Transcript HNRS379_S12_L23

Global Environmental Governance
James Gustave Speth and Peter M. Haas
Speth and Haas: Ten of the major global environmental challenges
are:
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5.
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10.
Acid rain and regional air pollution
Ozone depletion
Climate disruption [global climate change]
Deforestation
Land degradation and desertification
Freshwater degradation and shortages
Marine fisheries decline
Toxic pollutants
Loss of biological diversity
Excess nitrogen
Acid Rain
EPA
Acid Rain
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Effects
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Terrestrial
Leaches minerals (nutrients, metals) from soil
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Damages leaves of plants
Aquatic
Irritates gills of aquatic organisms
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Interferes with gas exchange
Erodes slime layer of fishes
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Reduces resistance to pathogens
Erodes shells of aquatic mollusks and arthropods
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Facilitates desertification
Impedes ability of crustaceans to recalcify after molting
Facilitates release of toxins bound to particles in
sediments
Lu et al. 2010
Lu et al. 2010
Air Pollution – Components
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EPA – NAAQS for six criteria pollutants
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Particulate matter
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PM2.5, PM10
Carbon monoxide (CO)
Nitrogen oxides (NOx)
Sulfur oxides (SOx)
Ground-level ozone (O3)
Lead (Pb)
Piccadilly Circus, Dec. 1952
PM10 Concentrations, 2005
Red Line: US NAAQS, pre-2006
Matus et al. 2012
Air Quality (Tropospheric NO2)
Summer 2006
1945
1960
1974
Bahia
http://www.nybg.org/bsci/res/bahia/Defor.html
1990
Tropical Forest Loss
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Four major types
1)
Tropical rain forests
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2)
Moist deciduous forests
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3)
Usually less diverse than rain forests
Dry zone forests
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4)
More than 50% in Africa
Tropical upland forests
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More than half in Brazil (41%) and Indonesia (13%)
Includes cloud forests
Current Status
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Not all tropical rain forests are the same or under the
same pressures
Worldwide – ~66% cleared for agriculture
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Africa – Population growth & subsistence farming
Asia – Logging; subsistence farming increasing
Latin America – Ranching; subsistence farming
increasing
Tropical Forest Loss
Region
Land
Area
Forest
1980
Forest
1990
Area
Annual
Change % Loss
(million ha)
Africa
2236
568
527
-41
0.7%
Asia
892
350
311
-39
1.2%
Latin
1650
America
992
918
-74
0.8%
World
1910
1756
-154
0.8%
4778
http://www.fao.org/docrep/t4450e/T4450E0k.htm
Fresh Water
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Historically limiting factor in arid regions
1940-1990
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World population more than doubled
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Per capita water use doubled
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400 m3 person-1 year-1  800 m3 person-1 year-1
Global water use increased fourfold
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A.
2.3 billion  5.3 billion
2000: USA ~2000 m3 person-1 year-1 (~1450 gal day-1)
Current Status
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In 1996, world human population using estimated 54%
of all accessible fresh water in rivers, lakes, aquifers
Many people predict disastrous consequences for
world’s fresh water supply in coming years
This potential disaster may have several causes
Fresh Water
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Current Status
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Distribution
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Uneven compared to population
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75% of annual rainfall in areas containing less than
one-third of global population
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Amazon River carries 20% of global runoff through
area containing 10 million people
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Congo River carries 30% of Africa’s runoff through
area containing 10% of population
Uneven in space
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North America contains 19,000 m3 per person per
year vs. 4700 m3 per person per year in Asia
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<10% of Mexico supplies >50% of annual runoff
Uneven in time
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India gets 90% of annual rainfall during summer
monsoon season (Jun-Sep); runs off too rapidly for
efficient use
Fresh Water
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Current Status
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Usage patterns
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Agriculture – 69%
Industry/Energy – 23%
Domestic – 8%
Varies among regions and with development
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Africa – 88% for agriculture (irrigation)
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Europe – >50% for industry
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Japan – Industrial but uses lots of water to grow rice
Personal use tracks standard of living
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Africa – 17 m3 year-1 (12.3 gal d-1)
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Asia – 31 m3 year-1 (22.4 gal d-1)
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UK – 122 m3 year-1 (88.3 gal d-1)
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US – 211 m3 year-1 (153 gal d-1)
By 2020, water shortages likely in Ethiopia, India, Kenya,
Nigeria, China (parts of China already face problems)
Fresh Water
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Possible Solutions
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World may have enough fresh water but
inadequate distribution mechanism
Long pipelines and movement of icebergs
have been proposed
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Excessively expensive
Technological limitations
Fresh Water
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Possible Solutions
1.
Improved irrigation efficiency
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2.
Drip irrigation reduces losses from evaporation
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Cuts water use by 40-60% compared to conventional
systems
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Used on <1% of irrigated land worldwide but used
extensively in some countries
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Ex: Israel uses DI on 50% of irrigated land
Municipal conservation
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Infrastructural losses can be substantial
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Ex: 40-70% of water lost in transit in 15 major
Mexican cities (similar rates in India)
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Ex: Djakarta, Indonesia could cut water losses an
estimated 20% by fixing leaky distribution pipes;
would save ~12 billion gallons of water a year,
enough to supply 800,000 people
Higher price could encourage conservation
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Ex: Bogor, Indonesia increased water prices 3-4x;
average household water use dropped by 30% in
less than one year
Fresh Water
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Possible Solutions
3.
Reuse of urban wastewater
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Use of treated wastewater for irrigation
Today, at least half a million hectares in 15 countries are
being irrigated with “gray water”
More water-efficient industry
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Practiced in industrialized nations.
Amount of water needed to produce a ton of steel ranges
from 23 to 56 m3 in China, compared to an average of
less than 6 m3 in US, Japan, and Germany
Desalination
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2010: Over 20 billion gallons of fresh water produced
daily in ~15,000 facilities worldwide
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Minimum cost = 0.2¢ gal-1
Current methods of desalination driven almost entirely
by combustion of fossil fuels
Solar powered desalination plants produced only 1.4
million gal d-1 in 2009
USA Today
Stratospheric Ozone Depletion
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Industrial processes release halocarbons
and other gases into the atmosphere,
reacting with ozone and destroying the
ozone layer
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More pronounced in colder Antarctic than Arctic
Reduced protection from harmful ultraviolet
radiation
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Ozone normally reacts with uv light but is
regenerated
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O3 + uv light  O2 + O
In presence of HCs and other compounds that
contain Cl
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O3 + Cl  O2 + ClO
Deforestation
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Less than 20% of original forest cover
remains in many countries
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Philippines, Madagascar
Loss of CO2 uptake capacity
Biomass burning
Decomposition of organic material
Increased erosion/nutrient loss
Water Pollution – Nutrients
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Nitrogen, phosphorus
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Common sources
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2)
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4)
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Crop and lawn fertilizers
Manure
Sewage
Detergents containing phosphates and nitrates
Excessive nutrient loading  eutrophication
Effects
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4)
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Plant growth can clog waterways (ecology, navigation)
Plants can interfere with recreation (swimming, boating)
Nighttime oxygen depletion
Nitrate  methemoglobinemia (blue baby syndrome)
Nutrients can be difficult to control once in a system
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Recycling and regeneration
Eutrophied water bodies can recover if sources are
removed
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Ex – Lake Washington
Kiely 1997 Environmental Engineering