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Grounds for climate change optimism?

When global warming and greenhouse gases are mentioned (and they are, seemingly endlessly, but does anybody listen? Does anybody do anything about it..?) [Ed. – Steady on, Mr C, the good people in Paris for COP 21 * have done their best!], the focus is usually upon carbon dioxide (CO2) . However, an even more potent greenhouse gas [i.e. one that ‘traps’ heat from the Earth in the atmosphere thereby preventing its release into space and as a consequence increases the atmosphere’s temperature, which if on a world-wide scale, is global warming] than carbon dioxide is methane [CH4].

The Coffee Bearer
The Coffee Bearer. John Frederick Lewis (1805–1876) / Wikipedia.

Attempts to either remove what’s already present in the atmosphere or to prevent further additions thereto are therefore of interest, to us all. An unusual source – but one of direct botanical relevance! – is the finding by Christian Kemp et al. that waste coffee grounds can generate a material that can be used not only to capture methane, but also to store it.

Coffee grounds are what remains after coffee beans have been ground (!) and the resultant coffee beverage made and consumed. For methane-storage the grounds need to be treated – which processing includes heating with potassium hydroxide and activation by annealing under an argon (Ar) atmosphere for 1 h at 700–900 °C – but this does provide a material with a high capacity for storage of methane. And the stored methane could be used as a fuel source (which upon combustion is converted to CO2 and H2O – both of which are greenhouse gases, but less damaging molecule-for-molecule than methane…).

Something to think about when you next have a cup of espresso-latte-mochaccino-instant coffee. And, who knows, maybe Starbucks could defray any UK corporation tax liabilities in activated coffee grounds, rather than just having them scattered on the garden?

[Ed. – for a listing of 10, 20 or even 34 other things you can do with coffee grounds, see the web sites indicated. And for those who thought coffee grounds were useful to deter slugs from eating your plants, experimentation suggests that this is a gardener’s myth **– see Robert Parvis’ account at]


or COP-OUT as some pessimists have nicknamed it, always expecting more from such global gatherings of the ‘great and the good’…


** and who is this ‘gardener Smith’ bloke..?

Nigel Chaffey

I am a Botanist and former Senior Lecturer in Botany at Bath Spa University (Bath, near Bristol, UK). As News Editor for the Annals of Botany I contributed the monthly Plant Cuttings column to that august international phytological organ for almost 10 years. I am now a freelance plant science communicator and Visiting Research Fellow at Bath Spa University. I also continue to share my Cuttingsesque items - and appraisals of books with a plant focus - with a plant-curious audience at Botany One. In that guise my main goal is to inform (hopefully, in an educational, and entertaining way) others about plants and plant-people interactions, and thereby improve humankind's botanical literacy. I'm happy to be contacted to discuss potential writing - or talking - projects and opportunities.
[ORCID: 0000-0002-4231-9082]

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