geoengineering governance and technology policy pdf

‘The erm “genonsiaerin cribs thn aray of teoloies tha aint large scale and cdeilerựe dications ofthe Ear’ enngy balance, to reduce temperatures asl counteract anthemic climate change.. G

Congressional Research

Summary

‘Asa ptticpant in several international agreements on climate change, the Unite Stats has Joined wih utter nations «express concerts aout climate shang Hove, te atonal evel the Unie Sats has oe yee developed a comprehensive climate change pli In the absence ot

‘Acomprchensive policy dcction shnoigiea advances are erating aleratves the

Teadtinal approaches ta ciate change (nidgtion as! adapation), Uf deploy, hese now lechnolosies omni the Ear’ climate oma linge scale: Moree, these no tehnoges

‘may become availble o foeign eovernments st ete in the private stor use

Uniaerliy—ithoo anoization from the Urited Slates government orn ineratona testy

‘The erm “genonsiaerin cribs thn aray of teoloies tha aint large scale and cdeilerựe dications ofthe Ear’ enngy balance, to reduce temperatures asl counteract anthemic climate change Ms of these lecologics ae a the conker research Stags, an ther effectiveness fred global temperatures has yet o be proven, Moreover,

‘ey fet stukes sve been publishes tht deuent the cost, enitonmenal eet, socio

Poles impacts, ad legs! implications of geoenginering W geoengineering technologies were

to be deployed they at expected to have the potential ease significant ransboundary effects,

‘Aerosol injcetion aa spce-baso eto ate examples of SRM avs, SRM hos do fot remove greeiuse gases from de atosphere but canbe ployed ester with relatively inmate global cooling els compared to CDR meth

In ation seeking an understating oF the science hein he diferey£geoetgjneein technologies, pliesmaers are consiering pices an states fr adenine gooeneeting

‘the nalionl and ngerntional levels Tot, there sine federal involvement i, oF

‘oversight of gevengincering However some sats as wells some federal agencies, notably the Envinvamerial Protection Agensy Dparunest of Ener Department of Agviulure and he Department of Defense, have tan dlons elatod lo goocnsincerna esarch or proses AI thc intentional evel thee no international agreement organization goveeing the tll

spectrum of possible peoensinceine activities, Nevertheless, provisions of many memati! ssteements nclaing those reiting to climate cee, maritime polation, and a paliation,

‘would Hikely inform the types of gevengincsting activites tai state partes to these greens Inigh choose to purses n 201, the Convention on Biologeal Diversity adopted provisions

‘sling fo emer pats to abstain trom geoenginecing antes the patss have flly

‘considered the risks and inputs of thse atv on bisiversiy,

‘With the possibilty that gonengincring tchnnlogies may he developed an climate change endie an ssde of global concern, plicymukers may determine whether gesengincering isan ies that warras attic tetnr the fedrl or otemaional level Hs policymakers will

ko need to consider whether gevengincerng can be effectively adresse by amerdient to vit las an ternational agreements sleratively, hte new lar and international treaties would nos tobe develop

Congolese ies

omngincring Coveraner and Techn

Cabon Dioxide Removal

Carbon Capeue and Sagustaion

‘Space Based Reflectors

The Debate ov the Methods of Oversight

‘The Status Quo

‘Threshold for Oversight

‘Methods for Oversight

“Table 1 Seinife Underpimings for Dilfer Perspectives on Geoenuinering #

“Table2.Six Types of Functions Federal Enies Can Perform and Selected Federal

Entities Authorized to Pofonh Them, 0

Km

Contacts

Congreso Research Sie

Gronnginering Coveranee and Tenoogy Peleg

Introduction

Climate change has neve considerable pie ltenton inthe pst several years bath

itemationaly and within the United States major report esse by the Tereavernmenta Panet on Climate Change IPCC) in 2007 found widespread evidence of elinate arming ad many ate cerned hat climate change ny he severe aM api with pote eatasttpbic

‘onsglences for humans andthe fancioning of ecosystems The Natonal Acalsnies mutans thatthe ctinute change challenges untkely tobe soe with any single teaegy or by the pve ofan single county

Policy eftns to adress limate change us a vary of methods, frquemiy including miigation

‘nl adalaton* Mitigation isthe roti of the pancpal greeioxe gas (GHG) carhon

ose (CO:) andl ether GH Caron conde i the dowinamt greeaboase gas ent

aturlly through the carbon cycle and thgh human activites He the Burning of fos acs Other commonly danse GHGs inelade methane, sts oxide, hydkollobrcarbons,

peflouroearns, an sf hexaioide.Adapation seks fo improve an individ sot

Insiaio’s sly to cưpe viltor socjd hạnHfi tnpasts f chat change, ưu she

vantage of potnsal heel ones

Some observrs ate concemed that cure itigation and adaptation statgies nay or prevent change quickly enough to avoid extreme clinste disruptions, Gevengincering has beon suggested

hy somes a oely ational method to mitigation afd adaplason that could be iselade 9

‘limite change policy ellons, Gooeagnssring techaologis, appled to the clint, im wo aces large-scale and ders molificaions ofthe Earth's caeray balance in order to race

temperatures und courteractantepogenc (i, humun-mak) climate hang: these climate notiietions woul por be limited by county bounds, Asan uaprosen concep,

psengincering eases stantial environmental sn thin! concers for soma observes” ters

Gronnginering Coveranee and Tenoogy Peleg

respond thatthe uncersines of geoenginssting Pay only he eslva tyough farther sine

tn tcchnical examination

Propose gcoonginseting technologies vay greatly in tes oftheir technological characteristics and posible consewlences They are generally casi in 0 main groups

+ Solar raison musnogement (SR) method: technologies that would increase the

reflectiviy orale of th Earths atmosphere or surface, and

+ Carhor iid nano (CDR) method: technologies or prseties that would

remove CO: and ther GHGs from the amesphete

‘Much of the geoensinering nology discussion enters om SRM methods fe enhanced ado, ersol jection), SRM neous could he deployed telaivelycuiely if aes, ae Thất npact on the elnste would be more innate than dha of CDK mes Because SRM Inet do os eae GHG fom the sunpspher,ploal warning could reste a rapa pace ita deployed SRM method fils os ernst a anytime, Al leas one relatively sinple SRM imc is already Being deployed with government assistance,” Other proposed SRM methods

te atte conepeualization stage, CDR methods inlode afforestation, oscunfeilzation, an the tse of bom to cape an store carbon

Ín 3009, the House Science ad Technology Commitee ofthe 110 Congres eld hearings on ssoenginocring that examina the potrial environmental risks a each various

Props associat domestic ad ierstonal governess, cealtation mht nd

“gia, sear sal develapanent (RAD) fos al economic rationales supine the

“Uployinat of govengineering actives" Som Foreign governments, incline the Unite Kingdom's, swell s scents rom Cierny a Tn, have heguncorsiering engaging in

th esearch or deployment of govengieering teholgies hecatse of concern over the shoe prosress of emissions reductions, the ubcertisies of climate ses the posible existence of

‘imate thresholds or spp pens) andthe politcal, seal and economic mnpat of

Tursing agaressive GHG mitiation sntegie

To date, congressional iret in geoenginering hus focused primarily on whether

ssvengincering isa ris lletve and appt to! forthe United States to use to adress

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"mcafee care ng rey he US vias Prin Any ee

Seino nd Tehncoy, Groening: Aces the Igloo of Lrg

hang seas y ne A Lge AS cote Chrono of he era

onc Nac" Gai Lm iets of Oran Fen, 308 Os ea tats

“Tis ep isatende as prime on the potey issues, scence and governance of

coanginceins thoes The rom wil rst set he policy parameters wader which

$Esvenginceringtechnolnscs may be comideved esi en dese selected wcngies a

‘oti ad discus hott, The tid section pronides a cseussion of possible apace to povernmenial involsement in as overiah of, geaenginering, inluding a xmnnnry f

comeicanlindentiiom instruments ad aston tha ay ae govengincsring projets

Geoengineering Governance

‘Gnenginering technologies sim to may the Fan's energy balance in ender to redoce

lemperatves and eoutersctansinopogenic cma change trough ltgeseale and dlibeate

‘nalfcations, Inplementtion af sie ofthe technics may be cost locally, while thor Icchaolosies muy require shel np om implementation, Additionally, where tvtnoogycan

he contolled or not once implement eifers by technology type: Lite rscarh hus beer done

‘onvmust senensinering methnds, ad no major vctal rèterch programs are in pcs Pest reviewer Hieratre is on, aa deploying othe tehology either oaeh eon ld tests or commercial enerpriso—fas heen minimal Most infereste observers anes that mone research wut requred wo tte easily effectiveness, cast, social and envionment inact, ara he possible united consaquences of geoenpinering baforedeploynent hers

‘eet exploration ofthe options as on risky The uncertainties have ll some policymakers 19

‘onside the noel athe oe or overnieatal oversight to pie esac nth shor term ad

tw oversee potesal deployment inthe long term Such soverapee seuetrss, oth domestic and intentional, col ether soppot or consrin gevengincring activites, depending on te isons of policymakers, As bth echnolagical development an policy considerations for psvengincering ten thir ery stages, several questions of povermance emai in py

‘+ What isk facts and policy eomsideratons eater inl the debate over

_goenginering atvitcs al governmen oversight?

f+ Atwhat point if ever should dene he wornmcnt oversight of gonenginesting

+ Afro‘ government erst, what form sho i ake?

+ Hheei wormnoat oversight, who sal e responsi fr i?

+ 1fthere ‘is pblely fade research and developmen, what shoot cover and

‘which apne shouldbe engaged i it

Risk Factors

Asa new and emerging St of technologies potentially able wo adds climate change

fsovenginsuring possesses oth isk ant uncertainty, From a earch perspective sk mst often ress inh uneeraietes ofthe technology (.e,the Fisk of failure, accu, oF usenet

‘onsoyences) However, ny observers belive tha he grester sk in yevenginering activites nay lia the soca, cba lpa and polieal uncertainties associated with deployient

‘Marner, given these sts, there ft agate tha appa mschansns for govern cavehisÖf shoald he cata hole the Fara goverment ais agers ake step 0 Promote geventinscrine techologes an Before ewe sacnineerine projets ae commenced Yet the uncetiny blithe teehaoogies makes icaneleae whieh meow, ian, may eer rire to the point of being dese suvinty effective, affordable safe, a sine a

am prema deploytnent.” Some ofthe more significant sks factors assoiated with

scoengineering area follows."

+ Tetnotogy Conn! Dilemma, An analytes impasse inherent in all emerging

serhnologs i tht pest aks may Be foescea in the sige phase bul con

‘nly be proven and resolved throush actual resarch, development za

cđemonsraion Iỏedl appropiate sfoguas are pot in place rng the carly

stages of eonceptualzaion an develpment bu amipating the evolution of a

new vehnolngy can be diet By the ime a tchnoloey is widely depfoyed i

‘ay be impossible to Bild desirable oversight and risk managernent provisions

‘thou major disruptions io exablished interests, Flexi fen routed to

oh spp investigative research and consti pent hal

seployen,

+ Reversi: Risk mitigation roles onthe aii to cease a eehnology’ program

nd terminate is adkerse eas i shot prio of me la piciple ll

‘Eeoeginceting options could be abandoned on shor notice, with ether a instant

‘cuit fret chat effets or sal tne lg Mer abandonmen

However the issue of versity applies more tha jst he tchologies

Iemselss Given de importance of itera austin an feedhacks inte

imate stem iil impericetly undersiood—it i unlikely that al sconary

‘lec from large-scale deploynsem wld chil intel Ako, choices made

reginling eoenginsering methods may ivlaeace oer xù, cconamie ai

Ischnoloetil choices resadng cme science, \vaneine seeninoer

‘options in fa of effectively nstigating GHG emissions, for example, cud

result in a aunber of advese etfs, nclading ocean aifiction, stesses On

diversity eioute sensitivity shocks, and uther ireversibfe consequences

anh investing francally inthe physical ineassrctre ro suppon

soctginscTing may create song economic resistance reversing gan

ant deployment acts

+ Encapsudaion Risk mitigation also roies on whather a technology pe

rmodlat and container whet inwoles the release of mara a the

‘wider enon, Te ise en he fra nthe coment polation

‘eapsnlaedtecholes ae often view a more "thc tha hey ate

“eens monoing Several euengineringfe-hlagjexaf demmtnHy

otrencapsulsed, stl thee release sin! deploy ment int the wider evironment

fray lead 1 echnical uncertiis, impacts on noo panteipams, ant complex

Policy choices Bu encapsulated techaologies may sil have localized

{environmental inpuets depending onthe nature, size, and ction ofthe

{nplication Te ao for esultory ston may ase as ch rem the nist

impacts of activites on agro foresty spc, ad habit fromthe det

iinpacts of released materia in stmsspherie or weenie ccowysters

+ ˆ Canaehial Imoiheneu: The rote of private-sector engagerent inthe

evelopnen and promition of peoenginvcring may be debuts Commercial

involvement including competition, nay he positive in tht it mabilizes

ination and capita investment, which cool ead to te development of more

cfc a less coil lseheloyie ai fase rate than i the pli ster

However, conti inselvemen could bypass oF nel socal, economic, and

cavironmenal Fisk assesses in favor of what one comment eles a

imesponsbleenrepreneoral Meavion”" Prvate-sector engagement wot

ely require some form of pubic sbsitis GH enissom pricing to

‘enue invesient, ss wll as ational considerations ieladins cess rnodel.itelecual property ahs and wate al sranser mechani forthe

sseminstion ofthe technol

+ Public Engagement Ths consequences of gevensinesing—ineluding hath

ene and risks discussed ubove—could afet people and communes asoss

the world, Publicaties toward seoenginscing and puble engagement inthe

Formation, developmen, and exesition of popesed powers ald Rave 3

‘ciel heaving on the ttre of the tspologie,Pereptions of Fs, level

Tre, iareney o ngon provisos for babies and compensation, ad

‘conoanies of investment eu playa significant fle in the pola feasibility

of geoenginvering Public acceptance ay tgitea wider dislogue Dewees

‘cont, poieynakers, arte pi

‘county or reaiondecms these activities, a their petetial consequences, acceptable will likely

“lspeu olonly on he scenic and techni underpinines Tor Ue Bonengnesring technology ino, bt also bya anes of soap, ad poate ha tan se xt eountiex anÏ

‘alas, Forexanmpl, while some may view peoeeineerine throne the ls of risks and tial concer abt its potential impacts ters ay fel tat he rsko elie inaction «lop

‘Goagesionl Raa aes

ata therefore, dat containing geoenginering atities sas maya baz a8

Promoting ant engaging in sooeagincsing actin

Pobiie opinion on geoengincring sie gauge at this e4fy stage Is key to both vole as moc information comes available al vary pending onthe particular ecinoloay hoàng điepesel Navenholeo 2009 report Hy the Utes Kinglonfs Royal Soviet." which is

‘wily consiere to het Gist comprctensive analysis of gonengncsring technologies, his rou identi thee etepories of perspectives held within the Scie community about the -loy tef 0F govensineering technologies

+ Gooengincoring wil help buy back time lost during international mitigation

‘The following tale lenis aa explains dhe scenic undeepinings for many ofthe

psspeatves on geoenginering that have een aicalte to dite

gai Roona ri

ign

Geoengineering Technologies

Avide range of peoenginering technologies have heen proposed to addes climate change

‘Geoenginering technolagies atten o mitigate continved Warming ofthe Earths eimate, The technologies vary in complexity from planting tec for earbon sequestration 1olaehing mirors imo space for sunight eetion Most ofthe technologies ae not yet proven and are atthe thoortel oe research phase, Several ofthe proposed techmoogics were recently conceived if they prove feasible und effective they would require large amount of funding for ullscale deployment: and generally they lack politcal, setentfic and public support

Figure 1 Geoongineering Technology Options

> Searatiaton management Sues

= Gan axe eral CON eingus > Ens om oxen Inn Sr adon Cabanas

thay đownanlng

Sourea TH Lens ALE Van, The Rade Forang Pose of Daren inate GecergnseirE pens sper hems nd pcs 99 18 (Aug 20%) Ate CRS

Note: The tre dys engroarad ow carbon aa spr grsrgaun ————— ¬ chop opin Hower,

‘The two main categories of gcoengineerng technologies are carbon oxide removal (CDR) and solar radiation management (SRM) sce Error! Reference source not found,) CDR methods renove CO; from the atmosphere SRM methods ineease the electvity ofthe Ears

atmosphere o surface thas relvcng incoming soa ration”

Ha fm UK Sean TC Te Rin seg HA Rept

Carbon Dioxide Removal

Carbon iosde she prvasey GHG hat has boon nk fo ineteases in atmosphere tempera

‘CDR mahodsremo¥e CO; fom the atwosphere anda intend ol the plant hy reducing the absorption of hcat inte atmosphere CDR methods vole th upake aa sorage of CO: by biological, physial ar cheeal means COs may be store (or seguessted) via afforestation.”

‘ocean fenliation, seaering of eortan sedimentary rocks, or combining carbon capre and Storage tecinlogy wth the prion of biofuel, among oes aporoaches, The drain

‘ishon storage lifer dcpenting onthe apreach, Fr inslan,carhon storage may las om decades to centres tor evan ferization, or thousand of years for weathering of earbonate tock

Altheueh CDR tecaigues cold lower atmospheric CO: eves eventually leading Wo decrease

in temperatures, they So qui considerably more tine to hatt an mgue on elinate change than SRM txhnighes.” This, CDR tongues arene del methods to deploy iFimmeiate aeration ofthe climate is nacessary While the impels of COR mods could take yeast realize, many CDR methds could he governed mre asly than SRM methods by existing a For example carbon capture and storage rom a biomass power plant cul be sujet to the same vironment and caoray laws as carbon copte a sorage fm ä coẲE poser pla,

“This scution doserines some ofthe beter examined CDR mates echo capture und

scesentrton, ocean fenton alflorsation a enhanced weathering

Carbon Capture and Sequestration

‘Carbon capeure aa saquesetion CCS) ithe capare au storage of CO: prevent i fom Ing release the atmosphere CCS generally pes to the process of using tetas 10 remove COs esas fm annapgesie sources her tah CO; that eau natal 2s put ofthe Earths carbon cys, "Heras CO, emissions rom enthropogemic sours conte

to ncrase CO; levels inthe atmosphere, CCS engineering technologies are being psc for three soures: biomass, bioenergy al fossil fuels (mainly power generation)

“CC technology tends te abo š gensreineein

baenergy Its nt clae why the dstintion of ab ‘echoniogy only if the sources biomass or

pends onthe source from which earon will be epmored, sn ott oteome, which ete rutin in the amount of COseeleased 0 the atmosphere According t this view CCS tron Fossil fuels nay be excluded as geoenpinecting technology because esi fuels ar earbon- pesitive while bioenergy an omss ae viewed as carhon- neal or carbone

Aina intervention eal incase the amount of CO, thai seguescred, Blomus tht fathervise would not he se for erops or energy pexliclon couÏl e bared in held or deep

‘cca fo slow the raat which CO fs release the tnepiere, Carbon cam als be suesered

iC toms is poly ito Bice a chron! peed uke high temperate ving cop resides, anal manure other organic mesa wily the penta sequester eo nthe Soil or hundreds thousands of years as stint Lange seal ebon cps thal ws mas wuld requitea steady Noms supply aad a place to sae ie

‘Capturing CO: is relatively ell uskestond compared 0 sauestering COs, Howeret, CCS technology fr fossil fuels has no been applied tthe commercial evel ts far det lack of a economic incentive or 4 rexulatory reuiremets to reduce CO, ensions Carbon dione hay esa cpu ona smal scale for comercial appcatinns fe afew decades fe for sid Production to eaance olf and gas rovers), bul not ofa lrg scale sequester CO: asa ng

‘Gem climate change mitigation method Estates of CO, sequestration perfomance are hase pualy ono sal eis covery ellorts shih have sequesiered CO fr aggwoxintsy 30 gears, Tay ke lens 10115 years before CCS fo fossil ic ready fr cinimereial deployment

“sparing sn sling the etbon feleased ding his proces.” BECS is expected 0 use

teshologs similar to CCS seco use To eating CO» fom fossil uel eombusion

hon hinmass i use» generate ele, the COs released ate process may be sequestered Ínpenbogie Formations ia th same way a= woul he used in 2 oss tui enerain CCN, seperation,

[ECS is an unproven CDR mattod because o commercial-scale CCS filiy exists for cher Foss fuck or iscnergy Many of te lesons ero rom CC inthe fossil uel sector over the next fs years should he applicable to BECS BECS deployinent could take as long or longer

es Repo LSE line Change Te aloft tyes Sr Baa khen

letomaton one Maway of Key Tshalops 0 Redws Caria lows Ents OAD-O-073, un 0,

‘ina gc ens Spa

Gronnginering Coveranee and Tenoogy Peleg

than fossil-fuel CCS, Some eter hac BEC

Signiticam’ impact on climate change.”

oul not he deployed ast ena ta have

‘One ofthe main challenges to CCS deployment is the lack af regulatory framework to pert seologe sequestration of COs An integrate stractre would be assess to deploy CCS ata large sale wheter for fossil acl or bioenergs This structure involves Weng who ovis the spestesd CO where to soquser the CO, defining what constitaes Kaka, iemfying

‘vo wil he Gel able if the sequestered CO leaks, developing « monitoring and maitenancs Pian and developing a wus pipeline intostretr veelieily lạt CO, đại MT bế segMetrei, ving cer thas” Some eaten ha if CCS sere implemented on large scale fr bath fos els and ioeneray, doce weld be ss motivation ta rabice The use of fossil fe, Ab nerease

in BECS, however might po face the sme agunen Furth, BECS might be consider sarhon-nepative” whereas CCS fom fos ac combustion i at Kast slightly carbon pose,” Aalto, thers enncer that COs storage frown fossil fuels, and peshaps bioenergy, may ead 'o contamination uf underground sources of dinking Water In 3010, the U.S Environmental Protection Agency finalize a rule hat sets requirement for geologic sequestration of carbon fos, ing the suthrity gram the ageney inthe 197 Sale Dring Wale Act”

‘Ocean fertilization ithe ation of rutin suc as ron to the ccean to expe carom

ssgetrddon ram phưuplaidon.” Phhloplunlaon photosyrfsize CO reidd the caBon in

‘thr cells, which then is sequesterod as carbon nthe deep nose when they die and stl tosh the waters tus suagest hat ono ion ads to cra put ofthe ocean could remove

30000 ta 1I0 000 cons af carbon from the at Oosan eration is stmt to cost,

Angoximately $30 (0 $30 po en of ean sequestered

Gronnginering Coveranee and Tenoogy Peleg

‘The ecological, economi, an efnatologieal impacts of acca fenton, in bot the she teem andthe loBe tern are uncertain" Some sggest tat ocean fei zation may eaance fist stocks

tn pment procuction of dimethylsFide,«chomical that ay coi thệaunssphkre, hút bác tindsiable characteristics a high concentrations" ies are concer that occa frsization

‘sll elo ocean aeiiiction, ational emissions of port sreeiiouse gases, al nelugon of

“oxygen to Levels a habitable by certain spies, Cries aso arate at acean Keiizaton is ơi lanelfective way to combat elma change house the echvigụe raNieev ilevesd long

implementation om a contin basis

Studs have yet to demonstrat ha oxen fetiizaton will work as an em catbon

Sequeteaton ttegy, Fuh esearch i key needed to ans aomnrons questions ineling

‘Will phytoplankton nerease i suiees names o sequester sigan amants of COs? Hise log Wille eatbon stay sequestered? What dstuptons will ccur to mine ecosystems?

‘Currently thee are ao analogues to compure what may ascr iocean fertilization is deployed on

‘large sel,

Some cnsision CO sedestered via sua feizaton sa potential carbon ert he sold as 8

‘arhon offset or toded within an environmental market” There appear toe no eal fameworks that endorse o ject ean fenilizaton forthe purpose of aeuirins carbon eres Thus, forthe Time being, ony earn enais earner for oe fertlizainn woud have wo be used ina

samt carbon mathe

Afforestation

Alforestatio involves planting tree Scolngs on sits tat ave been without tees for several years, genealy a decade or me." The primary climate change beset of afforestation

{sca in scion and pie iteratre carbon seqesration, fs rgande asa prime

‘athon sestraion strategy hevase forest comnuities ea store about Himes more carbon inher sesstation hn non forest sommaniies and fr long time periods (cas to hanes

‘ years) Other hei inside ersion como, etalon vl, sili habia,

reduction of foes gon, On a lane eae, afvettion ean moles elinate by increasing Thun, alesing load and precipitation pers, and redacing win spss Challenges

ssid with alforsttio inciade neasuroment and reporting of cathoa storage, lowers

Gronnginering Coveranee and Tenoogy Peleg

reluctance to grow es on private lan fr extensive time periods, aa tedsion in not hat nay impact te cology ofthe forested ares mn other sus" Potenialdrawbacks to wide- Scale implementation of afforestation ineude unexpected eleases of CO; fom ney forested lands deo acts of nature (efi drougho ature changes inland managemeat (es

artesingl that could rss nrlease af the cao, the potentially significa cos for

lfloresaton, and possible tft erp preston ad aici comity ries

Sienitiant erplaisae afforested

‘The planing of tes is well town, and well practiced alforstation san aeseped projet

activity ude the Clean Deelipnent Mechanisin (CDM) ofthe Kyoto Proto The aa

fs ate at shich CO là seguesered depends onthe re spies, ela, oi type, mann other stesposie features The eine sequestation poten anges fh 2109.5 Imcric ons of CO per acre por ye” Hemy take at fast 20 year to reap he earon

‘sentation Beelt deperdng om le goth ate of he ees, Cart accmlaton nthe ely sears of tce growth slow and increases dosing the strong goth period: here is conver

‘water carbon aectaton conn peaks when tations! wd prt is min

‘Mos alforesttion projets occur on mrgaal cropland, Certain models estmste that total of {s) milion to 65 nliom eres of U.S agricultural Lard cou be converte ta woud hy 2050, including 35 milion to 30 milion acres of expan Changes i elite my impact which Fovstry spies ae plated at aforestaton sites Therefore, fone species pat a

fiorsaton projects may othe sina to species fo tthe ite nthe pat Th cos

forsaton project ean Fane fom apronmately 86S Wo $20) pe ate de ptt the

pcsous land use ofthe ste ant ern”

Enhanced Weathering

Caron done ie nataraly remove from the amsphere slowly though weathering or

singin) of sate ad carbonate rocks, Expediting he weathering fces—enhancod

‘weuthering couldreniove lage amu of COs fro the slnonphete The diitepated

‘materia containing CO: removed from an enaned wethering projet could be stoned the {sep oseun or ine

‘paucity of erature exists about how to conduct an enhanced weathering payee ors

fnvinmimenal implications One propose! method i ta spe crise olvine, a type af sicte rock, cm agiowhuta ant forested lan to Segdsster COs and npove si quali THs

technique would reuice large arcs of rocks fob ino, grou and transported, The

llceyee carbon benefit has not hoon cakes Significant amovris of atonal resoures, such asenery and Water, may he reguted Wo coe an enaned weathering projet

Porter rescue wld be ned to asses the potential bong an cahacks ofthis

technology Barts enkanced weathering include scale, cost, etsy rere, and ptentialeaviznmental conseguees,” Decisions wo aed to heme o which amcape to dlr, where to disp of the dsintepates trae who pss fr the projet There may be longterm aderse imps air qu, water quali aa aquatic ite

Solar Radiation Management

Sola aation management mates work to radu over the amauta incoming solar Fadasion by making the Earth more reflective (he etncing sheds) al do so have any effect

‘1 GHG emission ats.” SRM wethods involve wuodiying abe via land hsed methods suc

1 dose reflector cloud hase mods suc as cloud whitening stratosphere based mols Such as aerosol injston, and spacod-basedmthods suchas sick The elesivenes of an SRM method depends ons eeaphical locaton, the atta at which is applied rac, nvsphee, space) an the radinive propre of the almosphee and sac

proven effective unl desirable, SRM methods cold fe deployed fase than CDR sncthue should the aged sis cool he plat icky, SRM mein have hoe dese, thoonfielly cela 4 and perfec.” However, se maths have no hen prover on ay sale Some ague the US goveramont shoud eeate a teste or eversight progam patently with

international cooperation hat exantines SRM technologies prior wo pei hasty deployment

by am individual or country, which could result in an amy of unaniipatel consequence" Resear could prove understating ofthe feasibility of ciferent SRM appnoaches, tit

“oppturitcs an Emitaons ad thei poteaial role in elit change mitigation.” Odher

“omcaiaors favor conseanis on SRM sesarch, ven the significant environmental sks posed hythese

System flare f'n SRM sechnigue breaks down oes shut down the imate

nay wart very guickly, possibly heaving tems for human ad nae

hệt

4 Changes insegonal and scusomal bites SRMT thnjggsx may alr

Precipitation pater, which ew hive consequcrees for seaystems and

Mloted soit,

+ Ovone depletion Unter cesin cicumstanees se oF SRM eb Suh as

sulfate actono injection may asta ozone dplction which would allow bara

UVB cays to each the Earth

+ Preservation of nom COs grcenhouse gases SRM cchigues app inthe

stratosphere o space lessen th umount of ultraviolet radiation striking the

Ent atisphers whic key to estend he taper iene of no

“CŨ; grsenhntse emes ạt ae more poten than CO:

+ Diversion fom more permanent solutions [societies conclude that SRM

Ischniguescun provide quick rl they may inves ess in developing a

{Spleying toe permanent GHG emission ration solsions,

+ “Unknown unknowns.” The hisory ofthe Ean’ climate demonstrates that

sina changes may rst nab chang, rising concemns about unk tan

lees of large-scale geossginserng.”

“The flloning section explores sme ofthe more widely discussed SRM tshnigues enhanced

be, aorsolinjston, ad space based electors

Enhanced Albedo (Surface and Cloud)

‘One suggested metho to modify the temperature of he pat sto increase dhe flit abd, of certain surfaces Increasing surface eesti els more solar ration Back toward save this Hinting tomperstre increases Sunfce types, application areas, and costs for seBaneed sibodn are all unr investigation,

‘One ofthe must widely dseused orgets for enansing surface abe is urban ares Applying enbaneed lhedotahodsn Đan an si as raiditg toi at paved areas white on a glahal brass estimate to cost several billion dollars for igrils and lab, bul could save money 0 nora cont" For example the U.S, Deporte of Energy (DOE) National Nuclear Seca

‘Administration (NNSA) has reduced bung heating and eoling ows by an average of 70, percent anally on retooled ares partly dco install el roots” Some draulacks to Increased recy of roofs and paved ars nclide uaconnonable glare, concer For the

Gronnginering Coveranee and Tenoogy Peleg

sesthsie spp ofthe roofer paved atea depending op its eation, the ss of refetivity eels ifthe roots poorly wna and izes energy contin coer elimates det reduced henetcial wittr inc heat gins.” Adaionally if eabanced surface albedo for pave eas is pursued aggressively there my be a decline inthe se of asphall—a pemoleum residue

Akigonal techniques ar being considered for enhancing surface albedo, One pros 1ø

‘moi plants trouah gent engncering to augment albedo with relatively fe plementation

‘ms Some mtntain wl ake a east a decade fr enhanced hed plat varieties w be vale commercially” A secon proposal seoserine oceans with efletve src to

Enhance aldo, There ate concerns about where an enhanced ales projet wold ake place in The aecan ak hat peti would have on agai ie

Clo shitening là anh props mao for enancing alle, Chad whitening isthe

‘lispersin af eloaenndensation ale (eg sia particles ose sal acho in dese areas

‘ma comtintal bass sce Figure 2) Asa ships, of unmanned, rao-contolled sacra eal disperse the nucle” Satlives ave been proposed s aay to measure clo albedo and

‘termine the amount of cooling eeded Spaying for eloud whitening could be aed quckly if expected consequences arose with ond peopetes expected to return to nora within a Fe

dc

Te long temn inpfiadion of deploying cloud whining are not et fully understood Depening

‘othe scale ofthe projet rine censystetr could he distr, Tur ressarch ie noce or Spray generator developmen, and wo asess potential impacts on decan curren apd precipitation ters Moccover te amoue of cooling dat could ake place and at which locations requires beater scaly One tnd idenaied the west eosst of Noh Anverie,anmn oer kacions 230 dea where cloud albedo might be effectively enhanced