What has C4MIP learned from CMIP5 Lessons for CMIP6

Pierre Friedlingstein University of Exeter

Modelling groups

•  11 modelling groups, about 15 models (BCC-CSM1, BNU-ESM, CanESM2, CESM1-BGC, GFDL-ESM2, HadGEM2-ES, INMCM4, IPSL-CM5, MIROC-ESM, MPI-ESM, NorESM)

•  Simulations performed – 1pct , BGC, RAD – C-Driven Historical + RCPs – E-driven Historical + RCPs

Outputs

•  30+ CMIP5/carbon related publications •  C4MIP special issue in J Climate: 10-15 papers •  Significant contribution to AR5 WG1 (chapters

6 & 12, TS and SPM)

AR5 SPM

Cumulative emissions of CO2 largely determine global mean surface warming by the late 21st century and beyond.

Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions.

VOL. CLXIII . . . No. 56,273 © 2013 The New York Times NEW YORK, SATURDAY, SEPTEMBER 28, 2013

Late EditionToday, mostly sunny skies, season-able temperatures, high 72. To-night, mostly clear skies, low 56.Tomorrow, partly sunny, still mild,high 73. Weather map, Page A13.

$2.50

By PETER BAKER

WASHINGTON — The long-fractured relationship betweenthe United States and Iran took asignificant turn on Friday whenPresident Obama and PresidentHassan Rouhani became the firstleaders of their countries tospeak since the Tehran hostagecrisis more than three decadesago.

In a hurriedly arranged tele-phone call, Mr. Obama reachedMr. Rouhani as the Iranian leaderwas headed to the airport toleave New York after a whirlwindnews media and diplomatic blitz.The two agreed to acceleratetalks aimed at defusing the dis-pute over Iran’s nuclear programand afterward expressed opti-mism at the prospect of a rap-prochement that would trans-form the Middle East.

“Resolving this issue, obvious-ly, could also serve as a majorstep forward in a new relation-ship between the United Statesand the Islamic Republic of Iran,one based on mutual interestsand mutual respect,” Mr. Obama,referring to Tehran’s nuclear pro-gram, told reporters at the WhiteHouse after the 15-minute phonecall. “It would also help facilitatea better relationship betweenIran and the international com-munity, as well as others in theregion.”

A Twitter account in Mr. Rou-hani’s name later stated, “In re-gards to nuclear issue, with polit-ical will, there is a way to rapidlysolve the matter.” The accountadded that Mr. Rouhani had toldMr. Obama, “We’re hopeful aboutwhat we will see from” the Unit-ed States and other major powers“in coming weeks and months.”

The conversation was the firstbetween Iranian and Americanleaders since 1979 when Presi-dent Jimmy Carter spoke by tele-phone with Shah MohammedReza Pahlavi shortly before theshah left the country, accordingto Iran experts. The Islamic Rev-olution that toppled the shah’sgovernment led to the seizure ofthe American Embassy and a444-day hostage crisis that haveleft the two countries at oddswith each other ever since.

Although both Republican andDemocratic presidents havereached out to Tehran in the in-terim, contact had been reservedto letters or lower-level officials.

The call came just days afterMr. Obama had hoped to encoun-ter Mr. Rouhani at a luncheon atthe United Nations and expectedto shake hands. Mr. Rouhaniskipped the luncheon and laterindicated it was premature tomeet Mr. Obama. But a meetingon Thursday between Secretaryof State John Kerry and ForeignMinister Mohammad Javad Zarifof Iran was described as con-structive and led Iranian officialsto contact the White House onFriday to suggest the phone call,according to American officials.

A senior Obama administra-tion official, who briefed report-

BREAKING GROUND,OBAMA CONVERSESWITH IRAN LEADER

First Talk Between Nations’ Heads Since1979 Is Geared to Nuclear Issue

DOUG MILLS/THE NEW YORK TIMES

President Obama announced having made a phone call to President Hassan Rouhani of Iran.

Continued on Page A6

By JONATHAN WEISMANand ASHLEY PARKER

WASHINGTON — The Senateon Friday approved stopgapspending legislation to keep thefederal government open with-out gutting President Obama’shealth care law, putting newpressure on Speaker John A.Boehner to find a way out of animpasse that had the govern-ment on a steady course to ashutdown at midnight Monday.

The 54-to-44 vote to send themeasure back to the House cameafter the Senate, in a bipartisanrebuke to Republican hard-liners,cut off debate on House legisla-tion that would fund the govern-

ment only if money for the newhealth law was eliminated. That79-to-19 vote included the top Re-publican leadership and easilyexceeded the 60-vote thresholdto break a filibuster. It was fol-lowed by a 54-44 vote to take outthe health law provision beforepassage.

Senator Harry Reid of Nevada,the majority leader, called thevotes “the first step towardwresting control from the ex-tremists.”

“This is it. Time is gone,” Mr.Reid warned. “Here’s a presidentwho less than a year ago wonelection by five million votes.Obamacare has been the law forfour years. Why don’t they get a

life and talk about somethingelse?”

After the vote, President Oba-ma called on Republicans to stopwhat he called “political grand-standing” on the health care lawand accept the Senate measureto avoid government disruptions.

“Over the next three days,House Republicans will have todecide whether to join the Senateand keep the government open,or shut it down just because theycan’t get their way,” he said Fri-day at the White House. “Thisgrandstanding has real effects onreal people.”

The series of Senate votesbrought Mr. Boehner to a defin-

Shutdown Looms as Senate Passes Budget Bill

Continued on Page A11

YOAN VALAT/EUROPEAN PRESSPHOTO AGENCY

The scent of hairspray filled the air as models prepared for Paris Fashion Week. Cathy Horyn re-views the spring 2014 collections of Christian Dior, Lanvin and others. Page B9.

In Paris, Thinking of Spring

By JUSTIN GILLIS

STOCKHOLM — The world’stop climate scientists on Fridayformally embraced an upper limiton greenhouse gases for the firsttime, establishing a target levelat which humanity must stopspewing them into the atmos-phere or face irreversible climat-ic changes. They warned that thetarget is likely to be exceeded in amatter of decades unless steps

are taken soon to reduce emis-sions.

Unveiling the latest United Na-tions assessment of climate sci-ence, the experts cited a litany ofchanges that were already underway, warned that they were likelyto accelerate and expressed vir-tual certainty that human activi-ty is the main cause. “Climatechange is the greatest challengeof our time,” said Thomas F.Stocker, co-chairman of the Inter-governmental Panel on Climate

Change, the United Nations-sponsored group of scientiststhat produced the report. “Inshort, it threatens our planet, ouronly home.”

The panel, in issuing its mostdefinitive assessment yet of therisks of human-caused warming,hoped to give impetus to interna-tional negotiations toward a newclimate treaty, which have lan-guished in recent years in aswamp of technical and politicaldisputes. The group made clear

that time was not on the planet’sside if emissions continued un-checked.

“Human influence has been de-tected in warming of the atmos-phere and the ocean, in changesin the global water cycle, in re-ductions in snow and ice, in glo-bal mean sea level rise, and inchanges in some climate ex-tremes,” the report said. “It is ex-tremely likely that human influ-

U.N. Climate Panel Seeks Ceiling on Global Carbon Emissions

Continued on Page A3

By TRIP GABRIEL

The calls and e-mails from topexecutives came toward the endof each month, former managersat USIS recalled. The companyneeded to swiftly complete in-vestigating security clearancesfor the government in order toreach its monthly revenue goal,the managers said they weretold. Finally, there was an order:“Flush” everything you’ve got.

The directive to give quick fi-nal approval of background in-vestigations without reviewingthem for quality — known asflushing — was sent, the manag-ers said, to a branch office ofUSIS, a company that has per-formed 700,000 yearly securitychecks for the government.Among the individuals the com-pany vetted were Edward J.Snowden, the National SecurityAgency leaker, and Aaron Alexis,who the police say shot and killed12 people at the WashingtonNavy Yard last week.

In interviews this week, formerand current USIS employees de-tailed how the company had anincentive to rush work because itis paid only after a file is marked“FF,” for fieldwork finished, andsent to the government. In thewaning days of a month, investi-gations were closed to meet fi-nancial quotas, without a re-quired review by the quality con-trol department, two former sen-ior managers said.

The details of how its contractwas structured provide new in-sight into the workings of USIS, acompany that is now the focus oftwo federal inquiries, including agrand jury investigation in Wash-ington, according to Congression-al testimony and people withknowledge of the proceedings.

The federal Office of PersonnelManagement confirmed that itpays USIS on a piecework basis.“The vendor is paid upon the de-livery of a completed case,” theagency said in a statement. Peo-ple familiar with the contract saidit was intended to give the com-pany an incentive to be efficient.

USIS, based in Falls Church,Va., and the largest outside in-vestigator for security clearancesfor the federal government, de-clined to comment.

A person familiar with theUSIS corporate structure saidthat two top executives, a divi-sion president and the chief fi-nancial officer, were fired afterbeing found responsible for or-dering the flushing.

Since the terrorist attacks of2001, the need for Americans withsecurity clearances to work forthe Pentagon and military con-tractors has soared, with a longbacklog building up in the earlyyears of the Bush administration.Investigations for a top-secretclearance took 400 days. Compa-nies used the Internet to identifyworkers with clearances at rivalfirms and paid them bonuses tojump ship. To speed investiga-tions, the federal personnel officehired private companies likeUSIS to do the majority of thework, which significantly eased

Shortcuts SeenBy Firm DoingSecurity Checks

Managers Say QuotasWere Set Monthly

Continued on Page A10

By BRIAN STELTER

Right now, Kyle Bauer fears“Breaking Bad” spoilers morethan a pop quiz in class.

At the University of Pittsburgh,where Mr. Bauer is studying en-gineering, students cram into hisdormitory lounge every Sundaynight to watch the latest episode.But not Mr. Bauer, who was, as ofMonday, still about 20 episodesbehind. That night, he startedbinge-viewing so that he can bein the lounge for Sunday’s all-important finale — figuring thatif he’s not there to see the endingwhen everyone else does, some-one will spoil it for him.

“My friends are telling me it’llbe the best decision of my life,” hesaid Wednesday night, withouteven hitting pause during hismarathon to talk to a reporter.

In its final season, “BreakingBad” on AMC has become the ItShow on cable television. All overthe country, converts to the se-

‘Breaking Bad’:Race to theEnd

FRANK OCKENFELS/AMC

The teacher turned drug lord.

Continued on Page A3

By KATE ZERNIKE and MARC SANTORA

A New Jersey judge ruled onFriday that the state must allowsame-sex couples to marry, say-ing that not doing so deprivesthem of rights that were guaran-teed by the United States Su-preme Court in June.

It is the first time a court hasstruck down a state’s refusal tolegalize same-sex marriage as adirect result of the SupremeCourt ruling, and with lawsuitspending in other states, it couldpresage other successful chal-lenges across the country.

The decision was a rebuff toGov. Chris Christie, a Republicanwho vetoed a bill passed by theLegislature last year that wouldhave allowed same-sex couplesto marry. His office said it wouldappeal to the state’s highestcourt. And he is likely to seek astay preventing same-sex mar-riages from beginning on Oct. 21,as the judge ordered.

New Jersey was particularlyripe for a challenge after the Su-preme Court ruling, because of aprevious ruling by the state’shighest court in 2006. In that deci-sion, in the case Lewis v. Harris,the New Jersey Supreme Courtruled unanimously that same-sexcouples were entitled to all of therights and benefits of marriage.But the court stopped short ofsaying they had a fundamentalright to marry, and in an unusualstep instructed the Legislature to

Judge OrdersGay Marriage

In New Jersey

Continued on Page A16

A five-story residential building col-lapsed in Mumbai, a city with crumblinghousing infrastructure and poor con-struction standards. At least 11 peoplewere confirmed dead, and scores werefeared trapped. Above, a girl was res-cued from the rubble. PAGE A4

INTERNATIONAL A4-8

Building Collapses in India

A school superintendent in the Ozarkfoothills has put together a plan with apatchwork of concealed-carry laws, spe-cial rules and local policies. PAGE A9

NATIONAL A9-12

Arming Teachers in ArkansasThe struggling BlackBerry company re-ported disastrous financial results, forc-ing devotees of its smartphones andtheir tiny buttons to ponder what theirtechnological life would be like withoutsmall keyboards. PAGE B1

BUSINESS DAY B1-7

More Trouble for BlackBerryIn her winning new novel “The Signa-ture of All Things,’’ Elizabeth Gilbert,the author of “Eat, Pray, Love,” exploresa botanist’s hunger for explanations asit carries her through the better part ofDarwin’s century!—!and to Tahiti. Re-viewed by Barbara Kingsolver.!

BOOK REVIEW

THIS WEEKEND

The Botany of Desire

The Station to Station train, above, hasbeen traveling west across the countryladen with artists and musicians, seek-ing to turn places like Barstow, Calif.,into temporary cultural destinationswith pop-up exhibitions and perform-ances. PAGE C1

ARTS C1-8

Art as Rolling Stock

A new survey finds that Hispanic votershave increasingly negative feelingsabout the Republican Party. PAGE A9

G.O.P.’s Hispanic Challenge

Hong Kong has among the highest costsin the world, forcing the poor to resort tocupboardlike spaces. PAGE B1

A Cubicle to Call Home

Tara Siegel Bernard answers questionson how the new health care insuranceexchanges will actually work. PAGE B1

Primer on Health Care LawGail Collins PAGE A19

EDITORIAL, OP-ED A18-19

Mayor Michael R. Bloomberg has apoint that New York’s income gap re-flects an influx of rich people. PAGE A14

NEW YORK A14-17

Statistics Support Mayor

The full United Nations Securi-ty Council approved a resolutionaimed at coercing Syria to giveup its chemical weapons, and theprocess for destroying those mu-nitions begins Tuesday. Page A7.

Swift Action on Syria

U(D54G1D)y+%!;!.!=!@

C M Y K Nxxx,2013-09-28,A,001,Bs-BK,E2

N A3THE NEW YORK TIMES, SATURDAY, SEPTEMBER 28, 2013

ence has been the dominantcause of the observed warmingsince the mid-20th century.”

The new report is a 36-pagesummary for world leaders of a900-page report that is to be re-leased next week on the physicalscience of climate change. Thatwill be followed by additional re-ports in 2014 on the most likelyimpacts and on possible steps tolimit the damage. A draft of thesummary!leaked!last month,and the final version did notchange greatly, though it wasedited for clarity.

Going well beyond its four pre-vious analyses of the emissionsproblem, the panel endorsed a“carbon budget” for humanity —a limit on the amount of the pri-mary greenhouse gas, carbon di-oxide, that can be produced by in-dustrial activities and the clear-ing of forests. No more than onetrillion metric tons of carboncould be burned and the resultinggases released into the atmos-phere, the panel found, if plane-tary warming is to be kept below3.6 degrees Fahrenheit (2 de-grees Celsius) above the level ofpreindustrial times. That tem-perature is a target above whichscientists believe the most dan-gerous effects of climate changewould begin to occur.

Just over a half-trillion tonshave already been burned sincethe beginning of the IndustrialRevolution, and at the rate ener-gy consumption is growing, thetrillionth ton will be burnedsometime around 2040, accordingto calculations by Myles R. Allen,a scientist at the University ofOxford and one of the authors ofthe new report. More than threetrillion tons of carbon are still leftin the ground as fossil fuels.

Once the trillion-ton budget isexhausted, companies that want-ed to keep burning fossil fuelswould have to come up with waysto capture carbon dioxide andstore it underground. In the Unit-ed States, the Obama administra-tion is moving forward with rulesthat would essentially require

such technology, which is likelyto be costly, for any future coal-burning power plants; the presi-dent’s Republican opponentshave accused him of waging a“war on coal.”

The Intergovernmental Panelon Climate Change is a world-wide committee of hundreds ofscientists that issues major re-ports every five or six years, ad-vising governments on the latestknowledge on climate change.!

The group has now issued fivemajor reports since 1990, each ofthem finding greater certaintythat the world is warming andgreater likelihood that human ac-tivity is the chief cause. The newreport finds a 95 to 100 percentchance that most of the warmingof recent decades is human-caused, up from the 90 to 100 per-cent chance cited in the last re-port, in 2007.

But the new document also ac-knowledges that climate sciencestill contains uncertainties, in-cluding the likely magnitude ofthe warming for a given level of

emissions, the rate at which theocean will rise, and the likelihoodthat plants and animals will bedriven to extinction. The scien-tists emphasized, however, thatthose uncertainties cut in both di-rections and the only way to limitthe risk is to limit emissions.

Climate-skeptic organizationsassailed the new report as alarm-ist even before it was published.

The Heartland Institute, a Chi-cago organization, issued a docu-ment last week saying that anyadditional global warming wouldlikely be limited to a few tenths ofa degree and that this “would notrepresent a climate crisis.”

One issue much cited by the cli-mate doubters is the slowdown inglobal warming that has oc-curred over the past 15 years.The report acknowledged that itwas not fully understood, but saidsuch pauses had occurred in thepast and the natural variability ofclimate was a likely explanation.

“People think that globalwarming means every year is go-ing to be warmer than the year

before,” said Gerald A. Meehl, anAmerican scientist who helpedwrite the report. “It’s more like astair-step kind of thing.”

Climate scientists not involvedin writing the new report said theauthors had made a series of cau-tious choices in their assessmentof the scientific evidence. Re-garding sea level rise, for in-stance, they gave the first firmestimates ever contained in an in-tergovernmental panel report,declaring that if emissions con-tinued at a rapid pace, the rise bythe end of the 21st century couldbe as much as three feet. Theythrew out a string of publishedpapers suggesting a worst-caserise closer to five feet.

Similarly, the authors went outof their way to include recent pa-pers suggesting that the earthmight be less sensitive to carbondioxide emissions than previous-ly thought, even though seriousquestions have been raised aboutthe validity of those estimates.

The new report lowered thebottom end of the range of po-tential warming that could be ex-pected to occur over the longterm if the carbon dioxide level inthe atmosphere were to double,reversing a decision that the pan-el made in the last report and re-storing a scientific consensusthat had prevailed from 1979 to2007. Six years ago, that rangewas reported as 3.6 to 8.1 degreesFahrenheit; the new range is 2.7to 8.1 degrees.

In Washington, President Oba-ma’s science adviser, John P. Hol-dren, cited increased scientificconfidence “that the kinds ofharm already being experiencedfrom climate change will contin-ue to worsen unless and untilcomprehensive and vigorous ac-tion to reduce emissions is under-taken worldwide.”

Ban Ki-moon, the United Na-tions secretary general, spoke todelegates at the meeting on Fri-day by video link, declaring hisintention to call a meeting ofheads of state in 2014 to pushsuch a treaty forward. The lastsuch meeting, in Copenhagen in2009, ended in disarray.

Climate Panel Seeks Ceiling on Global Carbon OutputSetting a Carbon LimitA new report by the Intergovernmental Panel on Climate Change proposes an upper limit of no more than one trillion metric tons of carbon burned and the resulting gases released into the atmosphere. That limit will likely be exceeded within decades unless emissions are reduced sharply.

Humans will likely release a trillion metric tons of carbon into the atmosphere by around the middle of this century.

An international agreement in 2009 recognized the need to limit global temperature increases to 3.6 degrees. !

µPossible increases through 2100, based on different I.P.C.C. emissions scenarios.

THE NEW YORK TIMESSource: I.P.C.C.

!

3.6°FIncrease in averageglobal temperature

1.8°

5.4°

1 trillion metric tonsof carbon burned

› 1›0

Cumulativecarbon emissions

through 2010

1870

1970

From Page A1

ries about a mild-manneredteacher turned drug lord have setaside schoolwork, dishes andlaundry to try to catch up on oldepisodes through Netflix, Ama-zon, iTunes and other Internetservices.

The hype around hit televisionshow finales has always been in-tense, but what has happenedwith “Breaking Bad” exemplifiesa twist in the relationship be-tween the parallel universes oflive, linear television (the kindsymbolized by Comcast and Di-recTV) and on-demand TV (asembodied by Netflix).

On-demand services are typi-cally thought to hurt live televi-sion viewing. In this case, theyare fueling it.

“Breaking Bad” made its debutin 2008 to an underwhelming 1.2million viewers — which wouldhave caused many programmingchiefs to drop it. But the showdodged cancellation and slowlybuilt a following — especiallyonce the old episodes were madeavailable en masse on Netflix.

By mid-2012, about 2.6 millionviewers were watching live epi-sodes; now, as the ending ap-proaches, that total has morethan doubled to 6 million, whichmight be small for a network tele-vision show but makes “BreakingBad” one of the biggest phenom-ena on cable.

“What’s remarkable about thisshow is we’ve created urgency tosee it,” said Charlie Collier, the

president of AMC, which hasbeen running a marathon of ev-ery episode since Wednesday.

DVDs and, before that, VHStapes have allowed audiences tocatch up on shows for a long time— in fact, the popularity of “Fam-ily Guy” DVDs were partly cred-ited with the 2005 revival of theonce-canceled Fox animatedcomedy. But binge-viewing be-havior has become much morepronounced in the last few years,

mainly because Netflix and serv-ices like it have made it so easy todo.

Last Sunday, as “BreakingBad” was finally winning thetelevision industry’s highest hon-or, an Emmy award for outstand-ing drama, the show set a newratings record for itself — 6.6 mil-lion, according to Nielsen — mak-ing it the biggest program on ca-ble that night. At the same time,many people were just startingtheir marathons. According toNetflix, each day for the last twoweeks, the most-streamed epi-sode of the show has been thevery first one, during which Wal-ter White crystallized metham-

phetamine for the first time. The show’s creator, Vince Gilli-

gan, credited the Internet whenaccepting his Emmy. “I thinkNetflix kept us on the air,” he toldreporters backstage, adding thathe did not believe that the showwould have survived more thantwo seasons without the audienceand revenue lifts that Netflix pro-vided, along with online chatter.As first reported by AdAge, thenetwork sought $300,000 to$400,000 for a 30-second ad in thefinal episode. AMC confirmed onFriday night that the episode wassold out. The network declined tocomment on pricing, but assum-ing it achieved $300,000 a spot, itwill be earning more for the air-time than even the highest-ratednetwork dramas normally do.

“It’s a new era in television,”Mr. Gilligan said, “and we’vebeen very fortunate to reap thebenefits.”

Mr. Bauer is ready for the fi-nale — as of Friday afternoon, hehad only five more episodes towatch, and he was saving themfor Sunday.

Justin Carroll, a bank employ-ee in Lexington, Ky., started tobinge a little bit earlier — Sept. 12— because he “wanted to be partof the discussion” with hisfriends.

Judy Weinstein, a human re-sources consultant in ShermanOaks, Calif., started on Sept. 22because of media coverage of theshow and a crucial endorsementfrom a more personal source: herspin class instructor, who would“come to class every Monday

morning and talk about how shecouldn’t sleep the night before af-ter watching,” she said. Ms.Weinstein is glad she did — al-though after she finished hermarathon on Thursday, therewas one downside. “In retro-spect, it is a difficult show tobinge-watch because it just keepsgetting darker and darker,” shesaid.

Mr. Collier of AMC said that so-cial networking Web sites hadamplified all the chatter aboutthe show. (Nielsen estimates thatthe average person’s Twittermessage about a TV show is seenby about 50 other people.) “Wordof mouth is still a great thing,” hesaid.

Netflix’s licensing contracts donot cover the eight most recentepisodes of “Bad,” so for those,new fans must rely on AMC, anonline rental service or a less le-gal route. AMC’s marathon hasbeen a big draw this week. Inprime time, it had 1.0 millionviewers on Wednesday and al-most 1.2 million on Thursday.(The totals will increase afterdigital video recorder viewing isfactored in.)

Perhaps aptly for a show abouta meth dealer, Melodie Holmeshas noticed its addictive tenden-cies. Ms. Holmes, of Kitchener,Ontario, said she and her hus-band “generally watch two epi-sodes a night, and look at eachother seeing whether or not wecould stay awake on a ‘schoolnight’ for more,” she said. Moreoften than not, they stayed up —and now they are all caught up.

ANDREW H. WALKER/GETTY IMAGES FOR AMC

Vince Gilligan, the “Breaking Bad” creator; Charlie Collier of AMC; and Bryan Cranston, the program’s star, at a party in July.

Race to End for ‘Breaking Bad’Fans Who Got BehindFrom Page A1

The finale is Sunday,and binge-watchersare fighting the clock— and sleep.

Nxxx,2013-09-28,A,003,Bs-BW,E1

AR5 SPM •  Climate change will affect carbon cycle processes

in a way that will exacerbate the increase of CO2 in the atmosphere (high confidence).

•  Ocean uptake of anthropogenic CO2 will continue under all four RCPs through to 2100, with higher uptake for higher concentration pathways (very high confidence). The future evolution of the land carbon uptake is less certain…

•  Earth System Models project a global increase in ocean acidification for all RCP scenarios. The corresponding decrease in surface ocean pH by the end of 21st century is in the range of …

Land & ocean uptakes

Projections of surface pH

Twelfth Session of Working Group I Approved Summary for Policymakers

IPCC WGI AR5 SPM-33 27 September 2013

Figure SPM.7 [FIGURE SUBJECT TO FINAL COPYEDIT]

AR5 SPM •  Cumulative CO2 emissions for the 2012–2100

period compatible with the RCP atmospheric CO2 concentrations, as derived from 15 Earth System Models, range from …

•  By 2050, annual CO2 emissions derived from Earth System Models following RCP2.6 are smaller than 1990 emissions (by 14% to 96%). By the end of the 21st century, about half of the models infer emissions slightly above zero, while the other half infer a net removal of CO2 from the atmosphere.

Compatible emissions

Lessons from CMIP5

•  More ESMs with carbon cycle •  More analysis and publications •  Compared to AR4 (C4MIP) more processes are

included (land use change, nitrogen cycle) but this artificially enhances the models spread

•  Still large uncertainties, mainly due to the land carbon cycle…

•  Model evaluation is quite embarrassing… –  Obviously, carbon cycle wasn’t part of the essential set of

metrics during development/adjustment phase of CMIP5

Simulated atmospheric CO2

Again, quite a large model spread. Models show biases in mean, growth rate, seasonal cycle, all of the above…

But keep in mind, only forcing is Fossil fuel emissions. May be it’s not that bad…

(good candidate for WGCM/WGNE metric for the carbon cycle)

Mauna Loa

400  

380  

360  

340  

320  

300  1960  1970  1980  1990  2000              

Final Draft (7 June 2013) Chapter 9 IPCC WGI Fifth Assessment Report

Do Not Cite, Quote or Distribute 9-161 Total pages: 205

Figure 9.8: Observed and simulated time series of the anomalies in annual- and global-mean surface temperature. All anomalies are differences from the 1961–1990 time-mean of each individual time series. The reference period 1961–1990 is indicated by yellow shading; vertical dashed grey lines represent times of major volcanic eruptions. (a) Single simulations for CMIP5 models (thin lines); multi-model mean (thick red line); different observations (thick black lines). Observational data (see Chapter 2) are HadCRUT4 (Morice, Kennedy, Rayner, & Jones, 2012), GISTEMP (Hansen, Ruedy, Sato, & Lo, 2010), and MLOST (Vose et al., 2012) and are merged surface temperature (2 m height over land and surface temperature over the ocean). All model results have been sub-sampled using the HadCRUT4 observational data mask (see Chapter 10). Following the CMIP5 protocol (Taylor et al., 2012), all simulations use specified historical forcings up to and including 2005 and use RCP4.5 after 2005 (see Figure 10.1 and note different reference period used there; results will differ slightly when using alternative RCP scenarios for the post-2005 period). (a) Inset: the global-mean surface temperature for the reference period 1961–1990, for each individual model (colours), the CMIP5 multi-model mean (thick red), and the observations (thick black, P. D. Jones, New, Parker, Martin, and Rigor (1999)). Bottom: single simulations from available EMIC simulations (thin lines), from Eby et al. (2013). Observational data are the same as in (a). All EMIC simulations ended in 2005 and use the CMIP5 historical forcing scenario. (b) Inset: Same as in (a) but for the EMICs.

Essential for CMI6 •  Model evaluation

–  Obviously, not enough tuning/validation has been done in the model development phase (allow time between “CMIP-core” and “CMIP6-core”

•  TCRE –  Can become the “TCR of ESMs”. Need to agree on simple

scenario to diagnose it (eg. a 1% scenario) •  Feedback quantification

–  CO2-carbon (b) and climate-carbon (g) (eg. from two or three 1% scenarios)

•  Future of carbon cycle and compatible emissions (impact and policy relevant) –  Diagnosed from new scenarios (SSPs/RCPs matrix)

CMIP6 roadmap •  Requested (core)

–  Control –  1%CO2 (COU, BGC, RAD) –  Historical and scenarios `

•  Emission driven or Concentration driven runs? – Both, sir.

•  C4MIP “Governance” –  P. Friedlingstein, C. Jones and V. Arora –  + “steering committee” (TBD) eg. L. Bopp, V. Brovkin, C.

Koven, T. Ilyiana, S. Zaehle,…)