Short-Lived Climate Pollutants (SLCP) and their role in climate change and variability

A. R. Ravishankara:•Importance of SLPCs •NOAA’s role •Examples of interconnections:Øwith air quality issues.Øwith stratospheric ozone issues

James Butler: Short-Lived Non-CO2 Greenhouse Gases

V. Ramaswamy:Quantitative understanding, with uncertainties, of emissions-to-transport-to-lifetime-to-climate (e.g., temperature, precipitation) using global models, for predictability in the 21st Century •Role of aerosols in the 20th C and present-day•Aerosols and climate projections in the 21st C

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Importance of SLPCs andNOAA’s role

A. R. RavishankaraNOAA / ESRL / Chemical Sciences Division / Boulder

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What are Short-Lived Climate Pollutants (SLCPs)?

GHGs or other constituents that influence radiative balance of Earth system that are short-lived ( <10 years?)

CO2

Ø Iconic anthropogenic climate forcer

Ø Essential issue for:• mitigation,• adaptation, and• understanding

o Climate forcing agents with “short” lifetimes

o Include CH4 (~10 yrs) and shorter-lived forcers

o Includes many HFCso Are chemically activeo Have impacts on other issues• Health• Precipitation• etc.o Aerosols are a big part of the SLCPso SLCPs have been target by U.S. and

G-8 nations - NOAA will be responsive to a National need.

3

Why SLCP?

(1) They can be dealt within through “win-win” options for multiple environmental issues;

(2) They can be influenced using existing regulations;(3) Their shorter lifetimes allow for some immediate

relief, while the larger CO2 issue is being worked on;

(4) Scientific insights on the workings of the climate system could be obtained by changes in these forcers; and

(5) Accounting for them is essential for regional climate change and variability predictions.

(6) NOAA has focused on many issues related to SLCPs (see additional slides)

The forcings from aerosols have offset the greenhouse gas forcings and the SLCP greenhouse gases significantly augment CO2 forcing. 4

Affect incoming solar radiation

Influence on outgoing infrared energy

Aerosols (PM)(direct + indirect)

Net

Greenhouse gases (+ soot)

Climate Air Quality IntersectionsSimplified Climate Forcing Diagram

Coupling between anthropogenic climate change and air quality: • Air Quality regulations can be a win-win for AQ & Climate• Many states/regions have legislated this approach• One does not need the “predicted climate state” to make relative choices• Direct application of science-based information (e.g., emissions, RF, etc.)

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Our Science: Evaluating multiple roles of SLCPs

Arctic, glacier, and snowpack melting?

�AIR QUALITY� �CLIMATE�HaloCarbs Trop

O3

BlackCarbon

Aerosols(direct + indirect)

CO2 CH4 N2O

�AQ��AQ�? �AQ�DO3Ocean Acidification

Food FoodDO3?

Visibility

Ø Air Quality roles: Trop. aerosols, CH4, trop. O3, and BC (indoor AQ)Ø Visibility: aerosols, (BC)Ø Ocean acidification: CO2

Ø Stratospheric ozone depletion/changes: Halocarbons (and substitutes?); CO2, CH4

Ø Water supply: (GHGs +aerosols), black carbonØ Food issues: CO2,- ocean acidification- trop O3, (aerosols?)

Multiple impacts that need simultaneous considerations: (1) Science for optimizing for best outcome.(2) Information for multiple issues!

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Soot: the joker in the deck

Key questions about soot (and aerosols) – the very short-lived pollutants: •What is the real soot forcing? Quantification of emissions•What is the net of soot and aerosols? Are they really separable?•What is the impact of soot on glaciers, snow ice, snow, ice-fields, precipitation?•Is reducing soot emissions a “no-regret” strategy?•Direct application of science-based information (e.g., emissions, RF, etc.)

�AIR QUALITY� �CLIMATE�Black

Carbon

Aerosols(direct + indirect)

�AQ�Visibility

Arctic, glacier, and snowpack melting?

Air Quality

Key new scientific findings of NOAA

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8

BalloonObservations

AM3/C180 (~50 km)

AM3/C48 (~200 km)

Alti

tude

(km

a.s

.l.)

Northern CA à Southern CAO3 [ppbv]

High-resolution atmospheric chemistry-transport model better captures stratospheric ozone intrusions (May 11, 2010)

Vertical cross section over California

model sampled at location and times of sonde launches

Courtesy: Meiyun Lin (NOAA/ GFDL, Princeton)

Stratospheric influence on surface ozone in the Los Angeles area during late spring and early summer of 2010 ; A.O. Langford et al., JGR, vol. 117; DOI: 10.1029/2011JD016766,

2012

CalNex and IONS-2010 (May 10 – June 19)

Exceedance of proposed NAAQS by stratospheric intrusion over LA Basin

29 May 2010

Joshua Tree

Courtesy: Langford NOAA/ESRL/CSD

Carpenteria

NOAA/ESRL/GMD ozonesonde

NOAA/ESRL/CSD airborne lidar

Proposed NAAQS

CARB ground site

Ø Intrusion of stratospheric (ozone rich) air can lead to large surface ozoneØ Implications for meeting AQ standards? 9

HFCs and climate change: Future emissions can be large but can be avoided

Ø Unabated, future HFC contribution radiative forcing can be large.Ø Radiative forcing by future HFC emissions can be ~25% of that of CO2

future emissions (SRES scenarios).Ø Future HFC emissions can significantly hinder the 450 ppm stabilization

target.Ø There are viable solutions to avoid this situation- with potentially

positive side benefits (see attached for NOAA information provision)

2.0

1.5

1.0

0.5

0.0

Chan

ge in

radi

a!ve

forc

ing

(W m

-2)

Change in radia!ve forcing since 2000

2000 2010 2020 2030 2040 2050Year

SRES CO2 range

Stabiliza!on of CO2 at 450 ppm

Upper range HFC scenario

0.5

0.4

0.3

0.2

0.1

0.0

Radi

a!ve

forc

ing

(W m

-2)

Radia!ve forcing

2000 2010 2020 2030 2040 2050Year

Current forcing

Upper range HFC scenario Life!me 15 yr

3 yr

1 yr1 month

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Short-Lived Non-CO2 Greenhouse Gases

James ButlerNOAA / ESRL / Global Monitoring Division / Boulder

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Nature Vol 476 No. 43 – August 4, 2011

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Example: Ozone-depleting gases

13

14

Ozone-depleting Gases• As a result of the Montreal Protocol, the impact of controlled substances

is decreasing.

2500

2700

2900

3100

3300

3500

3700

1980 1985 1990 1995 2000 2005 2010

Chlo

rine

(ppt

)

AGAGE

NOAAMeasured tropospheric changes

490

515

540ppt

CFC-12

235245255265275

ppt CFC-11

0

40

80

120

160

200

1990 1995 2000 2005 2010

ppt

CH3CCl3

HCFC-22

CCl4

CFC-113

HFC-134a

0

5

10

15

20

ppt

HCFC-142b

HCFC-141b

H-1211

H-1301

CH3Br

HFC-152a

Ozone-depleting Gases

• Most are long-lived• Some are shorter-lived• Success comes by addressing

all gases• Reductions began under the

Montreal Protocol

1990 1995 2000 2005 2010 1990 1995 2000 2005 2010

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How much are we emitting in the way of greenhouse gases?

16

0

10

20

30

40

50

1980 1990 2000 2010

Ant

hrop

ogen

ic E

mis

sion

(GtC

O2 -

eq/y

r)

Year

CO2 (ff+lu)

CO2 (ff)

Sum, non-CO2

CH4

N2OODSs

HFCs

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How do these changes affect the atmosphere?

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0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1980 2000 2020 2040 2060 2080 2100

Rad

iativ

e Fo

rcin

g (W

/m2 ) Sum

CO2

N2O

CH4

HFCs

ODSs*

Sum, non-CO2 GHGs

*ODSs future set by the Montreal Protocol

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

Radi

ativ

e Fo

rcin

g (W

/m2 )

1980 2000 2020 2040 2060 2080 2100

• These projections do not include consideration of feedbacks:

• Climate on emissions– Arctic release– Marsh emission

enhancements• Climate on loss– CO2 uptake– stratospheric circ.– [OH] variability

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Warming effect of short-lived substances

20

Proceedings of the National Academy of Sciences Vol. 107 No. 43 – October 26, 2010

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Solomon S et al. PNAS 2010;107:18354-18359

©2010 by National Academy of Sciences

Warming impact of short-lived substance

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Aerosols and their role in Climate Change and Variability

V. RamaswamyNOAA/ GFDL, Princeton

Quantitative understanding, with uncertainties, of emissions-to-transport-to-lifetime-to-climate (e.g., temperature, precipitation) using global models, for predictability in the 21st Century

• Attribution to GHGs versus aerosols in the 20th C and present-day• Aerosols and climate projections in the 21st C

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LandOcean

Droplets

InterstitialAerosols Activation

Advection

Emission

Reflection

SW Radiation

Aerosol-Cloud-Climate Interactions

Land

Advection

Emission

HygroscopicGrowth

Wet Particles

Clear Sky Cloudy Sky

Reflection

SW Radiation

“DIRECT” effects “INDIRECT” effects

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Surface Air Temperature change[WMGGO3 (warming) and Aerosol (cooling) effects dominant]

Tem

pera

ture

Cha

nge

(�C)

year

CM3 (All Forcings)WMGGO3

NAT (Solar+Volcano)Aerosols

OBS (HadCRU, GISS)

Horowitz et al. (in preparation)25

Attribution of the weakening of the South Asian summer monsoon using GFDL CM3: 20th Century simulations

Linear trends of average JJAS rainfall over central-northern Indian (mm day-1)

WMGGO3

All forcingCRU

AERO

NAT

Bollasina et al. (Science, 2011)

§ AERO trend opposite in sign to WMGGO3

§ AllForc trend compares well with CRU (Obs)

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Geophysical Fluid Dynamics Laboratory

How Hadley and Walker circulations respond to green-house gases and aerosols? Regional-scale forcing is also important

Climatology GG

All forcingAERONorth-South pattern of basic mechanism evident in earlier simulations

Chen and Ramaswamy (1996); Ramaswamy and Chen (1997) 27

Surface Air Temperature (RCP4.5 scenario)

28

year

Tem

pera

ture

Cha

nge

(�C) FullRCP4.5

scenario

Aerosols and ozone

held at 2005 levels

Large additional warming projected from aerosols over 21st century

Levy et al. (submitted, JGR)

Aerosols key for NA TS projections

Villarini and Vecchi (2012, Nature C.C.)

All ForcingNo future aerosol or O3

No future aerosol

Projected aerosol changes lead to

increase in NA TS frequency over 1st

half of 21st century

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Aerosols and their role in Climate Change and Variability

Key Uncertainties

Quantitative understanding, with uncertainties, of emissions-to-transport-to-lifetime-to-climate (e.g., temperature, precipitation) using global models, for predictability in the 21st Century

• Spatial distributions of aerosols and their properties è Forcing, with uncertainties

• Regional climate trends in temperature and precipitation• Atmospheric trends (e.g., changes in lapse rate)• Relative impacts versus long-lived greenhouse gases è Quantifying

with uncertainties

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Synopsis• There is a great demand for information on SLCPs• NOAA (with its partners) has the expertise and

capabilities to fulfill these needs• Have already developed great partnerships with

regions, states, and other users (e.g., State Dept.)• Have developed long-term collaborations with

extramural community to carry out such research• Have NOAA facilities that are well suited for this

work and collaborations

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The END

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Additional Material

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SLCP and NOAA’s effortsNOAA has focused on many issues related to SLCPs: • The physical and chemical nature of these species; • How they have forced the climate system;• How they will contribute in the future; • What are the telltale signatures of these forcers; and• What have been and will be the impacts of these changes

on climate, air quality, and precipitation

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Montreal Protocol, HFCs, and Climate

Ø ODS-Phase out led to a drop of ~ 8.0 GtCO2eq per year (1988 -2010)

Ø The avoided annual ODS emission (~ 10 Gt CO2eq in 2010 alone)

- x5 the Kyoto target for 2008-2012 (1st

commitment period)Ø ODS decrease: one of the largest intentional

global GHG emission reductions to date

0

10

20

30

40

Magnitude ofKyoto Protocolreduc!on target

2.0

1950 1970 1990 2010 2030 2050Year

CO2 e

q em

issi

ons

(Gt C

O2 e

q pe

r yea

r)

CO2

ODSs Without Montreal Protocol

HCFCsCFCs, Halons, others

MP effectively protected climate

1990 1995 2000 2005 2010Year

0

10

20

30

40

50

60

Abun

danc

es (p

pt)

HFC abundances

HFC -134a

HFC -143a

HFC -152a

HFC -125

HFCs increased because of MP

Ø Consumption of HFCs is increasing rapidly

Ø Consequent atmospheric growth rate of some HFCs are increasing very rapidly (some as much as 10% per year)

Ø The current contributions of HFCs to radiative forcing is still small (<1% of GHGs)

ESRL/GMD monitoring dataMontzka et al.

35

Back up Slide for Short-Lived Non-CO2 Greenhouse Gases (Jim Butler)

36