These chemicals create holes in the ozone layer and are powerful greenhouse gases. They’ve been banned since 2010, but pollution has kept growing. The latest research published in the journal Nature Geoscience suggests that chemicals, which were banned after they punched a hole in Earth’s ozone layer, are still building up at an alarming rate in the atmosphere. These chemicals were extensively used in air conditioning and refrigeration, but their use was supposed to be phased out globally by 2010. It is surprising that the concentration of several types of these chemicals has increased since then, and they reached a record high in 2020. The new research suggests that alternative refrigerants meant to replace the ozone-depleting substances could be responsible for this surge. However, researchers are unable to find where all these chemicals are leaking from. The recovery of the ozone layer has been remarkable in the past few decades, but if the emissions continue to rise, it could counteract the progress and worsen climate change. “It’s just the sheer size of it.” The Montreal Protocol was a landmark international agreement signed in 1987 to protect the Earth's ozone layer by phasing out the production and use of ozone-depleting substances, such as CFCs. The agreement was widely seen as a success, and the ozone hole over Antarctica has been slowly shrinking as a result. However, this new research highlights that the battle to protect the ozone layer is far from over. The fact that these banned chemicals are still present in the atmosphere at such high levels suggests that there is a major issue with enforcement and regulation. It's clear that urgent action is needed to identify the sources of these emissions and to prevent any further damage to our fragile atmosphere. The unexpected increase in CFC emissions is concerning because the chemicals have a long atmospheric lifetime, which means they can persist for decades and continue to damage the ozone layer. The new research suggests that the emissions are likely coming from somewhere in East Asia, but pinpointing the exact sources is difficult. It's possible that the increase is due to illegal production or use of the chemicals. In any case, the findings underscore the need for increased monitoring and enforcement of the Montreal Protocol to ensure the continued protection of the ozone layer.