Nitrogen Deposition
Effects of Ammonia
Ammonia Workshop
National Atmospheric Deposition Program
October 22-24, 2003
Washington, DC
USA
Contrasting NOx and NH3
 Historical
focus on NOx
 Growing focus on NH3
 Similarities
– Both have point and mobile sources
– Both, once emitted can be converted to any
other N species
 Both
contribute to all the N-related impacts.
Reactive N



vs
Unreactive N2
Unreactive N is N2 (78% of earth’s atmosphere)
Reactive N (Nr) includes all biologically, chemically and physically
active N compounds in the atmosphere and biosphere of the Earth
N controls productivity of most natural ecosystems
Reactive N





vs
Unreactive N2
Unreactive N is N2 (78% of earth’s atmosphere)
Reactive N (Nr) includes all biologically, chemically and physically
active N compounds in the atmosphere and biosphere of the Earth
N controls productivity of most natural ecosystems
Nature converts N2 to Nr by biological nitrogen fixation (BNF).
Humans convert N2 to Nr by fossil fuel combustion, the Haber
Bosch process, and cultivation-induced BNF.
Reactive N






vs
Unreactive N2
Unreactive N is N2 (78% of earth’s atmosphere)
Reactive N (Nr) includes all biologically, chemically and physically
active N compounds in the atmosphere and biosphere of the Earth
N controls productivity of most natural ecosystems
Nature converts N2 to Nr by biological nitrogen fixation (BNF)
Humans convert N2 to Nr by fossil fuel combustion, the Haber
Bosch process, and cultivation-induced BNF.
Primary Conclusions
–
–
–
–
Humans create more Nr than do natural terrestrial processes.
Nr is accumulating in the environment.
Nr accumulation contributes to most environment issues of the day.
NHx and its conversion products are key components.
Objectives
 Contrasting
NOx and NH3
 Human Alteration of N Cycle
– An agrarian to an industrializing world
 The
Consequences of Anthropogenic Nitrogen
(including NH3).
– Nitrogen is nutritious
– Nitrogen cascades
 Challenges!
The History of Nitrogen
--N becomes limiting?-7,000
200
6,000
150
5,000
4,000
100
3,000
2,000
N-Discovered N-Nutrient
BNF
50
1,000
0
1750
1800
1850
Humans, millions
1900
1950
2000
0
2050
Legumes/Rice, T g N
Galloway JN and Cowling EB. 2002; Galloway et al., 2003a
The History of Nitrogen
--N becomes limiting?-7,000
200
6,000
150
5,000
4,000
3,000
2,000
World is running out of N*
N-Discovered N-Nutrient
100
BNF
50
1,000
0
1750
1800
1850
Humans, millions
1900
1950
2000
0
2050
Legumes/Rice, T g N
*1898, Sir William Crookes, president of the British Association for the Advancement of Science
Galloway JN and Cowling EB. 2002; Galloway et al., 2003a
Fritz Haber (1868-1934)
Began work on NH3, 1904
First patent, 1908
Commercial-scale test, 1909
Developed Cl2 gas production, 1914
Nobel Prize in Chemistry, 1918
-”for the synthesis of ammonia from its elements”
Carl Bosch (1874-1940)
The perfect catalyst, 1910
Large-scale production, 1913
Ammonia to nitrate, 1914
Nobel Prize in Chemistry, 1931
-”chemical high pressure methods”
Smil, 2001
The History of Nitrogen
--Nr Creation, Haber Bosch process-7,000
200
6,000
150
5,000
N2 + 3H2
--> 2NH3
4,000
100
3,000
2,000
N-Discovered N-Nutrient
BNF
50
1,000
0
1750
1800
Humans, millions
1850
1900
Haber Bosch
1950
2000
0
2050
Legumes/Rice, T g N
Galloway JN and Cowling EB. 2002; Galloway et al., 2003a
The History of Nitrogen
--Nr Creation: Fossil Fuel Combustion-7,000
200
6,000
150
5,000
N2 + 3H2
--> 2NH3
4,000
100
3,000
2,000
N-Discovered N-Nutrient
BNF
50
1,000
0
1750
1800
Humans, millions
1850
1900
1950
Energy Production
2000
0
2050
Food Production
Galloway JN and Cowling EB. 2002; Galloway et al., 2003a
The History of Nitrogen
--Nr Creation, People and Nature-7,000
200
*
6,000
150
5,000
N2 + 3H2
--> 2NH3
4,000
{
3,000
2,000
100
Natural Range,
terrestrial
N-Discovered N-Nutrient
*
1,000
0
1750
1800
1850
Humans, millions
BNF
1900
50
1950
2000
0
2050
T otal N Fixed, T g
Galloway JN and Cowling EB. 2002; Galloway et al., 2003a
Nitrogen Drivers in 1860
Grain
Production
Meat
Production
Energy
Production
The Global Nitrogen Budget in 1860 and mid-1990s, TgN/yr
1860
NOy
5
N2
NHx
8
6
7
6
120
0.3
6
15
9
11 8
27
Galloway et al., 2003b
Nitrogen Drivers in 1860 & 1995
Grain
Production
Meat
Production
Energy
Production
The Global Nitrogen Budget in 1860 and mid-1990s, TgN/yr
1860
NOy
5
N2
NHx
8
6
6
6
9
120
7
11 8
15
0.3
mid-1990s
27
NOy
5
N2
NHx
33
16
21
25
110
25
6
23 26
18
39
100
N2 + 3H2
48
2NH3
Galloway et al., 2003b
Nitrogen Deposition
Past and Present
mg N/m2/yr
5000
2000
1000
750
500
250
100
50
25
5
1860
1993
Galloway et al., 2003b
Nr and Agricultural Ecosystems

Haber-Bosch has facilitated
agricultural intensification

40% of world’s population is
alive because of it

An additional 3 billion people
by 2050 will be sustained by it

Most N that enters
agroecosystems is released to
the environment.
Nr and the Atmosphere




NOx emissions contribute to
OH, which defines the
oxidizing capacity of the
atmosphere
NOx emissions are responsible
for tens of thousands of excessdeaths per year in the United
States
O3 and N2O contribute to
atmospheric warming
N2O emissions contribute to
stratospheric O3 depletion
Nr and Terrestrial Ecosystems

N is the limiting nutrient in
most temperate and polar
ecosystems

Nr deposition increases and
then decreases forest and
grassland productivity

Nr additions probably decrease
biodiversity across the entire
range of deposition
Nr and Freshwater Ecosystems

Surface water acidification
– Tens of thousands of lakes
and streams
– Biodiversity losses

As reductions in SO2
emissions continue, Nr
deposition becomes more
important.
Nr and Coastal Ecosystems
• Increased algal productivity
• Shifts in community structure
• Harmful algal blooms
• Degradation of seagrass and algal
beds
• Formation of nuisance algal mats
• Coral reef destruction
• Increased oxygen demand and
hypoxia
• Increased nitrous oxide (greenhouse
gas)
Sybil Seitzinger, 2003
There are significant effects
of Nr accumulation within each
reservoir
These effects are linked temporally
and biogeochemically in the
Nitrogen Cascade
Atmosphere
Terrestrial
Ecosystems
Food
Production
NHx
Agroecosystem Effects
Crop
People
(Food; Fiber)
Animal
Soil
Norg
Human Activities
The Nitrogen
Cascade
Galloway et al., 2003a
Aquatic Ecosystems
Atmosphere
PM &
Visibility
Effects
Food
Production
NHx
NH3
Agroecosystem Effects
Crop
People
(Food; Fiber)
Human Activities
The Nitrogen
Cascade
Galloway et al., 2003a
Animal
Soil
Terrestrial
Ecosystems
Forests &
Grassland
Soil
Norg
Groundwater
Effects
Surface water
Effects
Coastal
Effects
Ocean
Effects
Aquatic Ecosystems
Atmosphere
PM &
Visibility
Effects
Food
Production
NHx
NH3
Agroecosystem Effects
Crop
People
(Food; Fiber)
Human Activities
The Nitrogen
Cascade
Galloway et al., 2003a
Animal
Soil
Norg
Terrestrial
Ecosystems
Forests &
Grassland
Soil
NO3
Groundwater
Effects
Surface water
Effects
Coastal
Effects
Ocean
Effects
Aquatic Ecosystems
Atmosphere
PM &
Visibility
Effects
Ozone
Effects
NOx
Energy
Production
Food
Production
NOx
NHx
NH3
Agroecosystem Effects
Crop
People
(Food; Fiber)
Human Activities
The Nitrogen
Cascade
Galloway et al., 2003a
Animal
Soil
Norg
Terrestrial
Ecosystems
Forests &
Grassland
Soil
NO3
Groundwater
Effects
Surface water
Effects
Coastal
Effects
Ocean
Effects
Aquatic Ecosystems
Atmosphere
PM &
Visibility
Effects
Ozone
Effects
NOx
Energy
Production
Food
Production
NOx
NHx
NH3
Agroecosystem Effects
Crop
People
(Food; Fiber)
Human Activities
The Nitrogen
Cascade
--Indicates denitrification potential
Animal
Soil
Norg
Terrestrial
Ecosystems
Forests &
Grassland
Soil
NO3
Groundwater
Effects
Surface water
Effects
Coastal
Effects
Ocean
Effects
Aquatic Ecosystems
Stratospheric
Effects
Atmosphere
PM &
Visibility
Effects
Ozone
Effects
NOx
Energy
Production
Food
Production
NOx
NHx
NH3
Agroecosystem Effects
Crop
People
(Food; Fiber)
Human Activities
The Nitrogen
Cascade
--Indicates denitrification potential
Animal
Soil
Norg
Terrestrial
Ecosystems
GH
Effects
N2O
Forests &
Grassland
Soil
NO3
N2O
Groundwater
Effects
Surface water
Effects
Coastal
Effects
Ocean
Effects
Aquatic Ecosystems
Hog Production in USA
(1 dot= 10,000 Hogs and Pigs)
Meat Consumption in North America
(kg/capita/year)
140
120
100
80
60
Hogs and Pigs
40
20
0
1960
1965 1970
1975 1980
1985 1990
1995 2000
Conclusions
 NH3
contributes to every N-related issue
– Directly or indirectly
 Nr
and NHx are accumulating in
environmental reservoirs
 The impacts of N accumulation are
significant and inter-related
 NH3 emissions will increase with time
 There is need for an integrated approach to
manage N!
Meat Consumption in North America
(kg/capita/year)
140
120
100
80
Layers &
Pullets
(60,000/dot)
60
40
20
0
1960
1965 1970
1975 1980
1985 1990
1995 2000
Nr Creation Rates by Food and
Energy Production in 2050
2050
today
Nr Creation Rates
1995 (left) and 2050 (right)
TgN/yr
2050 rates scaled by:
-> population increase relative to 1995
after Galloway and Cowling, 2002
Nr Creation Rates
1995 (left) and 2050 (right)
TgN/yr
2050 rates scaled by:
-> population increase relative to 1995
-> N. Amer. per capita Nr creation in 1995
after Galloway and Cowling, 2002
The Fate of Haber-Bosch Nitrogen
N Fertilizer
Produced
100
Galloway JN and Cowling EB. 2002
The Fate of Haber-Bosch Nitrogen
N Fertilizer
Produced
100
N
Consumed
14
14% of the N produced in the Haber-Bosch process enters the
human mouth……….
Galloway JN and Cowling EB. 2002
The Fate of Haber-Bosch Nitrogen
N Fertilizer
Produced
N Fertilizer
Consumed
100
94
-6
-47
N
in Crop
N
Harvested
47
31
-16
N
in Food
N
Consumed
14
26
-5
-12
14% of the N produced in the Haber-Bosch process enters the
human mouth……….if you are a vegetarian.
Galloway JN and Cowling EB. 2002
The Fate of Haber-Bosch Nitrogen
N Fertilizer
Produced
N Fertilizer
Applied
100
94
-6
-47
N
in Crop
N
In Feed
47
31
-16
N
in Store
N
Consumed
7
-24
4
-3
4% of the N produced in the Haber-Bosch process and used
for animal production enters the human mouth.
Galloway JN and Cowling EB. 2002
Nr Riverine Fluxes
1860 (left) and 1990 (right)
TgN/yr
-> all regions increase riverine fluxes
-> Asia becomes dominant
Galloway et al, 2003b; Boyer et al., in preparation
Nr Formation
vs.
Nr Conversion back to N2
N2
160 Tg N/yr
Nr
Nr Formation
vs.
Nr Conversion back to N2
N2
160 Tg N/yr
??
Nr
• Is anthropogenic Nr accumulating in environmental systems?
• If so, where relative to point of introduction?
• If so, on what time scale?
Nr Formation
vs.
Nr Conversion back to N2
N2
160 Tg N/yr
Nr
< 160 Tg N/yr
• Is anthropogenic Nr accumulating in environmental systems?
• If so, where relative to point of introduction?
• If so, on what time scale?
• Nr is accumulating in the atmosphere.
• Nr is accumulating in terrestrial systems.
• Once Nr enters water (streams, rivers, estuaries) most will
eventually denitrify but generally far from point of entry.
• Accumulation occurs on short- and long-time scales.
International Nitrogen Initiative
 Formed in December 2002; SCOPE & IGBP sponsors
 Objective
optimize nitrogen’s beneficial role in sustainable food production
and minimize nitrogen’s negative effects on human health and
the environment resulting from food and energy production.
 Preliminary assessment in December 2004.
International Nitrogen Initiative
Approach
 establish Regional Centers for North America, Latin
America, Asia, Oceania, Europe and Africa
 use a three-phased approach, designed around the
program objectives, to work towards the overall goal of
the INI
Phase I: Assessment of knowledge on N flows and
problems
Phase II: Development of region-specific solutions.
Phase III: Implementation of scientific, engineering and
policy tools to solve problems.
 activities for a given Center will depend upon the
‘maturity’ of nitrogen science and policy for that region.
The Components of INI
politics
rivers
estuaries
forest
productivity
troposphereAfrica
emissions
North America
methemoglinemia
ocean CAFOs stratospheric ozone
decomposition policy
Imports/exports
legumes
Europe
fossil fuel combustion
forests
human health
economics
deposition manure
wetlands
assimilation eutrophication
nitrogen fixation
haze
Asia
agroecosystems
stratosphere
grasslands
Latin America
food production
denitrification
smog
nitrification
freshwaters
Oceania
Biodiversity losses
acid rain
fertilizers
cities
The Components of INI
politics
rivers
estuaries
forest
productivity
troposphereAfrica
emissions
North America
methemoglinemia
ocean CAFOs stratospheric ozone
decomposition policy
Imports/exports
legumes
Europe
fossil fuel combustion
forests
human health
economics
deposition manure
wetlands
assimilation eutrophication
nitrogen fixation
haze
Asia
agroecosystems
stratosphere
grasslands
Latin America
food production
denitrification
smog
nitrification
freshwaters
Oceania
Biodiversity losses
acid rain
fertilizers
cities
Phase I: Assessment of Science and
Identification of Problems
The N Biogeochemical Cycle
Systems
stratosphere
troposphere
cities
forests
grasslands
agroecosystems
wetlands
freshwaters
estuaries
ocean
Phase I: Assessment of Science and
Identification of Problems
The N Biogeochemical Cycle
Systems
stratosphere
troposphere
cities
forests
grasslands
agroecosystems
wetlands
freshwaters
estuaries
ocean
Processes
nitrogen fixation
assimilation
decomposition
nitrification
denitrification
Phase I: Assessment of Science and
Identification of Problems
The N Biogeochemical Cycle
Systems
stratosphere
troposphere
cities
forests
grasslands
agroecosystems
wetlands
freshwaters
estuaries
ocean
Processes
nitrogen fixation
assimilation
decomposition
nitrification
denitrification
Exchanges
emissions
deposition
imports/exports
rivers
Phase I: Assessment of Science and
Identification of Problems
The N Biogeochemical Cycle
Systems
stratosphere
troposphere
cities
forests
grasslands
agroecosystems
wetlands
freshwaters
estuaries
ocean
Processes
nitrogen fixation
assimilation
decomposition
nitrification
denitrification
Exchanges
emissions
deposition
imports/exports
rivers
Energy
Food
People
Phase I: Assessment of Science and
Identification of Problems
The N Biogeochemical Cycle
Systems
stratosphere
troposphere
cities
forests
grasslands
agroecosystems
wetlands
freshwaters
estuaries
ocean
Processes
nitrogen fixation
assimilation
decomposition
nitrification
denitrification
Exchanges
emissions
deposition
imports/exports
rivers
Energy
Food
People
Impacts
stratospheric ozone
smog
haze
acid rain
human health
eutrophication
biodiversity losses
forest productivity
Phase II: Development of Solutions
Phase III: Implementation of Solutions
Impacts
stratospheric ozone
smog
haze
acid rain
human health
eutrophication
biodiversity losses
forest productivity
These impacts can be lessened by
reducing the amount of reactive N
created and by converting reactive
N to N2.
To achieve these goals, while
maintaining food and energy
production, requires engineers,
policy makers, economists,
resource managers,etc. working in
a regional context.
International Nitrogen Initiative
Current Status
 Formed in December 2002
 Sponsored by SCOPE and IGBP
 INI has a 15-person Scientific Advisory
Committee
 members from Brazil, China, France, Netherlands,
Japan, South Africa, Sweden, Thailand,Uganda,
United Kingdom, United States
 First SAC meeting is hosted by Dutch
Government
 May 12-14, 2003, The Hague
The Challenge to all Parties
Maximize food and energy production
while maintaining environmental and
human health!