Increase in greenhouse gas emissions despite cuts

The substance HFC-23 is a by product of HCFC-22, a refrigerant in ACs and refrigerators and a starting material for producing heat and chemical-resistant products, cables and coatings.

"Without the international effort to reduce emissions of HFC-23, its emissions and atmospheric abundance would have been even larger in recent years," said Stephen Montzka, National Oceanic and Atmospheric Administration (NOAA) chemist.

"As it was, emissions in 2006-2008 were about 50 percent above the 1990-2000 average," added Montzka, who led the collaborative study between NOAA and university scientists.

HFC-23 is one of the most potent greenhouse gases emitted as a result of human activities.

Over a 100-year time span, one pound of HFC-23 released into the atmosphere traps heat 14,800 times more effectively than a pound of carbon dioxide.

To date, the total accumulated emission of HFC-23 is small relative to other greenhouse gases, making this gas a minor (less than one percent) contributor to climate change at present.

Because HFC-23 is such a potent greenhouse gas, the United Nations Framework Convention on Climate Change (UNFCCC) has facilitated the destruction of substantial quantities of HFC-23 in developing countries since 2003.

The study by Montzka and colleagues shows for the first time that even with these actions HFC-23 emissions from developing countries remained substantial compared to recent years, says an NOAA release.