Global ChangeGlobal ChangeGlobal ChangeGlobal Change

Rodel D. LascoRodel D. Lasco

What is Global Change?• Global changes are environmental changes

that threaten the capacity of the whole earth system to sustain life

What is Climate Change?

• UNFCCC: “Climate change: 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”

• IPCC: “any change in climate over time, whether due to natural variability or as a result of human activity”.

What can we do?

• Reduce fossil fuel emissions• Control deforestation• Promote forest conservation and

tree planting

Land use and cover change

• Land cover refers to vegetation and other materials that cover the surface of the Earth

• In recent decades, the scale of land cover and ecosystems change has accelerated

Forests land conversion

Fig. 3 Area of secondary (residual) forest and primary forest in the Philippines (Source: FMB, various dates)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

1971 1972 1975 1976 1977 1978 1979 1980 1981 1984 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997

Year

Area

('00

0 ha

)

Secondary Forest

Primary forest

Total Log Production vs Log Imports

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

4,000,000

4,500,000

5,000,000

1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998

Year

CU

M TLA production

Log Imports

Roundwood Exports and Imports

0

1000000

2000000

3000000

4000000

5000000

6000000

7000000

8000000

9000000

Year

1970

-71

1971

-72

1972

-73

1973

-74

1974

-7519

7619

7719

7819

7919

8019

8119

8219

8319

8419

8519

8619

8719

8819

8919

9019

9119

9219

9319

9419

9519

9619

9719

98

Year

Vo

lum

e

0

50000000

100000000

150000000

200000000

250000000

300000000

Va

lue

, U

S$ Imp $

Exp Volume

Imp Volume

Exp $

Impacts of forest loss• Biodiversity loss• Accelerated soil erosion• Impaired hydrology• Poverty in the uplands

Interannual climate variability

• most famous is ENSO (El Niño-Southern Oscillation) phenomenon

• exceptionally strong warm current intervals • increased rainfall in east Pacific and

drought in west Pacific • recurs every 2-9 years • 1982-83 El Niño episode: damages in the

country reached US$ 450 million

Ozone depletion• Life on Earth is protected from harmful

ultraviolet solar radiation by the ozone layer located between 20 and 40 km

• In 1974, it is discovered that chlorine-containing compounds such as chlorofluorocarbons (CFCs) and halons could damage the stratospheric ozone layer

• One chlorine atom from a CFC molecule can destroy thousands of protective ozone molecules

Ozone (cont)

• Satellite imageries have revealed the presence of a seasonal “ozone hole” above the Antarctic stratosphere

• Increased UV radiation has harmful effects on human health, fish populations, and many terrestrial and marine ecosystems.

• Impacts on humans and other animals include: immune system suppression, cataracts and epidermal lesions, reduced vitamin D synthesis, and cancer.

Ozone (cont)

• The global community responded to the threat of ozone depletion through the Vienna Convention and the Montreal Protocol.