Limits of Methane & CO2 Extraction and Promise of Geoengineering

A large, looming environmental threat that gets little attention is natural methane release from receding polar ice caps, and CO2 release from massive forest fires. There is controversy on whether and how to intercept these naturally-occurring (yet human-influenced), global warming gases. The difficulties in addressing these potential “runaway” climate change sources may imply oceanic or atmospheric preventatives.

A Carbon and Methane sequestering diagram

As with everything else in our country, there are currently highly polarized opinions regarding climate change. On one hand, there is climate change denial, or at least the opinion that climate change is not man-made. On the other, there are various “zero-carbon emissions by 2050” type plans that hope for complete renewable-supplied electrification within the next 30 years. The latter is noble and appropriate in the sense that it is certainly cleaner, and will help reduce CO2. However, a giant threat hanging over all of this is the runaway effect of warming (including receding polar ice and forest fires) that threaten to release methane, while releasing CO2 (from vegetation) that can no longer absorb CO2. There are technologies that can reduce these effects, including the mining of methane and biomass conversion of forests, but one wonders if these options may be “too little too late” or might create their own damage. One conclusion is that natural methane and CO2 release is a cascading problem, perhaps offset only by massive man-made projects such phytoplankton stimulation or artificial clouds.

Natural (yet human-influenced), global warming is rapidly accelerating

We are currently at roughly 412 ppm CO2, up from pre-industrial levels of 280 ppm in pre-industrial times roughly 300 years ago. Methane has risen from 700 ppb in pre-industrial time to its current level of over 1900 ppb. While arguments could be made that we are addressing this rise in CO2 and methane with renewable energy, batteries, cleaner natural gas extraction and perhaps carbon capture and nuclear energy, it is probably not happening fast enough to offset events already in place. In other words, whether related to human consumption, movements of the earth, or other natural cycles, a warming planet is causing accelerated warming, primarily due to receding ice caps, for three main reasons:

1) Receding ice leaves less white ice to reflect sunlight, and more dark ocean to absorb sunlight

2) Receding ice is exposing methane deposits in ancient swamps, and warming oceans to the point where methane ice may melt, releasing more captured methane

3) Receding ice is changing ocean currents, creating new weather patterns that are drier in forested areas, causing more forest fires.

(Buis,2019),(NOAA.gov,2022)

Methane Hydrate deposits and extraction

Methane Deposit Mining and Forest Biomass Conversion

Two potential solutions that come to mind are mining natural methane release (methane is similar to natural gas) and collecting/burning forest debris before fires have a chance to become devastating. While methane “swamp gas” may be easier to collect (through perforated pipes that feed to collection points), the resulting gas will need further refinement (removing CO2 and sulfur, for instance). This process will probably not run at a profit for the miners, since the gas seeps slowly and is often in remote areas. However, subsidies might be paid as a form of necessary environmental cleanup. The mining of methane ice (called methane hydrate) is less understood, and would appear to have pluses and minuses. First, methane hydrate extraction is potentially more commercial since it exists in large chunks (usually in deposits more than 500 ft below the surface). The extraction of methane ice is thought to create a danger of ocean landslides, which would have unknown environmental impacts. It is not even clear to what degree future warming will allow methane hydrate to escape, since most of it is in reliably deep and cold areas. Finally, the clearing of forest biomass (dead trees, pine needles, leaves and the like) and/or controlled burns are thought to be good solutions to the devastating forest fires that have recently plagued North America, Europe, and Australia. Not only do these fires do property damage and claim lives, but they remove carbon-soaking trees and volatilize them without our having a chance to burn them properly (extract energy and capture CO2). It is thought by foresters that forest undergrowth and debris are responsible for weakening larger trees (perhaps already weakened by drought), making them easier to burn. Although controversial (given that undergrowth/debris provides some habitat), most foresters believe that biomass conversion projects would give larger trees a better chance to survive, while providing a relatively clean energy source in the larger scheme. (Zhang, Zimmermann, Stenke, and Poulter, 2017),(worldoceanreview.com,2014),(Cleaves,2010)

The before/after of undergrowth removal. The former supports more diversity and habitat, yet sets the stage for devastating fires. It would appear that in these times, if we don’t clear undergrowth for biomass conversion, that Nature will do it for us. Many environmental questions about this process remain.

If these solutions don’t work, enter Geoengineering

Methods of Methane and CO2 capture are honestly not highly advanced, and they may also be too slow or expensive to work quickly enough for humanity to adapt. The world of Geoengineering (though not without its own problems), offers potentially quicker/broader solutions. Here are some examples:

Phytoplankton Stimulation: In normal glacial cycles, warming/CO2 release is ultimately offset when minerals exposed by receding ice are blown into the ocean, thereby providing food for phytoplankton, which then gobble up CO2 at a faster rate (reversing the warming process). Many scientists have suggested seeding the oceans with iron sulfite and other minerals to accelerate phytoplankton production. An MIT study showed that such seeding would indeed greatly offset arctic ice melt, but come at a cost of decreasing rainfall in many areas. There is ongoing study as to the efficacy of these methods. (Dwortzan,2015)

The SPICE project is one of many designed to add reflective particles into the atmosphere, stimulating clouds

Cloud Brightening: After the Pinatubo volcanic eruption in the Philippines in 1991, scientists noticed that the planet cooled temporarily (mostly due to the particles emitted that reflected sunlight away from the earth). There have been many suggestions regarding ways to reflect back sunlight, one of them being “cloud brightening” (basically introducing particles in the atmosphere that invite water vapor to congregate to a greater degree, thereby creating greater reflectivity). (Smedley,2019)

Both phytoplankton stimulation and cloud brightening might be thought of as enhancement of a natural process. There are several other geoengineering proposals, including placing light deflectors in space, and vertical pipes in the ocean (that would increase downward heat transport). (ametsoc.org,2013)

There is much discussion in geoengineering circles about the “unintended consequences” of introducing such interventions in Nature, which would probably involve some artificial imbalances in weather and/or habitat patterns. They could be tried first on a limited or experimental basis, then perhaps used in combination with other climate change offsetting strategies.

Other Climate Related Articles by Vern Scott

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Vern Scott

Scott lives in the SF Bay Area and writes confidently about Engineering, History, Politics, and Health