Agriculture and Air Pollution

Mark SuttonUnited Kingdom NERC Centre for Ecology & Hydrology

WGSR-55UNECE GenevaAir Convention

1 June 2017

TFRN

The Issues

• Nitrogen Flows and Pollution– Ammonia (NH3) emissions from manure and fertilizers– Nitric Oxide (NO) emissions from fertilized soils– Other key routes for agricultural pollution

• Nitrous oxide (N2O)• Nitrate leaching (NO3)• Di-nitrogen (N2)

• Methane from livestock and rice cultivation• Threats

– Human health, Ecosystems, Agricultural Crops

Nitrogen oxides(NOx)

Nitrous Oxide(N2O)

Ammonia(NH3)

Leached Nitrate (NO3

-)

Further emissionof NOx & N2O

carrying on the cascade

Natural ecosystems

Ammonium nitrate in rain (NH4NO3)

Nitrate in streams,groundwater &

coastal seas

High temperaturecombustion& industry

Nr

Livestock farmingfor food

Nr in manure

Eventual denitrification

to N2

Simplified view of the Nitrogen Cascade

Unintended N flows

N form in the cascade

Terrestrial Eutrophication

Freshwater Eutrophication

Greenhouse gas balance

Particulate Matter

Tropospheric ozone formation

Stratospheric ozone loss

Soil acidification

Urban air quality

Marine EutrophicationEnvironmental

concern from Nr

Fertilizermanufacture

Crops for food &animal feed

Crop biological nitrogen fixation

Intended N flow

European Nitrogen Assessment, 2011

The five key threats of excess Nitrogen

The WAGES of too much nitrogen

Water qualityAir qualityGreenhouse balanceEcosystems Soil quality

European Nitrogen Assessment, 2011

What is the priority for agricultural emissions?

€75-485 billion/y

Van Grinsven et al., ES&T, 2013 updating ENA

European nitrogen emissions expressed as lost fertilizer value

Loss as Nr to air: 8 M tonne/yrLoss as Nr to water: 5 M tonne/yrLoss as N2: 9 M tonne/yrTotal N loss: 22 M tonne/yrAt €0.8/kg N = €18 billion per year

Values for EU27 from ENA. Component N losses to air: NH3: 3.2 NOx: 3.5 N2O: 1.2 (M tonne/yr)

Gothenburg Protocol RevisionTFRN Five Priorities for Ammonia

1. Low emission land spreading2. Animal feeding strategies3. Covers on new slurry stores4. Farm N balances5. Low emission housing

Share of NOx emissions from agricultural soils is increasing – Need to include in future ceilings

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Anthropogenic NOx emissions and mineral N fertiliser consumption in Europe

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NO2-N emission N fertiliser consumption

http://ec.europa.eu/eurostat/data/database

Liu et al, Global Change Biology 23, 2017

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Agriculture and the Nitrogen Policy Arena

Biodiversity:CBD

Marine:GPA

+ regional

Stratosphere:Montreal Protocol

Air Quality: LRTAP + regional

INMSInternational Nitrogen Management System

(Science Support Process linking threats & benefits)

UNEA?

Climate:UNFCCC

Overarching Goals includingEconomy Wide Nitrogen Use Efficiency

More food and energy with less pollution

www.inms.international

Nitrogen Coordination Mechanism?

How can the Air Convention get the best from UNEA-3?

2007

Sphagnum Bog in Northern Ireland near a poultry farm

© Mark Sutton

How do damaged ecosystems look?

Recovering SphagnumBog in Northern Ireland

2017

© Mark Sutton

The bottom line

• Big emission reductions are possible for agriculture – it depends on political will

• Joining up agriculture and air pollution– NH3 mitigation options are now the “low-hanging fruit”– NOx from agricultural soils needs to be integrated– Multiple co-benefits in linking the N cycle (WAGES)– Joining up can help overcome the barriers– Profit opportunities in N mitigation: the Circular Economy