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The Global Warming Potential (GWP) of a gas relates the cumulative (integrated) warming over time caused by the emission of the gas to the cumulative warming caused by the emission of the same mass of CO2. The two basic factors that drive the GWP value are the “radiative forcing” (the infrared absorption of an incremental amount of the gas in the atmosphere) of the gas and the rate of decay of the gas in the atmosphere, compared to CO2. There are uncertainties in establishing quantitative values for both radiative forcing and atmospheric decay rate for both the fluorocarbons and CO2. As a result the IPCC estimated that the accuracy of the GWP values is+ 35%. As new data has been and continues to be developed, GWP values have been revised and are subject to future revision. A detailed presentation of the methodology for determining GWP is contained in [IPCC [2001]. The fundamental importance of GWP values to this study is that it permits the warming impact of fluorocarbon emissions to be compared to the warming impact caused by energy consumption (and the associated CO2 emissions) for the various applications that make use of HFCs.
Values of the 100-year ITH Global Warming Potentials of the fluorocarbons of interest in this study are summarized in Table B-1. Four sets of values are provided:
The GWP values from Climate Change 1995have been used for the LCCP calculations in this study, because both the current regime of national greenhouse gas emission accounting and the Kyoto Protocol targets continue to be based on these GWP values. The GWP values for the HFCs of interest to this study that are published inClimate Change 2001 are typically within 15% of the values published inClimate Change 1995. Most values increased, a few decreased or remained the same.
Table B-1: Global Warming Potentials (100 year ITH), Relative to Carbon Dioxide
| Fluorochemical | 100 Year ITH GWP (kg CO2/kg) | |||
| TEWI-3 Appendix B |
Climate Change 1995 |
WMO 19993 | Climate Change 20014 |
|
| HCFC-22 HCFC-123 HCFC-141b HCFC-142b |
1,700 93 630 2,000 |
1,5001 901 6001 1,8001 |
1,900 120 700 2,300 |
1,700 120 700 2,400 |
| HFC-23 HFC-32 HFC-125 HFC-134a HFC-143a HFC-152a HFC-227ea HFC-245fa HFC-365mfc HFC-43-10mee |
11,700 650 2,800 1,300 3,800 140 2,900 820 – 1,300 |
11,7002 6502 2,8002 1,3002 3,800 2 1402 2,9002 – – 1,3002 |
14,800 880 3,800 1,600 5,400 190 3,800 – 910 1,700 |
12,000 550 3,400 1,300 4,300 120 3,500 950 890 1,500 |
| HFE-7100 HFE-7200 |
– – |
– – |
390 55 |
390 55 |
| R-404A R-407A R-407C R-410A R-507 |
3,260 1,770 1,530 1,730 3,300 |
3,260 1,770 1,525 1,725 3,300 |
4,544 2,336 1,984 2,340 4,600 |
3,784 1,990 1,653 1,975 3,850 |
Source:
1Climate Change 1995, Table 2.8.
2Climate Change 1995, Technical Summary, Table 4.
3WMO Report No. 44 (1999), Table 10-8
4Climate Change 2001, Table 6.7
R-404A: R-125/143a/134a (44/52/4)
R-407A: R-32/125/134a (20/40/40)
R-407C: R-32/125/134a (23/25/52)
R-410A: R-32/125a (50/50)
R-507: R-125/143a (50/50)
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