the information contained in this report largely derives from the scientific assessment of ozone...
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The information contained in this report largely derives from the Scientific Assessment of Ozone Depletion: 2014
From CFCs to HCFCs to HFCs
Co-Chairs:
Ayité-Lô AjavonPaul A. NewmanJohn PyleA.R. Ravishankara
Scientific Steering Committee:Co-Chairs &David KarolyMalcolm KoTheodore ShepherdSusan Solomon
Coordinating Editor:Christine Ennis
Report of the Scientific Assessment PanelOpen-Ended Working Group Meeting
20 July 2015 - Paris
Ozone-depleting substances (ODSs) are decreasing
312 ppt (9%) decline of chlorine
20 July 2015 OEWG meeting Paris 2
Ozone-depleting substances (ODSs) are decreasing
2 ppt (12%) decline of Br
20 July 2015 OEWG meeting Paris 3
Ozone levels seems to have improved, but cannot say they are
statistically significant
20 July 2015 OEWG meeting Paris 4
We have previously reported on the response of the ozone layer to the changes in ODSs.
Ozone in the upper stratosphere is increasing, as expected. Both CO2 increases and ODSs decreases contribute to this increase
The global ozone and the ozone hole are not getting worse; they appear to be slightly better but it is too early to tell.
Stopping all future production of HCFCs has only a limited effect on the 2015 scenario
20 July 2015 OEWG meeting Paris 5
Destruction of all ODS banks by 2020 also has limited impact on the evolution of ODSs
20 July 2015 OEWG meeting Paris 6
Stopping all future emissions advances ODS recovery by about 11 years
20 July 2015 OEWG meeting Paris 7
CFCs emissions continue to decline, but other compounds are increasing
Let’s zoom in
20 July 2015 OEWG meeting Paris 8
In 2013, the emissions of CFCs, HCFCs, and HFCs were about equal in G tonnes CO2-equivalent
20 July 2015 OEWG meeting Paris 9
Evolution of strategy to eliminate ozone depleting substances
Some HFCs are potent greenhouse gases.e.g., HCFC-134a- GWP~1300 (compare with CFC-12 with GWP ~10,000)
20 July 2015 OEWG meeting Paris 10
HFCs are the main replacements in many ODS applications. HFCs growth is primarily due to their uses as ODS-substitutes. HFCs are increasing rapidly.
UNEP HFC
reportCons
umpti
on
(mill
ion
tonn
es C
O2-e
q.)
0
200
400
600
800
1000
1990 2002 2010
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.
WMO/UNEP 2014 SAP report
20 July 2015 OEWG meeting Paris 11
Emissions of HFCs are increasing
HFC emissions are increasing. Recent HFC-23 emission changes are consistent with effectiveness
of the CDM in recapture and destruction.
Total
HFC-23
HFCs used as ODS substitutesUsing data from
WMO/UNEP 2014 SAP report
20 July 2015 OEWG meeting Paris 12
Uses of HFCs (ODS substitutes)
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
20 July 2015 OEWG meeting Paris 13
Increases are consistent with estimates
Emissions from countries not expected to report to UNFCCC are increasing very rapidly.
From Montzka et al., 2014/2015
20 July 2015 OEWG meeting Paris 14
Consistent with Velders et al. 2009 Projections
Emissions from countries not reporting to UNFCCC
HFCs-
*
* HFCs other than 134a and 23, i.e., -125, -43a, -32, -152a, -227ea, 365mfc
Emissions are consistent with Velders et al. 2009 estimates for total and individual chemicals…. Lends confidence to projections
ODS contributions to climate forcing were large, but are declining as ODS levels decrease
20 July 2015 OEWG meeting Paris 15
By mid-century, HFCs are beginning to dominate the total radiative forcing
20 July 2015 OEWG meeting Paris 16
Future emissions of HFCs could make a large contribution to 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.
CFCs and HCFCs
Various HFCScenarios
WMO/UNEP 2014 SAP report
20 July 2015 OEWG meeting Paris 17
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.
From UNEP HFC report
20 July 2015 OEWG meeting Paris 18
There are ways to avoid large climate effects of HFCs
Possible to retain a <1% contribution in 2050 if HFCs with GWP <20 and other alternatives are used, even for the upper range emissions scenarios.
Such alternatives appear to be available.
Impacts of TFA from HFO-1234yf, a potential substitute, are negligible over the the next decade. Longer-term impacts require future evaluations.
Rad
iativ
e F
orci
ng
(W m
-2)
2000 2010 2020 2030 2040 2050 Year
Progressively lower GWPFrom UNEP
HFC report
20 July 2015 OEWG meeting Paris 19
Summary
• ODSs are declining in our atmosphere• The radiative forcing by CFCs and HCFCs will
decline over the course of the 21st century• Radiative forcing by future HFC emissions can
be ~25% of that of CO2 future emissions.
• Future HFC emissions may hinder the 450 ppm
CO2 stabilization target.
• Alternatives to use of high GWP HFCs are
available
20 July 2015 OEWG meeting Paris 20
Thank you for
your attention.
20 July 2015 OEWG meeting Paris 21
HFC emissions projections by sectors
Velders et al., 2015 (to be
published)
Emission projections for various geographical regions and usage sectors are becoming available
Regional Emissions Sectoral Emissions
20 July 2015 OEWG meeting Paris 22
20 July 2015 OEWG meeting Paris 23
By mid-century, HFCs are beginning to dominate the total radiative forcing
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
20 July 2015 OEWG meeting Paris 24