We've all heard about carbon capture and it's potential to impede climate change. What of methane; the primary greenhouse gas produced by industrial livestock farming?
Theoretically atmospheric methane removal has no limit, unlike carbon capture which is inconceivable because CO2 vital to ecosystem success (Boucher and Folberth, 2010). This combined with the greater potency of methane (25x) makes methane sequestration technologies worth exploring.
There are a number of ways methane can be broken down and removed from the atmosphere although collectively they require high temperatures and produce unwanted waste products. As is often the case, nature has provided us an answer to this problem in the form of methanotrophs, bacteria which serve the opposite function to those found in the gut of ruminant animal, converting methane into more favourable chemicals.
Yoon and others (2009) recently conducted a study on the feasibility of atmospheric methane removal using biotrickling filters containing methanotrophs. Their model suggested the method would only be effective where methane concentration exceeds 500 ppmv. One such location that this occurs would be on a factory farm! Unfortunately the cost of this method is a major drawback. At up to 20x more expensive for equivalent carbon capture devices it is not an economically appealing system.
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| Source: https://emis.vito.be/en/techniekfiche/biotrickling-filter |
It has been suggested that chemically mimicking these bacteria could be a more efficient and economically viable option (Ravilious, 2010). Rosenzweig and others (2010) were able to identify the make-up of the specific enzyme within methanotrophs that catalyzes the reaction which breaks down methane. It is hoped this finding could be implemented into previous biotrickling devices or future methane removal technologies.
Final thoughts...
Looking for studies that tackle the issue of methane sequestration specifically was difficult. Hypothetically methane-removal is a very appealing climate change mitigation strategy although it has become obvious to me that it is also an extremely complicated one. Small concentrations of methane in the atmosphere and it's low chemical reactivity mean sequestration is currently limited to specific environments and it is obvious in the literature that overcoming these problems remains the biggest concern.
Hi Finn, If capturing methane from the atmosphere has so much potential, why do you think that there is so little research into this?
ReplyDeleteFrom what I've read the process is incredibly complicated, and at this stage of development very expensive.
ReplyDeleteIt's potential is also limited to factory farms which unfortunately tend not to be at the forefront of thinking when it comes to climate change mitigation. I think because carbon sequestration so much cheaper and more applicable to a variety of industries this is where much of the focus has been.