Climate Crisis - Do we really have one? Is CO2 really the issue? Methane - Discussion and control measures.

The debate on the reality of climate change continues. Those who believe in the concept of global warming seem focused on reducing the levels of atmospheric CO2, to this end, most greenhouse gas reduction activity centres around this issue.

"Everyone blames Carbon Dioxide for the perceived climate crisis. But there is perhaps something far worse than CO2, this is said to be methane, perhaps the most significant climate crisis candidate! It is a fact that methane's greenhouse effect is around 80 times more potent than carbon dioxide over a 20-year period.

Controlling methane then must clearly become our first priority? Methane emissions are sky-rocketing even as we start reducing CO2. In the battle against the climate crisis, the worlds governments seem preoccupied in funnelling substantial investments into CO2-capture technology.

Yet, surprisingly, on global warming, Methane control resource provision languishes, with a mere 2% of the funding. This stark disparity underscores the critical need for a paradigm shift in our approach to environmental innovation.

Methane is a powerful greenhouse gas and short-lived climate pollutant (SLCP) primarily emitted by human activities. It has an atmospheric lifetime of around 12 years.

Methane severely exacerbates climate change, but also has a number of indirect effects on human health, crop yields and the health of vegetation through its role as a precursor to the formation of tropospheric ozone.

So, even if you do not accept the notion of climate change, reducing methane should be considered as a worthwhile goal.

While methane has a much shorter lifetime than carbon dioxide (CO2), it is much more efficient at trapping radiation. Per unit of mass, methane has a warming effect 86 times stronger than CO2 over 20 years. Over a 100-year period methane is 28 times stronger.

Methane’s relatively short atmospheric lifetime and its strong warming potential means that actions to reduce emissions can slow the rate of warming and provide many other societal and environmental benefits within a matter of decades. Maximum possible reductions in methane emissions are essential to limiting atmospheric warming to 1.5°C.

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Methane versus carbon dioxide

While the atmospheric stock of carbon dioxide (CO2) in the atmosphere has increased by about 50% since preindustrial time (417 vs 278ppm), that of methane (CH4) has more than doubled (1879 vs 722 ppb) Although the importance of CH4 as a greenhouse gas has been known about for many years, as reflected by the Kyoto protocol of 1997, until recently public attention focused mainly on CO2. Most mitigation and remediation proposals targeted CO2.

Methane has anthropogenic (human-caused) and natural sources. More than 90% of global anthropogenic methane emissions stem from three sectors.

?The main methane emitting sectors are:_

• ?Agriculture (40%), including from livestock rearing, animal manure, and rice production.
• Fossil fuels (35%), including through leakage from natural gas and oil production and distribution systems, and coal mines.
• Waste (20%), from food and other organic materials left in landfills, open dumps, and wastewater.

?Methane's potent climate warming effect means even small amounts have a significant impact on climate, environmental, and human health. Not only does methane have a warming effect, it also acts as a precursor for the toxic air pollutant tropospheric ozone.

Quick action would help limit dangerous climate feedback loops, while simultaneously delivering important health, environmental, and economic benefits from reducing tropospheric ozone.

The atmospheric concentration of CH4 is rising

In 2020, despite Covid-19 shutdowns, the annual increase in atmospheric CH4 was the largest recorded since 1983, when systematic measurements began. Since the preindustrial era, tropospheric concentrations of CO2 and CH4 have increased by 47% and 167%, respectively. Since 2007, tropospheric CH4 has been rising rapidly, concentrations have multiplied 3.28 times from a minimum of 570 ppb, reached 5000 years ago. The IPCC predicts that, over the next 10 to 20 years, CH4 and CO2 will have similar global warming impacts, as measured by heat absorbed (global warming potential, GWP) and temperature rise (Global Temperature change Potential, GTP).

A call to action

The United Nations Environment Program (UNEP) and the Climate and Clean Air Coalition in their "Global Methane Assessment" as well as the International Energy Agency are calling for urgent action to cut CH4 emissions, and scientists and non-governmental organisations (NGOs) are calling for atmospheric CH4 removal.

These calls and decisions are timely. In the absence of further climate action, by the end of the century, global-mean warming due only to CH4 emissions could contribute to about 0.9°C (±0.2°C), compared to a warming of about 0.5 °C (±0.1°C) currently, due to historical CH4 emissions, and compared to the Paris agreement target of less than 2°C global warming including all GHGs.

Principal methods for enhancing atmospheric methane removal

Enhancing the main natural CH4 sinks

Currently, in the troposphere, the principal natural CH4 sinks are the hydroxyl radicals (which remove nearly 90% of the CH4), chlorine atoms (which remove about 2.5% of the CH4), minerals in soils and dust, soil microbes, plants and trees. Enhancing those natural sinks is a positive strategy to increase atmospheric CH4 removal.

Enhancing the hydroxyl radical OH and targeting in majority point sources - The use of AOT (Advanced Oxidative Technologies).

Atmospheric natural self-cleansing and volatile organic compound (VOC) removal is mainly due to hydroxyl radicals. Hydroxyl radical generators, as well as ozone generators, are commercially available, and indoor VOC pollution can be efficiently controlled by natural short-wave ultraviolet (UVC) light in closed systems.

Several strategies to generate Reactive Species including OH radicals and apply them in atmospheric control are more than just possible, they are feasible, effective and available - based on the numerous methods and mechanisms by which they are produced.

Indoor air quality and VOC go hand-in-hand: High concentrations typically indicate conditions that are prone to accumulate pollutants of all kinds. Although VOC emission levels aren't the only thing that people should be concerned with, they're good hallmarks of general air quality for those seeking to get healthier.

• ?Fact - Air pollution can be defined as toxic chemicals or compounds in the air at levels that pose a health risk. such as SOX, NOX, CO, CO2 & VOCs & Hydrocarbons including Methane, these effluents, mainly generated from human activities, industrial plant, power stations, exhaust from cars & combustion of fossil fuels
• Fact - Impacts are severe, health issues, global warming & infertile land
• Fact - Traditional methods such as precipitation, filtration, scrubbing, coagulation, incineration, waste management & some chemical methods are ineffective in completely overcoming the problem, they cannot remove organic, non-biodegradable & toxic pollutants
• Fact - Advanced Oxidation process (AOP) has emerged as one of the most attractive & efficient choices for the removal of contaminants
• Fact - AOP has undoubtedly shown its sheer capability in treatment of pollutants, present in nature, it is far more efficient than conventional techniques
• Fact - The most effective AOP used for removal of airborne pollution is photocatalytic

Summary

• Action on methane is the easiest and faster way to slow down global warming
• At COP26 105 countries signed ‘the methane pledge’ for -30% CH4 emissions by 2030.
• CH4 removal (remediation) is complementary with reducing CH4 emissions (mitigation).
• Atmospheric CH4 removal methods are described and early costs estimates Co-benefits include–Human health, agriculture, economy, and ozone layer recovery.

?Unlike CO2 removal methods, the CH4 removal methods discussed here do not require capture and long-term geological sequestration as for CO2, as they only accelerate the natural oxidation processes that will anyway occur with the products remaining in the atmosphere. By returning to CH4 pre-industrial levels, the increase of atmospheric CO2 resulting from CH4 oxidation is small compared to global CO2 annual emissions, while the reduction of the radiative forcing could be significant. Net warming could be reduced by about 0.5°C."

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Compiled & Edited by S D Magee – Earth Science & Technology Association