Q What is the context ?
A The Global Methane Pledge was launched at the ongoing UN COP26 climate conference in Glasgow.
Q 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.
Q Why methane?
- 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.
Q What are some facts about Methane ?
- 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.
Q What is Coal-based Methane?
- 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.
Q 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.
Q What are 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 CH4 into 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.