Turning methane into carbon dioxide could help us fight climate change



It’s not cows’ fault they fart, but the methane they produce is warming the planet.
Robert Bye/Unsplash

Pep Canadell, CSIRO and Rob Jackson, Stanford University

Discussions on how to address climate change have focused, very appropriately, on reducing greenhouse gas emissions, particularly those of carbon dioxide, the major contributor to climate change and a long-lived greenhouse gas. Reducing emissions should remain the paramount climate goal.

However, greenhouse gas emissions have been increasing now for two centuries. Damage to the atmosphere is already profound enough that reducing emissions alone won’t be enough to avoid effects like extreme weather and changing weather patterns.

In a paper published today in Nature Sustainability, we propose a new technique to clean the atmosphere of the second most powerful greenhouse gas people produce: methane. The technique could restore the concentration of methane to levels found before the Industrial Revolution, and in doing so, reduce global warming by one-sixth.

Our new technique sounds paradoxical at first: turning methane into carbon dioxide. It’s a concept at this stage, and won’t be cheap, but it would add to the tool kit needed to tackle climate change.

The methane menace

After carbon dioxide, methane is the second most important greenhouse gas leading to human-induced climate change. Methane packs a climate punch: it is 84 times more powerful than carbon dioxide in warming the planet over the first 20 years of its molecular life.




Read more:
Methane is a potent pollutant – let’s keep it out of the atmosphere


Methane emissions from human activities are now larger than all natural sources combined. Agriculture and energy production generate most of them, including emissions from cattle, rice paddies and oil and gas wells.

The result is methane concentrations in the atmosphere have increased by 150% from pre-industrial times, and continue to grow. Finding ways to reduce or remove methane will therefore have an outsize and fast-acting effect in the fight against climate change.


Global Carbon Atlas

What we propose

The single biggest challenge for removing methane from the atmosphere is its low concentration, only about 2 parts per million. In contrast, carbon dioxide is now at 415 parts per million, roughly 200 times higher. Both gases are much more diluted in air than when found in the exhaust of a car or in a cow’s burp, and both would be better served by keeping them out of the atmosphere to start with.

Nonetheless, emissions continue. What if we could capture the methane after its release and convert it into something less damaging to climate?




Read more:
What is a pre-industrial climate and why does it matter?


That is why our paper proposes removing all methane in the atmosphere produced by human activities – by oxidising it to carbon dioxide. Such an approach has not been proposed before: previously, all removal techniques have only been applied to carbon dioxide.

This is the equivalent of turning 3.2 billion tonnes of methane into 8.2 billion tonnes of carbon dioxide (equivalent to several months of global emissions). The surprising aspect to this trade is that it would reduce global warming by 15%, because methane is so much more warming than carbon dioxide.

Proposed industrial array to oxidise methane to carbon dioxide.
Jackson et al. 2019 Nature Sustainability

This reaction yields energy rather than requires it. It does require a catalyst, though, such as a metal, that converts methane from the air and turns it into carbon dioxide.

One fit-for-purpose family of catalysts are zeolites. They are crystalline materials that consist of aluminum, silicon and oxygen, with a very porous molecular structure that can act as a sponge to soak up methane.

They are well known to industrial researchers trying to oxidise methane to methanol, a valuable chemical feedstock.

We envision arrays of electric fans powered by renewable energy to force large volumes of air into chambers, where the catalyst is exposed to air. The catalyst is then heated in oxygen to form and release CO₂. Such arrays of fans could be placed anywhere where renewable energy – and enough space – is available.

We calculate that with removal costs per tonne of CO₂ rising quickly from US$50 to US$500 or more this century, consistent with mitigation scenarios that keep global warming below 2℃, this technique could be economically feasible and even profitable.

We won’t know for sure, though, until future research highlights the precise chemistry and industrial infrastructure needed.

Beyond the clean-up we propose here, methane removal and atmospheric restoration could be an extra tool in humanity’s belt as we aim for stringent climate targets, while providing new economic opportunities.




Read more:
Why methane should be treated differently compared to long-lived greenhouse gases


Future research and development will determine the technical and economic feasibility of methane removal. Even if successful, methane- and other carbon-removal technologies are no substitute for strong and rapid emissions reductions if we are to avoid the worst impacts of global warming.The Conversation

Pep Canadell, Chief research scientist, CSIRO Oceans and Atmosphere; and Executive Director, Global Carbon Project, CSIRO and Rob Jackson, Chair, Department of Earth System Science, and Chair of the Global Carbon Project, globalcarbonproject.org, Stanford University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Sea the possibilities: to fight climate change, put seaweed in the mix



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Nadya Peek/Flickr, CC BY-SA

Adam Bumpus, University of Melbourne

The next stage of humanity’s fight to reduce greenhouse emissions may revolve around seaweed, according to tonight’s episode of ABC’s Catalyst, presented by Professor Tim Flannery, which asks the question “can seaweed save the world?”

With the help of me and colleagues around the world, the documentary explores seaweed’s enormous potential to reduce greenhouse gases and draw CO₂ out of the atmosphere. In the case of seaweed, that could include giant kelp farms that de-acidify oceans, or feeding algae to cattle and sheep to dramatically reduce their methane emissions.


Read more: How farming giant seaweed can feed fish and fix the climate


But while these possibilities are exciting, early adopters are dealing with unproven technology and complex international treaties. Globally, emissions are likely to keep rising, which means seaweed-related carbon capture should only be one part of a bigger emissions reduction picture.

Net negative emissions

To stay within the Paris climate agreement’s 2℃ warming threshold, most experts agree that we must remove carbon from the atmosphere as well as reduce emissions. Many scientists now argue that 2℃ will still cause dangerous climate change, and an upper limit of 1.5℃ warming by 2100 is much safer.

To achieve that goal, humanity must begin reducing global emissions from 2020 (in less time than it takes an undergrad enrolling now to finish their degree) and rapidly decarbonise to zero net emissions by 2050.


Read more: We need to get rid of carbon in the atmosphere, not just reduce emissions


Zero net carbon emissions can come from radical emissions reductions, and massive geoengineering projects. But it could be vastly helped by what Flannery calls “the third way”: mimicking or strengthening Earth’s own methods of carbon capture.

Studies support the need to remove carbon from the atmosphere, but there are serious technical, economic and political issues with many large-scale plans.

On the other hand, seaweed solutions could be put to work in the biologically desert-like “doldrums” of the ocean, and have positive side effects such as helping to clear up the giant ocean rubbish patches. However, there are many technical problems still to be solved to make this a reality.

We probably haven’t reached peak emissions

Removing carbon from the atmosphere is an attractive proposition, but we can’t ignore the emissions we’re currently pumping out. For any negative emissions technology to work, our global emissions from fossil fuels must start to drop significantly, and very soon.

But wait a second, haven’t we already hit peak emissions? It’s true that for the third year in a row, global carbon dioxide emissions from fossil fuels and industry have barely grown, while the global economy has continued to grow strongly.

This is great news, but the slowdown in emissions growth has been driven primarily by China, alongside the United States, and a general decline of emissions in developed countries.

China’s reductions are impressive. The country peaked in coal consumption in 2014, and tends to under-promise and over-deliver on emissions reductions. However, under the Paris agreement, China has committed to a 60-65% reduction in emissions intensity, which means there’s still room for them to rise in the future.

India’s emissions, on the other hand, are major wild card. With a population of 1.3 billion and rising, about 300 million of whom are still not connected to an electrical grid, and potential increases in coal use to provide energy, India will be vital to stabilising greenhouse gases.


Read more: To slow climate change, India joins the renewable energy revolution


India’s emissions today match those of China in 1990. A study that combined India’s Paris agreement targets with OECD estimates about its long-term economic growth, suggested India’s CO₂ emissions could still grow significantly by 2030 (although per capita emissions would still be well below China and the US).

The emissions reduction relay race

So how do we deal with many competing and interconnected issues? Ideally, we need an array of solutions, with complementary waves of technology handling different problems.

Clearly the first wave, the clean energy transition, is well under way. Solar installations are breaking records, with an extra 75 gigawatts added to our global capacity in 2016, up from 51 gigawatts installed in 2015. But this still represents just 1.8% of total global electricity demand.

In addition to renewable energy generation, limiting warming to below 1.5°C also means we must increase the efficiency of our existing grid. Fortunately, early-stage financiers and entrepreneurs are focusing on a second wave of smart energy, which includes efficiency and optimisation technologies. Others in Australia have also noted the opportunities offered by the increasing use of using small, smart devices connected to the internet that respond to user demand.

Although early user results have been mixed, research shows better system control reduces the emissions intensity of energy generation. These energy efficient devices and optimisation software are on the cusp of becoming widely commercially available.

Critically, these efficiency technologies will be needed to complement structural change in the fossil fuel energy mix. This is especially in places where emissions are set to grow significantly, like India. Building renewable energy capacity, optimising with new software and technologies, and better understanding the opportunity for net negative emissions all play an important part in the emissions reductions relay race over the next 50 years to get us to 1.5°C.

With further research, development, and commercialisation, the possibilities offered by seaweed – outlined in more detail in the Catalyst documentary – are potentially game-changing.

But, as we saw with the development of renewable energy generation technology, it takes a long time to move from a good idea to wide implementation. We must support the scientists and entrepreneurs exploring zero-carbon innovations – and see if seaweed really can save the world.


The ConversationCan Seaweed Save the World? airs on the ABC on Tuesday 22 August at 8.30pm.

Adam Bumpus, Senior Lecturer, Environment & Innovation, University of Melbourne

This article was originally published on The Conversation. Read the original article.

Volcanoes under the ice: melting Antarctic ice could fight climate change



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Furious winds keep the McMurdo Dry Valleys in Anarctica free of snow and ice. Calcites found in the valleys have revealed the secrets of ancient subglacial volcanoes.
Stuart Rankin/Flickr, CC BY-NC

Silvia Frisia, University of Newcastle

Iron is not commonly famous for its role as a micronutrient for tiny organisms dwelling in the cold waters of polar oceans. But iron feeds plankton, which in turn hold carbon dioxide in their bodies. When they die, the creatures sink to the bottom of the sea, safely storing that carbon.

How exactly the iron gets to the Southern Ocean is hotly debated, but we do know that during the last ice age huge amounts of carbon were stored at the bottom of the Southern Ocean. Understanding how carbon comes to be stored in the depth of the oceans could help abate CO2 in the atmosphere, and Antarctica has a powerful role.

Icebergs and atmospheric dust are believed to have been the major sources of this micronutrient in the past. However, in research published in Nature Communications, my colleagues and I examined calcite crusts from Antarctica, and found that volcanoes under its glaciers were vital in delivering iron to the ocean during the last ice age.

Today, glacial meltwaters from Greenland and the Antarctic peninsula supply iron both in solution and as tiny particles (less than 0.0001mm in diameter), which are readily consumed by plankton. Where glaciers meet bedrock, minute organisms can live in pockets of relatively warm water. They are able to extract “food” from the rock, and in doing so release iron, which then can be carried by underwater rivers to the sea.

Volcanic eruptions under the ice can create underwater subglacial lakes, which, at times, discharge downstream large masses of water that travel to the ice margin and beyond, carrying with them iron in particle and in solution.

The role of melting ice in climate change is as yet poorly understood. It’s particularly pertinent as scientists predict the imminent collapse of part of the Larsen C ice shelf.

Researchers are also investigating how to reproduce natural iron fertilisation in the Southern Ocean and induce algal blooms. By interrogating the volcanic archive, we learn more about the effect that iron fertilisation from meltwater has on global temperatures.

A polished wafer of the subglacial calcites. The translucent, crystalline layers formed while in pockets of water, providing nourishment to microbes. The opaque calcite with rock fragments documents a period when waters discharged from a subglacial lake formed by a volcanic eruption, carrying away both iron in solution and particles of iron.
Supplied

The Last Glacial Maximum

During the Last Glacial Maximum, a period 27,000 to 17,000 years ago when glaciers were at their greatest extent worldwide, the amount of CO2 in the atmosphere was lowered to 180 parts per million (ppm) relative to pre-industrial levels (280 ppm).

Today we are at 400 ppm and, if current warming trends continue, a point of no return will be reached. The global temperature system will return to the age of the dinosaurs, when there was little difference in temperature from the equator to the poles.

If we are interested in providing a habitable planet for our descendants, we need to mitigate the quantity of carbon in the atmosphere. Blooms of plankton in the Southern Ocean boosted by iron fertilisation were one important ingredient in lowering CO2 in the Last Glacial Maximum, and they could help us today.

The Last Glacial Maximum had winds that spread dust from deserts and icebergs carrying small particles into the Southern Ocean, providing the necessary iron for algal blooms. These extreme conditions don’t exist today.

Hidden volcanoes

Neither dust nor icebergs alone, however, explain bursts of productivity recorded in ocean sediments in the Last Glacial Maximum. There was another ingredient, only discovered in rare archives of subglacial processes that could be precisely dated to the Last Glacial Maximum.

Loss of ice in Antartica’s Dry Valleys uncovered rusty-red crusts of calcite plastered on glacially polished rocks. The calcites have tiny layers that can be precisely dated by radiometric techniques.

A piece of subglacial calcite coating pebbles. This suggests that the current transporting the pebbles was quite fast, like a mountain stream. The pebbles were deposited at the same time as the opaque layer in the calcite formed.
Supplied

Each layer preserves in its chemistry and DNA a record of processes that contributed to delivering iron to the Southern Ocean. For example, fluorine-rich spherules indicate that underwater vents created by volcanic activity injected a rich mixture of minerals into the subglacial environment. This was confirmed by DNA data, revealing a thriving community of thermophiles – microorganisms that live in very hot water only.

Then, it became plausible to hypothesise that volcanic eruptions occurred subglacially and formed a subglacial lake, whose waters ran into an interconnected system of channels, ultimately reaching the ice margin. Meltwater drained iron from pockets created where ice met bedrock, which then reached the ocean – thus inducing algal blooms.

We dated this drainage activity to a period when dust flux does not match ocean productivity. Thus, our study indicates that volcanoes in Antarctica had a role in delivering iron to the Southern Ocean, and potentially contributed to lowering CO2 levels in the atmosphere.

The ConversationOur research helps explain how volcanoes act on climate change. But it also uncovers more about iron fertilisation as a possible way to mitigate global warming.

Silvia Frisia, Associate Professor, School of Environmental and Life Sciences , University of Newcastle

This article was originally published on The Conversation. Read the original article.

South Georgia: Rat Fight


The link below is to an article that reports on the fight against rats on South Georgia island in the Atlantic Ocean.

For more visit:
http://news.nationalgeographic.com/news/2013/07/130729-rats-islands-invasive-species-animals-environment/