JohnS.Daniel · 2015-03-25 · Ozonedepleon,climatechange,andpolicy JohnS.Daniel...

Ozone deple*on, climate change, and policy John S. Daniel

ESRL/Chemical Sciences Division Laboratory Review 30 March – 1 April 2015 Poster 1-‐2

Image from NASA



Image from NASA

• Coordina*ng lead author of Chapter 5 (WMO, 2007, 2011) • Par*cipa*on in “policy” chapter of six ozone assessments (1995, 1999, 2003, 2007, 2011, 2015); contribu*ng author (IPCC, 1995, 2001, 2013)

• Calculated future CFC (and other ozone-‐deple*ng substance) projec*ons (Chapter 5, WMO, 2015), with an analysis of mi*ga*on impacts on ozone deple*on (Daniel et al., 2010)

• Contributed to RCP scenarios used in IPCC AR5 and elsewhere (Meinshausen et al., 2011)

• Developed approach for determining ODPs of short-‐lived species (Brioude et al., 2010)

• The Montreal Protocol yielded substan*al ozone and climate co-‐benefits • Reduc*on of long-‐lived ozone-‐deple*ng substance (ODS) emissions implies other emissions are rela*vely more important if there remains a desire to accelerate ozone recovery (e.g., N2O) • Inability to use ODSs in the future implies alterna*ves must be found for products such as air condi*oning, refrigera*on, foams, and others (e.g., HFC implica*ons)

0

1

2

3

4

Meg

aton

nes p

er ye

ar

Mass-weighted emissionsWithout Montreal ProtocolHFCsODSsHCFCsCFCs-onlyWithout acceleratedHCFC phaseout

high

low

0.0

0.5

1.0

1.5

2.0

Meg

aton

nes C

FC-1

1-eq

per

year

ODP-weightedemissions

Without MontrealProtocol

ODSsHCFCsCFCs, Halonsothers,

1950 1970 1990 2010 2030 2050Year

0

10

20

30

Giga

tonn

es C

O 2-e

q pe

r yea

r

HFCsODSsHCFCsCFCs, Halons,others

GWP-weighted emissionsWithout Montreal Protocol

Magnitude ofKyoto Protocolreduction target 2.0

low

Success of Montreal Protocol: A Changing Landscape

Adapted from Velders et al., 2007

Ozone benefit

Climate benefit

• worked with partners in industry, EPA, and academia to es*mate future demand for refrigera*on, A/C, foams, etc. • built on knowledge of current regula*ons and controls to project future HFC emissions • evaluate poten*al future climate impacts

Nitrous oxide (N2O): The dominant ozone-‐depleEng substance emiFed in the 21st century

Ravishankara, A.R., J.S. Daniel, and R.W. Portmann Science, 2009

The large contribuEon of projected HFC emissions to future climate forcing

G.J.M. Velders, D.W. Fahey, J.S. Daniel, M. McFarland, S.O. Andersen PNAS (Proceedings of the Na*onal Academy of Sciences), 2009

Two Examples of High Impact Research

• first *me an Ozone Deple*on Poten*al (ODP) was calculated for N2O • allowed for a direct comparison of ozone-‐relevant N2O emission with that of other ozone-‐deple*ng substances • ODPs are widely understood

CSD Author

What Did We Find? (e.g., foams in buildings) or in applications withcontinued demand and unavailability of suitablereplacements (e.g., halons for fire fighting andCFCs for medical uses). Based on our value ofthe ODP and the IPCC fourth assessment reportemission estimates for N2O, the total 2005 banks(3) of ODSs are equivalent to roughly 20 yearsof continued anthropogenic emissions of N2Oat today’s rate. Thus, although policy decisionsregarding banks of halons and CFCs do rep-resent the largest option for ozone protectiontoday, the effect of N2O can be expected todominate in the future as the banks of theseODSs are either released to the atmosphere or arecaptured and destroyed. Furthermore, the destruc-tion of the existing ODS bank represents a one-time benefit, whereas reductions in N2O emissionshave the ability to continue providing benefitsinto the future.

We also point out that increases in anthropo-genic N2O emissions or decreases due to abate-ment strategies would affect a number of issuesof importance to stratospheric ozone: (i) it would

affect the date for the recovery of the ozone layer;(ii) it would imply that the use of a single pa-rameter such as equivalent effective stratosphericchlorine (EESC) to estimate the recovery of theozone layer should be reevaluated; (iii) it wouldhave implications for the recovery of the polarozone hole that might differ from that of globalozone; (iv) N2O could be an unintended by-product of enhanced crop growth for biofuelproduction (21) or iron fertilization to mitigateCO2 emissions (22). Such an enhancement wouldlead to the unintended “indirect” consequence ofozone layer depletion and increased climateforcing by an alternative fuel used to curb globalwarming, as pointed out by Crutzen et al. (21).

For historical reasons, it is interesting to com-pare ozone depletion caused by anthropogenicN2O emissions with that from the original pro-jections for 500 U.S. supersonic transports (7),SSTs. The total increase in stratospheric NOx bythat fleet of SSTs is comparable to that fromtoday’s total anthropogenic N2O emission, indic-ative of the significance of anthropogenic N2O.

References and Notes1. The Montreal Protocol on Substances that Deplete the

Ozone Layer (1987).2. The Vienna Convention for the Protection of the Ozone

Layer (1985).3. WMO (World Meteorological Organization), Scientific

Assessment of Ozone Depletion: 2006 (Global OzoneResearch and Monitoring Project Report No. 50, Geneva,Switzerland, 2007).

4. D. J. Wuebbles, J. Geophys. Res. 88, 1433 (1983).5. P. J. Crutzen, Q. J. R. Meteorol. Soc. 96, 320 (1970).6. H. Johnston, Science 173, 517 (1971).7. R. P. Wayne, Chemistry of Atmosphere (Oxford Univ.

Press, Oxford, ed. 3, 2000), p. 775.8. M. P. Chipperfield, W. Feng, Geophys. Res. Lett. 30, 1389

(2003).9. D. Kinnison, H. Johnston, D. Wuebbles, J. Geophys. Res.

93 (D11), 14165 (1988).10. L. K. Randeniya, P. F. Vohralik, I. C. Plumb, Geophys. Res.

Lett. 29, 10.1029/2001GL014295 (2002).11. S. Solomon et al., Geophys. Res. Lett. 25, 1871 (1998).12. S. Solomon, M. Mills, L. E. Heidt, W. H. Pollock,

A. F. Tuck, J. Geophys. Res. 97, 825 (1992).13. Materials and methods are available as supporting

material on Science Online.14. R. W. Portmann, S. Solomon, Geophys. Res. Lett. 34,

10.1029/2006GL028252 (2007).15. L. J. Mickley, J. P. D. Abbatt, J. E. Frederick, J. M. Russell

III, J. Geophys. Res. 102, (D19), 23573 (1997).16. L. Thomason, Th. Peter, Eds. “Assessment of stratospheric

aerosol properties (ASAP),” SPARC Report No. 4, www.atmosp.physics.utoronto.ca/SPARC/ASAP%v3c1.pdf (2006).

17. D. P. van Vuuren et al., Clim. Change 81, 119 (2007).18. K. L. Denman et al., in Climate Change 2007: The

Physical Science Basis. Contribution of Working Group Ito the Fourth Assessment Report of the IntergovernmentalPanel on Climate Change, S. Solomon et al., Eds.(Cambridge Univ. Press, New York, 2007).

19. P. Smith et al., in Climate Change 2007: Mitigationof Climate Change. Contribution of Working Group III tothe Fourth Assessment Report of the IntergovernmentalPanel on Climate Change, B. Metz, O. Davidson, P. Bosch,R. Dave, L. Meyer, Eds. (Cambridge Univ. Press,New York, 2007).

20. L. Bernstein et al., in Climate Change 2007: Mitigationof Climate Change. Contribution of Working Group IIIto the Fourth Assessment Report of the IntergovernmentalPanel on Climate Change, S B. Metz, O. Davidson,P. Bosch, R. Dave, L. Meyer, Eds. (Cambridge Univ. Press,New York, 2007).

21. P. J. Crutzen, A. R. Mosier, K. A. Smith, W. Winiwarter,Atmos. Chem. Phys. 8, 389 (2008).

22. X. Jin, N. Gruber, Geophys. Res. Lett. 30, 2249 (2003).23. N. Nakicenovic et al., Special Report on Emissions

Scenarios: A Special Report on Working Group III of theIntergovernmental Panel on Climate Change (CambridgeUniv. Press, New York, 2008).

24. G. J. M. Velders, D. W. Fahey, J. S. Daniel, M. McFarland,S. O. Andersen, Proc. Natl. Acad. Sci. U.S.A. 106, 10949(2009).

25. We are extremely grateful to S. Solomon for helpfuldiscussion, suggestions for improving the paper, andencouragement and also thank S. Montzka for helpfulsuggestions and S. Montzka and G. Dutton of the GlobalMonitoring Division/Earth System Research Laboratory forproviding us with mixing ratio observations from whichwe could infer emission data for several ODSs in 2008and for helpful discussions. This work was supported inpart by NOAA’s Climate Goal Program.

Supporting Online Materialwww.sciencemag.org/cgi/content/full/1176985/DC1Materials and MethodsSOM TextFigs. S1 and S2References

28 May 2009; accepted 12 August 2009Published online 27 August 2009;10.1126/science.1176985Include this information when citing this paper.

1980 2000 2020 2040 2060 2080 2100Year

CH3BrHCFCsHFCs

CH3CCl3, CCl4

Halons

CFCs

N2O

1980 2000 2020 2040 2060 2080 2100Year

CH4

N2O

HFCs

CFCs

1200

1000

0

200

400

800

600

OD

P-W

eigh

ted

Em

issi

on, 1

06 kg C

FC-1

1/yr

20

10

15

5

GW

P-W

eigh

ted

Em

issi

on, G

tCO

2/yr

ODP-Weighted

GWP-Weighted

Fig. 2. Historical and projected ODP- and GWP-weighted emissions of the most important ODSs andnon-CO2 greenhouse gases. Non-N2O ODS emissions are taken from WMO (3). Hydrofluorocarbon (HFC)projections are taken from Velders et al. (24), do not include HFC-23, and are estimated assumingunmitigated growth. The HFC band thus represents a likely upper limit for the contribution of HFCs toGWP-weighted emissions. CH4 emissions represent the range of the Special Report on EmissionsScenarios (SRES) A1B, A1T, A1FI, A2, and B1 scenarios (23). The range of anthropogenic N2O emissionsis inferred from the mixing ratios of these same SRES scenarios [see (13) for details of calculation].

www.sciencemag.org SCIENCE VOL 326 2 OCTOBER 2009 125

REPORTS

on

Febr

uary

5, 2

010

ww

w.s

cien

cem

ag.o

rgD

ownl

oade

d fro

m

• N2O is currently the largest ODP-‐weighted emission, and is expected to remain so in the future

Informing Policy More Directly • Provide assessment of mi*ga*on op*ons • Instrumental in mo*va*ng and informing policy discussions involving controlling HFCs under the Montreal Protocol

values are derived from atmospheric concentrations of contrib-uting gases and their radiative efficiencies and do not depend ontheir GWPs. The projected RF from global HFCs monotonicallyincreases throughout the baseline scenarios (Fig. 1C and Fig.S1b). The RF contribution from developing countries surpassesthat of developed countries around 2030 (Fig. 1C), !10 yearslater than found in the comparison of GWP-weighted emissions(Fig. 1B). In 2050, the RF of global HFCs is in the range of0.25–0.40 W!m"2, which is more than a factor of 3 larger thanSRES HFC values (Fig. S1b). In a comparison with the SRESCO2 scenarios in 2050, the HFC RF fraction is 7–12% of the CO2values. The HFC RF in 2050 is equal to 6–13 years of RF growthfrom CO2 in the 2050 time frame (Table 2). In the comparisonwith the 450- and 550-ppm CO2 stabilization scenarios the HFCfraction increases to 10–16% and 9–14%, respectively (Fig. 2C).

HFC Mitigation ScenariosThe potentially large contribution of HFC emissions to futureclimate forcing in the coming decades has attracted the attentionof policymakers seeking climate protection. A recent regulatorydevelopment that influenced the new HFC scenarios is the EUF-gas directive on mobile AC (26) as discussed above. Otherregulatory actions that might affect future emissions include:USA cap-and-reduction proposals on HFCs, the intention of theEuropean Commission to reduce HFC emissions through aclimate treaty (28), and proposals of individual states in theUSA. In addition, the Montreal Protocol Parties have expressedconcern over the potential future climate contribution ofHFCs (29).

Five modifications to the new baseline scenarios illustrate theimpact of potential future regulatory actions. The first is the capand reduction of HFC consumption in the USA proposed in theLieberman–Warner (LW) Climate Security Act (30). In LW,HFC CO2-eq consumption in the USA is reduced in stepsbetween 2012 and 2040 to achieve a 70% reduction relative to apredefined 2012 level. The second is a global phaseout between2011 and 2017 of mobile-AC refrigerants with a 100-year GWP#150, as is in place in the EU. The third is a freeze in HFCconsumption in developed countries in 2014 and in developingcountries in 2024, each at the previous year’s level. Adopting alater freeze date for developing countries follows the practiceof the Montreal Protocol. The fourth and fifth scenarios startwith the 2014/2024 freeze followed by annual decreases inconsumption of 2% per year and 4% per year, respectively,

with a maximum reduction of 80%. The GWP-weighted emis-sions and RF results for these scenarios are shown in Fig. 3 andTable 2.

The LW scenario reduces cumulative GWP-weighted HFCconsumption by 13–14 GtCO2-eq over the 2013–2050 period andyields a small reduction in RF of !0.025 W!m"2 in 2050. Theglobal ban on high-GWP HFCs in mobile AC reduces consump-tion by 7–10 GtCO2-eq over the 2013–2050 period and RF by0.017–0.025 W!m"2 in 2050. The ranges result from the variationin GDP and population growth in the baseline scenarios. Bothof these mitigation scenarios yield an RF reduction that is equalto !0.4–1 year of CO2 RF growth in the 2050 time frame. Theglobal-freeze scenario yields reductions in cumulative consump-tion of 69–118 GtCO2-eq over the 2013–2050 period and in RFof 0.12–0.20 W!m"2 in 2050. The freeze followed by 4% per yearannual decreases in consumption yields reductions of 106–171GtCO2-eq over the 2013–2050 period and 0.18–0.30 W!m"2 by2050. The latter reduction corresponds to 4–10 years of CO2 RFgrowth in the 2050 time frame using the SRES scenarios or 8–13years of CO2 RF growth, using the 550-ppm CO2 stabilizationscenario. With the 4% per year annual decreases, HFC RFreaches a peak ca. 2040 and is decreasing before 2050 (Fig. 3C).Thus, in the scenarios considered here, a global freeze followedby modest annual reductions in both developed and developingcountries is more effective in limiting the RF contribution fromHFCs than is a single regional cap and reduction of HFCs.

The example mitigation scenarios presented here limit con-sumption of HFCs, not emissions. Mitigation options limitingconsumption, as used in the Montreal Protocol, and thoselimiting emissions (containment), as in the Kyoto Protocol, havedifferent implications. These different policy strategies for HFCsin refrigeration and AC have been explored for Germany (31).The comparison showed that containment strategies are gener-ally more effective in reducing emissions in the short term,whereas strategies based on consumption limits (as in a phaseoutor phasedown) have the potential for greater reductions in thelong term. With limits on emissions, the banks of HFCs generallyincrease implying increased importance of bank management,recovery, and destruction. Limits on consumption are expectedto stimulate containment in the short term and development anddeployment of new technologies in the longer term. Further-more, limits on consumption are easier to enforce with only a fewproducers worldwide compared with limits on emissions with

HFC global consumption

2000 2010 2020 2030 2040 2050Year

0

2

4

6

8

10

Cons

umpti

on (G

tCO 2

-eq y

r-1)

GWP-weighted (100-yr)HFC scenario range

New baselineFreeze (2014/2024)Freeze & (-2%/yr)Freeze & (-4%/yr)

high

low

HFC global radiative forcing

2000 2010 2020 2030 2040 2050Year

0.0

0.1

0.2

0.3

0.4

Radia

tive f

orcin

g (W

m-2)

HFC scenario rangeNew baselineFreeze (2014/2024)Freeze & (-2%/yr)Freeze & (-4%/yr)

high

low Reduction in RF equals 4-10 yr of CO2 increases

BA

Fig. 3. Global HFC consumption (A) and RF (B) for the new baseline scenarios and chosen mitigation scenarios for the period 2000–2050. The baseline scenarios(red) represent global HFC values (i.e., the sum of developing and developed country values in Fig. 1). The consumption values in A are multiplied by their GWPs(100-year time horizon) to obtain equivalent GtCO2 per year (3). Three mitigation scenarios are shown: a freeze in consumption in 2014 for developed countriesand in 2024 for developing countries at the previous year’s level (green); and 2% per year (blue) and 4% per year (purple) annual decreases relative to the freezelevel. The reduction of consumption in the mitigation scenarios has a maximum of 80%.

Velders et al. PNAS ! July 7, 2009 ! vol. 106 ! no. 27 ! 10953

GEO

PHYS

ICS

and CO2 concentrations have been explored with amodel of the middle atmosphere. The future evolutionof ozone will depend on all of these gases. The largenegative effect of the halocarbons evident in ozonebetween 1950 and the present will decrease in thecoming decades of the twenty-first century and non-halocarbon chemicals and climate change will largelycontrol future ozone changes. N2O is now the largestozone-destroying gas emitted by human activitiesbased on ODP-weighted emissions [26]. Whetherozone evolves to lower or higher values comparedwith pre-industrial values depends primarily on thelevels of CO2 relative to the level of N2O. High emis-sion of CO2 could cause a so-called ‘super recovery’of ozone but would have a large influence on theglobal climate and oceans.

There is a limit to the extent to which the effect of thesource gas emissions can be unambiguously separatedowing to nonlinear interactions between the chemicalfamilies. The largest of these effects is between CH4

and the halocarbons. The increase of CH4 during thetwentieth century likely reduced the effect of halo-carbons on global mean ozone by approximately 20per cent. There are also non-negligible interactionsbetween CO2 and N2O on ozone. These effects are ofthe order of 20 per cent and do not alter the above con-clusion of N2O’s dominant effect on ozone destructionin the future.

By 1980, the decrease in global mean ozone levelswas already relatively large when compared with1900 levels. The changes in ozone were not only dueto the halocarbons but also significant changes hadalready taken place due to N2O, CO2 and CH4. How-ever, there are opposing effects from these gases thatmake the combined effect smaller than the depletionowing to halocarbons alone. This should be kept inmind by those who use 1980 levels of ozone as abenchmark of recovery.

The elimination of anthropogenic N2O emissionswould have a much larger effect than any of the unregu-lated halocarbon emissions, singularly or combined[28]. This underscores the opportunity that controlling

N2O emissions provides for reducing future ozonedestruction, especially in the twenty-second centuryand beyond.

REFERENCES1 Crutzen, P. J. 1970 The influence of nitrogen oxide on

the atmospheric ozone content. Q. J. R. Meteorol. Soc.96, 320–327. (doi:10.1002/qj.49709640815)

2 Johnston, H. S. 1971 Reduction of stratospheric ozoneby nitrogen oxide catalysts from supersonic transportexhaust. Science 173, 517–522. (doi:10.1126/science.173.3996.517)

3 Molina, M. J. & Rowland, F. S. 1974 Stratospheric sinkfor chlorofluoromethanes: chlorine atomic-catalyseddestruction of ozone. Nature 249, 810–812. (doi:10.1038/249810a0)

4 Stolarski, R. S. & Cicerone, R. J. 1974 Stratosphericchlorine: possible sink for ozone. Can. J. Chem. 52,1610–1615. (doi:10.1139/v74-233)

5 Farman, J.,Gardiner, B. &Shanklin, J. 1985Large losses oftotal ozone in Antarctica reveal seasonal ClOx/NOx inter-action. Nature 315, 207–210. (doi:10.1038/315207a0)

6 Newman, P. A. et al. 2009 What would have happened tothe ozone layer if chlorofluorocarbons (CFCs) had notbeen regulated? Atmos. Chem. Phys. 9, 2113–2128.(doi:10.5194/acp-9-2113-2009)

7 Velders, G. J. M., Andersen, S. O., Daniel, J. S., Fahey,D.W.&McFarland,M. 2007The importance of theMon-treal Protocol in protecting climate. Proc. Natl Acad. Sci.USA 104, 4814–4819. (doi:10.1073/pnas.0610328104)

8 Montzka, S., Butler, J., Myers, R., Thompson, T.,Swanson, T., Clarke, A., Lock, L. & Elkins, J. 1996Decline in the tropospheric abundance of halogenfrom halocarbons: implications for stratospheric ozonedepletion. Science 272, 1318–1322. (doi:10.1126/science.272.5266.1318)

9 WMO (World Meteorological Organization). 2011Scientific assessment of ozone depletion: 2010. GlobalOzone Research Monitoring Project Report 52.Geneva, Switzerland, 516 pp.

10 Newchurch, M., Yang, E., Cunnold, D., Reinsel, G.,Zawodny, J. & Russell, J. 2003 Evidence for slowdown instratospheric ozone loss: first stage of ozone recovery.J. Geophys. Res. 108, 4507. (doi:10.1029/2003JD003471)

2000 2020 2040 2060 2080 2100year

0

1

2

3

4

DU

N2O emission (anthr)CFC bankHCFC bankHCFC productionHalon bankCH3Br emission (anthr)CCl4 emission

Figure 7. The changes in global mean ozone owing to elimination of anthropogenic N2O emissions after 2010 when comparedwith the effect of eliminating the emissions of the CFC banks, HCFC production and banks, the halon banks, anthropogenicmethyl bromide and carbon tetrachloride. The elimination of anthropogenic N2O emission has the largest potential forreducing ozone depletion in the future. Adapted from fig. 4 of Daniel et al. [28].

8 R. W. Portmann et al. Ozone depletion due to N2O

Phil. Trans. R. Soc. B (2012)

897

898

899

900

901

902

903

904

905

906

907

908

909

910

911

912

913

914

915

916

917

918

919

920

921

922

923

924

925

926

927

928

929

930

931

932

933

934

935

936

937

938

939

940

941

942

943

944

945

946

947

948

949

950

951

952

953

954

955

956

957

958

959

960

961

962

963

964

965

966

967

968

969

970

971

972

973

974

975

976

977

978

979

980

981

982

983

984

985

986

987

988

989

990

991

992

993

994

995

996

997

998

999

1000

1001

1002

1003

1004

1005

1006

1007

1008

1009

1010

1011

1012

1013

1014

1015

1016

1017

1018

1019

1020

1021

1022

1023

1024

ARTICLE IN PRESS

rstb20110377—8/2/12—21:18–Copy Edited by: L. Shobana

for this application grows in the scenarios with the same rate asfor other applications.

The baseline scenarios do not include HFC-23 because its useas a substitute for ODSs is negligible. Estimated future demandfor HFC-23, which is an unintentional byproduct in the produc-tion of HCFC-22, is small compared with other leading HFCs,especially past 2015 (2, 27). Nevertheless, continued emissions ofHFC-23 have significant potential to contribute to climateforcing because of its large GWP [14,800 (100-year)].

GWP-Weighted Consumption and EmissionsThe new HFC baseline scenarios are shown in Figs. 1 and 2 asconsumption, emissions, and RF values between 2000 and 2050.

Consumption and emissions are scaled to CO2-equivalent values,using 100-year GWPs (3) (Table S2). The high and low limits ofthe HFC ranges shown in the figures follow from the differencesin GDP and population growth in the underlying SRES scenar-ios. The high end of the range for developing countries followsA1 and the low end follows A2, both determined primarily byGDP. For developed countries the range, driven primarily bypopulation, follows A2 on the high end and B2 on the low end.Per-capita HFC demand (i.e., market penetration) is expected tosaturate in developed country markets in the next decade and indeveloping countries ca. 2040 at the high end of the scenariorange. Total HFC GWP-weighted consumption grows stronglyfrom 2012, primarily in developing countries, reaching 6.4–9.9

CFC and HCFC consumption

1990 1995 2000 2005 2010Year

0

100

200

300

400

500

600

Cons

umpt

ion (k

t yr-1

)HCFCsdevelopedcountries HCFCs

CFCs

developingcountries

HFC consumption

2000 2010 2020 2030 2040 2050Year

0

2

4

6

8

10

Cons

umpt

ion (G

tCO 2

-eq

yr-1)

GWP-weighted (100-yr)HFC range

Developingcountries (A5)Developedcountries (non-A5)

high

low

HFC radiative forcing

2000 2010 2020 2030 2040 2050Year

0.0

0.1

0.2

0.3

0.4

Radia

tive

forci

ng (W

m-2)

HFC rangeDevelopingcountries (A5)Developedcountries (non-A5) high

low

A B C

Fig. 1. CFC and HCFC consumption (A), HFC consumption (B), and HFC RF (C) for 2000–2050 in developing (A5) and developed (non-A5) countries. The CFC andHCFC mass consumption values in A are derived from reported data (1). The shaded regions for GWP-weighted consumption in B and RF in C are bounded byhigh and low limits as defined by the upper and lower ranges of the baseline scenarios in both developed and developing countries. The consumption valuesexpressed in equivalent GtCO2 per year in B are sums over the consumption of individual HFC compounds each multiplied by their respective GWP (100-year timehorizon) (3).

Global ODS and HFC emissions

2000 2010 2020 2030 2040 2050Year

0

2

4

6

8

10

Emiss

ions (

GtCO

2-eq

yr-1)

GWP-weighted (100-yr)HFCsHCFCsCFCs

Without acceleratedHCFC phase-out}

high

low

Global CO2 and HFC emissions

2000 2010 2020 2030 2040 2050Year

0

10

20

30

40

50

60

Emiss

ions (

GtCO

2-eq

yr-1)

GWP-weighted (100-yr)

SRES CO2 range

}CO2 stabilization scenarios

HFC range

550 ppm

450 ppm

high

low

ODS, HFC and CO2 global RF

2000 2010 2020 2030 2040 2050Year

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Radia

tive

forci

ng (W

m-2)

SRES CO2 rangeCO2 stabilizationscenarios:

550 ppm 450 ppm

HFCsHCFCsCFCs high

low

0.25-0.40 Wm-2

6-13 yr

A B C

Fig. 2. Global ozone-depleting substances (ODSs) and HFC emissions (A), global CO2 and HFC emissions (B), and ODS, HFC, and CO2 global RF (C) for the period2000–2050. Global emissions are the total from developing and developed countries. The CFC data include all principal ODSs in the Montreal Protocol exceptHCFCs. The emissions of individual gases are multiplied by their respective GWPs (direct, 100-year time horizon) to obtain aggregate emissions expressed in Aand B as equivalent GtCO2 per year (3). The color-shaded regions show emissions and RFs as indicated in the panel legends. The high and low labels identify theupper and lower limits, respectively, in the global baseline scenarios. The dashed lines in A show the HCFC and HFC scenario values calculated without the emissionchanges caused by the 2007 accelerated HCFC phaseout. Shown for reference in B and C are emissions and RF for the range of SRES CO2 scenarios and the 450-and 550-ppm CO2 stabilization scenarios (16, 17). The CO2 data from 2000 to 2007 are based on reported emissions and observed concentrations. The trianglein C shows the range of HFC RF in 2050 from the baseline scenarios compared with the range in years needed to obtain the same RF change from CO2 emissionsin the SRES scenarios near 2050.

Velders et al. PNAS ! July 7, 2009 ! vol. 106 ! no. 27 ! 10951

GEO

PHYS

ICS

0

1

2

3

4

Meg

aton

nes p

er ye

ar

Mass-weighted emissionsWithout Montreal ProtocolHFCsODSsHCFCsCFCs-onlyWithout acceleratedHCFC phaseout

high

low

0.0

0.5

1.0

1.5

2.0

Meg

aton

nes C

FC-1

1-eq

per

year

ODP-weightedemissions

Without MontrealProtocol

ODSsHCFCsCFCs, Halonsothers,

1950 1970 1990 2010 2030 2050Year

0

10

20

30

Giga

tonn

es C

O 2-e

q pe

r yea

r

HFCsODSsHCFCsCFCs, Halons,others

GWP-weighted emissionsWithout Montreal Protocol

Magnitude ofKyoto Protocolreduction target 2.0

high

low

• Without policy interven*on, HFCs could negate a significant amount of the future climate benefits projected to arise from the Montreal Protocol controls

• Strong CSD presence in both assessments (leadership and authorship) • Elevated discussions about N2O and HFCs • ODS scenarios also informed RCP scenarios, which were used in IPCC AR5, plus elsewhere

Science to “AcEonable” InformaEon

• CSD role in leadership/authorship • Interna*onal collaborators • Informs interna*onal discussions/policy

Special UNEP Reports

InternaEonal Assessments

Science to “AcEonable” InformaEon

• CSD role in leadership/authorship • Interna*onal collaborators • Informs interna*onal discussions/policy

Special UNEP Reports

InternaEonal Assessments

• Strong CSD presence in both assessments (leadership and authorship) • Elevated discussions about N2O and HFCs • ODS scenarios also informed RCP scenarios, which were used in IPCC AR5, plus elsewhere

CLIMATE CHANGE 2013The Physical Science Basis

WORKING GROUP I CONTRIBUTION TO THE

FIFTH ASSESSMENT REPORT OF THE

INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE

WG I

INTERGOVERNMENTAL PANEL ON�climate change



Image from NASA

Future Plans

• Con*nue providing leadership and scien*fic input to ozone and climate assessments

• Ensure that future scenarios remain current and relevant for ozone deple*on and climate change policy discussions

• Con*nue to evaluate the policy implica*ons of interac*ons between ozone deple*on and climate change to help iden*fy win-‐win policy op*ons

JohnS.Daniel · 2015-03-25 · Ozonedepleon,climatechange,andpolicy JohnS.Daniel...

Documents

Transcript of JohnS.Daniel · 2015-03-25 · Ozonedepleon,climatechange,andpolicy JohnS.Daniel...