Dozens of nations signed an agreement nearly 30 years ago to stop the expansion of a massive hole in Earth’s ozone layer. Today, thanks to the Montreal Protocol, the hole in the ozone layer has shrunk as countries reduced, then eliminated, the use of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). A new study from Geophysical Research Letters shows that the agreement not only achieved its stated aim, but has also been one of the most effective tools for fighting climate change in the United States.

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The recent study confirms what scientists and policymakers have been observing as the Montreal Protocol was enacted, though it focuses primarily on the United States. “This is something that’s been talked about for a while, this dual benefit of the Montreal Protocol limiting damage to the ozone layer, also curtailing climate change,” said Rachel Cleetus, climate policy manager and lead economist with the Climate and Energy program at the Union of Concerned Scientists. “It’s because all these ozone depleting substances are also very potent global warming gases.” The regulations enacted to fulfill the Montreal Protocol resulted in greenhouse gas reductions equivalent to approximately half of all other climate regulations between 2008 and 2014.

Related: Antarctic ozone layer shows “first fingerprints of healing”

ozone, ozone hole, NASA

The near-total removal of CFCs and steep decline in HCFCs in the United States was made possible by the Clean Air Act, a law that was used by the Obama Administration, as approved by the Supreme Court in Massachusetts v. EPA, to reduce greenhouse gas emissions. Though CFCs and HCFCs have been replaced by hydroflourocarabons (HFCs), which still contribute to climate change but do not burn a hole in the ozone layer, the signatories to the Montreal Protocol have amended the agreement to reduce HFCs as well in a move that was praised by US Secretary of State John Kerry as the “single most important step” in combating climate change. As the Trump Administration refuses to fulfill its duties under the Clean Air Act to protect public health, the success of the Montreal Protocol is a hopeful reminder of what can be done if dedicated parties work together and take action.

Via Gizmodo

Lead image via Depositphotos, others via NASA/Goddard Space Flight Center and Rémi Vincent/Flickr