Global Change Rodel D. Lasco. What is Global Change? Global changes are environmental changes that...
-
Upload
heather-simmons -
Category
Documents
-
view
218 -
download
4
Transcript of Global Change Rodel D. Lasco. What is Global Change? Global changes are environmental changes that...
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.