sign in sign up
<<
Home , 1257 Samalas eruption, Sunda Arc

Downloaded by guest on September 25, 2021 a Mann Graham Wade C. eruption David Samalas the Mount to CE response 1257 and climate the Reconciling www.pnas.org/cgi/doi/10.1073/pnas.1919807117 times 1.8 eruptions emitting Samalas large Mt. other of eruption and 1257 Samalas the Despite Mt. (14). to response sur- cooling the overestimate face simulations or previous observations Samalas most (11–13), with Mt. records 1257 compared the when to However, studies response eruption. modeling climate climate the previous investigated of have number a impacts societal socioeconomic 10). severe 9, the most (7, of England the in with impact reported Japan, consequences climatic and tur- The political Europe and in 7). famines amplified moil cold (1, Contemporary have to and 1258 8). suspected rainy, is in 7, eruption cloudy, Europe (1, unusually in 1258 an summer of suggest summer sources following the Hemisphere narrative in Northern the eruption, in the cooling surface strong a in stratosphere the into of emissions (4–6). gases Era the volcanic Common for the of responsible quantity it greatest making the (4), dioxide (Br) bromine of of that (Tg) suggests Analy- megatons inclusions 3). 158±12 (SO melt (2, released their cores eruption and ice the products erupted Common the and of of ses spike both largest the in of Era source the as (1) al. et T Samalas fully to needed are constraints issue. further the resolve that very suggest strato- the only and reaching inventory support sphere halogen the results sur- of (1%) model of fractions our minor records proxy changes, available temperature on face based by However, caused cooling eruption. surface inventory the the catas- halogen extending in depletion, result the ozone would on of trophic stratosphere the and 20% reaching atmosphere Samalas as Mt. sig- the little from to of As leads composition temperature. Samalas the surface Mt. on from impacts of reported nificant fractions modest emissions injections Including halogen significant stratosphere. the support the to into tree-ring evidence halogens of from little find temperature we surface of records, of response order the reconstructions temperature our of air multiple While eruption surface eruption. the a Samalas to Mt. support the the simulations into of species model result climate halogen a and and as sulfur chemical stratosphere of the injection assess the to from used impacts , model, sulfate treat- system microphysical of a Earth ment simu- and coupled chemistry present atmospheric fully we interactive a with Here to HadGEM3-ES, depletion. The speculated from ozone society. been lations wide-scale on also to impacts has led of species have range halogenated a of with coemission that climate sulfate Earth’s produced Com- emissions cooled the dioxide in Sulfur source gases Era. volcanic the of mon is injection () stratospheric Samalas largest Mount the of of review eruption for CE (received 2020 1257 3, The September approved and MA, Cambridge, Technology, 2019) of 25, Institute November Massachusetts Solomon, Susan by Edited and Kingdom; United 1EW, Kingdom; CB2 United Cambridge 3EN, Cambridge, CB2 Cambridge Cambridge, of University etefrAmshrcSine eateto hmsr,Uiest fCmrde abig B E,Uie Kingdom; United 1EW, CB2 Cambridge Cambridge, of University Chemistry, of Department Science, Atmospheric for Centre ie h antd fteeuto n h cl fthe of scale the and eruption the of magnitude the Given toward point narratives historical and records proxy Tree-ring ai xlsvt ne VI ,wsietfidb Lavigne by identified was 7, (VEI) Vol- Index with Explosivity (Indonesia), 1257 canic in Samalas Mount of eruption he 2 8T fclrn C)adu o13Tg 1.3 to up and (Cl) chlorine of Tg 227±18 with together ), | climate | d a ozone arnMarshall Lauren , C , ln .Vidal M. eline ´ | oeigvlai impacts volcanic modeling −1 ◦ ,promn elagainst well performing C, b a .Lk Abraham Luke N. , naSchmidt Anja , d colo at n niomn,Uiest fLes ed S J,Uie Kingdom United 9JT, LS2 Leeds Leeds, of University Environment, and Earth of School c ainlCnr o topei cec,Dprmn fCeity nvriyof University Chemistry, of Department Science, Atmospheric for Centre National a,b a,c n lxne .Archibald T. Alexander and , adpDhomse Sandip , doi:10.1073/pnas.1919807117/-/DCSupplemental at online information supporting contains article This 1 the under Published Submission.y Direct PNAS a is article This interest.y new competing no contributed declare and authors G.M. A.S., The C.M.V., and D.C.W., and J.K., paper.y data; P.T.G., the analyzed wrote C.M.V. S.D., A.T.A. and A.S., N.L.A., D.C.W. L.M., tools; research; D.C.W., reagents/analytic research; performed designed A.T.A. A.T.A. and and C.M.V., D.C.W., contributions: Author in oxidation (20). sulfur effects of climate effect their self-limiting size important for the an important is with being There (19), aerosols coagulation the from and of microphysical formed condensation through of are grow aerosols processes (18)] sulfate Volcanic planet SO (OH). the cal of cool the oxidation and into the from sunlight gases erup- scat- volatile back those [which Large aerosols their ter sulfate coupled. volcanic (like inject region, can this strongly In sulfur Samalas, stratosphere. are Mt. of chemistry like properties tions, injections aerosol in in Changes changes large 17). and (16, of climate on aspects Samalas) role important Mt. are the (chemistry) of composition gas-phase and radii effective aerosol prescribed (15). the important of very Timmreck size were while the (8), that injection found al. of assumed et height the the to and sensitive the month that very eruption shown was have response al. tree- temperature et surface and Stoffel but simulations to reconstructions, Ocean based able (AO-GCM) com- ring Atmosphere were Model modeling (8) their climate Circulation al. between et the General agreement Stoffel for broad and a puzzle (15) simulate a al. et been Timmreck has munity. This similar 8). relatively (7, is tree-ring methods, (MXD) by density latewood reconstructed maximum response, temperature Hemisphere SO more owo orsodnemyb drse.Eal [email protected] Email: addressed. be may correspondence whom To lrvoe xoueadhmnhealth. human for and implications exposure the with depletion reaching ozone significant inventory in response results halogen climate but “muted” the observed of the Includ- captures but fraction stratosphere stratosphere. all minor the out a reaching rule simulations ing emissions can model we halogen our response minor using climate but reconstructed consid- eruption, and are the emissions from halogen erable Reported scenarios. SO of range emission of a impacts using the eruption Samalas of Mount simulations the a model system Here proven Earth data. perform proxy has with we compared Era, response overes- climate generally the Common have timated which models the climate for in case complex eruptions explo- largest the volcanic of one sive 1257, in eruption Samalas Mount The Significance ohtecagsi eoo ubrcnetain n size and concentrations number aerosol in changes the Both 2 hnte11 rpino t abr,teNorthern the Tambora, Mt. of eruption 1815 the than NSlicense.y PNAS d alT Griffiths T. Paul , 2 ntegspaeb h yrxlradi- hydroxyl the by phase gas the in a,c,1 . y a,c https://www.pnas.org/lookup/suppl/ b eateto Geography, of Department NSLts Articles Latest PNAS ae Keeble James , 2 n halogen and a,c | , f9 of 1

EARTH, ATMOSPHERIC, AND PLANETARY SCIENCES the stratosphere (17, 21). As the size of the SO2 injected into the Table 1. Summary of experiments performed to reconcile the stratosphere increases, the ability of the OH to react with SO2 climate and ozone response to the Mt. Samalas eruption decreases, slowing down the rate of aerosol production, causing Stratospheric injection sulfate to be produced over a longer time period, and leading to a longer-lived forcing. In addition, the reduction in OH can cause Ensemble Nsims SO2, Tg HCl, Tg HBr, Tg levels of ozone to increase in the lower stratosphere (21) where HI-HAL (20%) 6 142.2 46.68 0.263 it can act as a climate-warming agent. LO-HAL (1%) 6 94.8 2.33 0.013 One aspect that affects our understanding of the effects of the BOTH-SO2 HI-SO2 (90%) 6 142.2 0.00 0.000 Mt. Samalas eruption, and potentially other future eruptions, BOTH-SO LO-SO (60%) 6 94.8 0.00 0.000 is in the role of coemitted halogens. The impacts of volcanic 2 2 halogens on stratospheric ozone were first discussed by Sto- Nsims refers to the number of ensemble members performed for each set larski and Cicerone (22). When halogens enter the stratosphere of simulations. In all simulations the same day of year and altitude is used they contribute to the catalytic destruction of ozone (23) and to inject the volatile gases from the eruption of Mt. Samalas. BOTH-SO2 lead to commensurate impacts on the composition and chem- refers to the SO2 only experiments, which are averaged in further analysis. istry of the troposphere. Tie and Brasseur (24) showed that there Percentages indicate the fraction of emissions compared to those estimated in ref. 4. is significant sensitivity in the response of stratospheric ozone following eruptions the size of 1991 Mt. Pinatubo eruption to the background chlorine levels. Kutterolf et al. (25) provided renewed interest in the topic of volcanic halogens and several The results from our HadGEM3-ES simulations are com- studies have recently been published using a range of models pared against results from the CESM-Last Millennium Ensem- and model setups (26–31) that have also identified important ble (CESM-LME) (34) and multimodel ensembles from the sensitivities to loading and levels of short-lived Coupled Model Intercomparison Project Phase V/Paleoclimate bromine compounds (e.g., ref. 31). Vidal et al. (4) identified Model Intercomparison Project Phase III (CMIP5/PMIP3) extremely large releases of halogens from the Mt. Samalas erup- Past1000 experiment (hereafter CMIP5) (35) and evaluated tion, which could have significantly affected the stratospheric against a range of tree-ring records and other evidence described ozone burden. However, in-plume dynamics governing the injec- below (see Materials and Methods for discussion on the tree-ring tion of halogens into the stratosphere are poorly understood, records). and the current understanding of these remains limited to the few explosive eruptions monitored in the satellite era (32). None Results of the previous modeling setups used in the studies described Surface Climate Response. Our Earth system model results show above allowed for the investigation of combinations of emis- that following the eruption of Mt. Samalas a complex cascade of sions of sulfur and halogens from the 1257 Mt. Samalas eruption physical and chemical processes occurred. These involved chem- and the commensurate impacts of these on surface weather and ical oxidative processes (changes to the amount of ozone and climate. hydroxyl radicals) and aerosol microphysical processes, which Using eruption source parameters calculated by Vidal et al. combined to affect the physical climate system [see Robock (18) (4, 6) and a fully coupled Earth system model (an AO-GCM and references therein for details of these processes]. Our results with interactive atmospheric chemistry and aerosol microphysics; confirm that using the estimates of SO2 emissions from Vidal see Materials and Methods), here we investigate the Earth sys- et al. (6) we are able to recreate a surface climate response tem response to the 1257 Mt. Samalas eruption and determine that is consistent with climate proxies and that inclusion of coin- through comparison with an array of proxy records whether the jected halogens significantly alters the composition of the atmo- surface climate response can provide evidence for large-scale sphere with knock-on effects for the simulation of the climate ozone depletion that would have been caused by the coemissions response. of volcanic halogens (4). We begin by assessing the surface temperature response Four emissions scenarios were developed based on scalings of between the CMIP5, CESM-LME, and HadGEM3-ES ensem- the budget of Vidal et al. (4) (Table 1). These scenarios reflect bles with a selection of tree-ring reconstructions from Wilson et the uncertainty in the amount of SO2 emitted from the erup- al. (36) (the Tree-Ring Network Devel- tion reaching the stratosphere obtained by comparing degassing opment; N-TREND), Schneider et al. (37) (SCH15), and Guillet budgets reconstructed from the eruption deposits with et al. (7) (SG17), shown in Fig. 1. For simplicity, the HadGEM3- records (3) and account for conservative minimum [1% of the ES data in Fig. 1 focus on the HI-HAL simulations and the mean estimates of Vidal et al. (4)] and maximum [20% of the estimates of the HI- and LO-SO2 ensembles (hereafter BOTH-SO2). The of Vidal et al. (4)] stratospheric injections of Cl and Br, reflect- LO-HAL simulations fall within the range of BOTH-SO2. The ing results obtained through experimental modeling and satellite model data presented in Fig. 1 show the range of results (max- observations (32, 33). imum to minimum) and highlight a significant spread in the As a prior study showed best model agreement for modeled response in the simulations. surface temperature with reconstructed surface temperature Fig. 1 shows that all three of the land surface tempera- from tree rings was with an eruption occurring between May ture reconstructions suggest the cooling from the eruption of and July (8), a 1 June eruption was selected for our simula- Mt. Samalas was only around 1 K over the Northern Hemi- tions at the latitude and longitude corresponding to the location sphere in the boreal summer. The cooling is strongest in the of Mt. Samalas (8.5◦S, 116.3◦E). The gases listed in Table 1 Guillet et al. (7) dataset, reaching almost 1.7 K and lasting for were injected between 19-km and 34-km altitude (Materials and up to 5 y. Our HadGEM3-ES model results are in excellent Methods). agreement with the temperature reconstructions for 1258 for all For each of the emissions scenarios six simulations were proxy datasets but fail to capture the reduction in surface air performed (ensemble members) to investigate the role of inter- temperature reconstructed between 1258 and 1259 by Guillet nal variability. These ensemble members were initialized from et al. (7). However, both the model results and proxy data show a long preindustrial control run (PI control) using starting that there is considerable variability in surface temperature in conditions spanning a range of El Nino˜ Southern Oscilla- the wake of the eruption of Mt. Samalas. The variability from tion and Quasi-Biennial Oscillation (QBO) states (SI Appendix, the model results comes from the internal variability of the Table S1). climate system simulated by the different ensemble members

2 of 9 | www.pnas.org/cgi/doi/10.1073/pnas.1919807117 Wade et al. Downloaded by guest on September 25, 2021 Downloaded by guest on September 25, 2021 once ihtetmn n anri hc hs models al. these et Wade which in manner likely is and and timing (34) the CESM-LME for with case Samalas connected the Mt. also 1257 the is to This response eruption. cooling a with strong eruption. 1, too the in Fig. after resulted years in the extended in warming be of to sign any) shown (if is little simulations very cooling HI-HAL of the to In duration subsequent 1). the years (Fig. the onward) in (1260 ensem- warming eruption the a the giving of and up Several warming end (7). members al. of ble et distribution Guillet spatial by reconstructed the cooling with well mem- ensemble agreeing individual with bers S1), Fig. Appendix , SO (SI of cases most amount (BOTH- the Samalas only Mt. varied exper- we 12 The where loading). sulfur iments and each halogen in (i.e., applied in experiment forcings each different members the ensemble from climate variability the internal and experiment) from the variability to (the both variability owing response, climate poten- climate simulated appropriate could an particular representing in tempera- not 1259 warmer as response. and excluded of 1258 be simulations tially in metric, can anomalies this simulations ture HadGEM3-ES by CESM- the excluded the of be of none all temperature While reconstructed and the anomalies. exclude outside simulations to lying able model as are simulations CMIP5 LME we the such As on of bound cooling. lower many of is a timing place and there data extent recon- these the While temperature 1, Fig. surface temperatures. in the presented in structions reconstructed uncertainty so the our lower and than much variability of addition lower any in much and than 1259 temperatures in surface simulations HadGEM3-ES in result data proxy ulations temperature the of S1.) region Fig. that Appendix, the members (SI ensemble in simula- several warming 24 were the showed there of performed Indeed, we effects. in local tions from uncertainty uncertainty the the temperatures from past and reconstructing about of techniques comes experimental the however, the from data, from variability proxy variability The the the emissions. the and around assumptions conditions) different initial different preeruption (with the to relative anomalies as models. calculated individual the are of of climatologies and minimum) bars to tical range (maximum (BOTH-SO uncertainty ranges HadGEM3-ES and The and lines shading. mean solid 40 the with simulated with with denoted 37)], indicated SD) 36, record (±1 [(7, each records for different values three from come peratures 40 JJA) August, 1. Fig. at-ee ta.(4 hwdta ayCI5simulations CMIP5 many that showed (14) al. et Hartl-Meier the in variability show ensembles HadGEM3-ES different The sim- CESM-LME and CMIP5 the that clearly shows 1 Fig. eosrce n iuae oelsme Jn,Jl,and July, (June, summer boreal simulated and Reconstructed ◦ o90 to ◦ N-90 ◦ ◦ adsraetmeauefrCI5 CESM-LME, CMIP5, for temperature surface land N adsraeartmeaue eosrce tem- Reconstructed temperature. air surface land N SO 2 2 n IHL nebe r niae sver- as indicated are ensembles HI-HAL) and hwarpdrcvr,wti in y 3 within recovery, rapid a show ) 2 netdfrom injected odtos u hsi o ni fe h rpin Con- eruption. the after y BOTH-SO 8 and until LO-HAL over not Hemisphere the is Northern versely, pre-Samalas-eruption this the to but in return a only conditions, show is simulations the It that the analyzed. land within we conditions y pre-Samalas-eruption is not and to 10 does return global eruption, a simulation the in the HI-HAL At result the anomaly following performed. scales, positive experiment mo Hemisphere a the Northern 12 is to there for sensitive which very temperature at surface time the in that date, highlights 2 return Fig. the Salamas. of eruption the following response CESM- 13th-century using in forcing when volcanic change. of exercised role climate the be assess to should results LME (39). in caution (and eruptions that here volcanic presented suggest results large the together other Taken of CESM-LME possibly the overestimation in and an Samalas Mt. to simulations, to leads response This cooling climatic to 20). the leading (16, clearly injection sizes is dioxide aerosol sulfur 34) larger of ref. associ- magnitude (e.g., processes larger with self-limiting studies ated depo- long-known of core to number ice due large from inappropriate a linearly in scaled forcing (38) climate sition a of SO use for choice The appropriate an using records models, tree-ring climate in and cooling of (7). magnitude al. the et between Guillet agreement by found and 1258 1259 than in 1259 cooling Schneider in the weaker the question is into in this puts response as reconstruction, climate see (37) the al. radius; et supports effective This in S3B). increase Fig. vol- decreased the (and in the cloud particles reducing of following canic growth then microphysical sedimentation and from time aerosol eruption residence to the due after 1259 year radiative in rapidly with the temperatures consistent is peaking cooler This mean. forcing simulate ensemble the to in 1258 unable than simulations al. also their et In were Stoffel 1259. climatologies, (8) in aerosol two-dimensional cooling with muted forced very showing as ies (38) al. imposed et the Gao the to in due 1259 in be reconstruction]. stronger could is which this forcing, [i.e., radiative eruption the simulated eyrcn td yMn ta.(8 n mle httesur- the that ozone implies models. of other and representative with a (28) is calculated here and perturbations al. calculated et (24)] response Ming Brasseur climate with face by consistent and study broadly Tie recent are [e.g., very results studies place These modeling takes later. definition) previous decade DU a 220 to a up (using Hemisphere greater Southern is depletion the loss ozone in ozone where particularly ozone the longer, latitudes column for high tropical persists At and where DU. eruption, 180 the below after drops y remains 4 depletion around ozone near- for Tropical a the represents loss. (DU), This case, ozone units case. stratospheric HI-HAL unperturbed Dobson total the the 242 For from by decrease 3. drops 75% unperturbed Fig. column in ozone the mean shown of global also mean are column control climatological ozone PI the mean zonal from BOTH-SO the halogen differences and shows LO-HAL, the HI-HAL, 3 of the Fig. for magnitude 40). the (24, and injection state chemical SO background stratospheric of injection HadGEM3-ES. the in Forcing discuss and we Composition which simulations LO-HAL associ- and impacts HI- societal below. number the potential a with with are LO-HAL ated there processes the Moreover, important However, out. of of happened. ruled amount be what simula- cannot the of HI-HAL simulation that the reflective unlikely in y. are stratosphere very tion 6 the is into within it injected that halogens conditions suggest climate data These pre-Samalas-eruption to back i.2sosterslsfrtegoa ufc temperature surface global the for results the shows 2 Fig. general a is there that show simulations HadGEM3-ES Our stud- earlier these from out stand therefore simulations Our 2 sepce odpn nthe on depend to expected is 2 NSLts Articles Latest PNAS h zn epneto response ozone The iuain l return all simulations 2 iuain.Ozone simulations. IAppendix) SI IAppendix, SI 2 loading. | f9 of 3

EARTH, ATMOSPHERIC, AND PLANETARY SCIENCES Fig. 2. Global (Left), Northern Hemisphere (Center), and 40◦ to 90◦ N land (Right) monthly mean surface air temperature anomalies simulated for each HadGEM3-ES simulation (light) and ensemble mean (dark). The x axis (time) starts at year zero, that is, at the point of the eruption, and continues after the eruption. The dark lines indicate the ensemble mean results for each of the HadGEM3-ES experiments, with individual ensemble members plotted as faint lines. Return dates, the time it takes for there to be a positive anomaly in surface temperature for the ensemble mean, are indicated as red dashed lines in each panel. Note the expanded temperature scale for > 40◦ N land, indicated in blue.

In the more conservative LO-HAL scenario, there is a latitu- downwelling). This suggests a more vigorous Brewer–Dobson dinal dependence in the ozone response, with decreases in the circulation in response to the injections of SO2 which brings up tropics and increases in the extratropical midlatitudes. Tropical ozone poor air from the troposphere and increases transport ozone depletion occurs only in the year following the eruption, of air masses away from ozone producing regions. In addi- ∗ with more limited Northern Hemisphere ozone loss. However, tion, the changes in w are sensitive to the magnitude of SO2 global mean ozone columns reduce by 25% 2 y after the erup- injected (SI Appendix, Fig. S2)—with HI-SO2 showing larger ∗ tion, representing a peak of 81 DU reduction. Declines in ozone changes in w than LO-SO2 (driven by the increase in aerosol are more persistent in the , where ozone loading and heating). In any case, the ozone column would oth- depletion still takes place up to 6 y after the eruption. Mean- erwise be expected to increase in BOTH-SO2 due to chemical while, global mean column ozone increases in BOTH-SO2 by 4% feedbacks—heterogeneous reaction of N2O5 on sulfate aerosol at the peak, 12 mo after the eruption. leads to a reduction in reactive nitrogen which reduces ozone The latitudinal dependence of the ozone changes in the depletion (24). BOTH-SO2 scenario suggests a dynamical response to the By contrast the sharp decreases in ozone column evident in aerosol heating (e.g., ref. 41). SI Appendix, Fig. S2 shows HI-HAL and LO-HAL are indicative of chemical changes. The the change in residual mean vertical velocity meridional circu- injection of HCl and HBr leads to reactive halogen species lation, w ∗ at 70 hPa. w ∗ increases in the tropics (in a region which can deplete ozone (40). The depletion of ozone result- of upwelling) and decreases in the extratropics (in a region of ing from these chemical changes (Fig. 3) is shown to have a

4 of 9 | www.pnas.org/cgi/doi/10.1073/pnas.1919807117 Wade et al. Downloaded by guest on September 25, 2021 Downloaded by guest on September 25, 2021 aee al. et Wade h 0 aoe msin oee,last substantial a to SO leads in LO-SO increase however, SO from emission, in halogens increase halogen 1% 20% of The injection SO in the increase as an to leads HI-SO and LO-SO the LO-HAL for the d 62 for and SO d of 68 injection experiments, simulations. initial the the across SO of nificantly average ensemble 1/e The SO effect. reach of this to time quantify e-folding taken the time use stratospheric we the Here of production. production aerosol the of SO of in lifetime the step aerosols, determining sulfate rate vapor) the water with is reaction subsequent and photolysis ozone from simulations. our in budget SO radiative of that Earth’s aerosols oxidation perturb sulfate life- the stratospheric ultimately also is of and formation it the formation but as to the leads stratosphere, ozone, which the on in in has aerosols climate ozone of changes radi- time the that the short-wave changes on to the and only through long-wave attributed not in primarily effect changes ation, an direct the have through will They important. i.S2 Fig. on impact further stipples. with indicated are test Kolmogorov–Smirnov the to according interval confidence 95% the at significant (Right isoline. DU 3. Fig. h diinlijcino SO of injection additional The SO of oxidation initial the As are environment oxidizing stratospheric the in changes These ). (Left OHL n (C and LO-HAL, (B) HI-HAL, (A) for column ozone mean zonal simulated mean Ensemble ) IHL ( E HI-HAL, (D) for change column ozone mean zonal simulated mean Ensemble ) 2 2 ieiewt h omsino C ssup- is HCl of coemission the with lifetime ieie rm6 o12di IHL An HI-HAL. in d 102 to 68 from lifetime, w ∗ , Appendix (SI simulations HI-HAL the in 2 experiments. 2 ieieo ,aon h same the around d, 6 of lifetime 2 ytehdoy aia (formed radical hydroxyl the by τ 2 SO 2 (τ rmLO- from 2 SO s12dfrteHI-HAL the for d 102 is 2 sapoyfrterate the for proxy a is ) 2 ieie aysig- vary lifetimes SO 2 2 2 oLO-HAL. to experiments, oHI-SO to 2 —to 2 — 2 2 ueo h oa imn h ugiglnwv decreased longwave outgoing the dimming 17 solar by the of top- around in tude peaking increase W·m an radiation, caused 20 shortwave cloud outgoing aerosol Samalas of-atmosphere Mt. the that i.S3 ). to Fig. response Appendix, climate (SI reasonable Samalas a Mt. simulate to employed (15) to al. 0.7 et the particle with consistent effective are while distributions Tg, 180 to from drops sub- Tg radius is 80 burden to aerosol reduced peak aerosol the stantially LO-HAL the case different HI-HAL the while the to between In Tg variability 0.94 simulations. the from 100 within is reduced to this slightly ever, 105 is from radius burden effective sulfate LO-SO peak LO-HAL the in the to in compared injected halogens case additional The stratosphere the quickly. from more sediment aerosols larger SO as in larger burden aerosol a larger with is consistent radius smaller is effective 33% peak a HI-SO with simulated the consistent The is size. and injection December in simulated is otdb oe iuain fteSrce ekvlaoin HI-SO Peak Sarychev the of (42). simulations 2009 model by ported i.S4 Fig. Appendix, SI o upiigy h ags eoo udni iuae nthe in simulated is burden aerosol largest the surprisingly, Not Wm 2 −2 ae o h LO-SO the For case. 2 u ihalnwv feta 0 ftemagni- the of 80% at effect longwave a with but , −2 aeta h LO-SO the than case rsligi e ocn rudafco f4 of factor a around forcing net a in (resulting 0.9 OHL n (F and LO-HAL, ) .I l ae hs iuae eoo size aerosol simulated these cases all In µm. BOTH-SO ) hw h LO-SO the shows 2 2 2 2 ae h eki uft burden sulfate in peak the case, h lc otu niae h 220 the indicates contour black The . neto n nerirpa in peak earlier an and injection BOTH-SO ) aela oasalreduction small a to lead case 2 ae .9vs 1.09 case, NSLts Articles Latest PNAS 2 1.3 ifrne htaenot are that Differences . 2 iuainpredicts simulation htTimmreck that µm 0.94 0.93 ,which µm, ;how- µm; | f9 of 5

EARTH, ATMOSPHERIC, AND PLANETARY SCIENCES greater than the effects of the 1991 Mt. Pinatubo eruption, e.g. ref. 43). This is due to the combination of scattering of short- wave radiation and the absorption of longwave radiation in the stratosphere. The shortwave and longwave contributions to the surface energy budget behave similarly (SI Appendix, Fig. S4). The surface energy budget also accounts for changes to sensible and latent heat fluxes, both positive (in the downward sense) in response to stratospheric aerosol. Sensible heat fluxes reduce in the upward direction in response to a cooler surface with respect to the troposphere and latent heat fluxes reduce in the upward direction as less water vapor is evaporated from the surface. SI Appendix, Fig. S4 shows the largest deviation in net surface short- wave radiation occurs for the HI-SO2 case, which is expected as it is a larger volcanic eruption. On the basis of this metric alone, we would expect the largest climatic cooling to be achieved with the HI-SO2 case and for HI-HAL to have the smallest climatic response. The top-of-atmosphere budgets (SI Appendix, Fig. S4, Left) show that while HI-HAL has a smaller peak in the top-of- atmosphere shortwave imbalance, the impact of the scenario on the shortwave (and net) radiative fluxes is extended compared to the HI-SO2 ensemble. SI Appendix, Fig. S4C shows the change to top-of-atmosphere (Left) and surface (Right) net radiative budget change. Compar- ing this with the surface shortwave fluxes shows that the surface shortwave metric is insufficient to describe the changes to the surface radiative budget. When accounting for changes to long- wave, sensible, and latent heat fluxes it is clear that all ensembles show a similar change to the surface radiative heat budget in the first year after the eruption. HI-HAL also shows an extended cooling, with negative net surface radiative flux anomalies up to 4 y after the eruption. This is due to the shorter residence time of sulfur in the stratosphere than halogens because sulfate aerosols sediment out of the stratosphere on timescales shorter than stratospheric circulation timescales. As a result, the impacts of the halogens persist longer. This would suggest that the short- term climate response to the different emissions scenarios should be similar.

Potential Societal Impacts. The changes to atmospheric composi- tion and climate in the aftermath of the 1257 Mt. Samalas erup- tion may be linked to the environmental and societal changes reported in several regions of the Northern Hemisphere in the years following the eruption (7, 9, 10). Fig. 4. Daytime-mean clear-sky UV index for (A) HI-HAL, (B) LO-HAL, and Ozone depletion can lead to an increase in surface ultravi- (C) BOTH-SO2. olet (UV) radiation which can have adverse effects on living beings at different timescales, including immediate immunosup- pression that favors infectious diseases (44), ocular diseases, and, much of the extratropics in the four summers following the erup- on the longer term, skin cancer (45, 46). Climate modeling and tion, that is, until 1261. Assessment of changes to surface UV environmental proxies showed that the gas emissions during the is made more challenging by the presence of volcanic aerosols, emplacement of Siberian Trap flood lead to ozone deple- which also scatter UV radiation. However, it is worth noting that tion and temperature changes which could have caused stressed similarly to the case for visible light, scattering peaks when the ecosystems and DNA mutations that would have contributed to diameter of the particle is of the order of the wavelength of the end-Permian extinction (47). A way to quantify the inten- radiation. Damaging UVB and UVC radiation will then be scat- sity of the UV exposure at the surface is the clear-sky UV index, tered even less effectively than visible light for the larger aerosol given by size distributions. Such a scenario could have caused immedi- ate immunosuppression and epidemic outbreaks in civilizations 2.42 −1.23 UVI = 12.5 µ0 (Ω/300) [1] from the to medium latitudes, as well as increased ocular diseases. Since famine also causes increased infectious diseases according to Madronich (48), where µ0 is the cosine of the solar due to immunosuppression, it is difficult to distinguish whether zenith angle and Ω is the total vertical ozone column (in Dob- the mass death toll in the mid-13th century (9) in Europe and son units). The 12.5 is a unitless scaling factor. This equation Japan would be partly linked to ozone depletion. However, only accounts for changes to ozone column and neglects aerosol European and Asian historical archives show that death tolls and cloud changes. Fig. 4 shows the daily-mean average UV significantly drop down in 1259, with a return to preeruption index colored by World Health Organization categories (Low numbers in 1260 (10). Similarly, the epidemic outbreaks among [0 to 2], Medium [3 to 5], High [6 to 7], Very High [8 to 10], the troops of the Song Dynasty of China that led to the victory of and Extreme [11+]) in the aftermath of the 1257 Mt. Samalas Mongol Emperor Mongke¨ Khan in 1259 (49) were not followed eruption for the high-, low-, and no-halogen scenarios. In the HI- by further epidemics. This would be inconsistent with extreme HAL scenario, high or extreme UV levels would be expected for UV index lasting until 1261. Investigation of environmental

6 of 9 | www.pnas.org/cgi/doi/10.1073/pnas.1919807117 Wade et al. Downloaded by guest on September 25, 2021 Downloaded by guest on September 25, 2021 ta.(8 rColye l 5)rcntutos n akof al. lack et Wade and reconstructions, compari- quantitative (57) a al. makes Gao et for- implementation the model Crowley either step in use or major clarity to (38) was a option al. is the et where This CMIP5, forcing. from ward (SAOD) volcanic Depth for Optical reconstruction Aerosol (56) the Stratospheric employing [CMIP6 (55) EVA(eVolv2k) Project experiments Past1000 Intercomparison perform Model will (54)] Coupled the of phase additional these from halo- stratosphere of the we levels metrics. into high but support injected disproved, to or being evidence proved gens limited deple- conclusively is ozone there be that of to find form open some left is of tion occurrence the and determined, the in perished Europe. whom in time of this many were at laborers, increases famines occupations farm UV whose as reported. those such be affect outdoors, to adversely life, most cancers, of also skin stage would the to preventing later for expected a lower, expectancy at life much be (53), developing be could century would 13th age the classes of in working While age y of century. y 21 13th 64 reached reach the who in aristocrats lower UK much date; to was exists longevity incidence evi- skin-cancer No however, in cancer. increase skin an or such cataracts for of dence incidence the in increase an HI-SO to the partic- in were marked which changes ular ozone stratospheric the to linked UV, H strato- in increases the show not peroxide in hydrogen a columns in increases (as ozone (H short-term troposphere to overhead lead the could in sphere) in decreases OH of in result Increases changes. pospheric over removal erup- ozone 1257 complete Samalas cause Antarctica. Mt. to the HCl that enough unlikely injected tion was able by it were that they obscured conclude data to was these from on analyzed nitrate), based they isotopic However, samples in Antarctica. core stable ice 15 best the in the the (delta variability of interannual signal, nitrate one that of ozone-depletion eruption. insights shown composition an have some the (28) for yield with al. candidates could et associated Ming record perturbation recently core Very chemical ice the the into in green- gases these of house records However, intensive. computationally too constrained. heavily to are shown so CH conditions, been used, has setup sulfate eling of drop CH deposition to reduce expected addition, be In would CH constituents further. of chemical these emissions of ratios biological reduce would opei Hadteeoela ofse eoa fCH of removal faster to tro- lead Ozone N increase therefore to unlikely. and expected very OH be are pospheric would stratosphere eruption the of an in 20% of depletion of inventory injections halogen stratospheric the that ozone suggests significant Mt. This in associated results depletion. for emissions still which the scenario, accurate out LO-HAL the are rule with cannot simulation we However, HI-HAL Samalas. the with associated Discussion. equatorial How- eruption. the Samalas y. Mt. affected 3 1257 to the depletion first lacking after ozone are regions the proxies localized in and that region latitude 4) the confirm high (Fig. for eruption records at historical the index ever, following UV year the medium in and Equator the at would index or hypothesis. pollen this as of such confirmation further change allow UVB to sensitive proxies 2 okn oteftr,mn oesta otiuet h sixth the to contribute that models many future, the to Looking be can above discussed metrics the in signal conclusive No tro- into insights some give also may gases trace Shorter-lived CH Including o neto fhlgn ol aecue ihUV high a caused have would halogens of injection low A 2 5) obndwt olrgoa eprtrs which temperatures, global cooler with Combined (50). O O 2 ;hwvr nlsso h uu(reln)rcr do record (Greenland) Tunu the of analysis however, ); 4 u eut ugs hti sulkl htemissions that unlikely is it that suggest results Our msin rmwtadsucs(1.I h mod- the In (51). sources wetland from emissions 4 n atclryN particularly and , 4 2 n N and O 2 2 cnro ol eepce olead to expected be would scenario, tti ie(2.Cagsi surface in Changes (52). time this at 2 eehl tlwrboundary lower at held were O 2 ,eisoswudbe would emissions O, 4 n N and 2 ,mixing O, 4 and a o enpromd ept ih iiain(2 n cddeposi- acid volcanic and large extremely (62) of aftermath limitation the light in important despite being performed, possibly tion been eruptions. volcanic reconstructions not while MXD after for (36) has data variables data confounding TRW of multiproxy to consideration a drawbacks to However, the compared of well and many perform methods overcoming differing to two dataset shown these N-TREND been between The has “bridge” data. to supe- developed multiproxy show for was to method (36) reconstructions comparison robust TRW in data more variability, performance TRW a rior long-term in is effects for MXD memory are However, to MXD. approaches (61). due or variability common (TRW) climate which most short-term width in the assessing ring ways but tree several analyzed are use There be to data. can model records tree-ring our tree-ring of anoma- with use temperature comparison make surface con- for reconstructing we be lies in Thus, can locations (60). forests these temperature boreal from by at records northern sites limited or moist be latitudes cool, to at mid sidered trees the of in growth the elevation that high previously growth, the shown tree been determine over which has eruptions factors it many volcanic are there with While associated millennium. last changes climatic the structing Methods. Methods and Materials volcanic to responses millennium. last model the of facil- over forcing to comparison implementation and quantitative its Toohey a document as itate interac- extensively such fully and or with (56), microphysics here Sigl aerosol demonstrated and have chemistry we tive as such forcing should aerosol 59), studies of (43, representation last-millennium based physically future more that a drawing include and when period during urged simulations Little time CESM-LME be this the of should results of the caution about context suggests conclusions the to This used in Age. widely change Ice being climate its despite 13th-century eruption, study Samalas Mt. study for 1257 data the tree-ring This against reconstructions. CESM-LME tree-ring assesses comprehensively all the to of compared effects response climate the the overestimates prescribing (38), SAOD noninteractive on via eruption based representation employs simple which a CESM-LME, eruptions. volcanic climatic large the of exploring impacts studies future for microphysics aerosol chemistry and interactive fully of use the supports HadGEM3-ES tion. SO the increasing sulfate the by stratospheric aerosol of altering evolution strato- the altering at the depletion and light surface, reaching UV ozone Earth’s incident halogens increasing substantial imbalance, erupted to radiative lit- the atmospheric lead As of possible. could yield been 1% sphere have the a still of but as could stratosphere injections tle injections the large small to out that (4) rule Samalas note Mt. to from able inventory been halogen tem- have surface tree-ring for we available proxies perature and the HadGEM3-ES with the Using agreement of record. good proxy eruption physical in 1257 the are the of Samalas from Mt. understanding resulting current processes our chemical and that and model confirm chemistry system can interac- Earth interactive we HadGEM3-ES key as the including in such By microphysics, processes, aerosol 15). system (8, consistent Earth data with more tive proxy be studies tree-ring to data shown the been proxy with have the CESM-LME tree-ring schemes to aerosol the to offline response and compared climate CMIP5 eruption, in the 1257 part overestimated taking simulations, those model as such els, Conclusions. or more experiment ways quan- Past1000 make different CMIP6 may in the challenging. this forcing of entirely, to comparisons radiative effects insufficient titative Sigl the important is and these on impacts which Toohey neglect the size for nm, and account aerosol 500 (57), models of If al. at forcing. radiative et AOD the Crowley quantify comparing still (38), by al. forcing” is (56) “volcanic et forcing the Gao volcanic compare of (55) of al. implementation et required—Jungclaus detailed the a Regardless, of 58). description (39, challenging models between son h nulrslto fte ig ae hmielfrrecon- for ideal them makes rings tree of resolution annual The hl rvoswr sn hsclciaemod- climate physical using work previous While 2 ieieadsrtshrccircula- stratospheric and lifetime NSLts Articles Latest PNAS | f9 of 7

EARTH, ATMOSPHERIC, AND PLANETARY SCIENCES eruptions. In our model analysis we made use of data from three main black carbon, biomass burning organic carbon, and natural emissions of sources: The MXD-based SCH15 dataset (https://www.ncdc.noaa.gov/paleo- mineral dust are treated by CLASSIC (Coupled Large-Scale Aerosol Simu- search/study/18875) (37) and the N-TREND merged tree-ring dataset lator for Studies in Climate), a bulk aerosol scheme. Aerosol microphysics (https://www.ncdc.noaa.gov/paleo-search/study/19743) (36), which provided tuned for stratospheric sulfate aerosol processes is treated by GLOMAP- annual varying reconstructions of Northern Hemisphere average JJA mode. GLOMAP-mode is a two-moment aerosol scheme which tracks both temperature anomaly data, and the combined TRW-MXD SG17 dataset number and mass (75). This allows for a three-dimensional evolution of (https://www.ncdc.noaa.gov/paleo-search/study/21090) (7), which is spatially the size distribution, which is assumed to be modal with an evolving resolved across the Northern Hemisphere. Model temperatures at 1.5 m mean width but a fixed variance (mode width). The model treats in detail above the surface were output at a monthly time resolution and compared the condensation, nucleation, coagulation, cloud processing, hygroscopic with the proxy data in Fig. 1 by focusing on JJA monthly averages and focus- growth, scavenging, and dry deposition of aerosols (75). As the primary ing on land grid cells only, between 40◦ and 90◦ N. The anomalies in the interest is stratospheric sulfate aerosol, only soluble modes are simulated tree-ring reconstructions were calculated relative to 1960 to 1990 whereas by GLOMAP-mode (nonanthropogenic sulfate aerosol and sea salt). The the anomalies in the model were calculated relative to a 30-y period of the use of a fixed modal width of 1.4 for the accumulation soluble mode, preindustrial control run (63). See SI Appendix for further details. combined with preventing mode merging between the accumulation and The emissions data used in our study are based on the work of Vidal et al. coarse modes, was found to improve the model fidelity compared to a more (4). Recent analysis of glass shards retrieved in Antarctic ice cores suggest detailed sectional scheme (74). Interaction between aerosols and radiation multiple volcanic sources for the 1259 sulfate spike (64), including the 1257 is simulated by RADAER (76). The model simulates the key modes of cli- Mt. Samalas , and two other eruptions, one local and one from New mate variability and the magnitude of the climate response to the Mount Zealand. This suggests that Mt. Samalas would not be the only source of the Pinatubo eruption (SI Appendix, Figs. S5 and S6). The use of GLOMAP-mode sulfur in Antarctic ice cores. However, high-resolution sulfur isotope anal- for simulating the 1991 eruption has been comprehen- yses of Greenland and Antarctic ice (65) have confirmed the tropical and sively validated (74), performing similarly to other aerosol-composition stratospheric origin of the sulfate for the 1259 spike, which corroborates climate models. that the 1257 Mt. Samalas eruption is most likely the only source of sulfate The emissions of gases from the eruption of Mt. Samalas were injected in ice cores. This is consistent with the amount of SO2 emitted by the erup- into the model in a column between heights of 19 to 34 km above the sur- tion estimated by Vidal et al. (4) and Toohey and Sigl (56) and reinforces the face. While the maximum plume height is estimated at 43 km (4), the height choice of emission scenario for this study. of the gas cloud is unknown. Previous model simulations of the eruption Simulations performed as part of the CMIP5 are analyzed. The Past1000 of Mt. Samalas have used injection heights based on the 1991 eruption of simulations were conducted in collaboration with the Paleoclimate Model- Mt Pinatubo (e.g., ref. 8). In our simulations we chose the top of the injec- ing Intercomparison Project Phase 3 (PMIP3) (66) and are transient simula- tion height to be 34 km [higher than that simulated for Mt. Pinatubo in tions between 850 and 1850 based on time-evolving climate forcing (35). Dhomse et al. (74)], as beyond this height aerosol properties in the model Six CMIP5 models performed both the historical and Past1000 simulations. are poorly constrained. CMIP5 data were obtained from the CEDA/BADC (Center for Environmental Data Analysis/British Atmospheric Data Center) archive on the JASMIN post- Data Availability. Model output data have been deposited on the processing system. An ensemble of 13 simulations of the last millennium was Zenodo archive and can be accessed at DOI 10.5281/zenodo.4011660 performed for the CESM-LME (34). The results were obtained from the Earth (77). In our model analysis we made use of data from three main System Grid. sources: The MXD-based SCH15 dataset (https://www.ncdc.noaa.gov/paleo- HadGEM3-ES is a coupled atmosphere–ocean GCM with interactive atmo- search/study/18875) (37) and the N-TREND merged tree-ring dataset (https:// spheric chemistry and microphysical sulfate aerosol. The atmosphere compo- www.ncdc.noaa.gov/paleo-search/study/19743) (36), which provided annual nent is the UK Met-Office Unified Model version 7.3 (67) in the HadGEM3-A varying reconstructions of Northern Hemisphere average JJA temperature ◦ r2.0 climate configuration (68). It employs a regular Cartesian grid of 3.75 anomaly data, and the combined TRW-MXD SG17 dataset (https://www. ◦ longitude by 2.5 latitude (N48). In the vertical, 60 hybrid height ver- ncdc.noaa.gov/paleo-search/study/21090) (7), which is spatially resolved tical levels are employed—“hybrid” indicating that the model levels are across the Northern Hemisphere. sigma levels near the surface, changing smoothly to pressure levels near the top of the atmosphere (69). The model top is 84 km, which permits ACKNOWLEDGMENTS. We acknowledge support from the Natural Envi- a detailed treatment of stratospheric dynamics and enables an internally ronment Research Council (NERC) and the National Center for Atmo- generated QBO to be simulated. The ocean component of the model is spheric Science for funding for UKCA and The North Atlantic Climate the NEMO-OPA [Nucleus for European Modeling of the Ocean (70)] model System: Integrated Studies. D.C.W. was supported by a NERC Doc- toral Training Partnership studentship (grant DTP-1502139). L.M., N.L.A., version 3.0 (68). The component of the model is CICE (Los Alamos and A.S. are funded by the NERC via “Vol-Clim” grant NE/S000887/1. Community Ice CodE) version 4.0 (71). Atmospheric chemistry is repre- S.D., G.M., and A.S. acknowledge funding via the NERC SMURPHS sented by the UKCA (United Kingdom Chemistry & Aerosols) model, with (“Securing Multidisciplinary UndeRstanding and Prediction of Hiatus and updates from the model version described by (72). The model simulates Surge periods”) project (NE/N006038/1). G.M. also acknowledges fund- the reactions and advection of 49 chemical tracers undergoing 187 chem- ing from the Copernicus Atmospheric Monitoring Service. Model inte- ical reactions. This represents a comprehensive treatment of stratospheric grations were performed using the ARCHER UK National Supercomput- chemistry. In addition, the model contains a thorough treatment of chem- ing Service and system, a collaborative facility supplied under ical Ox, NOx and ClOx catalytic cycles. The stratospheric heterogeneous the Joint Weather and Climate Research Program, which is a strate- gic partnership between the UK Met Office and the NERC. D.C.W. chemistry used includes recent updates documented by Dennison et al. (73). acknowledges Eric Wolff and David Stevenson for their comments on Sulfur chemistry is also simulated according to ref. 74, which includes the the PhD thesis of which this paper largely forms a part, and we thank rate-limiting SO2 + OH + M → HSO3 + M reaction. Aerosol processes for the Prof. A. Robock and another anonymous reviewer for their constructive emitted species anthropogenic sulfur, anthropogenic and biomass burning comments, which have greatly improved the paper.

1. F. Lavigne et al., Source of the great A.D. 1257 mystery eruption unveiled, Samalas 8. M. Stoffel et al., Estimates of volcanic-induced cooling in the Northern Hemisphere volcano, Rinjani volcanic complex, Indonesia. Proc. Natl. Acad. Sci. U.S.A. 110, 16742– over the past 1,500 years. Nat. Geosci. 8, 784–788 (2015). 16747 (2013). 9. B. M. S. Campbell, Global climates, the 1257 mega-eruption of Samalas volcano, 2. M. Sigl et al., Insights from Antarctica on volcanic forcing during the common Era. Indonesia, and the English food crisis of 1258. Trans. R. Hist. Soc. 27, 87–121 Nat. Clim. Change 4, 693–697 (2014). (2017). 3. M. Sigl et al., Timing and climate forcing of volcanic eruptions for the past 2,500 10. M. Bauch, “The samalas eruption revisited” in The Dance of Death in Late Medieval years. Nature 523, 543–549 (2015). and Renaissance Europe: Environmental Stress, Mortality and Social Response, A. Kiss, 4. C. M. Vidal et al., The (, Indonesia): The single greatest K. Pribyl, Eds. (Routledge, 2019), p. 175. stratospheric gas release of the common Era. Sci. Rep. 6, 34868 (2016). 11. A. Robock, Cooling following large volcanic eruptions corrected for the effect of 5. N. Metrich´ et al., New insights into differentiation and storage in diffuse radiation on tree rings. Geophys. Res. Lett. 32, L06702 (2005). crustal reservoirs of the lesser : The Rinjani–Samalas volcanic complex 12. G. A. Zielinski, Stratospheric loading and optical depth estimates of explosive volcan- (Lombok, Indonesia). J. Petrol. 58, 2257–2284 (2017). ism over the last 2100 years derived from the Greenland Ice Sheet Project 2 ice core. 6. C. M. Vidal et al., Dynamics of the major of Samalas in 1257 A.D. J. Geophys. Res. 100, 20937 (1995). (Lombok, Indonesia). Bull. Volcanol. 77, 73 (2015). 13. M. E. Mann, J. D. Fuentes, S. Rutherford, Underestimation of volcanic cooling in 7. S. Guillet et al., Climate response to the Samalas volcanic eruption in 1257 revealed tree-ring-based reconstructions of hemispheric temperatures. Nat. Geosci. 5, 202–205 by proxy records. Nat. Geosci. 10, 123–128 (2017). (2012).

8 of 9 | www.pnas.org/cgi/doi/10.1073/pnas.1919807117 Wade et al. Downloaded by guest on September 25, 2021 Downloaded by guest on September 25, 2021 4 .Nra,G .Hlia,Tecneune fU-nue muoupeso for immunosuppression UV-induced of consequences The Halliday, M. G. Norval, M. 44. Schmidt A. 43. Lurton T. 42. on aerosol volcanic of impacts The Rozanov, E. Raible, C. C. Arfeuille, F. of Muthers, S. archive new 41. A Esper, Wilka J. C. Hartl-Meier, 40. C. Pretis, F. Smerdon, E. J. Schneider, years: L. 1500 past 39. the over climate of forcing Volcanic Ammann, C. Robock, A. Gao, C. 38. Schneider L. 37. Wilson R. 36. Schmidt A. G. 35. 3 .Txo,H-.Ga,M ezg .M brue,Ijcino ae nothe into gases of Injection Otto-Bliesner Oberhuber, L. B. M. J. 34. Herzog, M. Graf, H.-F. Textor, C. 33. past Earth’s understanding for Lessons environment: the and Volcanoes Mather, A. T. Ozone Salawitch, 32. J. R. Anderson, G. J. Weisenstein, K. D. Wilmouth, M. D. Klobas, E. J. 31. Kr K. Mills, J. M. Kutterolf, S. Brenna, H. 30. 9 .Ben,S utrl,K Kr K. Kutterolf, S. Brenna, H. 29. Antarctica in ozone total of losses Large Shanklin, D. J. Gardiner, G. B. Farman, C. J. 23. Timmreck C. 20. 8 .Ming A. 28. eruptions: volcanic to Kutterolf ozone S. stratospheric 25. of response The Brasseur, G. Tie, X. X. 24. ozone. for sink possible A chlorine: Stratospheric Cicerone, J. R. Stolarski, S. R. 22. Robock A. 21. Kremser climate. S. and eruptions 19. Volcanic Robock, A. 18. 6 .Cdu,S rn,S ek,C pehie,T .Dut,Srtshrcozone Stratospheric Druitt, Cadoux H. A. T. Oppenheimer, 27. C. Bekki, S. Bruno, S. Cadoux, A. 26. SO volcanic of Oxidation volcanic Bekki, in S. effects chemical and 17. physical Self-limiting Toon, B. O. Turco, P. R. Pinto, P. J. 16. Timmreck C. 15. Hartl-Meier M. T. C. 14. aee al. et Wade rerns atI h ogtr context. term long The I: Part rings: tree ua health. human satellite and (2018). situ 12491–12508 in 123, to compared cloud eruption 2009 Peak observations. Sarychev heterogeneous the aerosol of lution enhanced to due effects direct chemistry. from radiative- Separating changes vortex: polar dynamical Hemisphere Northern the and ozone stratospheric recovery. summer reconstructed from derived millennium past the temperatures. over events volcanic large models. climate for index (2008). core-based ice improved An network. density wood a on (v1.1). Millennium Last model. (2016). system 754 earth community the with approach taopeeb xlsv ocnceruptions. volcanic (2003). explosive by stratosphere (2015). 160–179 emissions. volcanic 304, present-day of studies from future and eruptions. volcanic (2017). future following climate. depletion and atmosphere the on Chocoyos Phys. Los Chem. Atmos. as such supereruption halogen-rich eruptions. volcanic tropical pre-industrial (2019). by caused radiation oeln n c oeconstraints. core (2020). ice and Modelling interaction. ClOx/NOx seasonal reveal Chem. Lett., Res. Geophys. climate. bnacsi aua iiaegass plcto oS-R,L-C-SadSIMS and LA-ICP-MS SR-XRF, to Application glasses: techniques. silicate natural in abundances ozone? stratospheric to threat A eruptions: volcanic loading. chlorine (1995). atmospheric to Sensitivity glaciation? Lett. Res. etuto yteboz-g ioneuto Snoiivlao Greece). (2015). volcano, 12243 ( eruption 5, minoan bronze-age the by destruction clouds. eruption eruption. millennium. past the over simulations model 6011 (1974). 1610–1615 52, e.Geophys. Rev. epy.Rs Lett. Res. Geophys. 1–1 (1995). 913–916 22, nterl fhtrgnosceityi zn elto and depletion ozone in chemistry heterogeneous of role the On al., et epy.Rs Lett. Res. Geophys. taopei zn hne rmepoietoia volcanoes: tropical explosive from changes ozone Stratospheric al., et oe iuain fteceia n eoo irpyia evo- microphysical aerosol and chemical the of simulations Model al., et atmlenu otenhmshr umrtmeaue from temperatures summer hemisphere northern millennium Last al., et to.Ce.Phys. Chem. Atmos. i h oavlai rpino 7 aBP rdc widespread produce B.P. ka ?74 of eruption volcanic Toba the Did al., et ocncrdaiefrigfo 99t 2015. to 1979 from forcing radiative Volcanic al., et .Gohs Res. Geophys. J. hm Geol. Chem. e e fsadrsfri-iumaueeto bromine of measurement in-situ for standards of set new A al., et eiigmdaiuesme eprtrsbc oAD 0 based 600 A.D. to back temperatures summer midlatitude Revising al., et taopei eoo-bevtos rcse,adipc on impact and processes, aerosol-observations, Stratospheric al., et eoo iecnnsciaersos ovlai super-eruptions. volcanic to response climate confines size Aerosol al., et iie eprtr epnet h eylreA 28volcanic 1258 AD large very the to response temperature Limited al., et obndboieadclrn ees rmlreexplosive large from release chlorine and bromine Combined al., et to.Ce.Phys. Chem. Atmos. lmt ocn eosrcin o s nPI iuain fthe of simulations PMIP in use for reconstructions forcing Climate al., et nio.Rs Lett. Res. Environ. htce.Photobiol. Photochem. .Gohs Res. Geophys. J. lmt aiblt n hnesne80C:A ensemble An CE: 850 since change and variability Climate al., et 275(2010). L24705 37, 5163 (2020). 6521–6539 20, eprtr oainei rern eosrcin and reconstructions ring tree in covariance Temperature al., et 7–3 (2016). 278–335 54, esi oe Dev. Model Geosci. 07 (2017). 60–70 452, 117(2009). D10107 114, epy.Rs Lett. Res. Geophys. 8574 (2018). 7835–7842 45, 278(2009). L21708 36, 16–17 (2015). 11461–11476 15, gr lblooedpeinadices fUV of increase and depletion ozone Global uger, ¨ 16–17 (1989). 11165–11174 94, 905(2017). 094005 12, 2334 (2018). 3223–3247 18, 2 ikfrsrtshrcO n H and OH stratospheric for sink A : .Gohs e.Atmos. Res. Geophys. J. Nature 6–7 (2011). 965–977 87, ut c.Rev. Sci. Quat. gr h oeta mat faslu-and sulfur- a of impacts potential The uger, ¨ 8–9 (2012). 185–191 5, e.Geophys. Rev. epy.Rs Lett. Res. Geophys. 0–1 (1985). 207–210 315, epy.Rs Lett. Res. Geophys. .Gohs e.Atmos. Res. Geophys. J. 5646 (2015). 4556–4562 42, epy.Rs Lett. Res. Geophys. ul m eerl Soc. Meteorol. Am. Bull. Geology .Gohs Res. Geophys. J. –8(2016). 1–18 134, 9–1 (2000). 191–219 38, .Vlao.Gohr.Res. Geotherm. Volcanol. J. 0–1 (2013). 707–710 41, .Gohs e.Atmos. Res. Geophys. J. 4896 (2017). 9458–9469 44, e2019JD032290 125, c.Rep. Sci. 3035–3038 22, 7490–7499 44, 2 D23111 113, O. 4606 108, Geophys. 735– 97, c.Rep. Sci. 9435 9, a.J. Can. 6 .Braconnot P. 66. Burke A. for sources 65. Multiple Savarino, J. Batanova, V. Delmonte, B. Petit, Robert J. Narcisi, B. 64. tree-ring from reconstructions Temperature Nowack J. Huybers, P. P. 63. Stine, R. A. Tingley, P. M. Sch R. 62. B. Smerdon, E. J. Schneider, L. Esper, J. high 61. for case modeling A Briffa Newton, R. K. J. R. 60. Lenton, M. T. Belcher, M. C. Mills, climate W. Quantifying J. Sachs, B. P. J. 59. Battisti, S. D. Frierson, W. M. D. Wu, E. Atwood, R. A. 58. depth Crowley optical J. T. aerosol and 57. injections sulfur stratospheric Volcanic Sigl, M. Toohey, M. 56. Jungclaus H. J. 55. Eyring V. 54. Center, Lancaster, Data Arctic O. (NSF H. chemistry” core 53. ice 2013 Greenland “Tunu, McConnell, R. J. 52. CH atmospheric on depletion ozone Gauci of V. Effect cholera Pyle, 51. A. major J. trigger Law, S. may K. mega-eruptions Bekki, S. Volcanic Kern, 50. Z. Stephen, P. Pinke, Z. index. 49. and UV rain clear-sky Acid the for Kiehl, formula T. Analytic J. Madronich, Elkins-Tanton, S. T. L. 48. Shields, A. C. Lamarque, J.-F. Black, of A. exposure B. ultraviolet on 47. impact the and depletion ozone change, Climate Diffey, B. 46. Norval M. 45. 6 .Bloi,“neato fUC eooswt aito:UC AAR (Met RADAER” UKCA radiation: with Wade D. aerosols 77. UKCA of “Interaction Bellouin, N. 76. Mann W. G. 75. Dhomse S. S. 74. Dennison F. 73. and documentation model Morgenstern ice O. sea 72. Alamos Los “The Lipscomb, H. W. Hunke, P C. du E. (Note 71. engine” ocean “NEMO Madec, G. 70. Str R. Simmons, J. A. 69. Hewitt T. H. 68. Davies T. 67. t neatoswt lmt change. climate with interactions its osrie sn ihrslto ufriooe niecores. ice (2019). in 113–119 521, sulfur high-resolution using constrained cores. ice Antarctic (2019). in signal volcanic 1259 AD from tephra assessments. warming cooling. volcanic overestimate densities data. density and width tree-ring latitudes. northern . and (2016). 1023–1026 the during concentrations oxygen atmospheric models. CMIP5–PMIP3 the in (2016). millennium 1161–1178 last 29, the over feedbacks and forcings CE. 1900 to BCE simulations. 500 from past1000 PMIP4 the for design Dev. Model experimental Geosci. and objective, scientific organization. and (2016). design experimental (CMIP6) Mortality World of History 2016). centuries. 21st and 20th concentrations. outbreaks. (2007). 1537–1538 magmatism. traps Siberian pulsed from depletion ozone skin. human tp/diog1.21znd.016.Dpstd2Spebr2020. September 2 Deposited http://doi.org/10.5281/zenodo.4011660. 2011). Centre, Hadley Office model. composition-climate UKCA Dev. the for model microphysics aerosol (2014). model. composition-climate UM-UKCA the with (2019). reactions. 1239 heterogeneous and cycle Solar model: (v10.7) stratosphere. The Alamos I: Los report, Technical LA-CC-06-012. 2008). 4.0, Laboratory, (Version National manual” user’s software 2008). 27, No. Laplace Simon coordinate. vertical hybrid a with model a system. (2011). modelling climate office met next-generation atmosphere. the of modelling Change 5–3 (2010). 651–734 3, 1–2 (2012). 417–424 2, ufrpluinsprsino h eln ehn orei the in source methane wetland the of suppression pollution Sulfur al., et zn oundt rmWd ta Vrin1 Dt e] Zenodo. set]. [Data 1) (Version al et Wade from data column Ozone al., et taopei rpin rmtoia n xr-rpclvolcanoes extra-tropical and tropical from eruptions Stratospheric al., et vriwo h ope oe necmaio rjc hs 6 phase project Intercomparison model coupled the of Overview al., et h fet nhmnhat rmsrtshrcooedpeinand depletion ozone stratospheric from health human on effects The al., et e yaia oefrteMtOfiesgoa n regional and global Office’s Met the for core dynamical new A al., et lm Res. Clim. eue estvt frcn regot otmeauea high at temperature to tree-growth recent of sensitivity Reduced al., et einadipeetto fteifatutr fHdE3 The HadGEM3: of infrastructure the of implementation and Design al., et mrvmnst taopei hmsr ceei h um-ukca the in scheme chemistry stratospheric to Improvements al., et ag zn-iclto edakadisipiain o global for implications its and feedback ozone-circulation large A al., et hs e.Biol. Med. Phys. ocns n h iteIeAge. Ice Little the and Volcanism al., et vlaino lmt oesuigpleciai data. palaeoclimatic using models climate of Evaluation al., et ecito n vlaino LMPmd:Amdlglobal modal A GLOMAP-mode: of evaluation and Description al., et eoo irpyissmltoso h t iauoeruption Pinatubo Mt. the of simulations microphysics Aerosol al., et h MP otiuint MP at3 h atmillennium, last The 3: Part – CMIP6 to contribution PMIP4 The al., et Nature, vlaino h e KAciaecmoiinmdl–Part – model climate-composition UKCA new the of Evaluation al., et xettoso ie td nteDmgah,Saitc,and Statistics, Demography, the in Study A Life: of Expectations Nature 0543 (2017). 4005–4033 10, esi oe Dev. Model Geosci. fig ueia oeat fsrtshrcwrigeet using events warming stratospheric of forecasts Numerical ufing, ¨ 5–6 (2019). 151–162 79, a.Ci.Change Clim. Nat. 9–9 (1994). 595–597 371, rc al cd c.U.S.A. Sci. Acad. Natl. Proc. at yt c.Data Sci. Syst. Earth 7–8 (1998). 678–682 391, Srne-elg 1990). (Springer-Verlag, 1R1(2003). R1–R11 49, .J .Mtoo.Soc. Meteorol. R. J. Q. Dendrochronologia htce.Pooil Sci. Photobiol. Photochem. 8–3 (2008). 381–432 1, epy.Rs Lett. Res. Geophys. 14 (2014). 41–45 5, .J .Mtoo.Soc. Meteorol. R. J. Q. n,U B U. one, ¨ 0–3 (2017). 809–831 9, l emod de ole ˆ to.Ce.Phys. Chem. Atmos. esi oe Dev. Model Geosci. 28–28 (2004). 12583–12587 101, NSLts Articles Latest PNAS AE News. PAGES 7918 (2005). 1759–1782 131, ngn inl n eoyin memory and Signals untgen, 27 (2015). 62–70 35, ¨ esi oe Dev. Model Geosci. esi oe Dev. Model Geosci. Geology ut c.Rev. Sci. Quat. htce.Photobiol. Photochem. 8874 (2014). 7838–7845 41, lsto,Isiu Pierre- Institut elisation, ´ at lntSi Lett. Sci. Planet Earth 3–5 (2007). 232–251 6, 111(1983). 81–111 109, 77 (2014). 67–70 42, 22 (2008). 22–23 16, 11221–11246 14, esi Model Geosci. 1937–1958 9, 164–174 210, Geology 223–253 4, a.Clim. Nat. 1227– 12, 4 | n CO and .Clim. J. f9 of 9 83, 44,

EARTH, ATMOSPHERIC, AND PLANETARY SCIENCES