Climate Change Impacts and Potential Adaptation Strategies in Watersheds in the Philippines

Rodel D. LascoProfessor

University of the Philippines

7 Steps of Climate Impacts and Adaptations Assessment (UNEP, 1996)

DEFINING PROBLEM

SELECT METHOD

TEST METHOD/SENSITIVITY

FORMULATE INPUTS ANDASSUMPTIONS

ASSESS BIOPHYSICAL AND SOCIO-ECONOMIC IMPACTS

ASSESS AUTONOMOUS ADJUSTMENT

EVALUATE ADAPTATION STRATEGIES

1

2

3

4

5

6

7

APF Project Example (UNEP, 2003)

1. Scope project design

2. Assess Current Vulnerability

3.Characterise Future Climate-related Risks

4. Develop Adaptation Strategy

5. Continue Adaptation Process

EngageStake-holders

IncreaseAdaptivecapacity

Water Resources

Impacts of Climate Change on Water Resources

Increase in volume Decrease in streamflow Increase severity, frequency and

variability Increase in soil erosion and

sedimentation Increase in the demand for water

Table 1. Changes in precipitation, temperature, and runoff for Angat water reservoir from three GCMs (based on 2xCO2)

Source: Jose et al., 1996

GCM Change in Precipitation

Change in Temperature

(°C)

Change in Runoff

CCCMUKMOGFDL

-6%3%

15%

+2.0+3.1+2.4

-12%5%

32%

Comparison of Observed and Calibrated Daily Streamflow

-5.0000

0.0000

5.0000

10.0000

15.0000

20.0000

25.0000

30.0000

35.0000

40.0000

12/1/96 1/20/97 3/11/97 4/30/97 6/19/97 8/8/97 9/27/97 11/16/97 1/5/98 2/24/98

DATE

Str

eam

flow

(m2/s

)

OBSERVED CALIBRATED

Increase water supply Modify vegetation Impoundment Reduce evaporation Water importation

Adaptation Strategies

Decrease water demand Decrease water demanding activities Behavioral change Water reuse Recycling Economic instruments

Adaptation Strategies 2

Manage supply and demand Synchronize cropping systems to

match water availabilityMaximize multiple use of water

Adaptation Strategies 3

Table 5 Supply and demand adaptation strategies for the water resources sector of the Philippines

Source: Cruz, 2002

Supply Adaptation Demand AdaptationComprehensive watershed managementWater allocation system and procedures

Enhanced irrigation efficiencyLow water use crops and efficient farming practicesRecycling (reuse) of waterImprovement of monitoring and forecasting systems for floods and droughtsWater pricing policies and structuresEnhanced awareness of climatic change and variability

Forest resources

Impacts on Forest Resources in the Philippines most of the forest resources of the country are

in watershed areas tropical forests will likely expand as

temperature and precipitation increase Increased forest clearing due to:

Droughts and floods Inc population and dec in arable lands

Increase vulnerability to fires

T change may lead to a loss of a few species of plants and animals

changes in T and precipitation may result to the outbreak of pests and diseases

Potential Adaptation Options (IPCC, 2001) Forest management used to long term

decisions under uncertain future market and biological conditions

Most adaptation will occur under managed forests

Salvaging dead and dying timber Replanting with species better suited to new

climate Planting genetically modified species Intensifying or decreasing management

Exotics vs indigenous species?

Biodiversityconservation