From UPSC perspective, the following things are important :
Prelims level : GHGs, CO2 Equivalents
Mains level : Greenhouse Effect
The Global Methane Pledge was launched at the ongoing UN COP26 climate conference in Glasgow.
What is the Global Methane Pledge?
- Global Methane Pledge is an agreement to reduce global methane emissions.
- One of the central aims of this agreement is to cut down methane emissions by up to 30 per cent from 2020 levels by the year 2030.
- The pledge was first announced in September by the United States and the European Union.
- So far, over 90 countries have signed this pledge.
- According to the UN, 25 % of the warming that the world is experiencing today is because of methane.
- Methane is the second-most abundant greenhouse gas in the atmosphere, after carbon dioxide.
- According to IPCC, methane accounts for about half of the 1.0 degrees Celsius net rise in global average temperature since the pre-industrial era.
- Methane is a greenhouse gas, which is also a component of natural gas.
- There are various sources of methane including human and natural sources.
- The anthropogenic sources are responsible for 60 per cent of global methane emissions.
- It includes landfills, oil and natural gas systems, agricultural activities, coal mining, wastewater treatment, and certain industrial processes.
- The oil and gas sectors are among the largest contributors to human sources of methane.
- These emissions come primarily from the burning of fossil fuels, decomposition in landfills and the agriculture sector.
What is Coal-based Methane?
- CBM, like shale gas, is extracted from unconventional gas reservoirs — where gas is extracted directly from the rock that is the source of the gas (shale in case of shale gas and coal in case of CBM).
- The methane is held underground within the coal and is extracted by drilling into the coal seam and removing the groundwater.
- The resulting drop in pressure causes the methane to be released from the coal.
Try this PYQ:
Q. With reference to two non-conventional energy sources called ‘coalbed methane’ and ‘shale gas’, consider the following ‘statements:
- Coalbed methane is the pure methane gas extracted from coal seams, while shale gas is a mixture of propane and butane only that can be extracted from fi ne-grained sedimentary rocks.
- In India abundant coalbed methane sources exist, but so far no shale gas sources have been found.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Post your answers here.
Why is dealing with methane important for climate change?
- Methane has a much shorter atmospheric lifetime (12 years as compared to centuries for CO2).
- However, it is a much more potent greenhouse gas simply because it absorbs more energy while it is in the atmosphere.
- The UN notes that methane is a powerful pollutant and has a global warming potential that is 80 times greater than carbon dioxide, about 20 years after it has been released into the atmosphere.
Back2Basics: CO2 Equivalents
- Each greenhouse gas (GHG) has a different global warming potential (GWP) and persists for a different length of time in the atmosphere.
- The three main greenhouse gases (along with water vapour) and their 100-year global warming potential (GWP) compared to carbon dioxide are:
1 x – carbon dioxide (CO2)
25 x – methane (CH4) – I.e. Releasing 1 kg of CH4into the atmosphere is about equivalent to releasing 25 kg of CO2
298 x – nitrous oxide (N2O)
- Water vapour is not considered to be a cause of man-made global warming because it does not persist in the atmosphere for more than a few days.
- There are other greenhouse gases which have far greater global warming potential (GWP) but are much less prevalent. These are sulphur hexafluoride (SF6), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs).
- There are a wide variety of uses for SF6, HFCs, and PFCs but they have been most commonly used as refrigerants and for fire suppression.
- Many of these compounds also have a depleting effect on ozone in the upper atmosphere.