Yorkshire Philosophical Society

Event Information

The Trouble With Methane

John Cossham, BSc.

Café Scientifique York has been running in the city for 25 years with the Yorkshire Philosophical  Society  provisionally taking over from Science City York in October 2011 and officially from January 2012. Café Sci’s first speaker under the wing of the YPS was  John Cossham who gave a talk entitled ‘Climate Change, Peak Oil, Sex and Death’ on Wednesday October 5th, 2011. Fifteen years on John has enthusiastically agreed to return for a second appearance but this time talking  about methane.

He writes ‘Atmospheric methane is currently under 2 parts per million, but due to human activity has risen 160% since the industrial revolution, and it is responsible for almost a quarter of the warming the Earth is experiencing. Come and learn about this fascinating molecule from an entertaining climate expert.’

John has been learning about environmental issues and climate since the 1980s and has focused ​his life choices on being as low carbon as possible, winning a national award in 2008. He is  an outspoken advocate of low carbon living based in York, who earns a living mainly as a kids’ circus entertainer but makes compost as a ‘side hustle’.

It looks like an evening not to be missed in our new venue, fortyfive Vinyl Café at 29 Micklegate, York YO1 6JH   which we are trialling over the autumn courtesy of owner Ian Reid. Ian  who  took over the Café in November 2023 with his wife Rebecca have created a popular place to ‘hang out’ during the day but also a place to see  live Country and Americana music in the evening.

Doors open at 7.00pm for a start at 7.30pm. Admission is free but tickets are required.

https://www.ticketsource.com/yorkshire-philosophical-society

Member’s report:

John Cossham is a strong advocate of composting. He explained that methane is given off during anaerobic decomposition, whereas composting is aerobic decomposition.

Methane has the formula CH4 and is also known as firedamp or natural gas. There are thermogenic and biogenic sources of methane; thermogenic meaning sources such as volcanoes and biogenic meaning a biological source. Since the start of the industrial revolution, the methane concentration of the atmosphere has risen from 0.72 parts per million (ppm) to 1.9 ppm. Methane is a powerful greenhouse gas (GHG), but decomposes in the atmosphere to CO2 and H2O with a half-life of 7 years and is the second or third most important GHG. The “radiative forcing” (how much each chemical contributes to the greenhouse effect) per molecule compared to CO2 is 30x for CH4, 298x for N2O, 1550x for Hydroflurocarbons (HFC) and 5350x for chlorofluorocarbons (CFC). Water vapour is the most powerful GHG but is not usually considered for climate change. In terms of their contribution to radiative forcing, CO2 is 60%, CH4 is 20% and N2O is 6%. The main methane sink is via a complex reaction with OH, and OH is generated from ozone (O3) and UV light. OH has highest concentrations in the tropics, so methane lasts for shorter times in the tropics as compared to the poles.

John then discussed ice cores and how these can show the levels of CO2 in the atmosphere for many millions of years. CO2 gets trapped in ice bubbles. CH4 however, does  not last very long in the ice so cannot be used as a record of past methane concentrations. CO2 levels are at their highest now since about 30 million years.

John also discussed methane clathrates. These are ice lattice like structures (spongy like a snowball) that contain methane. The clathrates are mostly biogenic in origin, and they can potentially release the methane they contain into the atmosphere. There is a concern among some scientists that the warming oceans could cause the clathrates to release their methane thus contributing to positive feedback in climate change.

John gave an enthusiastic and informative talk at the new venue of the vinyl cafe. A lively discussion followed.

Chris Walker