united nations environment program report - black carbon

8/7/2019 United Nations Environment Program Report - Black Carbon

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K1170637 190211

UNITEDNATIONS

EP UNEP/GC.26/INF/20

Governing Councilof the United NationsEnvironment Programme

Distr.: General

17 February 2011

English only

Twenty-sixth session of the Governing Council/

Global Ministerial Environment ForumNairobi, 2124 February 2011

Item 4 (a) of the provisional agenda

Policy issues: state of the environment

Summary for decision makers of the integrated assessment of

black carbon and tropospheric ozone

Note by the Executive Director

Summary

The Executive Director has the honour to provide, in the annex to the present note, a

prepublication version of the summary for decision makers of the Integrated Assessment of Black

Carbon and Tropospheric Ozone, as referred to in the report by the Executive Director on the state ofthe environment and contribution of the United Nations Environment Programme to meeting

substantive environmental challenges (UNEP/GC.26/4). It has been reproduced without formal

editing.

UNEP/GC.26/1.


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Integrated Assessmentof Black Carbonand Tropospheric Ozone

Summary for Decision Makers


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A complete elaboration of the topics covered in this summary can be found in the Integrated Assessment of Black Carbon and

Tropospheric Ozone report and in the fully referenced underlying research, analyses and reports.

For details of UNEPs regional and sub-regional areas referred to throughout this document see

http://geodata.grid.unep.ch/extras/geosubregions.php.

Copyright: UNEP and WMO 2011 Integrated Assessment of Black Carbon and Tropospheric Ozone: Summary for DecisionMakers.

This is a pre-publication version of the Summary for Decision Makers. Please do not cite page numbers from thisversion or quote from it. These materials are produced for informational purposes only and may not be duplicated.

UNEP/GC/26/INF/20

Disclaimers

The views expressed in this document are not necessarily those of the agencies cooperating in this project. The designations

employed and the presentation do not imply the expression of any opinion whatsoever on the part of UNEP and WMOconcerning the legal status of any country, territory or city or its authority, or concerning the delimitation of its frontiers or

boundaries.

Mention of a commercial company or product in this document does not imply endorsement by UNEP and WMO. The use of

information from this document for publicity or advertising is not permitted. Trademark names and symbols are used in aneditorial fashion with no intention on infringement on trademark or copyright laws.

We regret any errors or omissions that may have been unwittingly made.

Maps, photos and illustrations as specified.

Writing team: Coordinators Drew Shindell (National Aeronautics and Space Administration, Goddard Institute for SpaceStudies, USA) and Johan C. I. Kuylenstierna (Stockholm Environment Institute, University of York, UK); Writers Kevin Hicks

(Stockholm Environment Institute, University of York, UK), Frank Raes (Joint Research Centre, European Commission, Italy),

Veerabhadran Ramanathan (Scripps Institution of Oceanography, USA), Erika Rosenthal (Earth Justice, USA), Sara Terry (US

Environmental Protection Agency), Martin Williams (Kings College London, UK).

With inputs from: Markus Amann (International Institute for Applied Systems Analysis, Austria), Susan Anenberg (US

Environmental Protection Agency), Volodymyr Demkine (UNEP, Kenya), Lisa Emberson (Stockholm Environment Institute,

University of York, UK), David Fowler (The Centre for Ecology and Hydrology, UK), Liisa Jalkanen (WMO, Switzerland), Zbigniew

Klimont (International Institute for Applied Systems Analysis, Austria), N. T. Kim Oahn, (Asian Institute of Technology, Thailand),Joel Schwartz (Harvard University, USA), David Streets (Argonne National Laboratory, USA), Rita van Dingenen (Joint Research

Centre, European Commission, Italy), Harry Vallack (Stockholm Environment Institute, University of York, UK), Elisabetta Vignati(Joint Research Centre, European Commission, Italy).

With advice from the High-level Consultative Group especially: Ivar Baste (UNEP, Switzerland), Adrin Fernndez Bremauntz

(National Institute of Ecology, Mexico), Harald Dovland (Ministry of Environment, Norway), Dale Evarts (US EnvironmentalProtection Agency), Rob Maas (The National Institute for Public Health and the Environment, Netherlands), Pam Pearson

(International Cryosphere Climate Initiative, Sweden/USA), Sophie Punte (Clean Air Initiative for Asian Cities, Philippines),

Andreas Schild (International Centre for Integrated Mountain Development, Nepal), Surya Sethi (Former Principal Adviser

Energy and Core Climate Negotiator, Government of India), George Varughese (Development Alternatives Group, India), RobertWatson (Department for Environment, Food and Rural Affairs, UK).

Editor: Bart Ullstein (Banson, UK).

Design and layout: Audrey Ringler (UNEP, Kenya).

Printing: UNON/Publishing Services Section/Nairobi, ISO 14001:2004-certified.

Cover photographs: credits

1. Kevin Hicks

2. Caramel/ickr

3. Veerabhadran Ramanathan

4. Christian Lagerek/Shutterstock Images5. John Ogren, NOAA

6. Raphal V/ickr

7. Robert Marquez

8. Jerome Whittingham/Shutterstock Images9. Brian Tan/Shutterstock Images

UNEP promotes

environmentally sound practicesglobally and in its own activities. This

publication is printed on 100% recycled paper

using vegetable based inks and other eco-

friendly practices. Our distribution policy aims to

reduce UNEPs carbon footprint.

1 2

4 5

7 8 9

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Table of Contents

Main Messages 1The challenge 1

Reducing emissions 2

Benetsof emissionreductions 3

Responses 3

Introduction 5

Limiting Near-Term Climate Changes and Improving Air Quality 8

Identifyingeffectiveresponsemeasures 8

Achievinglargeemissionreductions 8

Reducingnear-termglobalwarming 10

Stayingwithincriticaltemperaturethresholds 12

Benetsofearlyimplementation 13

Regionalclimatebenets 13

TropicalrainfallpatternsandtheAsianmonsoon 13

Decreasedwarminginpolarandotherglaciatedregions 15

Benetsof themeasuresforhumanhealth 16

Benetsofthemeasuresforcropyields 16

Relativeimportanceandscienticcondenceinthemeasures 18

Mechanismsforrapidimplementation 19

Potentialinternationalregulatoryresponses 22

Opportunitiesforinternationalnancingandcooperation 23

Concluding Remarks 24

Glossary 25

Acronyms and Abbreviations 27

Acknowledgements 28


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Summary or Decision Makers

Main Messages

Scientic evidence and new analyses demonstrate that control of black carbon

particles and tropospheric ozone through rapid implementation of proven

emission reduction measures would have immediate and multiple benets for

human well-being

Blackcarbonexistsasparticlesintheatmosphereandisamajorcomponentofsoot,ithas

signicanthumanhealthandclimateimpacts.Atgroundlevel,ozoneisanairpollutantharmful

tohumanhealthandecosystems,andthroughoutthetroposphere,orloweratmosphere,isalso

asignicantgreenhousegas.Ozoneisnotdirectlyemitted,butisproducedfromemissionsof

precursorsofwhichmethaneandcarbonmonoxideareofparticularinteresthere.

THE CHALLENGE1 The climate is changing now, warming at the highest rate in polar and high-

altitude regions Climatechange,eveninthenearterm,hasthepotentialtotrigger

abrupttransitionssuchasthereleaseofcarbonfromthawingpermafrostandbiodiversity

loss.Theworldhaswarmedbyabout0.8Cfrompre-industriallevels,asreportedbythe

Traditional brick kilns in South Asia are a major source o black carbon. Improved kiln design in this region issignicantly reducing emissions.

Credit:KevinHicks


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Integrated Assessment o Black Carbon and Tropospheric Ozone

IntergovernmentalPanelonClimateChange(IPCC).ThePartiestotheUnitedNations

FrameworkConventiononClimateChange(UNFCCC)haveagreedthatwarmingshould

notexceed2Cabovepre-industriallevels.

2 Black carbon and ozone in the lower atmosphere are harmful air pollutants

that have substantial regional and global climate impacts Theydisturb

tropicalrainfallandregionalcirculationpatternssuchastheAsianmonsoon,affectingthe

livelihoods of millions of people

3 Black carbons darkening of snow and ice surfaces increases their absorption

of sunlight, which, along with atmospheric heating, exacerbates melting of

snow and ice around the world, including in the Arctic, the Himalayas and

other glaciated and snow-covered regions Thisaffectsthewatercycleandincreases

risksofooding.

4 Black carbon, a component of particulate matter, and ozone both lead to

adverse impacts on human health leading to premature deaths worldwideOzone is also the most important air pollutant responsible for reducing crop

yields, and thus affects food security.

REDUCINGEMISSIONS

5 Reducing black carbon and tropospheric ozone now will slow the rate of

climate change within the rst half of this century. Climate benets from

reduced ozone are achieved by reducing emissions of some of its precursors,

especially methane which is also a powerful greenhouse gas.Theseshort-lived

climateforcersmethane,blackcarbonandozonearefundamentallydifferentfromlonger-livedgreenhousegases,remainingintheatmosphereforonlyarelativelyshorttime.

Deepandimmediatecarbondioxidereductionsarerequiredtoprotectlong-termclimate,

asthiscannotbeachievedbyaddressingshort-livedclimateforcers.

6 A small number of emission reduction measures targeting black carbon and

ozone precursors could immediately begin to protect climate, public health,

water and food security, and ecosystems.Measuresincludetherecoveryofmethane

fromcoal,oilandgasextractionandtransport,methanecaptureinwastemanagement,use

ofclean-burningstovesforresidentialcooking,dieselparticulateltersforvehiclesandthe

banningofeldburningofagriculturalwaste.Widespreadimplementationisachievable

withexistingtechnologybutwouldrequiresignicantstrategicinvestmentandinstitutionalarrangements.

7 The identied measures complement but do not replace anticipated carbon

dioxide reduction measures. Majorcarbondioxidereductionstrategiesmainly

targettheenergyandlargeindustrialsectorsandthereforewouldnotnecessarilyresultin

signicantreductionsinemissionsofblackcarbonortheozoneprecursorsmethaneand

carbonmonoxide.Signicantreductionoftheshort-livedclimateforcersrequiresaspecic

strategy,asmanyareemittedfromalargenumberofsmallsources.


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BENEFITSOFEMISSIONREDUCTIONS

8 Full implementation of the identied measures would reduce future global

warming by 0.5C (within a range of 0.20.7C, Figure 1). Ifthemeasureswere

tobeimplementedby2030,theycouldhalvethepotentialincreaseinglobaltemperatureprojectedfor2050comparedtotheAssessmentsreferencescenariobasedoncurrent

policiesandenergyandfuelprojections.Therateofregionaltemperatureincreasewould

alsobereduced.

9 Both near-term and long-term strategies are essential to protect climate

Reductionsinnear-termwarmingcanbeachievedbycontroloftheshort-livedclimate

forcerswhereascarbondioxideemissionreductions,beginningnow,arerequiredtolimit

long-termclimatechange.Implementingbothreductionstrategiesisneededtoimprovethe

chancesofkeepingtheEarthsglobalmeantemperatureincreasetowithintheUNFCCC

2Ctarget.

10 Full implementation of the identied measures would have substantial

benets in the Arctic, the Himalayas and other glaciated and snow-covered

regions ThiscouldreducewarmingintheArcticinthenext30yearsbyabouttwo-thirds

comparedtotheprojectionsoftheAssessmentsreferencescenario.Thissubstantially

decreasestheriskofchangesinweatherpatternsandamplicationofglobalwarming

resultingfromchangesintheArctic.Regionalbenetsoftheblackcarbonmeasures,such

astheireffectsonsnow-andice-coveredregionsorregionalrainfallpatterns,arelargely

independentoftheirimpactonglobalmeanwarming.

11 Full implementation of the identied measures could avoid 2.4 million

premature deaths (within a range of 0.74.6 million) and the loss of 52 million

tonnes (within a range of 30140 million tonnes), 14 per cent, of the globalproduction of maize, rice, soybean and wheat each year (Figure 1).The most

substantialbenetswillbefeltimmediatelyinorclosetotheregionswhereactionistaken

toreduceemissions,withthegreatesthealthandcropbenetsexpectedinAsia.

RESPONSES

12. Theidentiedmeasuresareallcurrentlyinuseindifferentregionsaroundtheworldto

achieveavarietyofenvironmentanddevelopmentobjectives.Much wider and more

rapid implementation is required to achieve the full benets identied in this

Assessment

13 Achieving widespread implementation of the identied measures would be

most effective if it were country- and region-specic, and could be supported

by the considerable existing body of knowledge and experience. Accounting

fornear-termclimateco-benetscouldleverageadditionalactionandfundingonawider

internationalscalewhichwouldfacilitatemorerapidimplementationofthemeasures.

Manymeasuresachievecostsavingsovertime.However,initialcapitalinvestmentcouldbe

problematicinsomecountries,necessitatingadditionalsupportandinvestment.


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14 At national and sub-national scales many of the identied measures could

be implemented under existing policies designed to address air quality and

development concerns Improved cooperation within and between regions

would enhance widespread implementation and address transboundary

climate and air quality issues Internationalpolicyandnancinginstruments

toaddresstheco-benetsofreducingemissionsofshort-livedclimateforcersneed

developmentandstrengthening.Supportingandextendingexistingrelevantregional

arrangementsmayprovideanopportunityformoreeffectivecooperation,implementationandassessmentaswellasadditionalmonitoringandresearch.

15 The Assessment concludes that there is condence that immediate and

multiple benets will be realized upon implementation of the identied

measuresThedegreeofcondencevariesaccordingtopollutant,impactandregion.

Forexample,thereishighercondenceintheeffectofmethanemeasuresonglobal

temperaturesthanintheeffectofblackcarbonmeasures,especiallywheretheserelate

totheburningofbiomass.Thereisalsohighcondencethatbenetswillberealizedfor

humanhealthfromreducingparticles,includingblackcarbon,andtocropyieldsfrom

reducingtroposphericozoneconcentrations.Giventhescienticcomplexityoftheissues,

furtherresearchisrequiredtooptimizenear-termstrategiesindifferentregionsandtoevaluatethecost-benetratioforindividualmeasures.

Figure 1. Global benets rom ull implementation o the identied measures in 2030 compared to the reerencescenario. The climate change benet is estimated or a given year (2050) and human health and crop benets are

or 2030 and beyond.

0

CH4measures

CH4 + BC

measures

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Climate change

Global mean

avoided

warming in 2050

(C)

0

CH4measures

CH4 + BC

measures

1

0.5

1.5

2

2.5

3

3.5

4

4.5

5

Human health

Annually avoided

premature

deaths

(million)

0

CH4measures

CH4 + BC

measures

25

50

75

100

125

150

Food security

Annually avoided

crop yield losses

(total maize,

rice, soybean

and wheat,

million tonnes)


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Introduction

Blackcarbon(BC,Box1)andtropospheric

ozone(O3,Box2)areharmfulairpollutants

thatalsocontributetoclimatechange.In

recentyears,scienticunderstandingofhow

BC and O3

affect climate and public health

hassignicantlyimproved.Thishascatalysed

ademandforinformationandaction

fromgovernments,civilsocietyandother

stakeholders.TheUnitedNations(UN)has

beenrequestedtourgentlyprovidescience-

basedadviceonactiontoreducetheimpacts

of these pollutants1

TheUnitedNationsEnvironment

Programme(UNEP),inconsultationwith

partners,initiatedanassessmentdesigned

toprovideaninterfacebetweenknowledge

andaction,scienceandpolicy,andto

provideascienticallycrediblebasisfor

informeddecision-making.Theresultis

acomprehensiveanalysisofdriversof

emissions,trendsinconcentrations,and

impactsonclimate,humanhealthand

ecosystemsofBC,troposphericO3 and itsprecursors.BC,troposphericO

3and

methane(CH4)areoftenreferredtoas

short-livedclimateforcers(SLCFs)asthey

haveashortlifetimeintheatmosphere

(daystoaboutadecade)relativetocarbon

dioxide(CO2).

TheAssessmentisanintegratedanalysisof

multipleco-emittedpollutantsreectingthe

factthatthesepollutantsarenotemittedin

isolation(Boxes1and2).TheAssessmentdeterminedthatundercurrentpolicies,

emissions of BC and O3precursorsare

expectedgloballyeithertoincreaseorto

remainroughlyconstantunlessfurther

mitigation action is taken

The Integrated Assessment of Black Carbon and

Tropospheric Ozone convenedmorethan50______________________________________________1 The Anchorage Declaration o 24 April 2009, adopted by the I ndigenous Peoples Global Summit on Climate Change; the Troms Declaration o 29 April

2009, adopted by the Sixth Ministerial Meeting o the Arctic Council and the 8th Session o the Permanent Forum on Indigenous Issues under the United

Nations Economic and Social Council (May 2009) called on UNEP to conduct a ast track assessment o short-term drivers o climate change, specically

BC, with a view to initiating the negotiation o an international agreement to reduce emissions o BC. A need to take rapid action to address signicantclimate orcing agents other than CO2, such as BC, was reected in the 2009 declaration o the G8 leaders (Responsible Leadership or a Sustainable

Future, LAquila, Italy, 2009).

authorstoassessthestateofscienceand

existingpolicyoptionsforaddressingthese

pollutants.TheAssessmentteamexamined

policyresponses,developedanoutlookto2070

illustratingthebenetsofpoliticaldecisions

madetodayandtheriskstoclimate,human

healthandcropyieldsoverthenextdecadesif

actionisdelayed.Placingapremiumonrobust

scienceandanalysis,theAssessmentwasdriven

byfourmainpolicy-relevantquestions:

Whichmeasuresarelikelytoprovide

signicantcombinedclimateandair-qualitybenets?

Howmuchcanimplementationofthe

identiedmeasuresreducetherateof

globalmeantemperatureincreasebymid-

century?

Whatarethemultipleclimate,healthand

crop-yieldbenetsthatwouldbeachieved

byimplementingthemeasures?

Bywhatmechanismscouldthemeasures

berapidlyimplemented?

Inordertoanswerthesequestions,the

Assessmentteamdeterminedthatnewanalyses

wereneeded.TheAssessmentthereforerelies

onpublishedliteratureasmuchaspossible

andonnewsimulationsbytwoindependent

climate-chemistry-aerosolmodels:one

developedandrunbytheNASA-Goddard

InstituteforSpaceStudies(GISS)andthe

otherdevelopedbytheMaxPlanckInstitute

inHamburg,Germany(ECHAM),andrun

attheJointResearchCentreoftheEuropeanCommissioninIspra,Italy.Thespecic

measuresandemissionestimatesforusein

developingthisAssessmentwereselectedusing

theInternationalInstituteforAppliedSystems

AnalysisGreenhouseGasandAirPollution

InteractionsandSynergies(IIASAGAINS)

model.Foramoredetaileddescriptionofthe

modellingseeChapter1.


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Box1:Whatisblackcarbon?Black carbon (BC) exists as particles in the atmosphere and is a major component o soot. BC is not

a greenhouse gas. Instead it warms the atmosphere by intercepting sunlight and absorbing it. BC

and other particles are emitted rom many common sources, such as cars and trucks, residentialstoves, orest res and some industrial acilities. BC particles have a strong warming eect in the

atmosphere, darken snow when it is deposited, and inuence cloud ormation. Other particles may

have a cooling eect in the atmosphere and all particles inuence clouds. In addition to having an

impact on climate, anthropogenic particles are also known to have a negative impact

on human health.

Black carbon results rom the incomplete combustion o ossil uels, wood and other biomass.

Complete combustion would turn all carbon in the uel into carbon dioxide (CO2). In practice,

combustion is never complete and CO2, carbon monoxide (CO), volatile organic compounds

(VOCs), organic carbon (OC) particles and BC particles are all ormed. There is a close relationship

between emissions o BC (a warming agent) and OC (a cooling agent). They are always co-emitted,

but in dierent proportions or dierent sources. Similarly, mitigation measures will have varying

eects on the BC/OC mix.

The black in BC reers to the act that these particles absorb visible light. This absorption leads to

a disturbance o the planetary radiation balance and eventually to warming. The contribution to

warming o 1 gramme o BC seen over a period o 100 years has been estimated to be anything

rom 100 to 2 000 times higher than that o 1 gramme o CO2. An important aspect o BC particles

is that their lietime in the atmosphere is short, days to weeks, and so emission reductions have an

immediate benet or climate and health.

High emitting vehicles are a signicant source o blackcarbon and other pollutants in many countries.

Haze with high particulate matter concentrations

containing BC and OC, such as this over the Bay o

Bengal, is widespread in many regions.

Credit:Carame

l/fickr

Credit:NASA-MODIS


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Box2:Whatistroposphericozone?Ozone (O

3) is a reactive gas that exists in two layers o the atmosphere: the stratosphere (the upper

layer) and the troposphere (ground level to ~1015 km). In the stratosphere, O3

is considered

to be benecial as it protects lie on Earth rom the suns harmul ultraviolet (UV) radiation. In

contrast, at ground level, it is an air pollutant harmul to human health and ecosystems, and it is

a major component o urban smog. In the troposphere, O3

is also a signicant greenhouse gas.

The threeold increase o the O3

concentration in the northern hemisphere during the past 100

years has made it the third most important contributor to the human enhancement o the global

greenhouse eect, ater CO2 and CH4.

In the troposphere, O3

is ormed by the action o sunlight on O3

precursors that have natural

and anthropogenic sources. These precursors are CH4, nitrogen oxides (NO

X), VOCs and CO. It is

important to understand that reductions in both CH4

and CO emissions have the potential to

substantially reduce O3

concentrations and reduce global warming. In contrast, reducing VOCs

would clearly be benecial but has a small impact on the global scale, while reducing NOX

has

multiple additional eects that result in its net impact on climate being minimal.

Some o the largest emission reductions are obtained using diesel particle lters on high emitting vehicles. The exhibits

above are actual particulate matter (PM) collection samples rom an engine testing laboratory (International Council o

Clean Transportation (ICCT)).

Retrotted withDiesel Oxidation Catalyst (DOC)

(Level 1)

Old technlogy

Little black carbon removal

Little ultrane PM removal

Does not remove lube oil ash

No retrot systemUncontrolled Diesel Exhaust

(Level 1)

Old technlogy




Retrotted withPartial Filter

(Level 2)




Retrotted withDiesel Particulate Filter (DPF)

(Level 3)

New Technology

Used on all new trucks since 2007

>85% black carbon removal

>85% ultrane removal

>85% lube oil ash removal

Credit:LuisaMolina

Credit:WarrenG

retz/DOE/NREL

Credit:LuisaMolina

Tropospheric ozone is a major constituent o urban smog, let Tokyo, Japan; right Denver, Colorado, USA


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LimitingNear-TermClimate

ChangesandImproving

AirQuality

emissionsofallsubstancesresultingfromthe

fullimplementationoftheidentiedmeasures

throughthetwoglobalcomposition-climate

modelsGISSandECHAM(seeChapter4).

Onehundredpercentimplementationofthe

measuresgloballywasusedtoillustratethe

existingpotentialtoreduceclimateandairqualityimpacts,butthisdoesnotmakeany

assumptionsregardingthefeasibilityoffull

implementationeverywhere.Adiscussion

ofthechallengesinvolvedinwidespread

implementationofthemeasuresfollowsafter

thepotentialbenethasbeendemonstrated.

Achieving large emissionreductions

ThepackagesofpolicymeasuresinTable1werecomparedtoareferencescenario(Table

2).Figure2showstheeffectofthepackages

ofpolicymeasuresandthereferencescenario

relativeto2005emissions.

Thereistremendousregionalvariability

inhowemissionsareprojectedtochange

bytheyear2030underthereference

scenario.EmissionsofCH4amajorO

3

precursorandapotentgreenhousegasare

expectedtoincreaseinthefuture(Figure

2).Thisincreasewilloccurdespitecurrent

andplannedregulations,inlargepartdue

toanticipatedeconomicgrowthandthe

increaseinfossilfuelproductionprojectedto

accompanyit.Incontrast,globalemissionsof

BCandaccompanyingco-emittedpollutants

areexpectedtoremainrelativelyconstant

throughto2030.Regionally,reductionsin

BCemissionsareexpectedduetotighter

standardsonroadtransportandmore

efcientcombustionreplacinguseofbiofuels

intheresidentialandcommercialsectors,

Identifying effective responsemeasures

TheAssessmentidentiedthosemeasures

mostlikelytoprovidecombinedbenets,

taking into account the fact that BC and

O3precursorsareco-emittedwithdifferentgasesandparticles,someofwhichcause

warmingandsomeofwhich,suchasorganic

carbon(OC)andsulphurdioxide(SO2)

leadtocooling.Theselectioncriterionwas

thatthemeasurehadtobelikelytoreduce

globalclimatechangeandalsoprovideair

qualitybenets,so-calledwin-winmeasures.

Thosemeasuresthatprovidedabenet

forairqualitybutincreasedwarmingwere

notincludedintheselectedmeasures.For

example,measuresthatprimarilyreduceemissions of SO

2werenotincluded.

Theidentiedmeasures(Table1)were

chosenfromasubsetofabout2000separate

measuresthatcanbeappliedtosourcesin

IIASAsGAINSmodel.Theselectionwas

basedonthenetinuenceonwarming,

estimatedusingthemetricGlobalWarming

Potential(GWP),ofallofthegasesand

particlesthatareaffectedbythemeasure.

The selection gives a useful indication of the

potentialforrealizingawinforclimate.All

emissionreductionmeasureswereassumed

tobenetairqualitybyreducingparticulate

matterand/orO3concentrations.

Thisselectionprocessidentiedarelatively

smallsetofmeasureswhichnevertheless

provideabout90percentoftheclimate

benetcomparedtotheimplementation

ofall2000measuresinGAINS.Thenal

analysisofthebenetsfortemperature,

humanhealthandcropyieldsconsideredthe


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Table 1Measures that improve climate change mitigation and air quality and have a largeemission reduction potential

Measure1 Sector

CH4 measuresExtended pre-mine degasication and recovery and oxidation o CH

4rom

ventilation air rom coal mines

Extraction and

transport o ossil uel

Extended recovery and utilization, rather than venting, o associated gas

and improved control o unintended ugitive emissions rom the production

o oil and natural gas

Reduced gas leakage rom long-distance transmission pipelines

Separation and treatment o biodegradable municipal waste through

recycling, composting and anaerobic digestion as well as landll gas

collection with combustion/utilization Waste management

Upgrading primary wastewater treatment to secondary/tertiary treatment

with gas recovery and overow control

Control o CH4

emissions rom livestock, mainly through arm-scale

anaerobic digestion o manure rom cattle and pigs Agriculture

Intermittent aeration o continuously ooded rice paddies

BC measures (aecting BC and other co-emitted compounds)

Diesel particle lters or road and o-road vehiclesTransport

Elimination o high-emitting vehicles in road and o-road transport

Replacing coal by coal briquettes in cooking and heating stoves

Residential

Pellet stoves and boilers, using uel made rom recycled wood waste or

sawdust, to replace current wood-burning technologies in the residential

sector in industrialized countries

Introduction o clean-burning biomass stoves or cooking and heating in

developing countries2, 3

Substitution o clean-burning cookstoves using modern uels or traditional

biomass cookstoves in developing countries2, 3

Replacing traditional brick kilns with vertical shat kilns and Homan kilns

IndustryReplacing traditional coke ovens with modern recovery ovens, including the

improvement o end-o-pipe abatement measures in developing countries

Ban o open eld burning o agricultural waste2 Agriculture

althoughtheseareoffsettosomeextentby

increasedactivityandeconomicgrowth.

TheregionalBCemissiontrends,therefore,

varysignicantly,withemissionsexpectedto

decreaseinNorthAmericaandEurope,Latin

AmericaandtheCaribbean,andinNortheast

Asia,SoutheastAsiaandthePacic,and

toincreaseinAfricaandSouth,WestandCentralAsia.

The full implementation of the selected

measuresby2030leadstosignicant

reductionsofSLCFemissionsrelativeto

currentemissionsortothe2030emissions

inthereferencescenario(Figure2).Italso

reducesahighproportionoftheemissions

relativetothemaximumreductionfromthe

implementationofall2000orsomeasuresintheGAINSmodel.Themeasuresdesignedto

1 There are measures other than those identied in the table that could be implemented. For example, electric cars would

have a similar impact to diesel particulate lters but these have not yet been widely introduced; orest re controls couldalso be important but are not included due to the diculty in establishing the proportion o res that are anthropogenic.

2 Motivated in part by its eect on health and regional climate, including areas o ice and snow.3 For cookstoves, given their importance or BC emissions, two alternative measures are included.


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reduceBCalsohaveaconsiderableimpact

onOC,totalneparticulatematter(PM25)

andCOemissions,removingmorethanhalf

thetotalanthropogenicemissions.Thelargest

BCemissionreductionsareobtainedthrough

measurescontrollingincompletecombustion

ofbiomassanddieselparticlelters.

ThemajorsourcesofCO2aredifferentfrom

thoseemittingmostBC,OC,CH4

and CO

Eveninthefewcaseswherethereisoverlap,

suchasdieselvehicles,theparticleltersthat

reduceBC,OCandCOhaveminimaleffect

on CO2.ThemeasurestoreduceCO

2over

thenext20years(Table2)thereforehardly

affecttheemissionsofBC,OCorCO.The

inuenceoftheCH4andBCmeasuresisthusthesameregardlessofwhethertheCO

2

measuresareimposedornot.

Reducing near-term globalwarming

TheEarthisprojectedtocontinuethe

rapidwarmingofthepastseveraldecades

and,withoutadditionalmitigationefforts,

underthereferencescenarioglobalmean

temperaturesareprojectedtoriseaboutafurther1.3C(witharangeof0.82.0C)by

themiddleofthiscentury,bringingthetotal

warmingfrompre-industriallevelstoabout

2.2C(Figure3).TheAssessmentshowsthat

themeasurestargetedtoreduceemissions

of BC and CH4couldgreatlyreduceglobal

meanwarmingratesoverthenextfew

decades(Figure3).Figure1showsthatover

halfofthereducedglobalmeanwarming

is achieved by the CH4measuresandthe

remainderbyBCmeasures.Thegreater

condenceintheeffectofCH4measureson

warmingisreectedinthenarrowerrangeof

estimates

Whenallmeasuresarefullyimplemented,

warmingduringthe2030srelativetothe

presentdayisonlyhalfasmuchasifno

measureshadbeenimplemented.Incontrast,evenafairlyaggressivestrategytoreduce

CO2emissionsundertheCO

2measures

scenariodoeslittletomitigatewarming

overthenext2030years.Infact,sulphate

particles,reectingparticlesthatoffsetsome

ofthecommittedwarmingfortheshorttime

theyareintheatmosphere,arederivedfrom

SO2thatisco-emittedwithCO

2in some

ofthehighest-emittingactivities,including

coalburninginlarge-scalecombustionsuch

asinpowerplants.Hence,CO2measuresalonemaytemporarilyenhancenear-term

warmingassulphatesarereduced(Figure3;

Table 2 Policy packages used in the Assessment

Scenario Description1

Reerence Based on energy and uel projections o the International Energy Agency

(IEA) World Energy Outlook 2009 and incorporating all presently agreed

policies aecting emissions

CH4

measures Reerence scenario plus the CH4

measures

BCmeasures Reerence scenario plus the BC measures (the BC measures aect many

pollutants, especially BC, OC, and CO)

CH4

+ BC measures Reerence scenario plus the CH4

and BC measures

CO2

measures Emissions modelled using the assumptions o the IEA World Energy

Outlook 2009 450 Scenario2 and the IIASA GAINS database. Includes CO2

measures only. The CO2

measures aect other emissions, especially SO2

3

CO2

+ CH4

+ BC measures CO2

measures plus CH4

and BC measures

1 In all scenarios, trends in all pollutant emissions are included through 2030, ater which only trends in CO2

are included.2 The 450 Scenario is designed to keep total orcing due to long-lived greenhouse gases (including CH

4in this case) at a

level equivalent to 450 ppm CO2

by the end o the century.3 Emissions o SO

2are reduced by 3540 per cent by implementing CO

2measures. A urther reduction in sulphur emissions

would be benecial to health but would increase global warming. This is because sulphate particles cool the Earth byreecting sunlight back to space.


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11


-90 -70-80 -60 -40 -20 20 40-50 -30 -10 100 30 50

ReferenceBC measures




ReferenceCH4 measuresCH4 + BCmeasures




Change in emissions in 2030 compared to 2005, %

Large-scale combustion Industrial processes

Residential-commercial combustion

Transport Fossil fuel extraction and distribution

Waste /landll

Agriculture

CO2

CO

NOX

SO2

CH4

TotalPM2.5

OC

BC

Figure 2. Percentage change in anthropogenic emissions o the indicated pollutants in 2030 relative to 2005 orthe reerence, CH

4, BC and CH

4+ BC measures scenarios. The CH

4measures have minimal eect on emissions o

anything other than CH4. The identied BC measures reduce a large proportion o total BC, OC and CO emissions.

SO2

and CO2

emissions are hardly aected by the identied CH4

and BC measures, while NOX

and other PM2.5

emissions are aected by the BC measures.

temperaturesintheCO2measuresscenario

areslightlyhigherthanthoseinthereference

scenarioduringtheperiod20202040).

The CO2measuresclearlyleadtolong-term

benets,withadramaticallylowerwarming

ratein2070thanunderthescenariowith

onlynear-termCH4+BCmeasures.Owing

tothelongresidencetimeofCO2

in the

atmosphere,theselong-termbenetswill

only be achieved if CO2emissionreductions

arebroughtinquickly.Inessence,thenear-

termCH4andBCmeasuresexaminedinthis

Assessmentareeffectivelydecoupledfromthe CO

2measuresbothinthattheytarget

differentsourcesectorsandinthattheir

impactsonclimatechangetakeplaceover

differenttimescales.

Near-termwarmingmayoccurinsensitive

regionsandcouldcauseessentiallyirreversible

changes,suchaslossofArcticland-ice,release

of CH4orCO

2fromArcticpermafrostand

speciesloss.Indeed,theprojectedwarming

inthereferencescenarioisgreaterinthe

Arcticthanglobally.Reducingthenear-term

rateofwarminghencedecreasestheriskof

irreversibletransitionsthatcouldinuencethe

globalclimatesystemforcenturies.


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Staying within criticaltemperature thresholds

Adoptionofthenear-termemissioncontrol

measuresdescribedinthisAssessment,togetherwithmeasurestoreduceCO2

emissions,wouldgreatlyimprovethechances

ofkeepingEarthstemperatureincrease

tolessthan2Crelativetopre-industrial

levels(Figure3).WiththeCO2measures

alone,warmingexceeds2Cbefore2050.

EvenwithboththeCO2measuresandCH

4

measuresenvisionedunderthesameIEA450

Scenario,warmingexceeds2Cinthe2060s

(seeChapter5).However,thecombination

of CO2,CH

4,andBCmeasuresholdsthe

temperatureincreasebelow2Cuntilaround

2070.WhileCO2emissionreductionseven

largerthanthoseintheCO2measures

scenariowouldofcoursemitigatemore

warming,actualCO2emissionsoverthepast

decadehaveconsistentlyexceededthemost

pessimisticemissionscenariosoftheIPCC.

Thus,itseemsunlikelythatreductionsmore

stringentthanthoseintheCO2

measures

scenariowilltakeplaceduringthenext

20years.

ExaminingthemorestringentUNFCCC

1.5Cthreshold,theCO2measuresscenario

exceedsthisby2030,whereasthenear-term

measuresproposedintheAssessmentdelay

thatexceedanceuntilafter2040.Again,while

substantiallydeeperearlyreductionsinCO2

emissions than those in the CO2measures

scenariocouldalsodelaythecrossingof

the1.5Ctemperaturethreshold,suchreductionswouldundoubtedlybeevenmore

difculttoachieve.However,adoptionofthe

Assessmentsnear-termmeasures(CH4+BC)

alongwiththeCO2reductionswouldprovide

1900 1950 2000 2050

Temperature(C)relativeto1890-1910

CH4+ BC measures

CO2measures

Reference

CO2 + CH4 + BC

measures

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Figure 3. Observed deviation o temperature to 2009 and projections under various scenarios. Immediate

implementation o the identied BC and CH4

measures, together with measures to reduce CO2

emissions, wouldgreatly improve the chances o keeping Earths temperature increase to less than 2C relative to pre-industrial

levels. The bulk o the benets o CH4

and BC measure are realized by 2040 (dashed line).

Explanatory notes: Actual mean temperature observations through 2009, and projected under various scenarios

thereater, are shown relative to the 18901910 mean temperature. Estimated ranges or 2070 are shown in the bars on

the right. A portion o the uncertainty is common to all scenarios, so that overlapping ranges do not mean there is no

diference, or example, i climate sensitivity is large, it is large regardless o the scenario, so temperatures in all scenarioswould be towards the high-end o their ranges.


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asubstantialchanceofkeepingtheEarths

temperatureincreasebelow1.5Cforthenext

30years.

Benets of early implementation

Therewouldclearlybemuchlesswarming

during20202060werethemeasures

implementedearlierratherthanlater(Figure

4).Hencethereisasubstantialnear-term

climatebenetinacceleratingimplementation

oftheidentiedmeasuresevenifsomeof

thesemighteventuallybeadoptedowing

togeneralair-qualityanddevelopment

concerns.Clearlytheearlierimplementation

willalsohavesignicantadditionalhuman

healthandcrop-yieldbenets.

Acceleratedadoptionoftheidentied

measureshasonlyamodesteffectonlong-

termclimatechangeincomparisonwith

waiting20years,however(Figure4).This

reinforcestheconclusionthatreducing

emissions of O3precursorsandBCcanhave

substantialbenetsinthenearterm,but

thatmitigatinglong-termclimatechange

dependsonreducingemissionsoflong-lived

greenhousegasessuchasCO2

Regional climate benets

Whileglobalmeantemperaturesprovide

someindicationofclimateimpacts,

temperaturechangescanvarydramatically

fromplacetoplaceeveninresponseto

relativelyuniformforcingfromlong-lived

greenhousegases.Figure5showsthat

warmingisprojectedtoincreaseforall

regionswithsomevariationunderthereferencescenario,whiletheAssessments

measuresprovidethebenetofreduced

warminginallregions.

Climatechangealsoencompassesmorethan

justtemperaturechanges.Precipitation,

meltingratesofsnowandice,windpatterns,

andcloudsareallaffected,andtheseinturn

haveanimpactonhumanwell-beingby

inuencingfactorssuchaswateravailability,

agricultureandlanduse.

Both O3andBC,aswellasotherparticles,

caninuencemanyoftheprocessesthatlead

totheformationofcloudsandprecipitation.

Theyaltersurfacetemperatures,affecting

evaporation.Byabsorbingsunlightinthe

atmosphere,O3

and especially BC can

affectcloudformation,rainfallandweather

patterns.Theycanchangewindpatternsby

affectingtheregionaltemperaturecontrasts

thatdrivethewinds,inuencingwhere

rainandsnowfall.Whilesomeaspectsof

theseeffectsarelocal,theycanalsoaffect

temperature,cloudiness,andprecipitation

farawayfromtheemissionsources.The

regionalchangesinalltheseaspectsofclimate

willbesignicant,butarecurrentlynotwell

quantied.

Tropical rainfall patterns andthe Asian monsoon

SeveraldetailedstudiesoftheAsian

monsoonsuggestthatregionalforcing

byabsorbingparticlessubstantiallyalters

precipitationpatterns(asexplainedinthe

previoussection).ThefactthatbothO3

and

particlechangesarepredominantlyinthe

northernhemispheremeansthattheycausetemperaturegradientsbetweenthetwo

hemispheresthatinuencerainfallpatterns

throughoutthetropics.Implementationof

themeasuresanalysedinthisAssessment

wouldsubstantiallydecreasetheregional

atmosphericheatingbyparticles(Figure6),

andarehenceverylikelytoreduceregional

shiftsinprecipitation.Asthereductionsof

atmosphericforcingaregreatestoverthe

Indiansub-continentandotherpartsof

Asia,theemissionreductionsmayhaveasubstantialeffectontheAsianmonsoon,

mitigatingdisruptionoftraditionalrainfall

patterns.However,resultsfromglobalclimate

modelsarenotyetrobustforthemagnitude

ortimingofmonsoonshiftsresultingfrom

eithergreenhousegasincreasesorchanges

inabsorbingparticles.Nonetheless,results

fromclimatemodelsprovideexamplesofthe

typeofchangethatmightbeexpected.Shifts

inthetimingandstrengthofprecipitation

canhavesignicantimpactsonhuman

well-beingbecauseofchangesinwater


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14


3.5

4

4.5

3

2.5

2

1.5

1

0.5

0Temperature(C)relativeto1890-191

0

Africa

Reference

CH4 + BC

measures

Northeast

Asia,

Southeast

Asia and

Pacic

Latin

America

and

Caribbean

North

America

and

Europe

South,

West and

Central Asia

Figure 4. Projected global mean temperature changes or the reerence scenario and or the CH4

and BC

measures scenario with emission reductions starting immediately or delayed by 20 years.

2010 2020 2030 2040

Year

2050 2060 2070

T

emperature(C)relataiveto1890-1910

2

3

0

1

Reference

CH4 + BC measures

from 20302050

CH4 + BC measures

from 20102030

Figure 5. Comparison o regional mean warming over land (C) showing the change in 2070 compared with 2005or the reerence scenario (Table 2) and the CH

4+ BC measures scenario. The lines on each bar show the range o

estimates.


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15


supplyandagriculturalproductivity,drought

andooding.TheresultsshowninFigure

6 suggest that implementation of the BC

measurescouldalsoleadtoaconsiderable

reductioninthedisruptionoftraditional

rainfallpatternsinAfrica.

Decreased warming in polar andother glaciated regions

Implementationofthemeasureswould

substantiallyslow,butnothalt,thecurrent

rapidpaceoftemperatureriseandother

changesalreadyoccurringatthepolesand

high-altitudeglaciatedregions,andthe

reducedwarmingintheseregionswouldlikely

begreaterthanthatseenglobally.Thelargebenetsoccurinpartbecausethesnow/ice

darkeningeffectofBCissubstantiallygreater

thanthecoolingeffectofreectiveparticles

co-emittedwithBC,leadingtogreater

warmingimpactsintheseareasthaninareas

withoutsnowandicecover.

StudiesintheArcticindicatethatitishighly

sensitive both to local pollutant emissions

andthosetransportedfromsourcescloseto

theArctic,aswellastotheclimateimpactofpollutantsinthemid-latitudesofthe

northernhemisphere.Muchoftheneedfor

implementationlieswithinEuropeandNorth

America.Theidentiedmeasurescould

reducewarmingintheArcticbyabout0.7C

(witharangeof0.21.3C)in2040.Thisis

nearlytwo-thirdsoftheestimated1.1C(with

arangeof0.71.7C)warmingprojected

fortheArcticunderthereferencescenario,

andshouldsubstantiallydecreasetheriskof

globalimpactsfromchangesinthissensitive

region,suchasseaiceloss,whichaffects

globalalbedo,andpermafrostmelt.Although

notidentiedasameasureforuseinthis

Assessment,thecontrolofborealforestres

mayalsobeimportantinreducingimpactsin

theArctic.

TheAntarcticisafarlessstudiedregionintermsofSLCFimpacts.However,there

arestudiesdemonstratingBCdeposition

evenincentralportionsofthecontinent,

andreductionsinO3and CH

4should

slowwarminginplacesliketheAntarctic

Peninsula,currentlythespotontheglobe

showingthemostrapidtemperaturerise

of all

TheHimalayasandtheTibetanPlateauare

regionswhereBCislikelytohaveseriousimpacts.InthehighvalleysoftheHimalayas,

forexample,BClevelscanbeashighasin

50

0

-50

-20 -10 -4 -3 -2 -1 1

-100 0 100 -100 0 100

50

0

-50

W/m2

GISS ECHAM

Figure 6. Change in atmospheric energy absorption (Watts per square metre, W/m2 as annual mean), an

important actor driving tropical rainall and the monsoons resulting rom implementation o BC measures.The changes in absorption o energy by the atmosphere are linked with changes in regional circulation and

precipitation patterns, leading to increased precipitation in some regions and decreases in others. BC solar

absorption increases the energy input to the atmosphere by as much as 515 per cent, with the BC measures

removing the bulk o that heating. Results are shown or two independent models to highlight the similarity in

the projections o where large regional decreases would occur.


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amid-sizedcity.Reducingemissionsfrom

localsourcesandthosecarriedbylong-range

transportshouldlowerglacialmeltinthese

regions,decreasingtheriskofimpactssuch

ascatastrophicglaciallakeoutbursts.

Benets of the measures forhuman health

Fineparticulatematter(measuredasPM25,

whichincludesBC)andground-level

O3

damage human health PM25

causes

prematuredeathsprimarilyfromheart

diseaseandlungcancer,andO3exposure

causesdeathsprimarilyfromrespiratory

illness.Thehealthbenetestimatesin

the Assessmentarelimitedtochangesinthesespeciccausesofdeathandinclude

uncertaintyintheestimationmethods.

However,thesepollutantsalsocontribute

signicantlytootherhealthimpacts

includingacuteandchronicbronchitis

andotherrespiratoryillness,non-fatal

heartattacks,lowbirthweightandresults

inincreasedemergencyroomvisitsand

hospitaladmissions,aswellaslossofwork

and school days

Underthereferencescenario,thatis,

withoutimplementationoftheidentied

measures,changesinconcentrationsof

PM25

and O3in2030,relativeto2005,

wouldhavesubstantialeffectsgloballyon

prematuredeathsrelatedtoairpollution.

Byregion,prematuredeathsfromoutdoor

pollutionareprojectedtochangeinline

withemissions.Thelatterareexpectedto

decreasesignicantlyoverNorthAmerica

andEuropeduetoimplementationoftheexistingandexpectedlegislation.

OverAfricaandLatinAmericaandthe

Caribbean,thenumberofprematuredeaths

fromthesepollutantsisexpectedtoshow

modestchangesunderthereferencescenario

(Figure7).OverNortheastAsia,Southeast

AsiaandPacic,prematuredeathsare

projectedtodecreasesubstantiallydueto

reductionsinPM25insomeareas.However,

inSouth,WestandCentralAsia,premature

deathsareprojectedtorisesignicantlydue

togrowthinemissions.

Incontrasttothereferencescenario,full

implementationofthemeasuresidentied

in the Assessmentwouldsubstantially

improveairqualityandreducepremature

deathsgloballyduetosignicantreductions

inindoorandoutdoorairpollution.The

reductionsinPM25concentrationsresulting

fromtheBCmeasureswould,by2030,

avoidanestimated0.74.6millionannual

prematuredeathsduetooutdoorairpollution

(Figure1).

Regionally,implementationoftheidentied

measureswouldleadtogreatlyimproved

airqualityandfewerprematuredeaths,

especiallyinAsia(Figure7).Infact,more

than80percentofthehealthbenetsofimplementingallmeasuresoccurinAsia.

Thebenetsarelargeenoughforallthe

worseningtrendsinhumanhealthdueto

outdoorairpollutiontobereversedand

turnedintoimprovements,relativeto2005.

InAfrica,thebenetissubstantial,although

notasgreatasinAsia.

Benets of the measures forcrop yields

Ozoneistoxictoplants.Avastbody

ofliteraturedescribesexperimentsand

observationsshowingthesubstantialeffects

of O3onvisibleleafhealth,growthand

productivityforalargenumberofcrops,

treesandotherplants.Ozonealsoaffects

vegetationcompositionanddiversity.

Globally,thefullimplementationofCH4

measuresresultsinsignicantreductionsin

O3concentrationsleadingtoavoidedyield

lossesofabout25milliontonnesoffourstaplecropseachyear.Theimplementation

oftheBCmeasureswouldaccountforabout

afurther25milliontonnesofavoidedyield

lossesincomparisonwiththereference

scenario(Figure1).Thisisduetosignicant

reductionsinemissionsoftheprecursors

CO,VOCsandNOXthatreduceO

3

concentrations.

Theregionalpictureshowsconsiderable

differences.Underthereferencescenario,

O3concentrationsoverNortheast,Southeast


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17


AsiaandPacicareprojectedtoincrease,

resultinginadditionalcropyieldlosses

(Figures7and8).InSouth,WestandCentral

Asia,bothhealthandagriculturaldamage

areprojectedtorise(Figure8).Damageto

agricultureisprojectedtodecreasestrongly

overNorthAmericaandEuropewhile

changingminimallyoverAfricaandLatin

AmericaandtheCaribbean.Forthewhole

Asianregionmaizeyieldsshowadecreaseof

115percent,whileyieldsdecreasebyless

than5percentforwheatandrice.These

yieldlossestranslateintonearly40million

tonnesforallcropsforthewholeAsianregion,

reectingthesubstantialcultivatedarea

exposedtoelevatedO3concentrationsinIndia

inparticulartheIndo-GangeticPlainregion.Riceproductionisalsoaffected,particularly

inAsiawhereelevatedO3concentrationsare

likelytocontinuetoincreaseto2030.Yield

lossvaluesforriceareuncertain,however,

duetoalackofexperimentalevidenceon

concentration-responsefunctions.Incontrast,

theEuropeanandNorthAmericanregional

analysessuggestthatallcropswillseean

improvementinyieldsunderthereference

scenariobetween2005and2030.Even

greaterimprovementswouldbeseenuponimplementationofthemeasures.

Theidentiedmeasuresleadtogreatly

reducedO3concentrations,withsubstantial

benetstocropyields,especiallyinAsia

(Figure8).Thebenetsofthemeasuresare

largeenoughtoreversealltheworsening

trendsseeninagriculturalyieldsandturn

themintoimprovements,relativeto2005,

withtheexceptionofcropyieldsinNortheast

andSoutheastAsiaandPacic.Eveninthat

case,thebenetsoffullimplementationare

quitelarge,withthemeasuresreducingby

60percentthecroplossesenvisagedinthe

referencescenario.

ItshouldbestressedthattheAssessments

analysesincludeonlythedirecteffectof

changesinatmosphericcompositiononhealthandagriculturethroughchangesinexposure

topollutants.Assuch,theydonotinclude

thebenetsthatavoidedclimatechange

wouldhaveonhumanhealthandagriculture

duetofactorssuchasreduceddisruptionof

precipitationpatterns,dimming,andreduced

frequencyofheatwaves.Furthermore,even

thedirectinuenceonyieldsarebasedon

estimatesforonlyfourstaplecrops,and

impactsonleafycrops,productivegrasslands

andfoodqualitywerenotincluded,sothatthecalculatedvaluesarelikelytobean

Figure 7. Comparison o premature mortality (millions o premature deaths annually) by region, showing the

change in 2030 in comparison with 2005 or the reerence scenario emission trends and the reerence plus CH4 +BC measures. The lines on each bar show the range o estimates.

1.5

2

1

0.5

0

-0.5

-1

-1.5

-2

-2.5

-3

Reference

Reference +

CH4 + BC

measures

Africa Northeast

Asia,

Southeast

Asia and

Pacic

Latin

America

and

Caribbean

North

America

and

Europe

South,

West and

Central Asia


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18


underestimateofthetotalimpact.Inaddition,

extrapolationofresultsfromanumberof

experimentalstudiestoassessO3

impacts on

ecosystemsstronglysuggeststhatreductions

in O3couldleadtosubstantialincreasesinthe

netprimaryproductivity.Thiscouldhavea

substantialimpactoncarbonsequestration,

providingadditionalclimatebenets.

Relative importance andscientic condence in themeasures

Methanemeasureshavealargeimpactonglobalandregionalwarming,whichis

achievedbyreducingthegreenhousegases

CH4

and O3 The climate mitigation impacts

of the CH4measuresarealsothemostcertain

becausethereisahighdegreeofcondence

inthewarmingeffectsofthisgreenhouse

gas.ThereducedmethaneandhenceO3

concentrationsalsoleadtosignicantbenets

forcropyields.

TheBCmeasuresidentiedherereduce

concentrationsofBC,OCandO3(largely

throughreductionsinemissionsofCO).

ThewarmingeffectofBCandO3

and

thecompensatingcoolingeffectofOC,

introduceslargeuncertaintyintheneteffect

ofsomeBCmeasuresonglobalwarming

(Figure1).UncertaintyintheimpactofBC

measuresisalsolargerthanthatforCH4

becauseBCandOCcaninuenceclouds

that have multiple effects on climate that

arenotfullyunderstood.Thisuncertainly

inglobalimpactsisparticularlylargeforthe

Figure 8. Comparison o crop yield losses (million tonnes annually o our key crops wheat, rice, maize and soy

combined) by region, showing the change in 2030 compared with 2005 or the reerence emission trends and thereerence with CH

4+ BC measures. The lines on each bar show the range o estimates.

100

50

0

-50

-100

-150

Africa

Reference

CH4 + BC

measures

Northeast

Asia,

Southeast

Asia and

Pacic

Latin

America

and

Caribbean

North

America

and

Europe

South,

West and

Central Asia

The measures identied in the Assessment include

replacement o traditional cookstoves, such as that

shown here, with clean burning stoves which wouldsubstantially improve air quality and reduce prematuredeaths due to indoor and outdoor air pollution.

Credit:Ve

erabhadranRamanathan


24/37

19


measuresconcerningbiomasscookstovesand

openburningofbiomass.Hencewithrespecttoglobalwarming,thereismuchhigher

condenceformeasuresthatmitigatediesel

emissionsthanbiomassburningbecausethe

proportionofco-emittedcoolingOCparticles

ismuchlowerfordiesel.

Ontheotherhand,thereishighercondence

thatBCmeasureshavelargeimpactson

humanhealththroughreducingconcentrations

ofinhalableparticles,oncropyieldsthrough

reducedO3,andonclimatephenomenasuch

astropicalrainfall,monsoonsandsnow-ice

melt.Theseregionalimpactsarelargely

independentofthemeasuresimpacton

globalwarming.Infact,regionally,biomass

cookstovesandopenbiomassburningcan

havemuchlargereffectsthanfossilfuels.This

isbecauseBCdirectlyincreasesatmospheric

heatingbyabsorbingsunlight,which,

accordingtonumerouspublishedstudies,

affectsthemonsoonandtropicalrainfall,and

thisislargelyseparatefromtheeffectofco-

emittedOC.ThesameconclusionapplieswithrespecttotheimpactofBCmeasuresonsnow

andice.BC,becauseitisdark,signicantly

increasesabsorptionofsunlightbysnowand

icewhenitisdepositedonthesebrightsurfaces.

OCthatisdepositedalongwithBChasvery

littleeffectonsunlightreectedbysnowand

icesincethesesurfacesarealreadyverywhite.

Henceknowledgeoftheseregionalimpacts

is,insomecases,morerobustthantheglobal

impacts,andwithrespecttoreducingregional

impacts,alloftheBCmeasuresarelikelytobesignicant.Condenceisalsohighthatalarge

proportionofthehealthandcropbenets

wouldberealizedinAsia.

Mechanisms for rapidimplementation

InDecember2010thePartiestothe

UNFCCCagreedthatwarmingshouldnot

exceed2Cabovepre-industriallevelsduring

thiscentury.ThisAssessmentshowsthat

measurestoreduceSLCFs,implemented

incombinationwithCO2controlmeasures,

wouldincreasethechancesofstayingbelow

the2Ctarget.Themeasureswouldalso

slowtherateofnear-termtemperaturerise

andalsoleadtosignicantimprovements

inhealth,decreaseddisruptionofregional

precipitationpatternsandwatersupply,and

inimprovedfoodsecurity.Theimpactsofthe

measuresontemperaturechangearefeltover

largegeographicalareas,whiletheairquality

impactsaremorelocalizedneartheregions

wherechangesinemissionstakeplace.

Therefore,areasthatcontroltheiremissions

willreceivethegreatesthumanhealthandfoodsupplybenets;additionallymanyofthe

climatebenetswillbefeltclosetotheregion

taking action

Thebenetswouldberealizedinthenear

term,therebyprovidingadditionalincentives

toovercomenancialandinstitutional

hurdlestotheadoptionofthesemeasures.

Countriesinallregionshavesuccessfully

implementedtheidentiedmeasuresto

somedegreeformultipleenvironmentanddevelopmentobjectives.Theseexperiences

Widespread haze over the Himalayas where BC

concentrations can be as high as in mid-sized cities.

Reducing emissions should lower glacial melt and

decrease the risk o outbursts rom glacial lakes.

Credit:Ve

erabhadranRamanathan

Credit:GovindJoshi


25/37

20


provideaconsiderablebodyofknowledge

andpotentialmodelsforothersthatwishto

take action

Inmostcountries,mechanismsarealready

inplace,albeitatdifferentlevelsofmaturity,

toaddresspublicconcernregardingair

pollutionproblems.Mechanismstotackle

anthropogenicgreenhousegasesareless

welldeployed,andsystemstomaximize

theco-benetsfromreducingairpollution

andmeasurestoaddressclimatechangeare

virtuallynon-existent.Coordinationacross

institutionstoaddressclimate,airpollution,

energyanddevelopmentpolicyisparticularlyimportanttoenhanceachievementofallthese

goals simultaneously

ManyBCcontrolmeasuresrequire

implementationbymultipleactorsondiffuse

emissionsourcesincludingdieselvehicles,

eldburning,cookstovesandresidential

heating.Althoughairqualityandemission

standardsexistforparticulatematterinsome

regions,theymayormaynotreduceBC,

andimplementationremainsachallenge.Relevance,benetsandcostsofdifferent

Field burning o agricultural waste is a common way to dispose o crop residue in many regions.

To the naked eye, no emissions rom an oil storage tank are visible (let), but with the aid o an inrared camera,escaping CH

4is evident (right).

Credit:USEPA

Credit:BrianYap

measuresvaryfromregiontoregion.

Manyofthemeasuresentailcostsavings

butrequiresubstantialupfrontinvestments.

Accountingforairquality,climateand

developmentco-benetswillbekeytoscaling

up implementation

Methaneisoneofthesixgreenhousegases

governedbytheKyotoProtocol,butthereare

noexplicittargetsforit.ManyCH4measures

arecost-effectiveanditsrecoveryis,inmany

cases,economicallyprotable.Therehave

been many Clean Development Mechanism

(CDM)projectsinkeyCH4emittingsectorsin

thepast,thoughfewsuchprojectshavebeenlaunchedinrecentyearsbecauseoflackof

nancing.

Casestudiesfrombothdevelopedand

developingcountries(Box3)showthatthere

aretechnicalsolutionsavailabletodeliver

allofthemeasures(seeChapter5).Given

appropriatepolicymechanismsthemeasures

canbeimplemented,buttoachievethe

benetsatthescaledescribedmuchwider

implementationisrequired.


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Box3:Casestudiesof implementationof measuresCH

4measures

Landll biogas energy

Landll CH4 emissions contribute 10 per cent o the total greenhouse gas emissions in Mexico.

Bioenergia de Nuevo Lon S.A. de C.V. (BENLESA) is using landll biogas as uel. Currently, the

plant has an installed capacity o 12.7 megawatts. Since its opening in September 2003, it has

avoided the release o more than 81 000 tonnes o CH4, equivalent to the reduction in emissions

o 1.7 million tonnes o CO2, generating 409 megawatt hours o electricity. A partnership between

government and a private company turned a liability into an asset by converting landll gas (LFG)

into electricity to help drive the public transit system by day and light city streets by night. LFG

projects can also be ound in Armenia, Brazil, China, India, South Arica, and other countries.

Recovery and faring rom oil and natural gas production

Oil drilling oten brings natural gas, mostly CH4, to the surace along with the oil, which is oten

vented to the atmosphere to maintain sae pressure in the well. To reduce these emissions,

associated gas may be ared and converted to CO2, or recovered, thus eliminating most o its

warming potential and removing its ability to orm ozone (O3). In India, Oil India Limited (OIL), a

national oil company, is undertaking a project to recover the gas, which is presently ared, rom

the Kumchai oil eld, and send it to a gas processing plant or eventual transport and use in the

natural gas grid. Initiatives in Angola, Indonesia and other countries are aring and recovering

associated gas yielding large reductions in CH4

emissions and new sources o uel or local markets.

Livestock manure management

In Brazil, a large CDM project in the state o Mina Gerais seeks to improve waste management

systems to reduce the amount o CH4

and other greenhouse gas emissions associated with

animal efuent. The core o the project is to replace open-air lagoons with ambient temperature

anaerobic digesters to capture and combust the resulting biogas. Over the course o a 10-yearperiod (20042014) the project plans to reduce CH4

and other greenhouse gas emissions by a total

o 50 580 tonnes o CO2

equivalent. A CDM project in Hyderabad, India, will use the poultry litter

CH4

to generate electricity which will power the plant and supply surplus electricity to the Andhra

Pradesh state grid.

Farm scale anaerobic digestion o manure rom cattle is one o the key CH4 measures

Credit:RaphalV/fickr


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Box3:Casestudiesof implementationof measures(continued)BC measures

Diesel particle lters

In Santiago, municipal authorities, responding to public concern on air pollution, adopted a new

emissions standard or urban buses, requiring installation o diesel particle lters (DPFs). Currently

about one-third o the eet is equipped with lters; it is expected that the entire eet will be

retrotted by 2018. New York City adopted regulations in 2000 and 2003 requiring use o DPFs in

city buses and o-road construction equipment working on city projects. London tted DPFs to

the citys bus eet over several years beginning in 2003. Low emission zones in London and other

cities create incentives or diesel vehicle owners to retrot with particle lters, allowing them to

drive within the city limits. Implementation in developing regions will require greater availability o

low sulphur diesel, which is an essential prerequisite or using DPFs.

Improved brick kilns

Small-scale traditional brick kilns are a signicant source o air pollution in many developing

countries; there are an estimated 20 000 in Mexico alone, emitting large quantities o particulates.

An improved kiln design piloted in Ciudad Jurez, near the border with the United States o

America, improved eciency by 50 per cent and decreased particulate pollution by 80 per cent.

In the Bac Ninh province o Viet Nam, a project initiated with the aim o reducing ambient air

pollution levels and deposition on surrounding rice elds piloted the use o a simple limestone

scrubbing emissions control device and demonstrated how a combination o regulation, economic

tools, monitoring and technology transer can signicantly improve air quality.

A traditional brick kiln (let) and an improved (right) operating in Mexico.

Potential international

regulatory responses

Internationalresponseswouldfacilitate

rapidandwidespreadimplementationof

themeasures.Sincealargeportionofthe

impactsofSLCFsonclimate,health,food

securityandecosystemsisregionalorlocal

innature,regionalapproachesincorporating

nationalactionscouldprovepromisingfor

theircost-effectivereduction.Thisapproach

isstillinitsveryearlystageinmostregionsof

theworld.Forexample,theConventiononLong-RangeTransboundaryAirPollution

Credit:AlbaCorralAvitia

Credit:RobertMarquez

(CLRTAP)recentlyagreedtoaddressBCin

therevisionoftheGothenburgProtocolin2011andtoconsidertheimpactsofCH

4as

an O3precursorinthelongerterm.

Otherregionalagreements(Box4)arefairly

new,andpredominantlyconcentrateon

scienticcooperationandcapacitybuilding.

Thesearrangementsmightserveasa

platformfromwhichtoaddresstheemerging

challengesrelatedtoairpollutionfromBC

andtroposphericO3andprovidepotential

vehiclesfornance,technologytransferandcapacitydevelopment.Sharinggoodpractices


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onaninternationalscale,asisoccurring

withintheArcticCouncil,inacoordinated

waycouldprovideahelpfulwayforward.

ThisAssessmentdidnotassessthecost-

effectivenessofdifferentidentiedmeasures

orpolicyoptionsunderdifferentnational

circumstances.Doingsowouldhelpto

informnationalairqualityandclimatepolicy

makers,andsupportimplementationona

widerscale.Furtherstudyandanalysesofthe

localapplicationofBCandtroposphericO3

reductiontechnologies,costsandregulatory

approachescouldcontributetoadvancing

adoption of effective action at multiple levels

Thisworkwouldbebestdonebasedonlocal

knowledge.Likewisefurtherevaluationofthe

regionalandglobalbenetsofimplementing

specicmeasuresbyregionwouldhelpto

bettertargetpolicyefforts.Insupportofthese

efforts,additionalmodellingandmonitoring

andmeasurementactivitiesareneededtoll

remainingknowledgegaps.

Opportunities for internationalnancing and cooperation

Thelargestbenetswouldbedeliveredin

regionswhereitisunlikelythatsignicant

nationalfundswouldbeallocatedtothese

issuesduetootherpressingdevelopment

needs.Internationalnancingandtechnology

supportwouldcatalyseandaccelerate

theadoptionoftheidentiedmeasuresatsub-national,nationalandregionallevels,

especiallyindevelopingcountries.Financing

wouldbemosteffectiveifspecicallytargeted

towardspollutionabatementactionsthat

maximizeairqualityandclimatebenets.

FundsandactivitiestoaddressCH4(such

astheGlobalMethaneInitiative;andthe

GlobalMethaneFundorPrototypeMethane

FinancingFacility)andcookstoves(theGlobal

AllianceforCleanCookstoves)existorare

underconsiderationandmayserveasmodels

forothersectors.Expandedactionwilldepend

ondonorrecognitionoftheopportunity

representedbySLCFreductionsasahighly

effectivemeanstoaddressnear-termclimate

change both globally and especially in

sensitiveregionsoftheworld.

BlackcarbonandtroposphericO3

may also

beconsideredaspartofotherenvironment,

developmentandenergyinitiativessuchas

bilateralassistance,theUNDevelopment

AssistanceFramework,theWorldBankEnergyStrategy,thePovertyandEnvironment

InitiativeofUNEPandtheUnitedNations

DevelopmentProgramme(UNDP),

interagencycooperationinitiativesintheUN

systemsuchastheEnvironmentManagement

GroupandUNEnergy,theUNFoundation,

andtheconsiderationbytheUNConference

onSustainableDevelopment(Rio+20)of

theinstitutionalframeworkforsustainable

development.These,andothers,couldtake

advantageoftheopportunitiesidentiedintheAssessmenttoachievetheirobjectives.

Box4:Examplesof regionalatmosphericpollution

agreementsThe Convention on Long-Range Transboundary Air Pollution (CLRTAP) is a mature policy

ramework covering Europe, Central Asia and North America. Similar regional agreements have

emerged in the last decades in other parts o the world. The Mal Declaration on Control and

Prevention o Air Pollution and its Likely Transboundary Eects or South Asia was agreed in

1998 and addresses air quality including tropospheric O3

and particulate matter. The Association

o Southeast Asian Nations (ASEAN) Haze Protocol is a legally binding agreement addresses

particulate pollution rom orest res in Southeast Asia. In Arica there are a number o ramework

agreements between countries in southern Arica (Lusaka Agreement), in East Arica (Nairobi

Agreement); and West and Central Arica (Abidjan Agreement). In Latin America and the Caribbean

a ministerial level intergovernmental network on air pollution has been ormed and there is a drat

ramework agreement and ongoing collaboration on atmospheric issues under UNEPs leadership.


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ConcludingRemarks

TheAssessmentestablishestheclimateco-

benetsofair-qualitymeasuresthataddress

blackcarbonandtroposphericozoneand

itsprecursors,especiallyCH4

and CO The

measuresidentiedtoaddresstheseshort-

livedclimateforcershavebeensuccessfully

triedaroundtheworldandhavebeen

showntodeliversignicantandimmediate

developmentandenvironmentalbenetsin

thelocalareasandregionswheretheyare

implemented

Costsandbenetsoftheidentiedmeasures

areregionspecic,andimplementation

oftenfacesnancial,regulatoryand

institutionalbarriers.However,widespread

implementationoftheidentiedmeasures

canbeeffectivelyleveragedbyrecognizing

thatnear-termstrategiescanslowtherate

ofglobalandregionalwarming,improving

ourchancesofkeepingglobaltemperature

increasebelowboundsthatsignicantlylowertheprobabilityofmajordisruptiveclimate

events.Suchleverageshouldspurmultilateral

initiativesthatfocusonlocalprioritiesand

contributetotheglobalcommongood.

ItisneverthelessstressedthatthisAssessment

doesnotinanywaysuggestpostponing

immediateandaggressiveglobalactionon

anthropogenicgreenhousegases;infactit

requiressuchactiononCO2 This Assessment

concludesthatthechanceofsuccesswithsuchlonger-termmeasurescanbegreatly

enhancedbysimultaneouslyaddressingshort-

livedclimateforcers.

ThebenetsidentiedinthisAssessmentcan

berealisedwithaconcertedeffortgloballyto

reducetheconcentrationsofblackcarbonand

troposphericozone.Astrategytoachievethis,

whendevelopedandimplemented,willlead

toconsiderablebenetsforhumanwell-being.

Aerosol measurement instruments

Credit:ChristianLagerek

Credit:JohnOgren,NOAA


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Glossary

Aerosol A collection o airborne solid or liquid particles (excluding pure water),

with a typical size between 0.01 and 10 micrometers (m) and residing in

the atmosphere or at least several hours. Aerosols may be o either natu-ral or anthropogenic origin. Aerosols may inuence climate in two ways:

directly through scattering or absorbing radiation, and indirectly through

acting as condensation nuclei or cloud ormation or modiying the opti-

cal properties and lietime o clouds.

Biofuels Biouels are non-ossil uels. They are energy carriers that store the energy

derived rom organic materials (biomass), including plant materials and

animal waste.

Biomass In the context o energy, the term biomass is oten used to reer to organic

materials, such as wood and agricultural wastes, which can be burned to

produce energy or converted into a gas and used or uel.

Black carbon Operationally defned aerosol species based on measurement o lightabsorption and chemical reactivity and/or thermal stability. Black carbon

is ormed through the incomplete combustion o ossil uels, biouel, and

biomass, and is emitted in both anthropogenic and naturally occurring

soot. It consists o pure carbon in several linked orms. Black carbon warms

the Earth by absorbing heat in the atmosphere and by reducing albedo,

the ability to reect sunlight, when deposited on snow and ice.

Carbon

sequestration

The uptake and storage o carbon. Trees and plants, or example, absorb

carbon dioxide, release the oxygen and store the carbon.

Fugitive

emissions

Substances (gas, liquid, solid) that escape to the air rom a process or a

product without going through a smokestack; or example, emissions o

methane escaping rom coal, oil, and gas extraction not caught by a cap-

ture system.

Global

warming

potential

(GWP)

The global warming potential o a gas or particle reers to an estimate o

the total contribution to global warming over a particular time that results

rom the emission o one unit o that gas or particle relative to one unit o

the reerence gas, carbon dioxide, which is assigned a value o one.

High-emitting

vehicles

Poorly tuned or deective vehicles (including malunctioning emission

control system), with emissions o air pollutants (including particulate

matter) many times greater than the average.

Hoffman kiln Homann kilns are the most common kiln used in production o bricks. A

Homann kiln consists o a main fre passage surrounded on each side byseveral small rooms which contain pallets o bricks. Each room is connect-

ed to the next room by a passageway carrying hot gases rom the fre. This

design makes or a very efcient use o heat and uel.

Incomplete

combustion

A reaction or process which entails only partial burning o a uel. Combus-

tion is almost always incomplete and this may be due to a lack o oxygen

or low temperature, preventing the complete chemical reaction.

Oxidation The chemical reaction o a substance with oxygen or a reaction in which

the atoms in an element lose electrons and its valence is correspondingly

increased.


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Ozone Ozone, the triatomic orm o oxygen (O3), is a gaseous atmospheric constit-

uent. In the troposphere, it is created both naturally and by photochemical

reactions involving gases resulting rom human activities (it is a primary

component o photochemical smog). In high concentrations, tropospheric

ozone can be harmul to a wide range o living organisms. Troposphericozone acts as a greenhouse gas. In the stratosphere, ozone is created by

the interaction between solar ultraviolet radiation and molecular oxygen.

Stratospheric ozone provides a shield rom ultraviolet B (UVB) radiation.

Ozone

precursor

Chemical compounds, such as carbon monoxide (CO), methane (CH4),

non-methane volatile organic compounds (NMVOC), and nitrogen oxides

(NOX), which in the presence o solar radiation react with other chemical

compounds to orm ozone in the troposphere.

Particulate

matter

Very small pieces o solid or liquid matter such as particles o soot, dust, or

other aerosols.

Pre-industrial Prior to widespread industrialisation and the resultant changes in the

environment. Typically taken as the period beore 1750.

Radiation Energy transer in the orm o electromagnetic waves or particles that

release energy when absorbed by an object.

Radiative

forcing

Radiative orcing is a measure o the change in the energy balance o the

Earth-atmosphere system with space. It is defned as the change in the

net, downward minus upward, irradiance (expressed in Watts per square

metre) at the tropopause due to a change in an external driver o climate

change, such as, or example, a change in the concentration o carbon

dioxide or the output o the Sun.

Smog Classically a combination o smoke and og in which products o com-

bustion, such as hydrocarbons, particulate matter and oxides o sulphurand nitrogen, occur in concentrations that are harmul to human beings

and other organisms. More commonly, it occurs as photochemical smog,

produced when sunlight acts on nitrogen oxides and hydrocarbons to

produce tropospheric ozone.

Stratosphere Region o the atmosphere between the troposphere and mesosphere,

having a lower boundary o approximately 8 km at the poles to 15 km at

the equator and an upper boundary o approximately 50 km. Depending

upon latitude and season, the temperature in the lower stratosphere can

increase, be isothermal, or even decrease with altitude, but the tempera-

ture in the upper stratosphere generally increases with height due to

absorption o solar radiation by ozone.Trans-

boundary

movement

Movement rom an area under the national jurisdiction o one State to or

through an area under the national jurisdiction o another State or to or

through an area not under the national jurisdiction o any State.

Transport

(atmospheric)

The movement o chemical species through the atmosphere as a result o

large-scale atmospheric motions.

Troposphere The lowest part o the atmosphere rom the surace to about 10 km in

altitude in mid-latitudes (ranging rom 9 km in high latitudes to 16 km in

the tropics on average) where clouds and weather phenomena occur. In

the troposphere temperatures generally decrease with height.


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Acronyms and Abbreviations

ASEAN Association o Southeast Asian Nations

BC black carbon

BENLESA Latin America Bioenergia de Nuevo Lon S.A. de C.V.CDM Clean Development Mechanism

CH4

methane

CLRTAP Convention on Long-Range Transboundary Air Pollution

CO carbon monoxide

CO2

carbon dioxide

DPF diesel particle lter

ECHAM Climate-chemistry-aerosol model developed by the Max Planck Institute in Ham-

burg, Germany

G8 Group o Eight: Canada, France, Germany, Italy, Japan, Russian Federation, United

Kingdom, United States

GAINS Greenhouse Gas and Air Pollution Interactions and SynergiesGISS Goddard Institute or Space Studies

GWP global warming potential

IEA International Energy Agency

IIASA International Institute or Applied System Analysis

IPCC Intergovernmental Panel on Climate Change

LFG landll gas

NASA National Aeronautics and Space Administration

NOX

nitrogen oxides

O3

ozone

OC organic carbon

OIL Oil India Limited

PM particulate matter (PM2.5

has a diameter o 2.5m or less)

ppm parts per million

SLCF short-lived climate orcer

SO2

sulphur dioxide

UN United Nations

UNDP United Nations Development Programme

UNEP United Nations Environment Programme

UNFCCC United Nations Framework Convention on Climate Change

UV ultraviolet

VOC volatile organic compoundWMO World Meteorological Organization


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Acknowledgements

The United Nations Environment Programme and World Meteorological Organization

would like to thank the Assessment Chair and Vice-Chairs, the members o the High-level

Consultative Group, all the lead and contributing authors, reviewers and review editors, and

the coordination team or their contribution to the development o this Assessment.

The ollowing individuals have provided input to the Assessment. Authors, reviewers

and review editors have contributed to this report in their individual capacity and their

organizations are mentioned or identication purposes only.

Chair: Drew Shindell (National Aeronautics and Space Administration Goddard Institute or

S

united nations environment program report - black carbon

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