Methane warming exaggerated by 400%

Reblogged from Watts Up With That:

By Barry Brill

The IPCC’s AR5 estimated the global warming caused by a tonne of livestock methane would be 28 times that of a tonne of carbon dioxide. New research destroys that estimate.

The war on meat has been gathering pace amongst our Western elites. The Economist makes a detailed case for “plant-based food” in the interests of quelling climate change –

The FAO calculates that cattle generate up to two-thirds of the greenhouse gases from livestock, and are the world’s fifth largest source of methane. If cows were a country, the United Herds of Earth would be the planet’s third largest greenhouse-gas emitter.

These calculations are based on figures supplied by the IPCC’s AR5, which contends that the global warming potential (GWP) of methane over 100 years is no less than 28 times the global warming it expects to be caused by an equivalent weight of carbon dioxide. This estimate is up from the GWP of 21 put forward in the IPCC’s previous report.

All this is now challenged by a new and authoritative research paper, Allen et al (2017): “A solution to the misrepresentations of CO2-equivalent emissions of short-lived climate pollutants, under ambitious mitigation”. This paper finds that conventional GWPs misrepresent the impact of short-lived gases (such as methane) on global temperature – and recommends the adoption of a new metric, denoted as GWP*.

This is a big advance. The abstract observes that, “measured by GWP*, implementing the Paris Agreement would reduce the expected rate of warming in 2030 by 28% relative to No Policy”. And who would know this better than lead author Myles Allen, who was also a co-author of the IPCC’s SR1.5 in 2018.

Currently visiting New Zealand, Professor Allen has recommended that enteric methane be entirely omitted from that country’s cap-and-trade scheme (ETS) because a steady-state herd of cattle can add very little to global warming. Methane has a half-life in the atmosphere of only about six years – so that every new molecule added is offset by the expiry of a molecule emitted by that herd a few years earlier.

He says:

“Traditional greenhouse gas accounting ignores the impact of changing methane emission rates while grossly exaggerating the impact of steady methane emissions”.   And –

“Climate policy the world over has traditionally treated every tonne of methane as supposedly “equivalentto 28 tonnes of carbon dioxide… It isn’t.

To find the carbon dioxide emissions that would actually have a similar impact on global temperature as methane emissions, you need to multiply those methane emissions by seven (not 28), and add the rate of change of methane emissions (measured in tonnes of methane per year per year), multiplied by 2100.”

If there is no “rate of change” (ie the quantity of emissions by weight is constant over time) then there is a one-off impact of only seven times the equivalent weight of CO2. Note that this should only be counted once – there is no accumulation as is the case for CO2 and other long-lived gases.

And, if the herd’s digestive efficiency is improved ever so slightly –

“Even more strikingly, if an individual herd’s methane emissions are falling by one third of one percent per year (that’s 7/2100, so the two terms cancel out) …then that herd is no longer adding to global warming. Yet if methane were included in a European-style Emission Trading System (ETS), the owner of the herd would have to pay just as if it was.”

Professor Allen is not beset by doubts regarding the error of the old ways:

“That this formula is vastly more accurate than the traditional accounting rule is indisputable.”

Not only are steady-state cattle herds climatically harmless, but they have the opportunity to help out the motorists and jet-setters. Professor Allen says in a further speech that if New Zealand reduced methane emissions by 30% over the next 30 years, that would actually contribute to global cooling:

“If a farmer is providing a service to the rest of the country by compensating for other people’s global warming, then that farmer might want to make a case that they should be compensated for that.”

As a co-author of SR1.5, the professor has a tip for the meat warriors that they should not rely on RCP scenarios:

“Those scenarios are based on economic models of the relative cost of different ways of reducing emissions. Some of the inputs to these models, like the estimated “cost” of a large fraction of the population turning vegetarian, are deeply subjective. The scenarios provide background information, but I would not rely on them as a basis for national policy.”

The findings of the Allen et al paper have been implicitly accepted by New Zealand’s Parliamentary Commissioner for the Environment, Simon Upton – formerly the head of the OECD Environment Directorate. He has this week published a lengthy and detailed report, Farms, Forests and Fossil Fuels, which recommends that the Government develop two separate targets for the second half of the 21st century – a zero target for fossil emissions, and a reduction target for biological emissions.

Let’s all enjoy a hearty guilt-free steak, served with lashings of cheese and butter!

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Climate Models Fail: Climate Warming Experiment Finds Unexpected Results 

Flawed experiment. Heating the test system without proportionally increasing water vapor is akin to desertification of the system. So much wrong with this study.

Tallbloke's Talkshop

Credit: klimatetochskogen.nu
Climate models are known to have their shortcomings, whether due to use of faulty theories or shortage of computing skills.

H/T The Global Warming Policy Forum (GWPF)

Tropical forests store about a third of Earth’s carbon and about two-thirds of its above-ground biomass.

Most climate change models predict that as the world warms, all of that biomass will decompose more quickly, which would send a lot more carbon dioxide into the atmosphere.

But new research presented at the American Geophysical Union’s 2018 Fall Meeting contradicts that theory.

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Melting ice sheets release tons of methane into the atmosphere, study finds

Reblogged from Watts Up With That:

From EurekAlert!

Public Release: 3-Jan-2019

Melting ice sheets release tons of methane into the atmosphere, study finds

University of Bristol

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Melting ice sheet release tons of methane into the atmosphere, study finds

The Greenland Ice Sheet emits tons of methane according to a new study, showing that subglacial biological activity impacts the atmosphere far more than previously thought.

An international team of researchers led by the University of Bristol camped for three months next to the Greenland Ice Sheet, sampling the meltwater that runs off a large catchment (> 600 km2) of the Ice Sheet during the summer months.

As reported in Nature, using novel sensors to measure methane in meltwater runoff in real time, they observed that methane was continuously exported from beneath the ice.

They calculated that at least six tons of methane was transported to their measuring site from this portion of the Ice Sheet alone, roughly the equivalent of the methane released by up to 100 cows.

Professor Jemma Wadham, Director of Bristol’s Cabot Institute for the Environment, who led the investigation, said: “A key finding is that much of the methane produced beneath the ice likely escapes the Greenland Ice Sheet in large, fast flowing rivers before it can be oxidized to CO2, a typical fate for methane gas which normally reduces its greenhouse warming potency.”

Methane gas (CH4) is the third most important greenhouse gas in the atmosphere after water vapour and carbon dioxide (CO2). Although, present in lower concentrations that CO2, methane is approximately 20-28 times more potent. Therefore smaller quantities have the potential to cause disproportionate impacts on atmospheric temperatures. Most of the Earth’s methane is produced by microorganisms that convert organic matter to CH4 in the absence of oxygen, mostly in wetlands and on agricultural land, for instance in the stomachs of cows and rice paddies. The remainder comes from fossil fuels like natural gas.

While some methane had been detected previously in Greenland ice cores and in an Antarctic Subglacial Lake, this is the first time that meltwaters produced in spring and summer in large ice sheet catchments have been reported to continuously flush out methane from the ice sheet bed to the atmosphere.

Lead author, Guillaume Lamarche-Gagnon, from Bristol’s School of Geographical Sciences, said: “What is also striking is the fact that we’ve found unequivocal evidence of a widespread subglacial microbial system. Whilst we knew that methane-producing microbes likely were important in subglacial environments, how important and widespread they truly were was debatable. Now we clearly see that active microorganisms, living under kilometres of ice, are not only surviving, but likely impacting other parts of the Earth system. This subglacial methane is essentially a biomarker for life in these isolated habitats.”

Most studies on Arctic methane sources focus on permafrost, because these frozen soils tend to hold large reserves of organic carbon that could be converted to methane when they thaw due to climate warming. This latest study shows that ice sheet beds, which hold large reserves of carbon, liquid water, microorganisms and very little oxygen – the ideal conditions for creating methane gas – are also atmospheric methane sources.

Co-researcher Dr Elizabeth Bagshaw from Cardiff University added: “The new sensor technologies that we used give us a window into this previously unseen part of the glacial environment. Continuous measurement of meltwater enables us to improve our understanding of how these fascinating systems work and how they impact the rest of the planet.”

With Antarctica holding the largest ice mass on the planet, researchers say their findings make a case for turning the spotlight to the south. Mr Lamarche-Gagnon added: “Several orders of magnitude more methane has been hypothesized to be capped beneath the Antarctic Ice Sheet than beneath Arctic ice-masses. Like we did in Greenland, it’s time to put more robust numbers on the theory.”

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This study was a collaboration between Bristol University, Charles University (Czechia), the National Oceanography Centre in Southampton, Newcastle University, the University of Toronto (Canada), the Université Libre de Bruxelles (Belgium), Cardiff University (UK), and Kongsberg Maritime Contros (Germany). It was funded by the Natural Environment Research Council (NERC), with additional funds from the Leverhulme Trust, the Czech Science Foundation, the Natural Sciences and Engineering Research Council of Canada, and the Fond de Recherche Nature et Technologies du Québec (Canada).

Paper: ‘Greenland melt drives continuous export of methane from the ice sheet bed’ by Guillaume Lamarche-Gagnon, Jemma L. Wadham, et al. Nature, Doi: 10.1038/s41586-018-0800-0

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