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It’s been several decades since scientists made a consequential discovery: humans were thinning the ozone layer. Without action, rates of cancer, cataracts, and immune deficiency diseases would have increased.
Luckily, the world did act, passing the landmark Montreal Protocol in 1987, which began phasing out ozone-depleting substances such as chlorofluorocarbons (CFCs). It is one of the most successful international treaties, passing with universal ratification.
The Protocol had an unintended harmful effect, however, which is that while HFCs, which were produced to replace CFC, helped fix the ozone problem, they created a new one by contributing greatly to climate change. In 2015, at the Climate and Clean Air Coalition’s (CCAC) 7th High-Level Assembly, Ministers affirmed their support for an amendment to the Protocol and called for an ambitious phasedown of high GWP HFCs, which had proliferated as an alternative to CFCs. In 2016, Coalition Ministers called for a special session during a critical point in negotiations to clear the way for an amendment in Kigali and an ambitious HFC phasedown in the Vienna Communique. This paved the way for the Kigali Amendment to be agreed upon by nearly 200 countries that same year.
The CCAC has been working to reduce HFCs for years, including through HFC alternative technology demonstration projects, HFC inventories, and helping facilitate end-of-life disposal of fluorocarbon refrigerants and is working with scientists like Ravishankara to continue to increase the ambition and force of international treaties that protect the climate and clean air.
CCAC Scientist A. R. Ravishankara, with Susan Solomon and Joseph Alcamo, recently published a paper in Nature Communications titled “Unfinished business after five decades of ozone-layer science and policy,” outlining the remarkable achievements of the Montreal Protocol— beginning to heal the life-threatening thinning of the ozone layer— while also discussing serious ongoing concerns several decades later. We spoke with him about why we still need to be concerned about ozone-depleting substances and what can be done to “plug the holes in the ozone treaty.”
You wrote this paper to point out some of the gaps in the Montreal Protocol— in what ways is it not working as well as we’d hoped?
ARR: The first important thing is that the Montreal Protocol controlled the production and consumption of chemicals that can deplete the ozone, which is not the only thing that determines what gets emitted into the atmosphere. These chemicals can still be held in equipment like refrigerators or in other places like foam products, which we call banks; they can slowly leak out.
Second, the Montreal Protocol contained some exemptions for some important technical or economic reasons. An example is the chemicals used in medical inhalers, which are essential for a lot of people, or the chemicals used to prevent bugs from traveling in food when it's shipped across continents. For some of the exempted chemicals, we still have huge amounts sitting around that can be held for a long time— such as the brominated chemicals considered essential because they’re firefighting agents. The question is, could they be accidentally or intentionally released?
An example of the Montreal Protocol’s adaptation is the Kigali Amendment. The Protocol stopped the production of ozone depleting gases but in its place the industry started to use HFCs— which it turned out can also be very potent greenhouse gases.
So the question was, since the Montreal Protocol was responsible for the production and usage of HFCs, what is its responsibility towards them? If in the process of making a successful protocol, it broke something— is it responsible for fixing it? Once you have a treaty and you adopted the treaty, is that the end of the work?
The Kigali Amendment addressed those substances but there is a substance called HFC-23 which has the highest global warming potential among HFCs. It was not addressed satisfactorily because it’s not intentionally produced as a substitute for CFCs, it’s an unintentional byproduct of production of some other gases.
One thing that is imperative is the accountability phase of a protocol or a treaty. Are we having the intended effects of the treaty? It takes time to see those intended effects and during that time, how do we manage the issue? How do we deal with unexpected things that come up?
What is an example of an unexpected finding that has come up? What are some ways the treaty is not working as well as expected?
ARR: In recent years, we noticed that CFC-11 was not decreasing as quickly as it should have been, which alerted us to possible illicit production. In fact, CFC-11 emissions increased by about 30 percent from the early-to-mid-2010s, which is not explainable unless there is new production in violation of the Protocol. The quick detection of the increase, however, is an important scientific success because the added CFC-11 is not yet sufficiently significant to delay healing the ozone layer.
Recent studies published in Nature show that the increase we were worried about is actually now decreasing because people took action. The Protocol must be nimble and to be able to react as we get new information. These papers showed that’s exactly what happened— the Montreal Protocol successfully responded to unwarranted production and release of CFCs and was able to shut it down. The cautious part of me says that this can happen again, so we’ve got to be vigilant.
Part of the reason this vigilance is necessary is that, unlike air pollutants where you can see the result of mitigation almost immediately, it takes a long time to cleanse the atmosphere of these kinds of chemicals.
Let me highlight this delay point: I will never see the day when the ozone hole goes away, but I hope my grandchildren will.
This delay in cleansing has a major lesson for CO2 mitigation because it is so long-lived: even if we stop emitting today, it’s going to be with us for a long, long time.
What concrete steps can we take now to plug these holes in the Protocol? What role can the CCAC play in helping strengthen it?
ARR: The most relevant thing the CCAC can do is figure out if there are steps we can take to make the HFC production smaller and phase them out quicker. Can we start using chemicals to bypass HFCs completely?
For the CCAC, the biggest issue with HFCs is not so much curing an existing disease, but it’s preventing a future pandemic: You want to avoid HFCs. If you’re trying to keep the world’s surface temperature below two degrees or 1.5 degrees Celsius, we really need to be taking all possible steps, and reducing HFCs is one of these steps.
It’s not just the use of HFCs that’s an issue, it’s also about what you use them for. We’re often using them as refrigerants for air conditioners and refrigerators that consume electricity. While reducing the use of HFCs as refrigerants, can we also minimize the amount of CO2 emitted by electricity production by improving the energy efficiency of these devices?
At the same time, can Kigali phase downs be enhanced? Can they be quicker?
This is partially what the Biarritz Pledge for Fast Action on Efficient Cooling aims to do— transform the global cooling sector and lower emissions by both phasing down HFCs and improving the energy efficiency of air conditioners and cooling equipment. Could you tell me about how Biarritz might help accomplish the goals you’re outlining?
The Biarritz pledge is a good step in the right direction. Quickly reducing the high Global Warming Potential (GWP) HFCs is important because they linger in the atmosphere. Whether the pledge can be implemented is where the CCAC can help by showing concrete ways to reduce HFC emissions and improve energy efficiency in practical ways.
You wrote about a possible “Kigali Plus” Amendment. What did you mean by this, and what could it look like?
Can we enhance the Kigali Amendment and make it faster? I think technology is going in a way that makes such steps feasible. For example, in a country like India where there is a growing demand for air conditioning and refrigeration, can we harness wind and solar power to run air conditioners or use natural refrigerants or other types of refrigerants in place of HFCs? Could the cold chain be improved to reduce cost and minimize HFC emissions? The CCAC has a significant role to play in showing how such transitions can be accomplished.
New refrigerators today have reduced the amount of refrigerant needed by a factor of three or four. Today, we use a totally different technology to insulate refrigerators instead of the CFCs we used to use. That’s the beauty of the Montreal Protocol, the success was so transparent to people and the success was made possible without undue hardship. I think that’s something to think about for policy.
What about HFC-23 emissions? They’ve also increased more than expected in the last few years. Why has that happened and what can we do to stop it?
This is an interesting issue. HFC-23 is a byproduct in the production of HCFC-22 and possibly other chemicals. The Clean Development Mechanism of the UNFCCC had paid for the capture and destruction of HFC-23. That financial mechanism has been slowly phased out. Is this phase out the reason for the HFC-23 increase? Would HFC-23 decrease when HCFC-22 is completely phased out? Are there other sources of this chemical we have not considered? These are some outstanding questions for me.
What about lifecycle management— what steps need to be taken to better care for existing HFCs and equipment that might emit them?
Lifecycle management is vital for ozone-depleting gases and HFCs. Part of this issue is the “banks” we talked about earlier. What do we do with the previously used chemicals that still exist in devices and materials? How do we ensure that servicing equipment does not leak out chemicals that should be captured (and reused or destroyed)? Such issues are very practical ways to minimize the impact and be responsible citizens.
Passing the Montreal Protocol required remarkable international collaboration on the part of researchers, governments, and nonprofits. What lessons can we learn for climate and air pollution work today from the successful passage of the Protocol?
ARR: The first lesson we learned was the importance of making science-based decisions and ensuring that there are technically and economically feasible alternatives to the compounds that are being phased out.
The second is the importance of sharing the costs and responsibilities for action. The Montreal Protocol implemented something called a multilateral fund which enabled developing countries to implement these policies, which can be initially costly to developing countries without too many problems.
The third is the importance of starting with baby steps. The original Montreal Protocol would not have saved the ozone layer. It only delayed some of the major consequences. But the subsequent amendments and adjustments that were possible after building trust amongst the parties helped create a protocol that could save the ozone layer.
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