Greenhouse gases (GHG) trap heat in the atmosphere and cause global warming. The most common GHGs are carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), which have the highest concentrations and the largest contribution to the radiative forcing of the climate system. However, other GHGs have been growing rapidly in the past 100 years but are less known or monitored. These are fluorinated gases (F-gases): synthetic gases are used in industrial and commercial applications.
F-gases include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6), and nitrogen trifluoride (NF3). These gases have low concentrations in the atmosphere, but their global warming potential (GWP) is very high compared to CO2. GWP is a measure of how much heat a gas can trap over a given period relative to CO2. For example, SF6 has a GWP of 23,500 over 100 years, which means it can trap 23,500 times more heat than CO2 over the same period.
F-gases account for about 3.5 per cent of the total GHG emissions, and they increase by about 5 per cent every year. F-gases are manmade compounds used in various industrial applications, such as air conditioning, refrigeration, aerosols, and foam blowing.
Some F-gases, such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), contain chlorine atoms that can deplete the ozone layer when they reach the stratosphere. The ozone layer is a thin layer of gas in the upper atmosphere that protects the Earth from harmful ultraviolet radiation from the sun. Ozone (O3) is a gas formed by the reaction of oxygen and sunlight. It can be found in the first two layers of the atmosphere, the stratosphere and the troposphere.
The double-edged ozone
In the stratosphere, ozone protects the Earth from harmful ultraviolet radiation, but in the troposphere, ozone is a pollutant that harms human health and vegetation. Ozone is also a GHG that contributes to global warming.
Most F-gases are increasing rapidly without being investigated or evaluated for their GWP. Studies generally focus on the quantity of the GHG, but their potential has not been seriously considered. N2O, for example, has a low concentration in the atmosphere but a high GWP of 298 over 100 years. If the GWP of all GHGs are tabulated, the ranking might be different.
Measuring the impact of global warming by quantity and ignoring the potential might be a misleading piece of information that could send different messages. Scientists need to assess the GWP of all GHGs and their trends over time, as they depend on the emissions, concentrations, and interactions of each GHG in the atmosphere.
However, we know that these gases are increasing remarkably in the last decade. N2O has risen by about 3 per cent, SF6 has increased by about 34 per cent, NF3 has soared by about 118 per cent, and F-gases have increased by about 50 per cent. These values of GWP and the rapid rise are taking place under the radar. This poses a severe threat to the climate and limits the ability to achieve the global warming target of 1.5°C above pre-industrial levels, as agreed in the Paris Agreement. Particularly as the GHG emissions need to be reduced by 45 per cent by 2030 and reach net zero by 2050.
What’s the Kigali amendment?
In 2016, the Kigali amendment was adopted as part of the Montreal Protocol. This treaty aims to phase down the production and consumption of hydrofluorocarbons (HFCs). The treaty was supposed to be enforced as of 2019 by all the signatories of the Montreal Protocol. Unfortunately, the global emissions of F-gases, including HFCs, are increasing.
These gases have increased by 20 per cent in the past five years. Many scenarios and projections were investigated to reduce the GWP of all GHGs, including reducing N2O emissions by 30 per cent by 2030, reducing the global warming effect of CH4 by 35 per cent by 2050, and implementing the Kigali amendment. These projections and scenarios remain uncertain and depend on the actual implementation and compliance of the policies and the adoption of alternative technologies and substances.
Other factors could affect the future GWP of these gases, such as their interactions with other GHGs and the feedback of the countries’ compliance. These will definitely present other future challenges for the Paris Agreement and its potential to sustain 1.5°C by the end of the century. Moreover, climate change will continue to impact our lives and the planet.
— Dr Abdulla Al Nuaimi is the Chairman of the Advisory Council of Sharjah. He is a former UAE minister of Infrastructure Development and for Climate Change and Environment