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The Ozone Layer’s Recovery Shows How to Protect the Planet

Three decades ago, the global community came together to protect Earth’s ozone layer from damaging chemicals. This effort, one of humanity’s greatest environmental achievements, offers a promising model for phasing out fossil fuels and remaining within planetary boundaries.

NEW YORK – There was a time, not so long ago, when the depletion of Earth’s ozone layer seemed like an insurmountable challenge. Decades of using harmful chemicals, such as chlorofluorocarbons (CFCs), had threatened to cause irreparable damage to our planet. Without swift action, we faced the risk of climate destabilization, ecosystem collapse, and the breakdown of our food system. Consequences that were once almost unthinkable became painfully real.

But then, the most remarkable thing happened: humanity united to protect the ozone layer. Heeding the warnings of Nobel laureate scientists Paul Crutzen, Mario Molina, and Sherwood Rowland, whose research underscored the severity of the threat, we did not ignore or dismiss the scientific evidence, nor did we bury our heads in the sand and claim that the challenge was too daunting. Instead, the global community recognized the urgent need for collective action.

By harnessing scientific knowledge, entire industries have been transformed, and equitable policies have been put in place to shield countries that did not contribute to the problem. Thanks to the Montreal Protocol, ratified by 197 countries, nearly 99% of ozone-depleting substances have been phased out. This includes the reduction and replacement of CFCs, which has slowed climate change by at least a decade.

The successful global effort to protect the ozone layer should serve as a beacon of hope for all of us. It is one of humanity’s greatest environmental achievements, showing what we can achieve when we act together with commitment, respect, and determination.

But it can also serve as a warning. A 2023 study by Johan Rockström and 28 other leading climate scientists revealed a startling new reality, underscoring the need to adopt a collaborative approach to protecting the planet before it is too late.

The planetary boundaries model, introduced by Rockström and others in 2009, provides a useful framework for assessing the planet’s health. It identifies nine interconnected factors – including climate, freshwater availability, biodiversity, and land use – that are crucial for the planet’s stability and habitability. In their recent study, Rockström and his co-authors found that six of these nine boundaries have already been breached, putting Earth on a dangerous course that undermines the planet’s resilience and jeopardizes human well-being. Notably, the ozone layer is the only area showing signs of improvement.

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Given that Earth functions as an interconnected system, we cannot solve one problem without addressing the others. Despite being aware of the critical role of planetary boundaries in preserving our Earth’s habitability, we have not acted decisively enough to halt our slide toward catastrophe.

For example, we know that more than a million species are on the brink of extinction, potentially triggering the collapse of entire ecosystems. We also know that nitrogen and phosphorous runoff leads to the proliferation of toxic algae blooms in oceans and freshwater systems, thereby breaching the biogeochemical flow boundary. Similarly, tolerating dangerous levels of chemical pollution and allowing our children to ingest microplastics compromise the life-support systems necessary for humanity’s survival.

To restore Earth’s stability, governments must recognize the need to respect the nine planetary boundaries. This requires a steadfast commitment to reducing greenhouse-gas emissions and protecting biodiversity and water resources. Moreover, our chances of success increase exponentially when we cooperate: if the international community can unite as it did when it agreed to repair the ozone layer, there is hope.

But first, we must heed the advice of indigenous peoples and local communities and listen to what nature is telling us. Despite making up less than 5% of the global population, indigenous communities act as the planet’s wise custodians, protecting at least one-quarter of the world’s land and seas and 80% of its biodiversity.

To advance this approach, we have joined forces with Planetary Guardians, an independent collective of global leaders, scientists, and environmental advocates championing the planetary boundaries model. Our goal is to promote its adoption as a framework for assessing and guiding collective climate action.

By bringing together leaders from various countries, industries, age groups, genders, and cultures, Planetary Guardians aims to leverage our diverse backgrounds and experiences to find solutions to protect the planet. While our planet’s resources are finite, there is no limit to human ingenuity and our capacity for solving complex problems. The real question is what Earth we wish to leave to future generations.

To be sure, there are no simple answers or quick fixes. Our future hinges on the steps each of us is willing to take. But in saving the ozone layer, we have already shown that taking swift, informed, collective action can facilitate the changes needed to sustain human life on Earth.