A post-Kyoto partner: Considering the ozone regime as a venue to manage nitrous oxide

David KanterA.R. Ravishankara

Ian Porter

November 13, 2012MOP 24 – Geneva, Switzerland

Outline

• Preview of forthcoming paper: “A post-Kyoto partner: Considering the ozone regime as a venue to manage nitrous oxide” – under review at the Proceedings of the National Academy of Science

• Authors: David Kanter (Princeton), Denise Mauzerall (Princeton), A.R. Ravishankara (NOAA), John Daniel (NOAA), Bob Portmann (NOAA), Pete Grabiel, Bill Moomaw (Tufts), Jim Galloway (U. of Virginia)

• Paper goal: An objective examination of major scientific, legal, technical and policy issues surrounding a potential decision by the Parties to take on N2O

ODP depends on:amount of sulfate aerosol, chlorine, and T

Ozone Depletion Potential of N2O

ODP of N2O = 0.017

To our knowledge, this is the first time ODP of N2O was calculated as in the case of the Montreal Protocol gases

4N2O side event_13Nov_2012. Geneva 2012

Compare 0.017 for N2O with:HCFC-123 = 0.02; HCFC-124 = 0.022; HCFC-225ca = 0.025; HCFC-225cb = 0.033

A significant part of N2O emission is of human origin

Preindustrial level ~270 parts per billion (ppb) Increases in N2O is due to human activity Anthropogenic sources: agricultural fertilization, combustion, industrial production,

etc.

5N2O side event_13Nov_2012. Geneva 2012

Current level ~325 ppb [N2O] increasing at ~0.25% (of total) per year; i.e., ~1% of anthropogenic

component per year.

Emissions, concentrations, and human-influenced contributions

6

Large Natural Emissions Even larger natural concentrations- due to lifetime and previous

emissions Anthropogenic concentrations growing rapidly Very similar to CO2!

12

12

Current Emissions Current Atmospheric Concentrations

Anthropogenic

Natural

6.7 TgN/yr

11 TgN/yr

55 ppbv

270 ppbv

N2O side event_13Nov_2012. Geneva 2012

ODP alone does not tell the story

ODP-weighted emission of anthropogenic N2O

ODP-weighted-emission of anthropogenic N2O was the fourth largest

emission even in 1987, i.e., prior to the MP.

Anthropogenic N2O is now the largest ozone depletion gas emission

N2O’s ODP is small- but its emissions are large

If unabated, it will continues its growth in the 21st century; even the most

optimistic projections shows an increasing N2O trendN2O side event_13Nov_2012. Geneva 2012 7

Ozone layer benefit of reducing a GHG

8N2O side event_13Nov_2012. Geneva 2012

Summarizing N2O issues

1. N2O, when viewed as any other ozone-depleting substance (CFCs, Halons, methyl bromide,…), has an ODP of ~0.02.

2. ODP weighted emission of anthropogenic N2O is very large

3. Anthropogenic N2O is now the largest manmade ozone-depleting gas emission (a recent development owing to the successful abatement of CFCs and other ODSs under the Montreal Protocol!), and it will remain so for the next century if anthropogenic emissions of N2O are unabated.

4. Reductions in N2O emissions or stabilization of N2O will have climate and ozone layer benefits.

9N2O side event_13Nov_2012. Geneva 2012

Why wasn’t N2O considered before?

Ozone regime’s legal authority

• N2O is largest known remaining anthropogenic threat to stratospheric ozone layer (Ravishankara et al. 2009)

• Neither VC nor MP define “ozone depleting substance” for purposes of inclusion under ozone regime (Art. 1, MP & VC)

• N2O included in list of substances that “modify the chemical and physical properties of the ozone layer” under VC (Art. 3 & Annex I at (4)(b))

N2O could therefore be controlled under ozone regime

Legal pathways for N2O’s inclusion

• Amendment to MP (Art. 2(10) – MP) or new protocol under VC (Art. 2, 8 – VC)

• Historical focus on regulating production and consumption could be useful for managing agricultural N2O emissions e.g. fertilizer efficiency standards

Interaction with current and post-2012 climate regime

• Establishing controls for N2O under ozone regime consistent with UNFCCC principles & ultimate objective (Article 2-3, UNFCCC).

• UNFCCC already delegates responsibility (aviation to ICAO, marine bunker fuels to IMO).

• Legal provisions could limit potential conflicts of authority (Grabiel & Roberts, 2010)

• Post-2012 climate regime in flux

Emissions & mitigation opportunities

Non-agricultural N2O mitigationSector Percentage of

total anthro. N2O emissions

Technology and/or practice

Mitigation potential

Mitigation co-benefits

Nitric & adipic acid Production

<4% Catalytic reduction

>90% NOx

Biomass burning

8%-9% Conservation tillage, wildfire prevention education…

Highly variable CO2, CH4, CO, PM (2.5 & 10), black carbon, sulphates, NOx

Stationary & mobile combustion

8%-14% Oxidation catalysts, catalytic reduction…

~70%, ~80%respectively

NOx

References – SEI (2010), IPCC (2006), EPA (2006), EPA (2012), Winiwarter (2005)

Agriculture - Behavior

• Fertilizer best management practices (Robertson & Vitousek 2009):• Crop residue recycling & use of cover crops• Precision & split fertilizer application • Watershed management• Livestock management• 4Rs: Right product, right rate, right time, right

place (IFA, 2007)• Consumer behavioral changes – food wastage, meat

consumption…

Agriculture - TechnologyTechnology Mitigation

potentialCurrent use Mitigation co-

benefits

Nitrification inhibitors

~35% High value crops, ~12% US corn cropland

NO3-, NH3, NOx

Controlled-release fertilizer

~40% High value crops, <1% of US corn cropland

NO3-, NH3, NOx

Genetically engineered crops/breeding

~30% NA NO3-, NH3, NOx

References – Mosier et al. (2004), Akiyama et al. (2009), O’Brien & Mullins (2009), Shrawat et al. (2008)

Nitrification inhibitors in action

• Ian Porter presentation

Existing policies - Direct

• Non-agricultural N2O:• UNFCCC Kyoto Protocol • EU Emissions Trading Scheme (ETS) • US EPA/Dept. of Transportation • Australia Carbon Tax & UK Climate Change Act

• Agricultural N2O:• Alberta Quantification Protocol for Agricultural N2O Emissions

Reductions (Canada)• Carbon Farming Initiative (Australia)• American Carbon Registry• US Climate Action Reserve

Existing policies - Indirect

• Reactive N (indirect impact on N2O):• Water Framework Directive (EU) – NO3

-

• Safe Drinking Water Act, Clean Water Act, Clean Air Act (USA) – NO3

-, NOx, NH3

• Convention on Long Range Transport of Air Pollution (1988 Sofia Protocol, 1999 Gothenburg Protocol) – NOx, NH3

Challenges & opportunities to managing agricultural N2O

• Food security– How to preserve and increase crop yields while reducing

N2O?

• Equity– How to allow regions that vastly under-fertilize to

increase fertilizer use while globally reducing N2O?

• Nitrogen cascade– Tight coupling of N cycle means that one atom of

nitrogen can cascade through a variety of chemical forms, each with a different impact on environment

Conclusions

• N2O largest remaining known anthropogenic threat to stratospheric ozone layer

• Ozone regime’s legal authority and possibility of cooperation with climate regime clear

• Mitigation opportunities exist across all major sectors• Challenges & opportunities exist for any international

attempt to manage N2O• Could mark welcome expansion of sustainable

development diplomacy

Possible next steps

• Parties could request TEAP scoping report (“Task Force”) on technical & economic feasibility of specific N2O control strategies

• MLF could look to its experience with MeBr for general lessons on dealing with agricultural sector

• Implementation strategy could begin with point sources, then expand