‘Gas-led recovery’: methane and the risk of mass extinction

May 28, 2021

“The smart way to keep people passive and obedient is to strictly limit the spectrum of acceptable opinion, but allow very lively debate within that spectrum” – Noam Chomsky (1998).

The level of atmospheric methane, a poisonous gas considered responsible for major mass extinction events in the past, has nearly tripled during the 20-21st centuries, from ~722 ppb (parts per billion) to above ~1866 ppb, currently reinforced by coal seam gas (CSG) emissions. As the concentration of atmospheric methane from melting Arctic permafrost, from Arctic sediments and from marshlands worldwide is rising, the hydrocarbon industry, subsidized by governments, is progressively enhancing global warming by extracting coal seam gas in defiance of every international agreement.

Methane (CH4), a powerful greenhouse gas ~80 times the radiative power of CO2 when fresh, sourced in from anaerobic decomposition in wetlands, rice fields, emission from animals, fermentation, animal waste, biomass burning, charcoal combustion and anaerobic decomposition of organic waste, is enriched by melting of leaking permafrost, heating of sediments and extraction as coal seam gas (CSG). The addition to the atmosphere of even a part of the estimated 1,400 billion tons of carbon (GtC) from Arctic permafrost would destine the Earth to temperatures higher than 4 degrees Celsius and thereby demise of the biosphere life support systems.

During the last and present centuries, global methane concentrations have risen from approximately ~700 parts per billion (ppb) to near-1900 ppb, an increase by a factor of ~2.7, the highest rate in the last 800,000 years.

Figure 1. Historical and modern variations in atmospheric methane

Since the onset of the Industrial age global emissions of carbon have reached near-600 billion tonnes of carbon (>2100 billion tonnes CO2) at a rate faster than during the demise of dinosaurs. According to research published in Nature Geoscience carbon dioxide (CO₂) is being added to the atmosphere at least ten times faster than during a major warming event about 55 million years ago.

Australia, possessing an abundance of natural gas, namely methane resources, is on track to become the world’s largest exporter. Leaks from hydraulic fracturing (fracking) production wells, transport and residues of combustion are bound to contribute significantly to atmospheric methane. However, despite economic objections, not to mention accelerating global warming, Natural gas from coal seam gas, liquefied to -161°C, is favoured by the government for domestic use as well as exported around the world

In the Hunter Valley, NSW, the release of methane from open-cut coal mining reached above 3000 ppb. In the US methane released in some coal seam gas fields constitute between 2 and 17 per cent of the emissions.

Whereas natural gas typically emits between 50 and 60 per cent less CO2 than coal the drilling and extraction of natural gas from wells, fugitive emissions, leaks from transportation in pipelines result in enrichment of the atmosphere in methane, the main component of natural gas, 34 times stronger than CO2 at trapping heat over a 100-year period and 86 times stronger over 20 years. But whereas natural gas burns cleaner than other combustible fuels doesn’t mean that it’s clean – the reason summed up in one word: methane.

Global warming triggered by the massive release of carbon dioxide may be catastrophic, whereas the release of methane from methane hydrate may be apocalyptic. According to Brand et al., (2016), the release of methane from permafrost and shelf sediment has constituted the ultimate source and cause for the dramatic life-changing global warming. The mass extinction at the end of the Permian 251 million years ago, when 96 per cent of species were lost, holds an important lesson for humanity regarding greenhouse gas emissions, global warming, and the life support system of the planet (Brand et al. 2016. Methane Hydrate: Killer cause of Earth’s greatest mass extinction).

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