea
・Change of Habitat Range in Freshwater・Invasion of Alien Species
・Impact on Plankton by Acidification in the Sea
・Expand of Coral Bleaching・Decrease in Sandy Shore

Water temperatures in Kiso River
raised by maximum 2 degree in1994, it caused flow reduction
and declining water quality.
Delay of Water
Circulation In Lake Biwa.

Tropical fish inTama River,Tokyo
Heavy rain caused
floods in Tokyo, 2005.
Amount of rainfall perhour is over 100mm.

Water circulation has
stooped in Lake Ikeda
since 1986. From 1990,
Anoxic layer is at under
200 meters deep.

Low Dissolved Oxygen
level in Tokyo bay.

Increase in watertemperature in 5 rivers in
Kagawa Pref in 27 years.

Examples of the Impact on Water Environment in Japan

3.Investigation Commission
Outline“Investigative Commission for Impact on Water
Environment by Climate Change” established in 2010
Goals:To clarify the impact on water environment in public water
body by climate change and to investigate the adaptation
measures.
Period: 4 years
FY2010:1.To get clear understanding about the items(water quality, water temperature ,etc.) effected byclimate change
2.To decide the basic concept about the forecasting method
3.To decide the plan of future investigation and scheduleTo clarify the impact on water environment in public
water body by climate change
・Impact on the water temperature・Impact on the quantity of water・Impact on the habitat

To clarify the impact on the water quality and aquaticecosystem
・Impact on the water quality
・Impact on the aquatic ecosystem

To investigate the adaptation method for the impact on
the water quality and aquatic ecosystem

4.Philosophy of Investigation
Water Quality
Study Items
・Change of the water temperatures
・Change of the quantity of water
Evaluation Items for Adaptation Measures
・Impact on water quality(Water quality standard items).

Aquatic Ecosystem
Study Items
・Change of the water temperature, quantity and qualityof water・Change of habitat
Evaluation Items for Adaptation Measures
・Impact on aquatic ecosystem(Representative species in river, lake, and sea)

5.Analysis of Previous Information
Macro-scale Analysis:
To clarify the water temperature changing trend
on a nationwide scale

Micro-scale Analysis:
To analysis the impact on water temperature,quantity of water , water quality, and aquatic ecosystem
To analysis the relation among water temperature, quantityof water , water quality, and aquatic ecosystem

Macro-scale Analysis
All Water quality analysis points on nationwide (in 2007)
8,756 (6,053 in River, 529 in Lake, 2,174 in Sea )To select the artifact-free point
To select the points that have enough data
Points under analysis
1,484 (1,023 in River, 98 in Lake, 363 in Sea )Calculation of the average water temperature in summer season andWinter season

To select the points that show theincrease in water temperature
Points show the increase in water temperature
413 (272 in River, 28 in Lake, 113 in Sea )RiverAverage Water temperature in Summer season

Average Water temperature in Winter season

Lake
Average Water temperature in Summer season

Average Water temperature in Winter season

Sea
Average Water temperature in Summer season

Average Water temperature in Winter season

Increase in Summerand WinterIncrease in Summer
Increase in WinterNo TrendFuture Plan
The Results of Macro-scale Analysis
To select the points that are as less affected by humanactivities as possible

Micro-scale Analysis
To make detailed analysis of the relation among watertemperature, quantity of water ,water Quality, and aquaticEcosystem
Object : Selected River, Lake, and Sea
Years: 1971 - present
Items : Water temperature, COD, Nitrogen, Phosphorus,
Dissolved Oxygen

6.Investigation of Forecasting Model
Basic Requirement of Forecasting Model:
・It is necessary to evaluate the impact on water quality andaquatic ecosystem in public water body with climate
condition and effects by human activities.
・It is necessary to analyze the sequence of relationship.
( Climate Change – Water Environment – Water Quality– Aquatic Ecosystem )・It is necessary to analyze the watershed basin relationship.
( Climate Change – Watershed Basin – River – Lake – Sea)

Future Works:
・To establish the method of down scaling(Time and Space )・To correct the data
・To improve the analysis precision of forecast modelThank you for your attention!