What's the go with Methane?

Many of you will have read that methane is an important component of world-wide greenhouse gas emissions (Ref 1), along with carbon dioxide and a few others. Greenhouse gases, of course, are now generally accepted as affecting the earth's temperature and climate system by trapping heat in the atmosphere. 

Methane and carbon dioxide are often referred by their molecular structure and so, for those of you who may have forgotten your school chemistry, the methane molecule comprises four atoms of hydrogen and one atom of carbon, whereas the carbon dioxide molecule consists of two atoms of oxygen and one of carbon (see figures below).  

At this point you may not all be aware of the significance of methane compared to carbon dioxide, but some of you may have heard that methane is the main greenhouse gas produced by ruminant livestock (such as cows and sheep). Furthermore, there are many of us (myself included until recently) who associate the word ‘methane’ with cow farts and, as a consequence, may be seriously considering giving up the consumption of meat, or even dairy products, in a bid to reduce global warming.

Well let's clear the air (pun intended) in relation to a few of these statements, shall we?

First of all, methane is colourless and odourless, and so it should come as no surprise that the natural gases emanating from the rear end of bovines is relatively low in methane, with the fart odour predominantly coming from such gases as hydrogen sulphide. Cows, however, still remain high on the methane production line, with cow burps (ie not cow farts) being reportedly responsible for between 90% and 95% of cow originating methane (Ref 3). In other words most of us have the wrong end of the stick (or beast in this instance).

So, what about the main constituents of greenhouse gases and why is methane considered to be important? According to the US EPA (Ref 2), greenhouse gases in 2022 comprised about 80% carbon dioxide, 11% methane, 6% nitrous oxide, and about 3% various fluorinated gases (see figure below, from Ref 2).

In other words there's just over 7 times as much carbon dioxide in greenhouse gases as there is methane.

It is well documented (Ref 2) that, 

“Carbon dioxide enters the atmosphere through burning of fossil fuels (coal, natural gas, and oil), solid waste, trees and other biological materials, and also as a result of certain chemical reactions (eg cement production). Carbon dioxide is removed from the atmosphere (or ”sequestered') when it is absorbed by plants as part of the biological carbon cycle". 

Indeed the reduction of carbon dioxide production, through use of renewable energy sources rather than fossil fuels, is the subject of much ongoing discussion and action. 

Why then is the reduction of methane emissions into the atmosphere now considered of such importance if, as illustrated above, it only constitutes about 11% of total greenhouse gases, compared to carbon dioxide's 80% approximately? Furthermore, carbon dioxide reportedly remains in our atmosphere for “hundreds to thousands of years”, whereas methane takes approximately 10 years to break down (Ref 6). 

Well it appears (Ref 1, 4, 5) that methane is more efficient at trapping radiation than carbon dioxide and hence the impact of methane is much greater than carbon dioxide on a weight for weight basis. In order to compare the impact that different greenhouse gases have on climate change, scientists (Ref 7) use the term Global Warming Potential (GWP).  This is a comparison between how much global warming a specific quantity of greenhouse gas causes  and the same quantity of carbon dioxide, over 100 years. The GWP for methane is calculated to be to be 28. In other words methane in the atmosphere is calculated to have 28 times more effect on global warming than equal parts carbon dioxide, over a period of 100 years. It follows from the above that reducing methane emission now will result in a serious and efficient reduction on climate change in the near term (Ref 6). Hence we need to concentrate not only on reducing our carbon emissions through reduction of our reliance on fossil fuels, but also on reducing our methane emissions.

                     [Extracted from Australian Science Illustrated (Ref 7)]

Currently (Ref 7), “the pace of lowering CO2 emissions is far too slow. We need quick wins, and atmospheric methane is a good option.”

An estimated 50% to 65% of global methane is produced by human activities in the following sectors:

• Agriculture (40% of global man-made methane) - due mostly (32%) to domestic livestock digestive processes (ie burps not farts) and manure storage, with rice cultivation being responsible for the remainder (8%).
• Fossil Fuels (35% of global man-made methane) - comprising oil and gas processing and distribution (23%) and coal mining (12%).
• Waste (20% of global man-made methane) - due predominantly to landfills and wastewater.

Some of the ways in which we can reduce our methane emissions are summarised in the table below (extracted from Ref 2).

Meanwhile, scientists at Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO), in collaboration with Meat & Livestock Australia and North Queensland's James Cook University, have developed FutureFeed (Ref 8), which they claim “significantly reduces their [livestock's] methane emissions and has potential to increase livestock productivity.” FutureFeed uses the Asparagopsis species of seaweed to prevent the formation of methane in the gut.

The CSIRO claims that “If just 10 percent of global ruminant producers adopted FutureFeed as an ingredient to feed their livestock, it would have the same impact for our climate as removing 100 million cars from the world's roads, and potential increases in livestock productivity could create enough food to feed an additional 23 million people.”

If the above sounds interesting, then please fell free to look through the reference material I have provided and share the information with other like-minded people. Remember that we can only instill change if we … 

References

1. Importance of Methane, US EPA  
2. Overview of Greenhouse Gases, US EPA . 
3. Methane isn't just cow farts, KT May https://ideas.ted.com/methane-isnt-just-cow-farts-its-also-cow-burps-and-other-weird-facts-you-didnt-know-about-this-potent-greenhouse-gas/#:~:text=Methane%2C%20which%20is%20created%20when,world's%20electricity%20(after%20coal).">https://ideas.ted.com/methane-isnt-just-cow-farts-its-also-cow-burps-and-other-weird-facts-you-didnt-know-about-this-potent-greenhouse-gas/#:~:text=Methane%2C%20which%20is%20created%20when,world's%20electricity%20(after%20coal). 
4. IPCC (2013), Climate Change 2013: The Physical Science Basis .
5. IPCC (2023), AR6 Synthesis Report, Climate Change 2023 .
6. UN Environment Program, Methane emissions are driving climate change. Here's how to reduce them .
7. Australian Science Illustrated (May 2024), Defuse the Methane Bomb, pp 60 - 67.
8. FutureFeed - CSIRO .

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When not researching the weird or the wonderful, the comical or the cultured, the sinful or the serious, I chase my creative side, the results of which can be seen as selected photographs of my travels on my website at:

https://ken-boddie.squarespace.com 

The author of the above, Ken Boddie, besides being a sometime poet and occasional writer, is an enthusiastic photographer, rarely leisure-travelling without his Canon, and loves to interact with other like-minded people with diverse interests.

Ken's work week (retired engineer), as a part-time or freelance English tutor to migrants, allows him to follow his photography interests, and to plan trips to an ever increasing list of countries and places of scenic beauty and cultural diversity.

#methane #carbondioxide  #climatechange  #globalwarming #fossilfuels #greenhousegases