HFC Workshop, Bangkok 1

Overview of current and projected atmospheric HFC abundances

A.R. Ravishankara

On behalf of co-Chairs of SAP

Ayité-Lo Ajavon

Paul Newman

John Pyle

A.R. Ravishankara

4/20/15

Evolution of strategy to eliminate ozone depleting substances

MP successfully phased out CFCs and is phasing out

HCFCs. Phase out done via use of substitute chemicals or other

approaches.

CFCs,Halons,CH3Br,CCl4, MCF,etc.

HCFCsHigh GWP HFCs

Low GWP HFCs

Alternate technologies

Burkholder, Cox, and Ravishankara, 2015

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HFCs are the outgrowth of the ODS-substitution strategy

HFCs are the main replacements in many ODS applications. HFCs growth is primarily due to their uses as ODS-

substitutes. HFC productions are increasing rapidly.

Some HFCs are potent greenhouse gases.e.g., HCFC-134a- GWP~1300 (compare with CFC-12 with GWP ~10,000)

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UNEP HFC report

HFC Workshop, Bangkok 4

Atmospheric observations show increases in HFCs

All HFCs are increasing. Most HFCs are increasing rapidly… Current HFC abundances are still small – together their

abundance is roughly < 115 ppt (excluding HFC-23), i.e.,

20% of the current CFC-12 abundance.

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WMO/UNEP 2014 SAP report

Emissions of HFCs are increasing

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Atmospheric observations show that HFC emissions are increasing.

Recent HFC-23 emission changes are consistent with effectiveness

of the Clean Development Mechanism (CDM) in recapture and

destruction.

Total

HFC-23

HFCs used as ODS substitutes

Using data from WMO/UNEP 2014 SAP report

Uses of HFCs (ODS substitutes)

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MAC, refrigeration, and other uses are roughly the same.

Emissions from all uses are increasing at roughly the

same rate.

From Montzka et al. 2014/2015

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Increases are consistent with estimates

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Emissions from countries not reporting to UNFCCC

Emissions from countries not expected to report to UNFCCC are

increasing very rapidly. Emissions are consistent with Velders et al. 2009 estimates for

total and individual chemicals…. Lends confidence to projections.

From Montzka et al., 2014/2015

Consistent with Velders et al. 2009 Projections

From Observations

Reported to UNFCCC

Details of HFC emissions projections are becoming available

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Velders et al., 2015 (to be published)

Emission projections for various geographical regions and usage sectors

are becoming available

Regional Emissions Sectoral Emissions

HFC could contribute largely to future climate change

Future HFC contribution to climate change (as measured by

radiative forcing) can be large.o Radiative forcing by future HFC emissions can be ~25%

of that of CO2 future emissions.

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CFCs and HCFCs

Various HFCScenarios

WMO/UNEP 2014 SAP report

HFCs contribution to climate change by future emissions can be large

Radiative forcing by future HFC emissions can be ~25% of

that of CO2 future emissions (scenarios from SRES).

Future HFC emissions can significantly undermine

achievements of the 450 ppm stabilization targets.HFC Workshop, Bangkok 104/20/15

From UNEP HFC report

There are ways to avoid large climate effects of HFCs

Use low-GWP HFCs (GWP <20) and other alternatives will retain a <1% contribution in 2050 by, even for the upper range emissions scenarios.

Such alternatives appear to be available.

Impact of TFA from HFO-1234yf, a potential substitute, are considered to be negligible over the the next decade. Potential longer-term impacts require future evaluations.

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Rad

iativ

e F

orci

ng (

W m

-2)

2000 2010 2020 2030 2040 2050 Year

Progressively lower GWPFrom UNEP

HFC report

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Thank you for

your attention.

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Backup slides

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Detailed projections

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HFCs are increasing in the atmosphere

e.g., HFC-134a used in mobile air conditioners has increased about 7% a year over the past two years.

HFC-23, a byproduct of HCFC-22 production, is also increasing.

The current contribution of HFCs to climate change is still small (<1% of GHGs).

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Part

s pe

r Tril

lion

(ppt

)

Em

issi

on (

kilo

Tonn

es p

er y

r)

HFC-23 HFC-23

Abundances Emissions

Montreal Protocol phased out CFCs!

“Unnecessary”, e.g., Propellant, usage dropped very quickly- easy step

Allowed use of existing equipment with “drop in” substitutes- by using HCFCs

Allowed a gradual switching to better substitutes Allowed emergence of “not-in-kind” technologies and other chemicals

RefrigerantsFoam Expansion

SolventsPropellants

Fire Extinguishants Other

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HFC future contribution to climate: can be large but can be avoided

Future HFC contribution to climate change (as measured by radiative forcing) can be

large.

o Radiative forcing by future HFC emissions can be ~25% of that of CO2 future

emissions.

o Future HFC emissions can hinder the 450 ppm CO2 stabilization target.

o Replacement of current mix of high-GWP HFCs with low-GWP compounds and not-

in-kind technologies would essentially avoid these climate effects of HFCs.o TFA from HFO-1234yf, a potential substitute, are considered to be negligible over the

the next few decades. Potential longer-term impacts require future evaluations.

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Various HFCScenarios

Future HFCs contributions

Radiative forcing by future HFC emissions can be ~25% of that of future CO2

emissions (scenarios from SRES).

Future HFC emissions can significantly hinder the 450 ppm stabilization target.

Possible to retain a <1% contribution in 2050 by using low-GWP HFCs (GWP

<20) and other alternatives, even for the upper range emissions Scenarios.

HFC Workshop, Bangkok 194/20/15

Assuming the current mix of HFCs