Many years go by (I am now 72). I, like all of us, became concerned about the climate crisis, ozone layer etc. An important factor, apparently, is methane and other gases burped by cows. Last summer, I had a sudden ‘Eureka’ moment. I woke up at 2 a.m., convinced that I had come up with a solution to the problem of global warming. All we had to do is to make charcoal biscuits for cows in sufficient quantities, persuade cows in sufficient numbers to eat the biscuits, and lo and behold, harmony should be restored. I enlisted the help of a nephew as research assistant, and he found that several people had got there before me (Dash!, but I was also rather amazed to have been on the right track).

Coffee Room (now dining room) designed by Charles Barry at The Travellers Club
Photograph © The Travellers Club London, who gave kind permission for its reproduction to illustrate this article.

The ‘medicinal’ properties of charcoal are said to have been known as early as the third century, but a more recent learned article on the subject by Dr. Gerhard K. Heilig appeared in 1994 : “The greenhouse gas methane (CH4): Sources and sinks, the impact of population growth, possible interventions.”
Methane (CH4) is one of the trace gases in the atmosphere that is considered to play a major role in what is called the “greenhouse effect.” There are six major sources of atmospheric methane: emission from anaerobic decomposition in (1) natural wetlands; (2) paddy rice fields; (3) emission from livestock production systems (including intrinsic fermentation and animal waste); (4) biomass burning (including forest fires, charcoal combustion, and firewood burning); (5) anaerobic decomposition of organic waste in landfills; and (6) fossil methane emission during the exploration and transport of fossil fuels. Obviously, human activities play a major role in increasing methane emissions from most of these sources. Especially the worldwide expansion of paddy rice cultivation, livestock production and fossil fuel exploration have increased the methane concentration in the atmosphere. Several data sets help estimate atmospheric methane concentration up to 160,000 years back. Major sources and sinks of present-day methane emission and their relative contribution to the global methane balance demonstrate great uncertainties in the identification and quantification of individual sources and sinks. Most recent methane projections of the Intergovernmental Panel on Climate Change (IPCC) for 2025 and 2100 are discussed and used to estimate the contribution of population growth to future methane emission. Finally the paper discusses options and restrictions of reducing anthropogenic methane emissions to the atmosphere. Heilig, G.K. The greenhouse gas methane (CH4): Sources and sinks, the impact of population growth, possible interventions. Popul Environ 16, 109–137 (1994). https://doi.org/10.1007/BF02208779
The importance of tackling methane has become more apparent in the past decade and a half. After a plateau which began in 1999, concentrations of the gas in the atmosphere started rising again in 2007, a trend that continues to this day. At the moment, more than 300m tonnes are emitted every year as a consequence of human activity, and that rate is growing. As a result, methane concentrations are now more than two-and-a-half times what they were before the Industrial Revolution, and are rising faster than allowed for in all but the most pessimistic climate projections for the 21st century…… Besides leaky wells and pipelines, and gassy coal mines, methane is also emitted by belching cattle, rice paddies, forest fires, slash-and-burn agriculture, rubbish dumps, wastewater-treatment plants, cars and lorries, and natural ecosystems such as swamps, rivers and lakes….The lion’s share of agricultural methane, though, comes from ruminant livestock—cows and sheep, mainly. Such husbandry generates 79% of the sector’s contribution…This is now being investigated experimentally, to see if changing what the animals eat can damp down methanogenic activity. The Economist, 3 April 2021 This article appeared in the Science & technology section of the print edition under the headline “The other greenhouse gas” For more coverage of climate change, visit The Economist’s climate-change hub
  In the Antipodes, Mikki Cusack wrote for ‘Future Planet‘ on 7 February 2020:
The cowpats that these particular beetles are burying are not ordinary cowpats. On this farm near Manjimup in south-west Australia, they are rich in a substance called biochar – essentially charcoal produced through a slow-bake process – that has been added to the cattle’s feed. This black, coal-like substance is leading a quiet revolution in this pocket of rural Australia, in an effort to reduce the cows’ methane emissions and to sink more carbon into the soil.
Greta Thunberg takes us in ‘A Year to Change the World’ Episode 3 (28.0-34.0 min) to Denmark, where she visits a team who are experimenting on cattle feed in an effort to reduce methane emissions. We are not told what this secret additive might be, but the existing examples above would suggest that it might well contain carbon? It’s both a humbling and an exciting experience to have ‘dreamed’ this idea, when it turns out to be already in practice by professionals in the field. It was not like Kekulé’s dream about the structure of Benzene, since he was a scientist, but it does perhaps show that any one of us, the ‘general public’, might have a role to play in how we deal with the climate crisis. Maybe..?

Further Reading

The United States Environmental Protection Agency has a useful Overview of Greenhouse Gases, which sets the threat posed by methane in relation to other gases.

The Government of Western Australia has also produced an almost jargon-free summary of the use of feed additives in reducing methane emissions in cattle.

https://daily.jstor.org/can-cows-help-mitigate-climate-change-yes-they-can