Hydrofluorocarbons

They’re invisible, nontoxic, and ozone friendly. You can find them in refrigerators, spray paints, and fire extinguishers. However, the more you use them, the greater their potential to contribute to global warming.

Hydrofluorocarbons (HFCs) are man-made greenhouse gases. They were developed to replace ozone-depleting gases found in a variety of applications, including refrigeration systems, aerosol propellants, and fire suppression.

HFCs do not exist in nature and have no natural means of removal from the atmosphere, unlike other greenhouse gases such as carbon dioxide, which can be used by plants. HFCs have a much higher global-warming potential than that of carbon dioxide.

The Ozone Layer and HFCs

The ozone layer is a trace gas found in the atmosphere. It blocks certain ultraviolet (UV) rays that can damage and mutate plant and animal cells. It also helps to regulate the Earth’s climate. It is essential for the existence of life on this planet.

The HFC problem originally started as a solution for another problem. In the 1930s chlorofluorocarbons (CFCs) were developed for use in refrigeration systems and in aerosols because they were stable, nontoxic, nonflammable compounds. It wasn’t until the 1970s that scientists discovered that CFCs contributed to ozone depletion.

The first step in CFC reduction came with the development of hydrochlorofluorocarbons (HCFCs) to replace them. Although HCFCs also depleted the ozone, they did less damage than their predecessor.

The Montreal Protocol

As more and more developed countries became concerned about the depleting ozone layer, their governments decided to do something about it by creating the Montreal Protocol in 1987. Its mandate was to phase out CFCs and HCFCs.

This treaty to protect the ozone was signed by 196 nations in Montreal and was the first treaty to meet with international approval.

The solution for ozone-damaging CFCs appeared to be HFCs. These were introduced in the 1990s; since then their use has been on the rise as ozone-depleting gases are phased out.

The protocol deemed HFCs to be “super” greenhouse gases because of their ability to trap hundreds to thousands of times more heat than carbon dioxide (the variance in heat absorption of HFCs depends on their application, which affects their molecular structure).

However, the Montreal Protocol does not regulate production or consumption of HFCs, as greenhouse gases fall under the jurisdiction of the Kyoto Protocol.

The Kyoto Protocol

Created in 1997 and enforced in 2005, the Kyoto Protocol commits 37 industrialized countries and European communities to stabilize greenhouse gas emissions by binding them to specific targets. The protocol spans a five-year period (2008 to 2012) and sets targets based on 1990 greenhouse gas levels.

Since carbon dioxide is the largest contributor to Canada’s greenhouse gas emissions (78 percent), all emission figures are given in carbon dioxide equivalents. Canada’s 1990 greenhouse gas emission levels were 592 megatonnes (Mt). Canada’s Kyoto Protocol target was set at a 6 percent reduction from 1990 figures, which translates into approximately 558 Mt of emissions per year.

Overall, Canada’s total greenhouse gas emissions increased by 24.1 percent from 1990 to 2008. In 2008 Canada was releasing around 734 Mt.

The former federal Liberal government developed a plan to meet our Kyoto targets, but the current Conservative government is not trying to meet Kyoto targets and has even cut several climate change programs.

What does all this have to do with HFCs?

Although greenhouse gas emissions from the industrial processes sector decreased by 4.1 percent from 1990 to 2008, emissions from HFC use in some subsectors has risen by over 5 Mt since 1995 (a 1,000 percent increase). This is due to the replacement of ozone-depleting gases with HFCs.

What is being done?

Efforts are being made to encourage an amendment to the Montreal Protocol to include the phasing down of HFCs. “Their [HFCs’] current contribution to climate change to date has been quite small in comparison to other gases such as HCFCs, CFCs, N₂O [nitrous], CH⁴ [methane], and, of course, CO₂,” says Dr. Stephen A. Montzka of the US National Oceanic and Atmospheric Administration.

However, if left unchecked, these levels could skyrocket and reach levels by 2050 that would negate the long-term efforts to reduce carbon dioxide emissions.

In May 2010 Canada, the US, and Mexico spearheaded a proposal for amending the Montreal Protocol. If accepted by the other nations, this proposal will require a reduction in HFC emissions that would deliver climate mitigation equivalent to preventing over 100 billion tonnes of carbon dioxide between now and 2050. That would be 10 to 20 times greater than the reduction proposed under the Kyoto Protocol.

What will replace HFCs?

A few options are currently being studied for air conditioner replacements.

Short-lived HFCs
“Short-lived HFCs don’t persist in the atmosphere nearly as long as most currently used HFCs, and so will have a much smaller climate influence for a given emitted amount,” says Montzka.

Carbon dioxide
Although it has a lower global-warming potential than HFCs and no ozone-depleting potential, it does have a toxicity issue in confined spaces and efficiency losses under normal operating conditions of air conditioners.

Hydrocarbons
The most common hydrocarbon being investigated is propane. The challenges with propane are high flammability and efficiency compared to HCFCs of the same volume.

Although there are currently challenges associated with these replacements they do show promise. Currently HFCs are still the best alternative when it comes to replacing ozone-depleting substances.

In the meantime

Nations participating in the Montreal Protocol met in Bangkok in November 2010. Although no decision was made on HFCs, 91 countries signed a declaration of support for phasing out HFCs, up significantly from the 41 countries that supported the proposal in 2009.

China, India, and Brazil argued for further discussion of the amendments put forth by Canada, the United States, Mexico, and the Federated States of Micronesia.

Reliance on HFCs to keep our foods cold and us comfortable presents us with the challenge of balancing our lifestyles with climate change. Acceptance of the amended Montreal Protocol will be a big step toward finding this balance.

While our governments work out the details, we can all help by choosing nonaerosol products whenever possible, maintaining our vehicles and appliances to operate as efficiently as possible, and by looking into retrofitting appliances with greener options.

Canada’s top 5 HFC polluters*

* Based on the 2006 data from Pollution Watch