Methanogens and methanotrophs are microbes that interact with methane, but in different ways. Methanogens are microorganisms that produce methane as a byproduct of their metabolism in anaerobic environments, while methanotrophs are microbes capable of consuming methane as their energy source in aerobic or oxygen-rich environments.

The CO₂ cycle and the methane cycle are different processes within the global carbon cycle. The CO₂ cycle primarily involves the exchange of carbon dioxide (CO₂) between living organisms, the atmosphere, and the oceans through processes like photosynthesis, respiration, and carbonate reactions. On the other hand, the methane cycle involves the production and consumption of methane (CH₄) by various biological and geological processes, including methanogenesis, methanotrophy, and methane oxidation, among others.

Methanogens vs Methanotrophs

Methanogens are microorganisms that are capable of generating methane from organic sources.

Methanotrophs or Methanophiles are microorganisms which are capable of utilizing methane as a source of carbon and energy.

Methanogens are obligatory anaerobic (Methanogenesis takes place under anaerobic conditions).

Methanotrophs are aerobic (Methane digestion takes place under aerobic conditions).

Precursors of methanogenesis are hydrogen, carbon dioxide and C-1 compounds.

Methane is the precursor of methanotroph reactions.

Methane is the end product of methanogenesis.

Carbon dioxide and energy are produced during the methane utilization.

Methanogens are used in waste water purification plants in anaerobic digesters and sludge treatment systems, and in bio gas production plants.

Methanotrophs are used in degrading methane based products and methane emissions in industrial reactions.

What is Methane?.

• Methane (CH₄) is the simplest hydrocarbon, consisting of one carbon atom and four hydrogen atoms. 
• It is a colorless, odorless, and highly flammable gas, and the main component in natural gas.
• It is an important greenhouse gas because it is such apotent heat absorber. The concentration of methane in the atmosphere has risen by about 150% since 1750, apparently largely due to anthropogenic activities. 
• Methane is the second most abundant anthropogenic GHG after carbon dioxide (CO₂), accounting for about 20 percent of global emissions. 

Methane release in ruminants

• Agriculture is the largest single source of global anthropogenic methane (CH₄)emissions, with ruminants the dominant contributor.
• Unlike other animals, ruminants have specialized digestive systems consistingof stomachs that have four compartments instead of one.
• Plant material is initially taken to rumen, the largest compartment in the stomach that is inhabited by microorganisms such as fungi, bacteria, protozoa and archaea.
• These microorganisms break down the otherwise indigestible cellulose-rich plants to release protein and energy for their host animal in exchange for nutrition and shelter.
• But during this process, which scientists call enteric fermentation, one particular microbe, the archaea, combines CO₂ and hydrogen made by the cellulose-digesting microbes to create methane. 

Other Sources of Methane

• Agricultural methane doesn’t only come from animals. Paddy rice cultivation– in which flooded fields prevent oxygen from penetrating the soil, creating ideal conditions for methane-emitting bacteria – accounts for another 8 percent of human-linked emissions.
• Methane is also emitted during the production and transport of coal, natural gas, and oil. Other agricultural practices, land use and the decay of organic waste in municipal solid waste landfills also contribute to methane emissions.

Emission by India

• India is currently the world’s fourth largest methane emitter after China, the United States and Russia.
• India has the world’s largest cattle population and is the second largest rice producer, the agriculture sector emits five times as much methane as the energy sector. 
• Agriculture accounts for 61% of total methane emissions, while India’s energy sector accounts for 16.4% and waste 19.8%, as per the Global Methane Tracker 2022.

How does  Methane Emissions affect the Environment?

• Methane is the primary contributor to the formation of ground-level ozone, a hazardous air pollutant and greenhouse gas, exposure to which causes 1 million premature deaths every year. 
• Over a 20-year period, methane is 80 times more potent at warming than carbon dioxide.
• Methane has accounted for roughly 30 percent of global warming since pre-industrial times and is proliferating faster than at any other time since record keeping began in the 1980s.

How much methane can we really cut?

• CO₂ stays in the atmosphere for centuries, methane breaks down quickly and most is gone after a decade, meaning action can rapidly reduce the rate of global warming in the near-term. 
• Human-caused methane emissions could be reduced by as much as 45 percent within the decade. This would avert nearly 0.3°C of global warming by 2045, helping to limit global temperature rise to 1.5?C and putting the planet on track to achieve the Paris Agreement targets. 
• Every year, the subsequent reduction in ground-level ozone would also prevent 260,000 premature deaths, 775,000 asthma-related hospital visits, 73 billion hours of lost labour from extreme heat and 25 million tonnes of crop losses.

        UNEP is at the front in support of the Paris Agreement goal of keeping the global temperature rise well below 2°C and aiming - to be safe - for 1.5°C, compared to pre-industrial levels. To do this, UNEP has developed a Six-Sector Solution roadmap to reducing emissions across sectors in line with the Paris Agreement commitments and in pursuit of climate stability. The six sectors are Energy; Industry; Agriculture and Food; Forests and Land Use; Transport, and Buildings and Cities. 

Global Methane Pledge

• The Global Methane Pledge was established during the UN COP26 climate meeting in Glasgow. Over 90 countries have signed the pledge, which is led by the United States and the European Union.
• The goal of this project is to reduce worldwide methane emissions.
• The Pledge seeks to catalyse global action and improve support for current international methane emission reduction programmes in order to develop technical and policy work that will serve as the foundation for Participants'' domestic measures.
• Participants who sign the Pledge promise to take voluntary activities to contribute to a collaborative effort to cut global methane emissions by at least 30% from 2020 levels by 2030, potentially avoiding more than 0.2 degrees Celsius of warming by 2050.
• This is a worldwide aim, not a national one.
• How would the project be beneficial - If adopted globally, it would reduce global warming by 0.2 degrees Celsius by the 2040s as compared to expected temperature increases.
• The Earth is currently 1.2 degrees Celsius hotter than it was before the Industrial Revolution.
• India, the third-largest producer of methane emissions, is currently not a signatory.

 Significance

• The Global Methane Pledge aim has the potential to have a massive influence on climate change, akin to the whole global transportation industry adopting net zero emission technology.
• Action will be especially critical in the period leading up to 2030 since dramatic reductions in methane emissions can provide a net cooling impact in a very short period of time.
• This might keep the door open to a 1.5 °C stability in global average temperatures as the world pursues long-term CO2 reductions.
• The Global Methane Pledge has brought together several key international parties, including large consumers such as the European Union, Japan, and Korea, as well as big producers like Iraq and Saudi Arabia.
• For other nations, the Global Methane Pledge is the first substantial policy commitment on methane, either domestically or internationally.
• The Pledge also recognises and appreciates the critical contributions that the corporate sector, development banks, financial institutions, and philanthropy play in supporting the Pledge''s implementation.

Why is dealing with methane crucial for climate change?

• Methane is the second-most prevalent greenhouse gas in the atmosphere after carbon dioxide, therefore efforts to reduce its emissions are crucial.
• According to the most recent Intergovernmental Panel on Climate Change study, methane is responsible for over half of the 1.0 degree Celsius net rise in global average temperature from the pre-industrial period.
• Rapidly lowering methane emissions is supplementary to action on carbon dioxide and other greenhouse gases, and is seen as the single most effective option for reducing global warming in the short term and keeping the goal of limiting warming to 1.5 degrees Celsius within reach.
• According to the International Energy Agency (IEA), while methane has a significantly shorter atmospheric lifespan (12 years versus millennia for CO2), it is a lot more effective greenhouse gas simply because it absorbs more energy when in the atmosphere.
• The UN emphasises in its methane fact sheet that methane is a formidable pollutant with a global warming potential 80 times that of carbon dioxide, around 20 years after it is released into the atmosphere.
• Significantly, the average methane leak rate of 2.3% "erodes much of the climate advantage gas has over coal."
• According to the IEA, more than 75% of methane emissions may be reduced with current technology, and up to 40% of this can be accomplished at no additional cost.

India Refused to Sign The Methane Pledge

• India refused to sign the ''Global Methane Pledge,'' a proposal by the United States and the European Union to reduce global methane emissions by 30% by 2030 compared to 2020 levels.
• The administration recently explained in detail to Parliament why it declined to sign the methane promise.

In India, methane emissions are survival emissions

• Methane emissions are fundamentally survival emissions, not ''luxury'' emissions, as in the case of the West.
• In India, the two main sources of methane emissions are:
• Enteric fermentation (methane from animal intestines)
• rice agriculture (from standing water).
• These emissions are the product of agricultural operations carried out by small, marginal, and medium farmers across India, whose livelihoods are jeopardised by the aforementioned pledge.
• This can have an influence on agricultural productivity, particularly paddy yield, in addition to farmers'' revenue. India is one of the world''s major rice producers and exporters.
• In contrast, industrial agriculture dominates agriculture in wealthy countries.
• As a result, this pledge. has the potential to have an impact on India''s trade and economic prospects.

Agriculture is not included in India''s emission intensity target

• According to India''s pre-2020 voluntary pledges, agriculture is not included in the emission intensity objective.

Indian cattle contribute little to global methane emissions

• Furthermore, India boasts the world''s biggest cow population, which provides a living for a substantial portion of the people.
• Because Indian livestock consume huge amounts of agricultural byproducts and unusual feed material, their contribution to the world pool of enteric methane is quite modest.

Methane Pledge Outside of the UNFCCC and the Paris Agreement

• While India is a signatory to the United Nations Framework Convention on Climate Change (UNFCCC) and the Paris Agreement, the government claims that the Methane Pledge falls beyond the scope of the UNFCCC and its Paris Agreement.

Indian Efforts to Reduce Methane Emissions

• The Indian Council for Agricultural Research''s (ICAR) National Innovations in Climate Resilient Agriculture (NICRA) initiative has created numerous technologies with the potential to reduce methane emissions.
• System for Rice Intensification: It has the ability to increase rice output by 36-49 percent while using about 22-35 percent less water than traditional transplanted rice.
• Direct seeded rice: It minimises methane emissions since it eliminates the need for nurseries, puddling, and transplanting. Unlike transplanted paddy farming, this approach does not retain standing water.
• Crop Diversification Programme: Methane emissions are reduced by shifting rice to other crops such as pulses, oilseeds, maize, cotton and agroforestry.
• Seaweed-Based Animal Feed: The Central Salt & Marine Chemical Research Institute (CSMCRI) created a seaweed-based animal feed additive formulation that seeks to minimise methane emissions from cattle.
• Harit Dhara: The Indian Council of Agricultural Research (ICAR) developed an anti-methanogenic feed additive called ''Harit Dhara'' (HD), which can reduce cow methane emissions by 17-20%.