Published online 9 November 2010 | Nature | doi:10.1038/news.2010.584


Ozone treaty could be used for greenhouse gases

Montreal Protocol might find a new role in helping to reduce emissions of hydrofluorocarbons.

Air conditioning units mounted on the outside of a building.The Montreal Protocol could offer a way of of scaling back the use of a class of potent greenhouse gasses.CHRIS HELLIER / SCIENCE PHOTO LIBRARY

International negotiators might be bogged down in the ongoing United Nations climate talks, but there could yet be hope for an agreement on reducing emissions of a class of powerful greenhouse gases — using the same treaty that is responsible for the phasing out of gases responsible for destroying the ozone layer.

As nations that are party to the Montreal Protocol meet in Bangkok this week, at issue are hydrofluorocarbons (HFCs), common refrigerants that can be thousands of times more potent than carbon dioxide at trapping heat in the atmosphere. HFCs are the third-generation chemical designed to replace hydrochlorofluorocarbons (HCFCs), themselves a replacement for the original ozone-eater, chlorofluorocarbons.

At present, HFCs are covered under the UN Framework Convention on Climate Change, but governments are warming to the idea of creating a direct and comprehensive HFC regulatory structure under the Montreal Protocol, which has successfully phased out dozens of chemicals over the past two decades. Advocates say the protocol could be used to tackle global warming now that its work on ozone is wrapping up. Negotiators faced the same issue last year but decided to hold off, in part to see what might come out of the climate summit in Copenhagen in December 2009. As for whether nations are ready to reach an agreement on scaling back the use of HFCs, most observers expect the answer will be no different this week: not quite yet.

Rapid reductions?

Pressure to scale back HFCs is mounting from all directions, however, including small-island nations that want rapid greenhouse-gas reductions as well as industrial giants such as the United States and Europe. "The writing is on the wall," says Stephen Andersen, co-chair of the Montreal Protocol's Technical and Economic Assessment Panel, a research arm for the negotiators. Even if the decision on HFCs doesn't happen now, he adds, "people are pretty confident that 2011 could be the year".

“The writing is on the wall.”

Stephen Andersen
Montreal Protocol's Technical and Economic Assessment Panel

Cumulatively, HFC emissions are projected to skyrocket in the coming decades, owing to increased demand for air conditioning in homes and vehicles in the developing world, and as a result of the ongoing phase-out of HCFCs. By one estimate1, HFC emissions could contribute the equivalent of between 5.5 billion and 8.8 billion tonnes of carbon dioxide annually by 2050. By comparison, greenhouse gas emissions by the United States in 2007 totalled 6.1 billion tonnes.

Some observers says the debate has stalled in part owing to controversy over payments for HFC-23, a by-product from manufacture of the refrigerant and chemical feedstock HCFC-22. HFC-23 is 11,700 times more potent than CO2 as a greenhouse gas, and as such it fetches a high price on the carbon market. The London-based Environmental Investigation Agency (EIA) estimates that Europe will have spent roughly 6 billion euros on payments for HFC-23 destruction by 2012 — 75 times more than the 80 million euros companies receiving such payments in places like India and China actually spent destroying the chemical.

"You have the countries that are benefiting financially from this there at the table, and those are the countries that are opposing meaningful action," says Fionnuala Walravens, who works on the issue of HFCs for the EIA.


In response to such concerns, the European Commission is currently considering a proposal to scale back or eliminate HFC-23 payments; commission officials say that their decision is expected before the UN climate meeting in Cancun, Mexico, which begins in late November. Meanwhile, the executive board of the Clean Development Mechanism (CDM) — the emissions-trading scheme to meet the greenhouse-gas reduction targets set by the Kyoto Protocol — in August put a hold on issuing carbon credits to HFC-23 reductions, pending an internal review.

Companies make more money destroying HFC-23 than they do selling HCFC-22, and that has led to concerns that firms are boosting HCFC-22 production just to collect HFC-23 credits. A recent study in the journal Atmospheric Chemistry and Physics2 compared atmospheric HFC-23 trends with published statistics for HCFC-22 production and the production and destruction of HFC-23. The researchers, led by Ben Miller of the University of Colorado, Boulder, found no evidence that companies are intentionally tweaking their numbers or falsifying reductions, but the basic criticism that the destruction of HFC-23 is sucking up resources that could be used to reduce emissions elsewhere still stands.

Clever coolant

Andersen says an additional boost to the proposal to include HFCs in the Montreal Protocol has come from the global automobile industry, which makes up about 30% of the HFC market and is converging on a new refrigerant for use in future vehicles. Produced by DuPont in Wilmington, Delaware, and Honeywell of Morristown, New Jersey, in response to a 2006 European Union law requiring car makers to reduce the greenhouse-gas potential of their refrigerants, the chemical (dubbed HFO-1234yf) is 360 times less potent as a greenhouse gas than the current refrigerant, HFC-134a, and just four times more powerful than CO2.

“This is the simplest thing we can do on global warming right now.”

Durwood Zaelke
Institute for Governance and Sustainable Development

Ultimately, the Montreal Protocol must tackle all HFCs in a comprehensive fashion in order to speed up the transition towards more climate-friendly chemicals, says Durwood Zaelke, who heads the Institute for Governance and Sustainable Development, an advocacy group in Washington DC. What's missing for quick action, he says, is high-level leadership.

"This is the simplest thing we can do on global warming right now," Zaelke says, adding that it would buy the globe another decade to work on carbon dioxide. "It's an insurance policy." 

  • References

    1. Velders, G. J. M. et al. Proc. Natl Acad. Sci. USA 106, 10949-10954 (2009). | Article
    2. Miller, B. R. et al. Atmos. Chem. Phys. 10, 7875-7890 (2010). | Article
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