On World Ozone Day, there is HOPE: A new platform for observing the stratosphere
September 16, 2024: World Ozone Day
Far above us, in the stratosphere, the world’s ozone layer protects people and natural systems from the sun’s harmful ultraviolet rays. Much of the life on Earth has adapted to live under this protection. In the twentieth century, as society developed new technologies, especially refrigeration and cooling, we released chemicals that traveled to the stratosphere and depleted some of this stratospheric ozone, creating expanding “holes” through which protection did not occur. With the use of these chemicals growing rapidly, projected damage to the ozone layer posed an existential threat to humanity.
Scientists began sounding the alarm in the 1970s. They joined with governments and industry to develop replacement chemicals and establish a legal framework for protecting the ozone layer. All countries in the world have since joined the international treaties that protect the ozone layer: the Vienna Convention and the Montreal Protocol. Today on World Ozone Day we celebrate the ozone layer and the world’s efforts to protect it.
The Montreal Protocol: Successful, science-based environmental governance
In the most successful environmental protection effort in human history, the ozone layer recovered. A large part of this success was due to adherence to robust, independent science and democratic mechanisms that provide equitable influence for countries around the world. This includes the Multilateral Fund, which funds technical experts in developing countries and their efforts to phase out artificial substances that deplete the ozone layer. Today, World Ozone Day, is a celebration of the world’s ozone layer and of our success in protecting it.
Some ozone-depleting chemicals are also super-polluting greenhouse gases. In reducing them, the Montreal Protocol has become the most successful climate treaty in history. Its mandate was recently extended by the Kigali Amendment, ratified by 160 countries as of mid-2024, to regulate other GHG super-pollutants that do not deplete ozone — hydrofluorocarbons.
New threats to the ozone layer
Today, the ozone layer faces new threats from human-caused pollution. Climate change has induced wildfires so powerful that they create atmospheric dynamics that push soot into the stratosphere. Rocket traffic is leaving aerosol pollution in its wake. Satellites at the end of life disintegrate and leave metallic particulates in the upper atmosphere. This space pollution is minor today, but a growing threat for the future. And as climate changes escalate, scientists, advocates, governments and the UN are raising the possibility of the introduction of particles into the stratosphere to cool the climate. One of the significant side effects of this could be depletion of the ozone layer.
Critical gaps in observations of the stratosphere
Since the 1990s, when the world seemed to be victorious over the ozone hole problem, monitoring of the stratosphere has gradually declined, leaving gaps in scientists’ ability to monitor the ozone layer’s recovery and identify new threats. The satellite with the most specialized capabilities for measuring particles in this thin layer of the atmosphere, AURA, is projected to end its orbit soon. There are only four research aircraft in the world that fly in the stratosphere for sampling sparse substances, all owned by NASA. NOAA’s important but modestly funded SABRE program discovered the new pollution in the stratosphere, but its funding allows only one flight to one part of the stratosphere every two years.
Balloons offer advantages as relatively inexpensive platforms for monitoring the stratosphere. Balloons that can observe the stratosphere include those that can carry heavy payloads, fly long periods at altitude and return to their launch site, generally costing hundreds of thousands of dollars, limiting their use. Inexpensive commercial balloons pop when they reach high altitudes and can thus carry only cheaper, disposable instruments. Together, this means that while threats to the ozone layer are growing, observing capabilities for measuring them are scarce and not accessible to researchers in most of the world.
HOPE: Expanding and democratizing stratospheric observations
In August, in an effort led by lighter-than-air platform specialists Sarah Schubert and Dan Bowen, SilverLining launched a navigable, high-altitude, long-duration balloon with instruments for stratospheric observations: High-altitude Observing Platform Explorer (HOPE). Developed using standard materials, HOPE is also affordable. It is designed to help expand measurements of the stratosphere and the number and geographies of people who can make them.
The first HOPE flight was a technical success, reaching 58 thousand feet and flying at altitude for 10 hours. It carried a particle measurement instrument that detected aerosols from wildfires in California, as well as weather instruments. With a successful test of the platform, the team is now working with science agencies on calibrating instruments so that data from future flights can be provided openly for research. Those flights will add advanced instruments including, we hope, a next-generation ozone instrument that can take readings over extended periods of time.
HOPE is one of a number of science and innovation programs within SilverLining’s Safe Climate Research Initiative. It is a step forward in advancing a roadmap of research and innovation to provide information and capabilities, and equitable and responsible governance of them, to ensure a safe climate within a decade.We celebrate the scientists, policymakers and advocates who have protected the ozone layer until today. Our HOPE is to provide a new tool for researchers around the world to help them.
