A new article in PNAS (Velders et al 2009) argues that HFC (hydrofluorocarbon) emissions will grow at a surprising rate, becoming a substantial greenhouse gas later this century.  HFCs were developed  as a replacement for ozone damaging CFCs.  Production and release of HFCs have grown quickly since the 1995 ban on CFCs.

From the abstract – The consumption and emissions of hydrofluorocarbons (HFCs) are projected to increase substantially in the coming decades in response to regulation of ozone depleting gases under the Montreal Protocol. The projected increases result primarily from sustained growth in demand for refrigeration, air-conditioning (AC) and insulating foam products in developing countries assuming no new regulation of HFC consumption or emissions…Global HFC emissions significantly exceed previous estimates after 2025 with developing country emissions as much as 800% greater than in developed countries in 2050. Global HFC emissions in 2050 are equivalent to 9–19% (CO2-eq. basis) of projected global CO2 emissions in business-as-usual scenarios and contribute a radiative forcing equivalent to that from 6–13 years of CO2 emissions near 2050. This percentage increases to 28–45% compared with projected CO2 emissions in a 450-ppm CO2stabilization scenario.

Read and download the article in PNAS here

Read a related post on Andrew Revkins Dot Earth blog here