Chapter 1: The Importance of Methane in Climate Discussions

Recently, methane has been receiving more media coverage, particularly as various countries have committed to reducing their emissions. Often overshadowed by carbon dioxide, methane is crucial in discussions about greenhouse gases (GHGs). It’s encouraging to see it gain the attention it deserves.

While methane constitutes approximately 18% of total global GHG emissions, it is responsible for at least 30% of the warming that has occurred since the mid-19th century, indicating its significant impact.

Comparing methane and carbon dioxide can be complicated since methane doesn’t remain in the atmosphere as long. Therefore, specifying a timeframe is essential for accurate comparisons. For instance, a single methane molecule is about 80 times more effective at trapping heat than a carbon dioxide molecule. However, methane only lingers for around 10 to 12 years before it reacts with other substances and converts to carbon dioxide. When examining the first decade, methane is indeed much more detrimental to the environment than carbon dioxide.

Yet, when we assess climate effects over longer periods, the comparison shifts. If equal amounts of methane and carbon dioxide are released today, their impacts on global warming after 100 years differ. Methane’s immediate effects are severe, but it largely converts to carbon dioxide through reactions with hydroxyl molecules. After a century, methane's overall impact remains approximately 25 times worse than that of carbon dioxide.

However, not all methane sources have the same environmental consequences. The most harmful type comes from underground reserves, released during coal mining or oil and gas extraction—accounting for about one-third of methane emissions. Additionally, the thawing of Arctic permafrost releases ancient carbon into the atmosphere, exacerbating the situation.

Conversely, some methane is part of a natural cycle involving carbon atoms. To understand this, we need to delve into a bit of biology and chemistry.

Ruminant animals, such as cattle, sheep, and goats, possess a specialized stomach called a rumen, which allows them to digest cellulose from grass—something most animals cannot do. Their rumens contain microorganisms that facilitate this process through enteric fermentation, producing methane as a byproduct. This methane is expelled when animals regurgitate their food to chew the cud, and some is released through flatulence and manure.

Livestock contribute approximately 36% of methane emissions in the United States, surpassing emissions from coal, oil, and gas. Globally, livestock account for around 14% of total GHG emissions, while the airline industry contributes only 2.4%.

Despite its harmful effects, there is a silver lining regarding methane from livestock. The carbon in methane (CH4) originates from carbon dioxide (CO2) already present in the atmosphere, meaning it does not introduce additional carbon. Instead, it transforms existing carbon into a more potent greenhouse gas.

Photosynthesis is the process that converts carbon dioxide and water into oxygen and glucose using sunlight and plant chloroplasts. The glucose produced consists of long chains of carbon, hydrogen, and oxygen.

When cattle consume grass, they take in carbon through glucose. Enteric fermentation converts much of this glucose into methane, which then enters the atmosphere, trapping heat and contributing to global warming. Unlike carbon dioxide, which remains in the atmosphere until absorbed by plants, methane breaks down naturally.

In the atmosphere, methane interacts with hydroxyl molecules (OH) to form formaldehyde (CH2O), which subsequently reacts with hydroxyl again to yield carbon dioxide and water. Thus, carbon cycles between the air, grass, and cattle. While this process seems manageable, it’s essential to recognize that ruminants convert carbon dioxide into methane for about a decade, intensifying the heat-trapping effects of those carbon atoms.

It's important to note that this type of methane accounts for only about one-third of total methane emissions; the remainder directly introduces additional carbon into the atmosphere. Consequently, reducing beef consumption can positively impact the climate, but the most effective action remains curbing coal, oil, and gas production.

This week’s Global Methane Pledge marks a significant step forward. Unfortunately, the world’s top three methane emitters—China, Russia, and India—did not participate in this agreement. Clearly, more work lies ahead.

I regularly write about Climate Change, Philosophy, and Literature. You can follow my insights here.

Chapter 2: Exploring Methane Emissions from Livestock

In the video "Cows and Methane | Simply Science," the focus is on how cattle contribute to methane emissions and their implications for climate change. This informative piece highlights the scientific principles behind enteric fermentation and its role in greenhouse gas production.

The second video, "Why We MUST Reduce Methane Emissions From Livestock | @EarthshotPrize," discusses the urgent need to address methane emissions from livestock. It emphasizes strategies for reducing these emissions and the broader impact on global warming.