WHAT IS METHANE?

Methane is a hydrocarbon, which means that it is a compound made up of hydrogen and carbon atoms. It naturally occurs as an odourless, colourless, and tasteless gas. It is 25 times more dangerous Greenhouse gas than carbon dioxide. It can either be introduced into the environment by natural processes like the decomposition of the organic matter or by human activities like coal oil and natural gas extractions from the Earth, uncovered or poorly managed landfills and the burning of fossil fuels to name a few.

PRIMARY SOURCES OF METHANE EMISSIONS

Atmospheric methane concentrations have grown as a result of human activities related to agriculture, including rice cultivation and ruminant livestock; coal mining; oil and gas production and distribution; biomass burning; and municipal waste landfilling. Emissions are projected to continue to increase by 2030 unless immediate action is taken.

In agriculture, rapid and large scale implementation of improved livestock feeding strategies can reduce of 20% of global methane emissions by 2030, while full implementation of intermittent aeration of continually flooded rice paddies (known as alternate wetting and drying cultivation) could reduce emission from rice production by over 30%.

Emissions from coal mining and the oil and gas sector could be reduced by over 65% by preventing gas leakage during transmission and distribution, recovering and using gas at the production stage, and by pre-mine degasification and recovery of methane during coal mining.

METHANE IMPACTS

  • CLIMATE IMPACTS

Methane is generally considered second to carbon dioxide in its importance to climate change. The presence of methane in the atmosphere can also affect the abundance of other greenhouse gases, such as tropospheric ozone, water vapor and carbon dioxide.

Recent research suggests that the contribution of methane emissions to global warming is 25% higher than previous estimates.>

  • HEALTH IMPACTS

Methane is a key precursor gas of the harmful air pollutant, tropospheric ozone. Globally, increased methane emissions are responsible for half of the observed rise in tropospheric ozone levels.

While methane does not cause direct harm to human health or crop production, ozone is responsible for about 1 million premature respiratory deaths globally. Methane is responsible for about half of these deaths.

SOLUTIONS

The relatively short atmospheric lifetime of methane, combined with its strong warming potential, means that targeted strategies to reduce emissions can provide climate and health benefits within a few decades.

The Coalition supports implementation of control measures that, if globally implemented by 2030, could reduce global methane emissions by as much as 40%. Several of these emission reductions could be achieved with net savings, providing quick benefits for the climate as well as public health and agricultural yields.

Credit : Climate & clean air coalition   

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WHAT ARE HYDROFLUOROCARBONS?

Hydrofluorocarbons (HFCs) are a group of industrial chemicals primarily used for cooling and refrigeration. HFCs were developed to replace stratospheric ozone-depleting substances that are currently being phased out under the Montreal Protocol on Substances that Deplete the Ozone Layer.

Many HFCs are very powerful greenhouse gases and a substantial number are short-lived climate pollutants with a lifetime of between 15 and 29 years in the atmosphere.

Though HFCs currently represent around 1% of total greenhouse gases, their impact on global warming can be hundreds to thousands of times greater than that of carbon dioxide per unit of mass. Assuming no new regulation, HFC consumption is projected to double by 2020, and emissions could contribute substantially to radiative forcing in the atmosphere by the middle of the century.

The Kigali Amendment to phase down HFCs under the Montreal Protocol entered into force in 2019. Under the amendment, countries commit to cut the production and consumption of HFCs by more than 80% over the next 30 years to avoid more than 70 billion metric tons of carbon dioxide equivalent emissions by 2050 -- and up to 0.5° C warming by the end of the century. Solutions are available to replace high-global warming potential HFCs in many sectors and reduce emissions.

HFCs CLIMATE IMPACTS

HFCs are potent greenhouse gases that can be hundreds to thousands of times more potent than carbon dioxide (CO2) in contributing to climate change per unit of mass. A recent study concluded that replacing high-GWP HFCs with low-GWP alternatives could avoid 0.1°C of warming by 2050. Fast action under the Montreal Protocol could limit the growth of HFCs and avoid up to 0.5°C of warming by 2100.

SOLUTIONS

HFCs can be most effectively controlled through a phase down of their production and consumption.

In addition to the direct climate benefits from HFC mitigation, a global HFC phase down could also provide indirect benefits through improvements in the energy efficiency of the refrigerators, air conditioners, and other products and equipment that use these chemicals. These efficiency gains could also lead to reduced emissions of CO2 and other air pollutants.

Credit : Climate and clean air coalition 

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WHAT ARE GREENHOUSE GASES?

Atmospheric gases that absorb infrared radiation and trap heat are called greenhouse gases. These gases let sunlight pass through the atmosphere and prevent the heat from the sunlight from leaving the atmosphere - just like a greenhouse. The main greenhouse gases are water vapour, methane, carbon dioxide, ozone, nitrous oxide and chlorofluorocarbons. While some amount of greenhouse gases in the atmosphere is required to keep the earth habitable, too much, induced by human activity is bad.

Greenhouse gases are gases that can trap heat. They get their name from greenhouses. A greenhouse is full of windows that let in sunlight. That sunlight creates warmth. The big trick of a greenhouse is that it doesn’t let that warmth escape.

That’s exactly how greenhouse gases act. They let sunlight pass through the atmosphere, but they prevent the heat that the sunlight brings from leaving the atmosphere. Overall, greenhouse gases are a good thing. Without them, our planet would be too cold, and life as we know it would not exist. But there can be too much of a good thing. Scientists are worried that human activities are adding too much of these gases to the atmosphere.

Human activities since the beginning of the Industrial Revolution (around 1750) have increased the atmospheric concentration of carbon dioxide by almost 50%, from 280 ppm in 1750 to 419 ppm in 2021. The last time the atmospheric concentration of carbon dioxide was this high was over 3 million years ago. This increase has occurred despite the absorption of more than half of the emissions by various natural carbon sinks in the carbon cycle.

At current greenhouse gas emission rates, temperatures could increase by 2 °C (3.6 °F), which the United Nations' Intergovernmental Panel on Climate Change (IPCC) says is the upper limit to avoid "dangerous" levels, by 2050. The vast majority of anthropogenic carbon dioxide emissions come from combustion of fossil fuels, principally coal, petroleum (including oil) and natural gas, with additional contributions from cement manufacturing, fertilizer production, deforestation and other changes in land use.

Credit : Climate kids 

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WHAT ARE FLUORINATED GASES?

Fluorinated gases or F-gases are a family of human-made fluorine-based gases. They are powerful greenhouse gases that trap heat and hasten global warming. Though they find wide applications in households and industries, many countries such as the UK have imposed regulations on their use as a step towards combating the climate crisis.

There are three main types of F-gases:

  • hydrofluorocarbons (HFCs)
  • perfluorocarbons (PFCs)
  • sulphur hexafluoride (SF6).

Main uses of F-gases F-gases are used in a number of ways:

  • Stationary refrigeration, air conditioning and heat pump (RAC) equipment are some of the largest sources of F-gas emissions.
  • Some stationary fire protection systems and portable fire extinguishers currently use HFCs.
  • Mobile air conditioning in cars and light vans currently uses HFCs. Other air-conditioned and refrigerated transport also uses F-gases.
  • Solvents containing F-gases are used to clean components, eg in the electronics and aerospace industries. 
  • F-gases have many specialist uses such as in the production of magnesium, different types of foam and high voltage switchgear.

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WHAT IS CHLOROFLUOROCARBONS?

Any of several organic compounds composed of carbon, fluorine, and chlorine, chlorofluorocarbons (CFCS) are non-toxic non-flammable chemicals. If it contains hydrogen in place of one of the chlorines, they are called hydrochlorofluorocarbons (HCFCS) Originally developed as refrigerants in the 1930s. CFCs gained commercial and industrial value as they found use in the manufacture of aerosol sprays, solvents and foam-blowing agents. CFCS, however, were eventually discovered to pose an environmental threat at a serious: level as they contribute to the depletion of the ozone layer and hence are being phased out throughout the world.

What are the applications of CFC?

Chlorofluorocarbons are used in a variety of applications because of their low toxicity, reactivity and flammability. Every permutation of fluorine, chlorine and hydrogen-based on methane and ethane has been examined and most have been commercialized.

Furthermore, many examples are known for higher numbers of carbon as well as related compounds containing bromine. Uses include refrigerants, blowing agents, propellants in medicinal applications and degreasing solvents.

How do CFCs impact the environment?

However, the atmospheric impacts of CFCs are not limited to their role as ozone-depleting chemicals. Infrared absorption bands prevent heat at that wavelength from escaping the earth’s atmosphere. CFCs have their strongest absorption bands from C-F and C-Cl bonds in the spectral region of 7.8–15.3 µm—referred to as “atmospheric window” due to the relative transparency of the atmosphere within this region.

The strength of CFC absorption bands and the unique susceptibility of the atmosphere at wavelengths where CFCs (indeed all covalent fluorine compounds) absorb creates a “super” greenhouse gas (GHG) effect from CFCs and other unreactive fluorine-containing gases such as perfluorocarbons, HFCs, HCFCs, bromofluorocarbons.

Use of certain chloroalkanes as solvents for large-scale application, such as dry cleaning, have been phased out, for example, by the IPPC directive on greenhouse gases in 1994 and by the volatile organic compounds (VOC) directive of the European Union in 1997. Permitted chlorofluoro alkane uses are medicinal only.

According to scientific communities, the hole in the ozone layer has begun to recover as a result of CFC bans. India is one of the few countries that are pioneers in the use of non-Ozone Depleting technologies and have a low Global Warming Potential (GWP).

Credit : BYJUS.com 

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