A study from Columbia Engineering and the University of Exeter reveals that the Montreal Protocol, a global treaty established in 1989 to reduce ozone-depleting substances (ODSs), is delaying the onset of an ice-free Arctic summer by up to 15 years. ODSs are less prevalent than carbon dioxide but are significantly more potent in their warming effects. The treaty was initially focused on protecting the ozone layer, crucial for shielding Earth from harmful ultraviolet radiation, and has since demonstrated substantial climate benefits. Researchers found that, without the Montreal Protocol, global temperatures could be 0.5 °C higher and the Arctic polar cap nearly 1 °C warmer by 2050. The decline in ODS concentrations since the mid-1990s has contributed to reducing Arctic ice melt, which is a clear signal of climate change. Although the ozone layer is showing signs of recovery, recent increases in ODS levels call for continued monitoring. As Lorenzo Polvani, a co-author, emphasizes, the Montreal Protocol’s benefits are observable in the present, and vigilance is crucial to maintain these gains against powerful greenhouse gases that affect global warming, particularly in the Arctic. The research underscores the importance of international cooperation in climate treaties.
