Humankind faces the imminent loss of vigilance over the ozone layer, as NASA’s Aura and the Canadian Space Agency’s SCISAT satellites are set to be decommissioned. This threatens the ability of scientists to closely monitor the compounds that destroy ozone and impact stratospheric circulation. The lack of planned replacement missions for these satellites will result in a discontinuity in data collection in the stratosphere, as warned by researchers in the March Bulletin of the American Meteorological Society.
Atmospheric scientist David Fahey of the National Oceanic and Atmospheric Administration, based in Boulder, Colo., explains that the satellites will cease operations soon, leaving a gap in the ability to closely observe the stratosphere. The recovery of the ozone layer has stalled, particularly over the midlatitude Northern Hemisphere. Moreover, increasing space debris from decommissioned satellites could contribute to more ozone-depleting substances in the atmosphere. Losing the satellites means scientists will no longer be able to monitor harmful impacts to the ozone layer from events like wildfires or stratospheric aerosol injections aimed at combating climate change.
While other instruments will continue to monitor the ozone layer itself, the satellites offer a comprehensive scanning ability to detect substances that can harm the ozone layer. Losing the satellites means losing the insights into why certain changes are occurring in the ozone layer. This loss will impair the understanding of how substances such as halogenated gases and nitrogen oxides, which primarily originate from human activities, are impacting the ozone layer.
The SCISAT and Aura satellites have significantly advanced scientists’ knowledge of the stratosphere and ozone layer since their launch in 2003 and 2004, respectively. However, with the projected end of operations for Aura’s solar panels by mid-2026 and SCISAT reaching the end of its intended lifespan, the scientific community faces the challenge of losing access to critical ozone-destroying gas measurements. These gases include hydrogen chloride, chlorine monoxide, and others regulated by the Montreal Protocol to phase out ozone-depleting substances.
Data from SCISAT and Aura have revealed unexpected impacts such as the 2019-2020 Australian wildfires damaging the ozone layer. With wildfires predicted to increase in intensity and frequency due to climate change, understanding their impact on stratospheric ozone becomes crucial. Additionally, large-scale stratospheric aerosol injections for climate mitigation could present risks resembling volcanic winters, potentially harming the ozone layer. Thus, the inability to monitor these effects is a significant concern for experts in the field.
Potential successor missions being considered include the Changing-Atmosphere Infra-Red Tomography Explorer (CAIRT) by the European Space Agency and the Stratosphere Troposphere Response using Infrared Vertically-resolved light Explorer (STRIVE) by NASA. These missions aim to provide enhanced capabilities for monitoring ozone, water vapor, aerosols, and ozone-damaging compounds globally. The decisions on these missions are expected later this year, with plans for a potential launch in the early 2030s. The implementation of these missions could offer hope for continued diagnostics of the atmosphere and ozone layer to ensure the health of our planet.
