The World Just Took Another Huge Step Forward On Fighting Climate Change

Last week, we learned that the Paris climate agreement will go into effect in November after the European Union formally joined the accord, tipping it past the threshold needed to become a reality.

Now this week brings another major foray in international climate diplomacy, as close to 200 countries adopted an amendment to the 1987 Montreal Protocol to phase down the use of hydrofluorocarbons, or HFCs, which are super-polluting, powerful greenhouse gases.

President Obama also hailed the accord in a statement Saturday morning. “Today’s agreement caps off a critical ten days in our global efforts to combat climate change,” he said. “In addition to today’s amendment, countries last week crossed the threshold for the Paris Agreement to enter into force and reached a deal to constrain international aviation emissions. Together, these steps show that, while diplomacy is never easy, we can work together to leave our children a planet that is safer, more prosperous, more secure, and more free than the one that was left for us.”

HFCs don’t get much attention. But here’s why they matter: When the original Montreal Protocol phased out chlorofluorocarbons, which were destroying the planet’s ozone layer, manufacturers had to find a replacement chemical to use as refrigerants and in other industrial applications. Along came HFCs, which were much better for the ozone layer but, like CFCs, also happen to be a strong global warming agent. The chemicals are vastly more powerful than carbon dioxide over a 100 year time frame when it comes to warming the atmosphere. So one huge environmental crisis was, in effect, replaced by another problem lingering on the horizon.

Scientists fear that a forecast explosion in air conditioning all around the world, especially in developing economies like India, could result in so much HFC leakage that it could warm the global temperature by an additional half a degree Celsius by the end of the century, which would blow past warming thresholds outlined in the Paris agreement. Unless, that is, HFCs are curbed.

Under the “Kigali Amendment” approved early Saturday, the planned reduction of HFCs would have an impact similar to the removal of 80 billion tons of carbon dioxide from the atmosphere over the next 35 years, according to the Natural Resources Defense Council.

The way the new amendment works is this: Developed and developing countries will have different “freeze dates,” or years when they must peak their HFC emissions and then begin to bring them down steadily over time. And in many cases, those freeze dates will be quite soon. For developed nations like the United States, the date will be 2019. For the majority of developing nations, it will be 2024, except for a few nations, including India and Pakistan, which will take a little longer, until 2028.