On April 9, 2025, Lewis & Clark Law School hosted the 2025-2026 Distinguished International Law Visitor, Durwood Zaelke, president of the Institute of Governance & Sustainable Development and professor, author, and advocate. Melding law, policy, and science, Zaelke has served as a guardian of the planet for more than five decades, most recently by facilitating the adoption of phase outs of climate pollutants under the Montreal Protocol of Substances that Deplete the Ozone Layer.
The Montreal Protocol is a global agreement aimed at restoring the stratospheric ozone layer by phasing out ozone depleting substances, such as CFCs and HCFCs. The Montreal Protocol, ratified by 198 countries across the world, has successfully put the planet on course to restore the ozone layer and avoid serious human health impacts, including cancer. However, many of the substitutes for ozone depleting substances are also powerful greenhouse gases. In 2007, Zaelke tirelessly and successfully advocated for a faster phaseout of HCFCs, chemicals that are both ozone depleters as well as potent greenhouse gases. He then spearheaded efforts to adopt what became the Kigali Agreement to the Montreal Protocol to phase out hydrofluorocarbons (HFCs), substitutes for HCFCs that have no ozone depleting potential but which are powerful greenhouse gases. HFCs, mainly used in air conditioning and refrigeration, trap significantly more heat than carbon dioxide molecule for molecule, our most abundant greenhouse gas. The Kigali Amendment is expected to prevent up to 0.5°C of global warming by the end of the century, and double that if we can improve the energy efficiency of air conditioners.
The Kigali Agreement was not a lone effort. Zaelke first tested the concept with Pacific island countries and worked closely with John Kerry, the former secretary of state in the Obama administration. In his lecture, Zaelke emphasized the importance of working with climate scientists and statisticians to create palatable and persuasive statistics to convince world leaders to phase out HFCs. The calculation of the 0.5°C benefit of the Kigali Amendment became a key political talking point that even heads of State could remember and repeat.
Despite these successes, Zaelke is not done. He warned that we are nearing climate tipping points beyond which climate change will accelerate and impacts may be irreversible. To avoid reaching catastrophic tipping points, Zaelke is currently emphasizing the need for speed. By reducing short-lived climate super pollutants, such as methane, we can buy the time we need to reduce emissions of carbon dioxide.
“In his informative talk, I realized how much one person’s passion can prevent climate change from reaching tipping points,” remarked Zoe Morton ’27, an environmental law student at Lewis and Clark. Jocelyn Harlan ’27, a first-year law student, observed, “Knowing the ins and outs of how an environmental treaty is implemented was an amazing experience, and it made me feel like I was in the room when these earth-saving programs were made.”
Professor Chris Wold, chair of the law school’s International Law Committee, was pleased to see students respond positively to Zaelke’s talk. “Climate change is, indeed, our greatest environmental challenge. Durwood’s creativity, inspiration, and persistence is a reminder to all of us — particularly our students who are our future environmental leaders — to not be complacent, to remain hopeful, and to work diligently to protect the planet.
