The recent wildfires in Los Angeles starkly remind us of the worsening impacts of climate change. Each year, humanity grapples with intensifying heatwaves, forest fires, and droughts—events that increasingly disrupt daily life, particularly for vulnerable populations. As global temperatures rise, cooling solutions such as air conditioning and refrigeration become indispensable. However, these very solutions have historically contributed to the problem they aim to mitigate.

The Evolution of Cooling Technologies and the Ozone Crisis

In the earlier days of cooling systems, chlorofluorocarbons (CFCs) were commonly used as refrigerants due to their efficiency. However, in the 1980s, scientists discovered a massive hole in the ozone layer, primarily caused by the release of CFCs into the atmosphere. The ozone layer, located in the stratosphere, plays a vital role in absorbing harmful ultraviolet (UV) radiation. Without it, UV-B and UV-C rays can cause irreparable harm to living organisms, including increased risks of skin cancer, cataracts, and harm to crops and marine life.

CFCs, released from refrigeration and air-conditioning systems during their lifecycle, repair, and disposal, migrate to the upper atmosphere. With a lifespan of up to 100 years, they break down ozone molecules, disrupting the natural ozone replenishment cycle. This led to the formation of the infamous ozone hole over Antarctica. This alarming discovery prompted global leaders, scientists, and policymakers to take collective action, leading to the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer in 1987.

Montreal Protocol: a model for global collaboration

The Montreal Protocol is widely regarded as the most successful environmental treaty in history, with universal ratification by all 198 UN member states. Its primary objective was to phase out the production and consumption of ozone-depleting substances (ODS), including CFCs, in a systematic manner.

This treaty has achieved remarkable milestones:

Complete phase-out of CFCs: By phasing out CFCs in air-conditioning, refrigeration, and fire-suppression systems, the protocol has significantly reduced ozone depletion. According to United Nations Environment Programme (UNEP), this has averted more than 135 billion metric tonnes of CO₂-equivalent emissions.

Healing the ozone layer: The National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA) report that the ozone layer is on track to recover to 1980 levels by 2066.

Preventing global warming: The protocol has also indirectly mitigated climate change, as many ODS are potent greenhouse gases (GHGs).

Supporting Developing Nations: The Multilateral Fund

To ensure equitable implementation, the Montreal Protocol established the Multilateral Fund (MLF) to provide financial and technical assistance to developing countries. As of 2024, the MLF has supported over 8000 projects, enabling countries to transition to energy-efficient and environmentally friendly cooling systems. These initiatives include:

This innovative financial mechanism exemplifies how well-designed climate finance can drive transformative change. Under the guidance of the Montreal Protocol on Substances that Deplete the Ozone Layer (MLF), Article 5 (Developing) countries have successfully phased out the consumption of over 756,000 metric tonnes of baseline ozone-depleting substances. This achievement translates to an estimated avoidance of 2.2 billion tonnes of CO₂ emissions.

Challenges with HFCs and the Kigali Amendment

While the Montreal Protocol successfully phased out CFCs, their replacements—hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs)—posed new challenges. Although HCFCs and HFCs have low ozone-depleting potential (ODP), they are potent GHGs with high global warming potential (GWP). For instance, HFC-134a has a GWP of 1430, meaning its impact on global warming is 1430 times that of CO₂ over 100 years.

In 2016, the Kigali Amendment to the Montreal Protocol was adopted to phase down HFCs. It aims to reduce HFC consumption by over 80% by 2047, preventing up to 0.4°C of global warming by 2100. This amendment is a testament to the evolving nature of the protocol, ensuring it remains relevant in addressing emerging climate challenges.

The Role of Natural and Next-generation Refrigerants

The focus has now shifted to natural refrigerants like hydrocarbons (propane and isobutane) and ammonia, which have negligible GWP and minimal environmental impact. These alternatives are being adopted in various sectors, from commercial refrigeration to cold storage.

India has been actively exploring the adoption of next-generation refrigerants, such as hydrocarbon-based refrigerants (R-290), in room air conditioners which are now commercially available in the market. R290 refrigerant possesses a GWP of 3, signifying a significantly lower impact on global warming compared to many other refrigerants. The Government of India has undertaken several innovative measures to promote sustainable cooling. The India Cooling Action Plan (ICAP), the first of its kind, launched by the Ozone Cell, Ministry of Environment, Forest and Climate Change outlines a visionary road map to reduce cooling demand by 25–30% by 2037–38 through energy-efficient technologies and sustainable refrigerants. The Energy Efficiency Labelling Programme, spearheaded by the Bureau of Energy Efficiency, ensures star-rated appliances like air conditioners and ceiling fans meet high-performance standards. Additionally, India is actively transitioning to low-GWP refrigerants in line with the Kigali Amendment to phase down HFCs. Efforts to explore district cooling systems and develop energy-efficient cold chain infrastructure for agriculture and health care further highlight the government's commitment to climate-resilient cooling solutions. Such initiatives demonstrate a commitment to sustainable cooling solutions. Additionally, innovations such as desiccant-based cooling and thermally driven systems are gaining traction.

The journey of sustainable cooling: from Montreal Protocol to next-generation solutions

Cooling Beyond Refrigerants

Cooling isn't just about refrigerants. Ancient Indian architectural designs, like Jaipur's Hawa Mahal, leveraged passive cooling techniques such as natural ventilation, courtyards, and shading to maintain thermal comfort. Such passive cooling solutions remain relevant today, especially in rural and resource-constrained settings.

Even cutting-edge technologies, like the NASA's recent James Webb Space Telescope (JWST), employs an innovative cryogenic cooling system using a five-layer sunshield and helium-based cryocoolers to maintain its instruments at ultra-cold temperatures. These examples underscore the importance of interdisciplinary approaches to cooling innovation.

Cooling as a Necessity, Not a Luxury

The COVID-19 pandemic highlighted the critical role of cold chains in preserving vaccines and ensuring food security. According to the Food and Agriculture Organization (FAO), 14% of the world's food is lost due to inadequate cold storage, costing billions annually and exacerbating hunger. Investments in sustainable cold chain infrastructure can mitigate these losses, enhance food security, and combat climate change.

Conclusion

Cooling is no longer a luxury; it is a necessity integral to modern life. While early cooling technologies posed significant environmental risks, the Montreal Protocol exemplifies how collective action, innovation, and progressive policymaking can address global challenges. As we transition to next-generation cooling technologies, the lessons learned from the protocol can guide us in building a resilient and sustainable future.

Web Resources

https://earthobservatory.nasa.gov/world-of-change/Ozone

https://www.unep.org/ozonaction/who-we-are/about-montreal-protocol

https://ozone.unep.org/sdg13#:~:text=The%20Montreal%20Protocol%20protects%20our%20climate%20as,around%20135%20billion%20tonnes%20of%20CO2%20emissions.

https://earthobservatory.nasa.gov/images/153523/ozone-hole-continues-healing-in-2024

https://www.multilateralfund.org/our-impact

https://www.unep.org/news-and-stories/press-release/world-takes-stand-against-powerful-greenhouse-gases-implementation

https://ozonecell.nic.in/wp-content/uploads/2019/03/INDIA-COOLING-ACTION-PLAN-e-circulation-version080319.pdf

https://science.nasa.gov/mission/webb/cryocooler/

 https://openknowledge.fao.org/server/api/core/bitstreams/cf42e3c6-157e-4ea9-8873-8b3cc9242b96/content #