Climate Action
The World Unites in the Face of Crisis
September 16, 2025
In these trying times for the environmental movement, it can sometimes feel impossible to find the (solar-powered) light. However, on September 16th for International Day of Preservation of the Ozone Layer (or World Ozone Day), we remember one of the world’s greatest environmental victories — the Montreal Protocol,
Adopted 38 years ago today, this landmark agreement regulates the production and use of man-made chemicals known as ozone depleting substances (ODS), such as chlorofluorocarbons (CFCs), after scientists found a correlation between their release into the atmosphere and ozone layer decay. The ozone layer is the Earth’s natural protective shield against intense ultraviolet radiation from the sun.
This global response stands as a testament to genuine international cooperation, one that was driven by science, guided by a willingness to set aside national interests for the greater good, and grounded in a shared commitment to a brighter future. In honor of this spirit of scientific discovery and global collaboration, here are three times we’ve joined together for much needed environmental action.
#1 The Montreal Protocol (1987)
In 1985, scientists released a report detailing a significant hole in the stratospheric ozone layer that allowed dangerous ultraviolet radiation (UVB) to reach the Earth’s surface. The depletion of the ozone layer would lead to serious consequences for both the environment and human health. UVB rays are considered to cause non-melanoma skin cancers and are associated with the development of malignant melanoma. UVB radiation also reduces agricultural yields and disrupts marine life. Repairing the hole required global action.
After two years of debate, negotiation, and compromise, the international community came together, proving that humanity can — despite political and cultural divisions — unite to solve pressing environmental problems. The result was the 1987 Montreal Protocol, a landmark international agreement where parties agreed to regulate nearly 100 ozone-depleting substances.
The ozone repair process was gradual but decisive, driven by a universal recognition of the ozone hole as an existential threat. Phase-out of ozone-depleting substances happened progressively, with different targets for developed and developing countries. As new scientific data on ODS emerged, nations came together to adjust targets, agreeing to accelerate the phase-out of hydrochlorofluorocarbons (HCFCs) which have a global warming potential 2000 times greater than carbon dioxide.
The protocol has been astonishingly successful. The 2022 UN Scientific Assessment Report on Ozone found that ozone levels are estimated to return to 1980 levels at around 2066 in the Antarctic, around 2045 in the Arctic, and around 2040 globally. Additionally, the report found that measures taken to reduce ozone-depleting substances have simultaneously helped prevent an extreme global warming scenario of an estimated 0.5 – 1 °C by mid-century which could have occurred if ODS emission rates increased uncontrollably beyond 1980 levels.
Today, the healing of the ozone layer serves as a beacon of hope. It demonstrates the potential for collective action to address even the most daunting environmental challenges as long as we maintain a unified front.
#2 Acid Rain (1990-1999)
Acid rain sounds like something out of a sci-fi movie, but it was a very real problem for the lakes, streams, forests, and wildlife across the northeastern United States and much of Europe from the 1950s through the 1980s.
When power plants, vehicles, and factories release sulfur dioxide and nitrogen oxides into the air, these pollutants react with water vapor to form acidic compounds which make acid rain. This acid rain lowers the pH of lakes, rivers, and soils, creating highly acidic conditions that are harmful to aquatic life: fish eggs often fail to hatch below pH 5 aquatic insects can die from acid exposure, and plants essential to food chains may decline .
In soils, acid rain leaches important nutrients, like calcium and magnesium, and releases toxic aluminum, harming trees and plants. Trees at higher altitudes may also be damaged by acidic clouds and fog which strip nutrients from leaves and needles, weakening them against disease, pests, and cold weather.
In the United States, acid rain gained national attention after a senior research associate in the Department of Natural Resources, Carl Schofield, reported the presence of acidic cold water lakes making them uninhabitable in the Adirondack region of northeastern New York State, in the U.S.
Scientists quickly realized that emissions from fossil-fuel-burning power plants in the midwestern United States and regional wind currents were responsible for the phenomenon. In response to growing concerns, the United States’ government passed amendments to the Clean Air Act in 1990, establishing the Acid Rain Program, which created an innovative emissions trading system (cap-and-trade).
This program set strict limits on sulfur dioxide and nitrogen oxide emissions from power plants and allowed them to buy and sell emissions allowances, incentivizing cost-effective reductions. This market-based approach was groundbreaking and led to significant reductions in acid-rain-causing pollutants in the following decades.
The act effectively eliminated the threat of acid rain in the United States, proving that science and policy can go hand-in-hand. In 2022, the EPA Long Term Monitoring program (LTM) examined wet sulfate deposition, a form of acid rain. It is a common indicator of acid rain, and compared deposition from 2021-2022 with data from 1989-1999. Scientists found an encouraging over 70% decrease in sulfate levels.
In 1999, this can-do attitude went international when the United Nations amended the Convention on Long-Range Transboundary Air-Pollution (LRTAP) to include the Gothenburg Protocol, making it the first international agreement to adopt a multi-pollutant approach and recognize the combined impact of various air pollutants. Today, more than 51 countries have joined the convention and are committed to keeping the air we breathe and the water we drink clean.
# 3 The Convention on Biological Diversity (1992)
Today, it’s easy to go online to visit national government websites or the Red List and see a (slightly terrifying) list of endangered species. But, those resources weren’t always available. It wasn’t until 1964 that the first list of rare and threatened species was published by the International Union for Conservation of Nature. The original list included 204 mammals and 312 birds. It created an international base-line for at risk species and helped spark global conservation efforts.
A cornerstone of those efforts is the Convention on Biological Diversity (CBD) Adopted at the 1992 Rio Earth Summit, the Convention on Biological Diversity, grew from the understanding that biological diversity is an asset for current and future generations. Since then,196 nations have ratified the convention, and parties continue to meet biennially to adjust targets and set new goals.
One of those goals is the expansion of protected areas worldwide. Target 11 from the 2010 Aichi Biodiversity Targets aimed to protect at least 17% of terrestrial and inland water areas and 10% of coastal and marine areas by 2020. While the marine goal was not fully met, the terrestrial target was, with the 2024 Protected Planet Report sharing that 17.6% of the world’s land is now under some form of protection.
Building on this progress, the Kunming-Montreal Global Biodiversity Framework (GBF), incorporated under the CBD in 2022, set an even more ambitious “30×30″ target to conserve 30% of the world’s land and oceans by 2030. Progress so far has been slow, but financially, the convention is on firm footing for future growth. In June, the Global Environment Facility (GEF) — the financial mechanism for the CBD and other international treaties — committed more than $261 million in funding for various environmental projects.
How You Can Use Your Voice to Protect the Planet?
There’s always more work to be done, but these successes show that progress is always possible. When we trust science, look ahead to future generations, and are unafraid to set ambitious targets, change happens. With a strong history of environmental action to stand on, let’s keep moving forward to tackle the climate crisis.
Sign our Renewable Energy Petition today to demand that global leaders commit to renewable energy investments, phase out fossil fuels, and stick to the goals established by the Paris Climate Agreement. Plus join us at EARTHDAY.ORG in standing up for the Environmental Protection Agency. The EPA faces attacks that could weaken protections for clean air and safe drinking water, putting our communities and future generations at risk. If you are in the U.S., we need your voice. Add your name to our public comments on the EPA’s intentions to gut the agency’s ability to regulate pollution due to climate change, also known as the Endangerment Finding.
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