How the Montreal Protocol Helped Save Earth from a Climate Time Bomb

How the Montreal Protocol Helped Save Earth from a Climate Time Bomb

The Montreal Protocol did more than preserve the ozone layer. It also helped to save Earth from a climate war time bomb.

The landmark ozone treaty was agreed 35 years ago this month, at a time when both climate and ozone science was far less developed than it is today. Every nation signed on to the treaty, committing to reduce the consumption, production, and emissions of chemicals that thin the ozone layer, which protects the planet from the sun’s most harmful radiation. These chemicals were also powerful greenhouse gases and cutting them gave the world time to address the climate crisis.

“If we let the [chlorofluorocarbons (CFCs)] keep growing, we would have had the impacts of climate change that we’re feeling now … a decade ago,” said David Doniger, a lawyer with the Natural Resources Defense Council who has worked on the issue since the 1980s. “And things would be that much worse now.”

The protocol’s status as a climate treaty was enhanced by the 2016 Kigali Amendment–named for the Rwandan capital where the deal was drafted–which targeted a class of coolants that weren’t ozone-depleting but were climate-forcing. Scientists say the global hydrofluorocarbon (HFCs) phasedown, which the U.S. is now poised to join after a key Senate vote Wednesday, has the potential to avoid half a degree Celsius of warming by 2100.

Scientists and lawyers who have been involved in the debate for decades claim that the ozone agreement had prevented a particular harmful set of climate superpollutants being baked into refrigerators and air conditioners that developing countries finally possessed long before international negotiators reached the HFCs deal.

David Fahey, director of NOAA’s Chemical Sciences Laboratory and co-chair of the Montreal Protocol’s scientific assessment panel, was among the scientists who in 1987 flew a NASA research aircraft into the ozone hole that had appeared over Antarctica. He said that there were many theories at the time as to why the hole was visible.

But he stated that the NASA journey “created a smoking guns plot, as we refer to it, that was really pivotal evidence that chlorine had been destroying ozone on a scale that would cause the Antarctic Ozone hole .”

The world responded quickly.

” While we were in Chile flying into Antarctica in the month of March, Montreal was signing the Montreal Protocol,” he stated. “And it was basically signed, without knowing for certain what was causing Antarctic ozone hole .”

The new agreement was not only a leap in faith from science, but also had attributes that have never before been replicated in any climate treaty, despite much higher levels of scientific certainty.

The treaty is universal with 197 member countries. It is legally binding and punishes countries that violate its provisions. It is fully funded, which means that countries with less resources that were not able to reach its targets to phase out chemicals have access to financial assistance from those with more resources.

“There’s no other forum that has those three dimensions,” Fahey said, noting the 2015 Paris Agreement on climate change relies on voluntary commitments with no penalties for breaking them.

” “Probably the underlying problem in the climate change situation, is that we don’t possess such a forum,” said he.

DuPont scientist’s crucial role

Fahey stated that scientists had a general understanding from the beginning that CFCs were responsible for climate change and the destruction of the ozone layer. But that role was clarified by a scientific study that he and four other scientists published in 2007, which looked at the “worlds avoided” by stemming the growth of the chemicals.

The report found that CFC use would have exploded if the Montreal Protocol was not in place. Under a conservative scenario by 2010, the chemicals would have had a greenhouse gas content nearly equal to half the carbon dioxide emissions from all other sources. The climate impact would have been devastating.

” I think the estimates are something like an extra 2 degrees by mid-century,” stated Susan Solomon, a professor of environment studies at the Massachusetts Institute of Technology.

She noted that had the world continued on its trajectory of increasing CFC use through 2050, the consequences for the ozone layer would have threatened the health and survival of every living thing on the planet, including humans. She suggested that this might have compelled her to take action.

” The great news is that all of this was avoided and that we not only saved the atmosphere layer but also had a huge win for the climate,” she stated.

While CFCs packed the biggest punch on climate change, the hydrochlorofluorocarbons (HCFCs) that temporarily replaced them still had significant consequences for the climate. After the 2007 paper was published, parties to the Montreal Protocol quickly moved to shorten the treaty’s timeline for phasing down HCFCs, an adjustment that Fahey said was the first decision made under the Montreal Protocol to reduce global warming.

HCFCs have been replaced by HFCs. HFCs, which have no impact on the ozone, were to be the Montreal Protocol’s last destination. They are climate superpollutants, which can be thousands times more potent than carbon dioxide.

Industry initially resisted the idea of HFC use having a significant impact upon climate change. Fahey attributes the change to Mack McFarland, a DuPont industry scientist.

” Mack understood the growth in the developing countries,” he stated. “That the developing world was catching up to the developed world .”

Fahey stated that

McFarland began talking to delegates at Montreal Protocol meetings about how HFCs could be used to drive climate change.

” This became one of his main messages not only to the delegates but also to the scientists, and the technologists,” he stated. It wasn’t immediately received or well-received. Even scientists, including myself, didn’t get it, .”

But in 2009, McFarland, Fahey and the other scientists who had collaborated on the 2007 paper on the climate implications of the protocol published a paper on the effects of running the world’s air condition and refrigeration units on HFCs. Its conclusions sparked negotiations that led to the creation of the Kigali Amendment eight years later.

Solomon said she was shocked when the Senate voted this week by a 69-27 margin to join the Kigali treaty. The accord took effect Jan. 1, 2019, after reaching a ratification threshold. The U.S. is the 138th country to sign on.

But Solomon said that in the 1970s and ’80s, the U.S. led the charge on global ozone protection.

” “I believe the primary credit should go to the American people,” she stated.

Help to poor countries

When ozone science was in its infancy, not long after scientists Sherwood Rowland and Mario Molina demonstrated in 1974 that CFC damaged the ozone, but before the extent of the damage was known, U.S. consumers stopped buying aerosol deodorant and hair spray.

The results were transformative. U.S. personal care products made up 75 percent of global CFC use in 1974. The Montreal Protocol was created to address the crisis of demand.

And countries that are now demonstrating leadership on climate change, and other issues, clung to aerosol products.

” The Europeans were actually on the opposite side of the negotiating tables,” Solomon stated. “It was us who said, ‘We should get rid these compounds, we can find substitutes, let’s move on. Let’s save the world. Europe said, “We don’t see the need for these compounds in the same way that you do .'”


Solomon also gave credit to former President Barack Obama, and former Secretary John Kerry for creating the geopolitical momentum which carried Kigali over the finish line.

The protocol’s reductions in CFCs, HCFCs, and now HFCs are not the only thing that will have a direct impact on the climate.

Solomon noted that the protocol’s multilateral funds helped poor countries get refrigeration, reducing food waste and spoilage emissions.

NRDC’s Doniger referenced a study published in Nature last year that found that without the ozone preservation benefits of the Montreal Protocol, much less CO2 would have been absorbed over the past 35 years as the world’s biosphere disintegrated.

“The damage done to trees and other vegetation would have meant that they would have soaked up a lot less CO2 from the atmosphere,” he said.

The Nature study argues that the protocol helped avoid 2.5 degrees Celsius of warming. For context, scientists warn that the world and especially vulnerable countries will suffer catastrophic consequences if global warming exceeds 1.5 C .


Reprinted from E&E News with permission from

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