Varsha Goswami |
It’s been 30 years since September 16 marked the International Day for the Preservation of the Ozone Layer. This day holds global significance as it raises awareness about the critical role of the ozone layer in protecting life from harmful ultraviolet (UV) radiation. It also celebrates the success of international cooperation under the Montreal Protocol, which has significantly reduced ozone-depleting substances (ODS). This day encourages continued vigilance and action to ensure the ongoing recovery of the ozone layer and highlights its broader connection to climate action and sustainable development.
Ozone (O₃) is a triatomic molecule formed when high-energy UV radiation splits oxygen (O₂) molecules, releasing oxygen atoms that bond with O₂ to create ozone. Located in the stratosphere at altitudes of 10 to 16 kilometers, and up to 50 kilometers, this “good ozone” absorbs most UV-B and UV-C radiation, protecting life on Earth from increased risks of skin cancer, cataracts, and ecosystem damage. Conversely, in the troposphere, “bad ozone” forms from reactions involving nitrogen oxides (NOₓ) and volatile organic compounds (VOCs), contributing to smog and respiratory issues.
The Underlying Cause of Ozone Depletion:
Before 1979, atmospheric ozone concentrations below 220 Dobson Units had not been observed. However, in the early 1980s, scientists using both ground-based and satellite measurements began to notice that Earth’s natural protective layer was rapidly thinning over the South Pole each spring. British Antarctic Survey scientists had been monitoring the Antarctic ozone layer since the International Geophysical Year of 1957-58. By 1985, they discovered a consistent decline in ozone levels over the Halley and Faraday Research Stations each spring, starting in the mid-1970s when the sun reappeared after winter.
Fig: 1 Instruments on the ground at Halley and high above Antarctica, such as the Total Ozone Mapping Spectrometer (TOMS), Ozone Monitoring Instrument (OMI), and Ozone Mapping and Profiler Suite (OMPS), detected a sharp decline in total atmospheric ozone during October in the early to mid-1980s. (This data from Halley was provided by J. D. Shanklin of the British Antarctic Survey)
The discovery of the ozone hole highlighted the global impact of human activities on the atmosphere. Scientists identified chlorofluorocarbons (CFCs), chemicals used since the 1930s in products like refrigerators and aerosol sprays, as the primary culprits. In the troposphere, the layer closest to Earth, CFCs remained stable for decades, neither breaking down nor reacting with other chemicals. However, upon reaching the stratosphere, their behaviour changed. Exposed to ultraviolet light in the upper stratosphere, beyond the protective ozone layer, CFCs broke apart, releasing chlorine atoms. These highly reactive atoms catalyzed the destruction of ozone, causing the depletion.
Fig:2 Ozone depletion by Chlorofluorocarbons (https://www.compoundchem.com/2018/01/19/solomon-cfcs/)
The emergence of the Montreal Protocol:
To prevent the destruction of the ozone layer, the international community adopted the Montreal Protocol in 1987, aiming to phase out chemicals like chlorofluorocarbons (CFCs) used in refrigerators, fire extinguishers, and foams. By 2020, chlorine entering the stratosphere from these substances had decreased by 11.5% from its 1993 peak, and bromine by 14.5% from its 1999 peak. CFCs also act as greenhouse gases, and their ban through the Protocol has helped avoid a potential global temperature increase of 0.5 to 1 degree Fahrenheit by 2100. Regulating nearly 100 man-made ozone-depleting substances (ODS), the Montreal Protocol has been a landmark environmental agreement, successfully protecting Earth’s ozone layer and achieving universal ratification since its adoption on September 16, 1987.
Hydrofluorocarbons (HFCs) were introduced as non-ozone-depleting alternatives to replace CFCs and HCFCs and are now widely used in products like air conditioners and refrigerators. However, many HFCs have high global warming potentials (GWPs), contributing to climate change. HFC emissions are growing by 8% annually and could account for 7-19% of global CO2 emissions by 2050, posing a challenge to limiting global temperature rise. In response, the 2016 Kigali Amendment to the Montreal Protocol set a plan to phase down HFCs by 80-85% by the late 2040s to protect the climate.
India’s Progress on the Montreal Protocol: An Overview of HCFC Phase-Out Efforts
Since joining the Montreal Protocol in 1992, India has successfully phased out several ozone-depleting substances, including CFCs, halons, and methyl chloroform, by 2010. Currently, India is focused on phasing out hydrochlorofluorocarbons (HCFCs). The Hydrochlorofluorocarbons Phase-out Management Plan (HPMP) Stage-I (2012-2016) was completed successfully, and HPMP Stage-II (2017-2024) is underway, with India becoming the first developing country to fully eliminate HCFC-141b in rigid foam production. India exceeded its 2020 reduction target by cutting HCFC consumption by 44%.
HPMP Stage-III (2023-2030) aims to phase out HCFCs in new equipment by 2024, reducing emissions by 19.2 million tonnes of CO₂-equivalent from 2030 onward. India also supports the Kigali Amendment to reduce HFCs, targeting a phased reduction of 85% by 2047, contributing to climate change mitigation.
“ICAP: Boosting Climate Action and HFC Phase-Down”
The India Cooling Action Plan (ICAP), launched in March 2019, represents a pioneering effort to develop a long-term, integrated vision for sustainable cooling, addressing cooling demand reduction, refrigerant transition, energy efficiency enhancement, and technology advancement. As part of this strategy, ICAP aligns with ongoing government programmes to maximize socio-economic and environmental benefits, including climate change mitigation and progress towards Sustainable Development Goals (SDGs). The implementation of ICAP’s recommendations, particularly in space cooling, cold chains, domestic manufacturing, alternative refrigerants, and research, is actively contributing to India’s climate goals. By promoting climate-friendly refrigerants and energy efficiency, ICAP supports the phasedown of hydrofluorocarbons (HFCs) under the Kigali Amendment, significantly aiding India’s climate action efforts. Recent initiatives, such as the development of indigenous low-GWP refrigerants and the upskilling of the workforce, further enhance India’s capability to manage the HFC transition effectively, in close collaboration with research institutions and government bodies.
Way Forward:
The journey towards ozone layer recovery and climate action is ongoing and requires sustained commitment and innovation. As we continue to implement the Montreal Protocol and Kigali Amendment, it is crucial to address emerging challenges such as the growth of HFCs and their impact on global warming. The India Cooling Action Plan (ICAP) provides a comprehensive framework for advancing sustainable cooling solutions and achieving climate goals. Moving forward, it is essential to strengthen international cooperation, enhance technological advancements, and support policy measures that facilitate the transition to low-GWP refrigerants. By doing so, we can ensure the continued protection of the ozone layer, mitigate climate change, and advance towards a more sustainable and resilient future.
References:
- https://pib.gov.in/PressReleaseIframePage.aspx?PRID=1957968
- https://www.genevaenvironmentnetwork.org/resources/updates/international-day-for-the-preservation-of-the-ozone-layer/
- https://ozonewatch.gsfc.nasa.gov/facts/history_SH.html
- https://earthobservatory.nasa.gov/world-of-change/Ozone
- https://www.noaa.gov/news-release/montreal-protocol-emerges-as-powerful-climate-treaty