Tag Archives: co2

In Iceland, CO2 is sucked out of the air and turned into rock

A facility in Iceland is taking atmospheric carbon dioxide (CO2), the main culprit of climate change, and injecting it into volcanic rocks deep underground. While this is still early days and the volume of CO2 isn’t too great, this type of technology could be very important in the future.

The Orca plant. Image credits: Climeworks.

Even if we’d magically stop all our greenhouse gas emissions tomorrow, the inertia of our past emissions would still push the planet to warm a bit. If we continue “business as usual”, things will be way worse. So why don’t we just take greenhouse gases out of the air and store them somewhere safe where they can’t contribute to global warming?

The idea is not new, but of course, it’s easier said than done. Separating out the right gases, processing them, and storing them somewhere where they can’t escape back into the atmosphere are all big challenges — and doing them all together is even more demanding. But a company working in Iceland is not deterred.

Climeworks is a Swiss company specializing in carbon dioxide air capture technology. They’ve recently built a plant in Iceland called Orca that can capture 4000 tons of CO2 per year, making it the biggest climate-positive facility in the world.

Orca (the Icelandic word for energy) lies near the Hellisheiði Power Station — the third largest geothermal power plant in the world. It consists of eight containers stacked up two by two; fans in front of a collector draw ambient air, the air passes through a selective material that collects CO2, and the CO2-depleted air is then released at the back. It’s a bit like “mining” the sky for CO2 — simple in principle, though very difficult to implement.

What happens next is also not exactly simple. After the filter is full, it’s heated to around 100 degrees Celsius to clear the CO2 of any impurities, and then piped underground a distance of three kilometres (1.8 miles) to dome-shaped facilities in a moon-like landscape where it is dissolved in water and then injected under high pressure into basalt rock 800-2000 meters deep. The injection facility was developed by Carbfix which pioneered underground carbon storage.

The injection facility. Image credits: Carbfix.

The dissolved solution starts filling the cavities of the subsurface basalt and reacting with the rock, solidifying and turning into minerals in about two years.

To do this, you need the right geology, and Iceland offers just that. Much of Iceland is a basaltic field, where this dissolved gas can be safely injected. The only way the CO2 would be released into the air is in the case of a volcanic eruption, but the injection site was chosen in an area where the risk of an eruption is very low.

A core of basalt rock (black part) with the injected CO2 (white part). Image credits: Climeworks.

However, as exciting and promising as this technology is, it won’t save us from climate change on its own. While Orca can suck up to 4000 tons of CO2 per year, the yearly global emissions are around 33.4 billion tons of CO2 — so the plant can dispose of 0.00001% of our yearly emissions. Climeworks says this is mostly a trial and it will achieve megaton removal capacity in the second part of the decade, but even one megaton is still a very small percentage of our emissions. To make matters even more complicated, the process is costly and requires large amounts of energy. While the plant is run on renewable energy, this still makes scaling more difficult.

In fact, carbon capture is making such a small dent in our total emissions that critics have argued that it’s a costly distraction from the real policy measures needed to fight climate change. It’s true that only reducing our emissions can prevent catastrophic climate change, but “you have to learn to walk before you can run,” says Julie Gosalvez, in charge of marketing for Climeworks.

Carbon storage is just emerging as a technology. It won’t help us fix climate change yet, but it can be important down the line — provided we have the right conditions for it. The only way it can work is if the world implements a carbon tax, and extracting carbon from the air is incentivized. This makes economic sense, but for now, there’s no such carbon tax on the horizon.

A new study says it’s time to start recycling anesthetics

Times are tough for everybody — but are they ‘recycle our anesthetics’ tough? A team of researchers says yes.

Healthcare can be an important source of greenhouse gas emissions. It accounts for around 5% of all emissions in the UK, for example, or around 10% for the US, a new study from the University of Exeter explains. Inhaled general anesthetics make up a significant part of that, as they are potent greenhouse compounds and very little of them are broken down in the bodies of patients.

Image via Pixabay.

The authors explain that recycling these substances can thus have a meaningful and beneficial effect on the climate. An hour-long administration of two common anesthetics, sevoflurane and desflurane, produce around 1.5 and 60kgs of carbon dioxide equivalent, they add. However — these figures don’t take into account emissions from the anesthetics’ manufacturing process, meaning the total figures are much higher.

Running on fumes

What the authors propose is that inhalable anesthetics would be recycled after every use. This would both limit their greenhouse effect in the atmosphere and reduce emissions from manufacturing as lower quantities would be needed overall. They suggest doing this through the use of new vapor-capture technology to harvest, purify, and eventually remarket the anesthetics.

“Our results are an important step in supporting healthcare providers to reduce their carbon footprint. To reduce the carbon footprint of inhalational anesthetics, this study encourages the continued reduction in the use of nitrous oxide and recommends a wider adoption of anesthetic recycling technology,” said lead author Dr. Xiaocheng Hu, of the University of Exeter Medical School.

The study builds on previous analyses around the carbon footprint of inhalable anesthesia including sevoflurane, isoflurane and desflurane, the footprint associated with the use of nitrous oxide, and the carbon footprint of injectable anesthetic Propofol.

Modeling (using typical gas combinations used for anaesthesia in the UK) revealed that sevoflurane and propofol have roughly similar footprints. This likely comes down to the fact that sevoflurane is generally administered mixed with oxygen through a recycling feed. When taking into account their manufacturing processes, however, the carbon footprint of sevoflurane was much higher, similar to that of desflurane. The authors add that nitrous oxide has a disproportionately high effect on the total carbon footprint of anesthesia.

The carrier gases these compounds are delivered in also have an important effect on their final carbon footprint. An air-oxygen mix, according to the team, produces fewer emissions than nitrous oxide. The research showcases why it’s important to consider manufacturing processes as well when calculating a good’s environmental impact. It also goes to show that, at least as far as aesthetics are concerned, this has been underestimated so far.

At the same time, such research might usher in the age of recycled anesthetics — which sounds a bit strange. But hey, if it helps the polar bears, I’ll take it. It’s not like I’m going to feel any difference.

The paper “The carbon footprint of general anaesthetics: A case study in the UK” has been published in the journal Resources, Conservation and Recycling.

Atmospheric CO2 levels this year could reach 150% of those before the Industrial Revolution

Our climate is changing, and the cause is our own emissions. To put those into perspective, new research estimates that atmospheric CO2 levels in 2021 will be 50% higher than the average value in the 18th century (the onset of the Industrial Revolution).

Image credits Chris LeBoutillier.

The Met Office, Britain’s national weather service, estimates in a new report that average annual CO2 levels this year (as measured at the Mauna Loa Observatory in Hawaii), will rise by roughly 2.29 ppm (parts per million) compared to 2020. That is around 150% of the concentration this gas registered in the 18th century, before industrial emissions started to output in significant quantities.

Bad air

“Since CO2 stays in the atmosphere for a very long time, each year’s emissions add to those from previous years and cause the amount of CO2 in the atmosphere to keep increasing,” said Richard Betts, lead producer of the Met Office’s annual CO2 forecast.

The most worrying observation is that CO2 levels are still expected to rise in 2021 despite a significant drop in total emission levels due to the pandemic.

Mauna Loa is used as a gold-standard for the measurement of CO2 levels in the atmosphere. The site has been in operation monitoring this gas since 1958. These show seasonal variation , but they’re also influenced by local factors and geography, so having a single monitoring point in operation for so long makes the readings more reliable, as they can be easily compared to past readings.

Still, the news leaves us in an unenviable spot. According to the United Nations, emissions from energy, food production, transport and industry must drop by 7% per year every year throughout the next decade if we’re to meet the target of the Paris climate deal. This international deal aims to keep global warming “well below” 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels — ideally below 1.5 degrees Celsius.

We’ve only seen 1 degree Celsius of warming (compared to pre-industrial levels) so far, and yet, we have seen extreme weather events such as floods, droughts, and tropical storms pick up around the globe. The seas are also rising to meet us.

According to the Met Office, it took 200 years for atmospheric CO2 concentrations to rise 25% above pre-industrial levels; it only took an extra 30 to get to double that. It might take even less to double that figure yet again unless we take serious action — and do so quickly.

“Reversing this trend and slowing the atmospheric CO2 rise will need global emissions to reduce, and bringing them to a halt will need global emissions to be brought down to net zero.”

Wetter, warmer soils will intensify climate change

Climate change is poised to make tropical ecosystems wetter — which will make them release more carbon dioxide, according to a new paper.

Image via Pixabay.

The study focused on an analysis of ancient tropical soils from the submarine delta of the Ganges and Brahmaputra rivers. Throughout history, the data reveals, these soils have emitted higher levels of CO2 gas during warmer and wetter periods. The team writes that the same mechanism can amplify the effect of climate change as tropical soils today will release more CO2 into the atmosphere on top of (and due to) human emissions.

A study in the May 6th issue of Nature indicates the increase in rainfall forecast by global climate models is likely to hasten the release of carbon dioxide from tropical soils, further intensifying the climate crisis by adding to human emissions of this greenhouse gas into Earth’s atmosphere.

Worse with water

“We found that shifts toward a warmer and wetter climate in the drainage basin of the Ganges and Brahmaputra rivers over the last 18,000 years enhanced rates of soil respiration and decreased stocks of soil carbon,” says Dr. Christopher Hein of William & Mary’s Virginia Institute of Marine Science, lead author of the paper.

“This has direct implications for Earth’s future, as climate change is likely to increase rainfall in tropical regions, further accelerating respiration of soil carbon, and adding even more CO2 to the atmosphere than that directly added by humans.”

Soil respiration represents the CO2 gas released by microbes into the atmosphere as they munch on and decompose organic material at or just below the ground surface such as leaves, roots, and dead organic matter. It’s not very different, actually, from the way humans and other animals generate CO2 from cellular processes that they then breathe out.

Plant roots also contribute to soil respiration during the night when plants can’t photosynthesize, and so burn off some of the carbohydrates (sugars) they produced during the day for energy.

The team analyzed three cores collected from the ocean floor at the mouth of the Ganges and Brahmaputra rivers in Bangladesh — which form the world’s largest delta and abyssal fan with sediments eroded from the Himalayas. These cores allowed the team to track environmental changes in the region over the last 18,000 years. Their data showed that there is a strong link between soil age and runoff rates.

Younger soils, which formed during wetter epochs, showed more rapid respiration rates, while older ones — which formed in cooler, drier times — showed less respiration and held higher quantities of carbon for longer periods of time. The wetter times correlate with periods of the Indian summer monsoon, the primary source of precipitation across India, the Himalayas, and south-central Asia, was stronger. The team confirmed this link by analyzing other paleoclimatic evidence in geologic formations and fossil phytoplankton.

“Small changes in the amount of carbon stored in soils can play an outsized role in modulating atmospheric CO2 concentrations and, therefore, global climate, as soils are a primary global reservoir of this element,” Hein explains.

The team notes that soils hold an estimated 3,500 billion tons of carbon or around four times as much as the quantity of this element in the atmosphere.

The feedback process seen by the team here — where atmospheric CO2 drives global warming which increases the release of CO2 — is only one piece of a larger image. Similar findings on permafrost soils of the Arctic circle have been made in the past. There, widespread thawing is allowing for more extensive microbial activity and is responsible for an estimated 0.6 billion tons of carbon emissions to the atmosphere each year.

The paper “Millennial-scale hydroclimate control of tropical soil carbon storage,” has been published in the journal Nature.

Wooden buildings could help stabilize the climate

Replacing steel and concrete with wood could help in our efforts to stabilize the climate, a new paper reports. The shift would slash emissions generated by the production of such materials and further acts as a carbon sink.

Image via Pixabay.

Despite the advantages of using wood over other materials in construction, the findings should be taken with a grain of salt: harvesting enough timber for all buildings could place huge pressure on the environment. The authors thus caution that sustainable forest management and governance is key to the success of such a shift.

Going back to the basics

“Urbanization and population growth will create a vast demand for the construction of new housing and commercial buildings — hence the production of cement and steel will remain a major source of greenhouse gas emissions unless appropriately addressed,” says the study’s lead-author Dr. Galina Churkina from the Potsdam Institute for Climate Impact Research in Germany (PIK).

For the study, the team analyzed four different scenarios spanning thirty years into the future. The business as usual scenario considered that only 0.5% of all new buildings constructed by 2050 will be made out of timber. The second and third scenarios considered that figure to sit at 10% and 50% respectively, to simulate a mass transition towards timber. The final scenario considered that 90% of all new buildings will be constructed out of wood, simulating what would happen if even underdeveloped countries make the transition towards this building material.

The first scenario could store around 10 million tons of carbon per year, while the last would be close to 700 million tons. The team explains that reductions in cement and steel production would help further reduce emissions, which currently sit at around 11,000 million tons of carbon per year. Assuming that steel and concrete would still be in use (scenario 2 and 3) and assuming an increase in floor area per person, as has been the trend up to now, the team estimates that timber buildings could slash up to 20% of the CO2 emissions budget by 2050 by reducing emissions from building material manufacturing. The carbon budget is the quantity of CO2 emissions we can release and still meet the 2°C threshold set by the Paris agreement.

The authors argue that society needs some kind of effective CO2 sink to meet this budget to counteract hard-to-avoid emissions, such as those from agriculture. A five-story building made of laminated timber can store up to 180 kilos of carbon per square meter, they explain, which is around three times more than what a natural forest could hold. However:

“Protecting forests from unsustainable logging and a wide range of other threats is key if timber use was to be substantially increased,” explains co-author Christopher Reyer from the PIK. “Our vision for sustainable forest management and governance could indeed improve the situation for forests worldwide as they are valued more.”

Currently, the team estimates, unexploited wood resources would cover the demands of the 10% scenario. If floor area per person remains as it is now worldwide, the 50% or even 90% scenario could be feasible. An important goal here is to reduce the use of wood as fuel to free it up for use as a construction material.

Reducing the use of roundwood for fuel — currently roughly half of the roundwood harvest is burnt, also adding to emissions — would make more of it available for building with engineered timber. Moreover, re-using wood from demolished buildings can add to the supply.

“There’s quite some uncertainty involved, yet it seems very worth exploring,” says Reyer. “Additionally, plantations would be needed to cover the demand, including the cultivation of fast-growing Bamboo by small-scale landowners in tropical and subtropical regions.”

The paper “Buildings as a global carbon sink” has been published in the journal Nature Sustainability.

More atmospheric CO2 could reduce cognitive ability, especially in children

New research from the University of Colorado Boulder, the Colorado School of Public Health, and the University of Pennsylvania found that higher levels of atmospheric CO2 in the future could lead to cognitive issues.

Image via Pixabay.

A new study found that higher concentrations of atmospheric CO2 could negatively impact our cognitive abilities — especially among children in the classroom. The findings were presented at this year’s American Geophysical Union’s Fall Meeting.

Heavy breathing

Prior research has shown that higher-than-average levels of CO2 can impair our thinking and lead to cognitive problems. Children in particular and their academic performance can be negatively impacted by this, but, so far, researchers have identified a simple and elegant solution — open the windows and let some fresh air in.

However, what happens when the air outside also shows higher-than-usual CO2 levels? In an effort to find out, the team used a computer model and looked at two scenarios: one in which we successfully reduce the amount of CO2 we emit into the atmosphere, and one in which we don’t (a business-as-usual scenario). They then analyzed what effects each situation would have on a classroom of children.

In the first scenario, they explain that by 2100 students will be exposed to enough CO2 gas that, judging from the results of previous studies, they would experience a 25% decline in cognitive abilities. Under the second scenario, however, they report that students could experience a whopping 50% decline in cognitive ability.

The study doesn’t look at the effects of breathing higher-than-average quantities of CO2 sporadically — it analyzes the effects of doing so on a regular basis. The team explained that their study was the first to gauge this impact, and that the findings — while definitely worrying — still need to be validated by further research. Note that the paper has been submitted for peer-review pending publication but has yet to pass this step.

All in all, however, it’s another stark reminder that we should make an effort to cut CO2 emissions as quickly as humanly possible. Not only because they’re ‘killing the planet’, but because they will have a deeply negative impact on our quality of life, and mental capacity, in the future.

A preprint of the paper “Fossil fuel combustion is driving indoor CO2 toward levels harmful to human cognition” is available on EarthArXiv, and has been submitted for peer-review and publication in the journal GeoHealth.

Carbon emission growth rates go down, overall emissions reach record highs (again)

The rate of carbon emission growth in 2019 has dropped compared to those of 2018 and 2017. However, overall CO2 emission levels are expected to reach 37 billion tons — a record high.

Industrial zone in the Rhur area, Germany.
Image via Pixabay.

The estimates come from the Global Carbon Project, an initiative led by Stanford University scientist Rob Jackson, and have been published in advance of the 25th conference of the United Nations Framework Convention on Climate Change in Madrid. Overall, emission levels in 2019 are projected to rise by 0.6% over 2018 levels, compared to a 2.1% and 1.5% rise in 2018 and 2017, respectively.

The authors warn that while the rise in emissions is slowing down, emission rates are very likely to keep increasing through to 2030 unless world leaders take meaningful action to reduce fossil fuel use in national energy, transportation, and industry sectors.

Good, not good enough

“When the good news is that emissions growth is slower than last year, we need help,” said Jackson, a professor of Earth system science at the Stanford School of Earth, Energy & Environmental Sciences.

“When will emissions start to drop?”

On the one hand, we see reasons for hope: coal use is in decline across most developed, western states (such as the EU and US). On the other hand, reductions here are canceled out by increased use of oil and natural gas around the world. Fossil fuel use accounted for roughly 90% of all emissions from human activities in 2018, according to Carbon Brief.

Global carbon dioxide emissions by fuel type and emissions from cement production and flaring, with the average annual growth rate for 2013-2018.
Image credits Jackson et al., 2019, Environmental Research Letters.

Rich, developed countries also release a disproportionately high level of emissions per capita, although they are in the best position to switch to alternative energy sources. This is particularly worrying and likely to throw a wrench in climate negotiations, the team explains, as developing countries are (understandably) keen on using fossil fuels to strengthen their economies and provide better lives for their citizens — which, in essence, is exactly what developed countries have done in the past.

“Because per capita oil consumption in the US and Europe remains 5- to 20-fold higher than in China and India, increasing vehicle ownership and air travel in Asia are poised to increase global CO2 emissions from oil over the next decade or more,” notes one of three papers detailing the findings, published in Environmental Research Letters.

About 40% of fossil-fuel-related carbon dioxide emissions were attributable to coal use, 34% from oil, 20% from natural gas, and the remaining 6% from cement production and other sources, they report. The US, EU, and China together account for over half of all carbon emissions globally. Some success has been registered in the US and EU, whose emissions are projected to drop by 1.7% compared to 2018. However, this is more than offset by increases in other countries. China, for example, is projected to emit 2.6% more carbon in 2019 than it did in 2018 — and it’s far from the only place to see such a trend.

Changes in the energy grid mosaic

“Emissions cuts in wealthier nations must outpace increases in poorer countries where access to energy is still needed,” said Pierre Friedlingstein, a mathematics professor at the University of Exeter and lead author of the Environmental Research Letters study.

So where is all this carbon coming from? The good news is, it’s not from coal. This old-timer of a fossil fuel has seen a 0.9% drop in use, worldwide, compared to 2018. Its fading popularity — displaced by cheaper natural gas, wind, and solar power — can explain much of the drop in emissions seen by the US: coal use dropped 11% here compared to last year. The EU has reduced its coal use by around 10%. China, the single largest coal consumer in the world (making up around half the global demand for coal), has registered an increase of only 0.8% in coal use this year, largely due to an economic downturn.

At the same time, natural gas use has risen sharply. While it does indeed result in fewer emissions than coal or oil, its greater availability and the lower price have encouraged consumption so, overall, we’ve seen 2.6% more use and 2.5% more emissions (to 7.7 billion tons) from natural gas compared to 2018. The team singles out natural gas as a leading cause of carbon emission growth in recent years, accounting for around 60% of the total increase.

“Liquified natural gas exports from Australia and the United States are surging, lowering natural gas prices in Asia and increasing global access to this fossil resource,” Friedlingstein’s team adds.  

“The global LNG trade grew 10% in 2018 to 317 million tonnes, the fifth consecutive year of record trade. [….] Greater natural gas supply coupled with cheaper prices could extend the market penetration of natural gas for decades.”

However, natural gas has been marketed as a “bridge fuel” — a stop-gap measure to help countries wean off of fossil fuels. The team says this hope is somewhat grounded in reality, but only if policymakers take concrete action to help make it so. Measures in support of carbon capture and storage (to mediate CO2 emissions) and a reduction in methane leakage from natural gas infrastructure are vital for this goal.

Some are more equal than the others

Global fossil carbon dioxide emissions (including cement production) for five regions, showing the average annual growth rate for 2013-2018.
Image credits Jackson et al., 2019, Environmental Research Letters.

And now for the contentious part: per capita emission inequality. The average human today is responsible for around 4.8 tons of fossil carbon dioxide emissions per year. The average US citizen, in contrast, emits three to three-and-a-half times as much. Developing countries are catching up, both in the standard of living and emission levels — per capita emissions in China now rival or even exceed those in the EU, for example. The Global Carbon Project explains that oil consumption per capita in the US is 16 times greater than in India, and 6 times greater than in China. In the US, there’s almost one car on the road for every citizen — there’s one for every 6 people in China, and one for every 40 people in India.

This leaves calls to reduce fossil fuel open to critique for a holier-than-thou attitude. If wealthy nations got where they are by burning and polluting, why should developing countries ‘pay the bill’?

Do I think this is a healthy attitude? No, I think it leaves us all worse off and will come around to bite us, all of us, in the back. But I do see the point. National governments, first and foremost, have to answer to their citizens. In their view, people in other countries made this mess and got rich off of it, and those people are now are asking everybody else to give up the same wellbeing to clean it up — without compensation. It’s a very raw deal if you ignore the whole ‘climate emergency’ bit.

What to do about it

Not all is lost, however. Previous research has found that 18 or so countries have managed to both expand their economies and reduce emissions over the last decade, most notably the United Kingdom and Denmark, showing that countries (especially rich ones) can switch to clean energy without sacrificing prosperity. Key to their success was a reduction in energy use overall while new renewable fuel capacity was being installed to displace fossil fuels.

The team writes that stronger commitments and policy, both at a national and global level, can help us out of this bind. They list carbon pricing, improvements in the energy sector, reductions in energy use, the use of electric vehicles, as well as carbon capture and storage as some areas to focus on in the future. Of course, there’s also the straightforward way: doing our absolute best in phasing out fossil fuels for clean energy.

“We need every arrow in our climate quiver,” Jackson said. “That means stricter fuel efficiency standards, stronger policy incentives for renewables, even dietary changes and carbon capture and storage technologies.”

The three papers describing the findings are:

“Persistent fossil fuel growth threatens the Paris Agreement and planetary health”, published in the journal Environmental Research Letters.

“Global Carbon Budget 2019”, published in the journal Earth System Science Data.

“Carbon dioxide emissions continue to grow amidst slowly emerging climate policies”, published in the journal Nature Climate Change.

New capture technology scrubs atmospheric CO2 on the cheap

A novel carbon capture technique can scrub the gas out from the air even at relatively low concentrations, such as the roughly 400 parts per million (ppm) currently found in the atmosphere.

We have a climate problem: namely, we’re making the planet hotter and hotter. This change is caused by a build-up of greenhouse gases released by our various activities, and carbon dioxide (CO2) is the single most important such gas. Tackling climate heating hinges on our ability to reduce emissions or to find ways of scrubbing them from the air. Since the former would involve at least some economic contraction, neither industry nor politicians are very keen on it. So there’s quite a lot of interest in developing the latter approach.

Most of the methods available today need high concentrations of CO2 (such as the smoke emitted by fossil fuel-based power plants) to function. The methods that can work with low concentrations, on the other hand, are energy-intensive and expensive, so there’s little economic incentive for their use. However, new research from MIT plans to change this state of affairs.

Convenient cleaning

“The greatest advantage of this technology over most other carbon capture or carbon absorbing technologies is the binary nature of the adsorbent’s affinity to carbon dioxide,” explains MIT postdoc Sahag Voskian, who developed the work during his PhD.

“This binary affinity allows capture of carbon dioxide from any concentration, including 400 parts per million, and allows its release into any carrier stream, including 100 percent CO2.”

The technique relies on passing air through a stack of electrochemical plates. The process Voskian describes is that the electrical charge state of the material — charged or uncharged — causes it to either have no affinity to CO2 whatsoever or a very high affinity for the compound. To capture CO2, all you need to do is hook the material up to a charged battery or another power source; to pump it out, you cut the power.

The team says this comes in stark contrast to carbon-capture technologies today, which rely on intermediate steps involving large energy expenditures (usually in the form of heat) or pressure differences.

Essentially, the system functions the same way a battery would, absorbing CO2 around its electrodes as it charges up, and releasing it as it discharges. The team envisions successive charge-discharge cycles as the device is in operation, with fresh air or feed gas being blown through the system during the charging cycle, and then pure, concentrated carbon dioxide being blown out during the discharge phase.

The electrochemical plates are coated with a polyanthraquinone and carbon nanotubes composite. This gives the plates a natural affinity for carbon dioxide and helps speed up the reaction even at low concentrations. During the discharge phase, these reactions take place in reverse, generating part of the power needed for the whole system during this time. The whole system operates at room temperature and normal air pressure, the team explains.

The authors hope the new approach can help reduce CO2 production and increase capture efforts. Some bottling plants burn fossil fuels to generate CO2 for fizzy drinks, and some farmers also burn fuels to generate CO2 for greenhouses. The team says the new device can help them get the carbon they need from thin air, while also cleaning the atmosphere. Alternatively, the pure carbon dioxide stream could be compressed and injected underground for long-term disposal, or even made into fuel through a series of chemical and electrochemical processes.

“All of this is at ambient conditions — there’s no need for thermal, pressure, or chemical input,” says Voskian. “It’s just these very thin sheets, with both surfaces active, that can be stacked in a box and connected to a source of electricity.”

Compared to other existing carbon capture technologies, this system is quite energy efficient, using about one gigajoule of energy per ton of carbon dioxide captured. Other existing methods use up to 10 gigajoules per ton, depending on the inlet carbon dioxide concentration, Voskian says.

The paper “Faradaic electro-swing reactive adsorption for CO2 capture” has been published in the journal Energy & Environmental Science.

New material selectively captured CO2 molecules and turns them into useful products

Japanese researchers at the University of Kyoto have recently demonstrated a porous polymer that selectively binds to carbon dioxide molecules. It is ten times more efficient than similar other materials and is made from inexpensive materials. In the future, such a material could be incorporated into the exhausts of fossil fuel power generators or carbon capture stations. The CO2 would not only be prevented to reach the atmosphere, where it raises temperatures, it could also be turned into a useful product.

This new porous polymer has propeller-shaped molecular structures that enables selectively capturing CO2. Credit: Mindy Takamiya.

The new material belongs to a class called porous coordination polymer (PCP), also known as metal-organic frameworks (MOF). It mainly consists of zinc metal ions and an organic component, known as a ligand, with a propeller-like molecular structure.

When CO2 molecules approach the structure, the ligands rotate and rearrange themselves, thereby trapping the carbon. This results in slight changes in the molecular channels of the PCP, which basically acts as a sieve.

X-ray structural analysis revealed that the material only interacts with carbon dioxide molecules, which are captured 10 times more efficiently than other PCPs.

No energy input is required for the process to occur because it is favorable for the CO2 to bind to the zinc ions. Once bound, the CO2 molecules become activated and capable of reacting with other molecules.

“We have successfully designed a porous material which has a high affinity towards CO2 molecules and can quickly and effectively convert it into useful organic materials,” says Ken-ichi Otake, a materials chemist at Kyoto University.

The researchers claim that the CO2 can be incorporated into useful organic materials, such as cyclic carbonates which can be used in petrochemicals and pharmaceuticals.

The findings appeared in the journal Nature Communications.

Mosquito.

Mosquitoes hunt first by smell, then by eyesight

Smelling is key if you’re a hungry female mosquito, a new study reports.

Mosquito.

Image via Pixabay.

A team of researchers led by members from the University of Washington has looked at the brains of female mosquitoes in real-time to understand how they identify, track, and home in on their next meal. The process integrates information from the visual and olfactory sensory systems, they report. The insect’s olfactory system catches the scent of its target and triggers chemical changes in the brain of the female mosquito that makes her visually scan her surroundings for specific types of shapes and fly toward them.

Smell first, find targets later

“Our breath is just loaded with CO2,” said corresponding author Jeffrey Riffell, a UW professor of biology. “It’s a long-range attractant, which mosquitoes use to locate a potential host that could be more than 100 feet away.”

Only female mosquitoes feed on blood — the guys dine on pollen. However, this also means that only female mosquitoes bite people and spread diseases such as malaria. The present research comes as an effort from the team to better understand how the insects find their prey (or ‘hosts’) to bite, which could help develop new methods to control and reduce the spread of mosquito-borne diseases.

The olfactory cue that triggers the hunting behavior in female mosquitoes is carbon dioxide (CO2), Riffell’s prior research has shown. For the insects, smelling CO2 is a telltale sign that a potential meal is nearby, “priming” their visual systems to hunt for a host — so the team focused their study on this gas. They analyzed the changes triggered by CO2 in mosquito flight behavior and recorded how it impacts the brain activity in the olfactory and visual centers.

Data was collected from roughly 250 individual mosquitoes during behavioral trials conducted in a small circular arena, about 7 inches in diameter. The arena was fitted with a 360-degree LED display frame, and each mosquito was tethered in the middle of the rig using a tungsten wire. The mosquito’s wings were monitored from below with an optical sensor, while the LED display showed different types of visual stimuli and odors were fed into the area using an air inlet and vacuum line. What the team wanted to see was how the tethered Aedes aegypti mosquitoes responded to visual stimuli and puffs of air rich in CO2.

The researchers report that one-second-long puffs of air with 5% CO2 — for comparison, we exhale air containing 4.5% CO2 — made the mosquitoes beat their wings faster. Certain visual elements (a fast-moving starfield for example) didn’t much influence their behavior. Other elements (the team used a horizontally moving bar)  caused the mosquitoes to beat their wings faster and attempt to steer in the direction of the bar. This response was more pronounced if researchers introduced a puff of CO2 before showing the bar.

“We found that CO2 influences the mosquito’s ability to turn toward an object that isn’t directly in their flight path,” said Riffell. “When they smell the CO2, they essentially turn toward the object in their visual field faster and more readily than they would without CO2.”

The team also repeated the experiment with a genetically modified Aedes aegypti strain created by Riffell and co-author Omar Akbari, an assistant professor at the University of California, San Diego. The neurons in this strain’s central nervous system were engineered to glow fluorescent green when active.  The team could cut a small portion of the mosquito’s skull and use a microscope to record its neuronal activity in 59 areas in the lobula (part of the optic lobe) in real time.

When the mosquitoes were shown a horizontal bar, two-thirds of those regions lit up, the team reports, suggesting a response to the visual stimulus. When exposed to a puff of CO2 before being shown the bar, 23% of the regions had even higher activity than before. This indicates that the CO2 primed the areas of the brain that control vision to elicit a stronger response to the bar. The authors report that the reverse — a horizontal bar triggering increased activity in the parts of the mosquito brain that control smell — didn’t happen.

“Smell triggers vision, but vision does not trigger the sense of smell,” Riffell concludes.

“Olfaction is a long-range sense for mosquitoes, while vision is for intermediate-range tracking. So, it makes sense that we see an odor — in this case CO2 — affecting parts of the mosquito brain that control vision, and not the reverse.”

Mosquitoes can pick up scents over 100 feet away, the authors explain in their paper. Their eyesight, however, is most effective at distances of between 15 to 20 feet.

The paper “Visual-Olfactory Integration in the Human Disease Vector Mosquito Aedes aegypti” has been published in the journal  Current Biology.

Credit: Pixabay.

The Earth has room for a trillion more trees — which might be our best bet against climate change

Credit: Pixabay.

Credit: Pixabay.

In order to stave off potentially catastrophic climate change, not only does the world have to urgently stop emitting carbon dioxide, but it also has to find a way to absorb a good portion of it from the atmosphere. Luckily nature has evolved just the right technology that can achieve this goal: good old trees. According to a new study, although humans have massively expanded their reach across the planet, there is still enough room to accommodate 0.9 billion hectares of forest.

Nature’s CO2 removal tool

The study, which didn’t include areas currently occupied by agriculture, cities, and existing forests, estimates that there’s enough room for 1-1.5 trillion trees. Currently, there are an estimated 3 trillion trees sucking CO2 from the atmosphere all around the globe. Forests in the United States absorb and store about 750 million metric tons of carbon dioxide each year, an amount equivalent to 10% of the country’s CO2 emissions.

If allowed to mature, these extra forests would store 205 gigatons of carbon, roughly equal to two-thirds of all the carbon humans have added to the atmosphere since the Industrial Age. This would bring down heat-trapping greenhouse gases to levels not seen for nearly 100 years, according to the authors from the Swiss Federal Institute of Technology, Zurich (ETH Zurich).

“We all knew restoring forests could play a part in tackling climate change, but we had no scientific understanding of what impact this could make,” said study senior author Thomas Crowther, an assistant professor of ecology at ETH Zurich.

During photosynthesis, trees use carbon dioxide (CO2) from the atmosphere with water from rain or irrigation and nutrients from the soil to form carbohydrates, which make up the tree’s biomass. The amount of carbon stored by a tree will depend on its size, which in turn is influenced by the species and local environmental conditions.

Tree biomass percentages (approximate). Credit: Ecometrica.

Previously, the Intergovernmental Panel on Climate Change’s (IPCC) issued a report advising that planting 1 billion hectares of forest is necessary in order to prevent global temperatures from rising over 1.5°C by 2050. This figure inspired Crowther and colleagues to see whether there even was enough room left on the planet’s surface for this many trees.

The researchers analyzed more than 80,000 satellite images, from which they subtracted existing forests, crop fields, and urban areas. Russia has the most space available to accommodate new forests at 583,000 square miles (1.5 million square km), followed by the United States with 397,700 square miles (1 million square km), Canada with 302,700 square miles (784,000 square km), Australia with 223,900 square miles (578,900 square km), Brazil with 191,900 square miles (497,000 square km), and China with 155,200 square miles (402,000 square km).

The reasons why trees are such an appealing solution to tackling climate change is that they’re cheap and do not necessarily require government permission or oversight — anyone can do it, basically. Indeed, various NGOs have so far planted millions of trees. Meanwhile, some government-led projects have also proven highly successful. China has spent more than $100 billion on trees in the last decade alone. Nearly 22 percent of the country is now covered in forest, compared to 19 percent in 2000, according to the Ministry of Environmental Protection.

Meanwhile, the Bonn Challenge, signed and backed by 48 nations, pledged to restore 350 million hectares of forest by 2030. The new study, which was published in the journal Sciencenow offers these countries evidence that they could be even more ambitious. There is, after all, plenty of room to spare!

Desert tank.

The military is the largest emitter in the US Gov’t — in fact, it’s the world 55th largest polluter

The American military is actually one of the largest emitters of greenhouse gases in the world — more than many nations.

Desert tank.

Image via Pixabay.

A new analysis by Dr. Neta Crawford, a professor of Political Science and Department Chair at Boston University, shows that the Pentagon was responsible for around 59 million metric tons of carbon dioxide and other greenhouse gas emissions in 2017. This figure places the U.S. military higher on the list of the world’s largest emitters than industrialized countries such as Sweden or Portugal.

The Costs of War

“In a newly released study published by Brown University’s Costs of War Project, I calculated U.S. military greenhouse gas emissions in tons of carbon dioxide equivalent from 1975 through 2017,” Dr. Crawford explains in a piece for LiveScience.

“Since 2001, the DOD has consistently consumed between 77 and 80 percent of all US
government energy consumption,” her paper explains.

In “any one year”, she explains, the Pentagon’s emissions were greater than “many smaller countries’ [emissions],” the study explains. In fact, if the Pentagon were a country, it would be the world’s 55th largest greenhouse gas emitter, overtaking even industrialized countries.

The largest single sources of military greenhouse gas emissions identified in the study are buildings and fuel. The DoD maintains over 560,000 buildings, which account for about 30% of its emissions. “The Pentagon building itself emitted 24,620.55 metric tons of [CO2 equivalent] in the fiscal year 2013,” the study says. The lion’s share of total energy use, around 70%, comes from operations. This includes moving troops and material about, as well as their use in the field, and is kept running by massive quantities of jet and diesel fuel, Crawford said.

Where to?

This January, the Pentagon listed climate change as “a national security issue” in a report it presented to Congress. The military has launched several initiatives to prepare for its impacts but seems just as thirsty for fuel as ever before. It is understandable; tanks, trucks, planes, bombers without fuel — and a lot of fuel — they’re just fancy paperweights.

But, at the same time, the use of fossil fuels is changing the climate. Global climate models estimate a 3ºC to 5ºC (5.4ºF to 9ºF) rise in mean temperatures this century alone under a business as usual scenario. In a paper published in Nature that we covered earlier today, we’ve seen how 4ºC would increase the effect of climate on conflict more than five-fold. More conflict would probably mean more fuel guzzled by the army’s engines.

The paper also looks at how the U.S. military “spends about $81 billion annually defending the global oil supply” to ensure both domestic and military life can continue without a hitch.

“The military uses a great deal of fossil fuel protecting access to Persian Gulf Oil,” the paper explains. “Because the current trend is that the US is becoming less dependent on oil, it may be that the mission of protecting Persian Gulf oil is no longer vital and the US military can reduce its presence in the Persian Gulf.”

“Which raises the question of whether, in protecting against a potential oil price increase, the US does more harm than it risks by not defending access to Persian Gulf oil. In sum, the Persian Gulf mission may not be as necessary as the Pentagon assumes.”

However, not all is dead and dreary. Crawford says the Pentagon had reduced its fuel consumption significantly since 2009, mainly by making its vehicles more efficient and shifting towards cleaner sources of energy at bases. Further reductions could be achieved by cutting missions to the Persian Gulf, the paper advises, seeing as it is no longer a top priority to protect oil supply from this area as renewable energy is gaining in the overall grid make-up.

“Many missions could actually be rethought, and it would make the world safer,” Crawford concludes.

The paper “Pentagon Fuel Use, Climate Change, and the Costs of War” can be accessed here.

CO2 sticker.

May 2019 sets new record for highest average atmospheric CO2 levels in history

This month set a record for the highest average CO2 concentration in the atmosphere. Yes, a new one.

CO2 sticker.

Image credits Gerd Altmann.

Atmospheric CO2 levels have continued to rise throughout 2019, shows data published by the NOAA and Scripps Institution of Oceanography earlier today. This May, those levels averaged 414.7 parts per million (ppm) as recorded at NOAA’s Mauna Loa Atmospheric Baseline Observatory.

This value is the highest seasonal peak recorded over 61 years of observations at the Mauna Loa Observatory. The highest in 61 years because that’s how long the observatory has been up and running. It’s also the seventh consecutive year of increases in atmospheric levels of CO2 — and it’s also the highest average concentration recorded this year, which already broke a record. The value of 414.7 ppm CO2 is 3.5 ppm higher than the peak recorded in May 2018, and just shy of the 415 ppm peak value recorded in May 2019. Researchers at NOAA report that this increase is the second-highest annual jump on record.

“It’s critically important to have these accurate, long-term measurements of CO2 in order to understand how quickly fossil fuel pollution is changing our climate,” said Pieter Tans, senior scientist with NOAA’s Global Monitoring Division.

“These are measurements of the real atmosphere. They do not depend on any models, but they help us verify climate model projections, which if anything, have underestimated the rapid pace of climate change being observed.”

While still lower than the peak value, the number is still very worrying. It’s worrying because, while fluctuations can lead to high-value but transient peaks in CO2, average concentration readings show the larger trend: and that trend is that levels of CO2 in the atmosphere keep increasing year after year, and that the rate of increase is accelerating.

Some of the earliest recordings at Mauna Loa found annual increases of 0.7 ppm on average per year. This rate increased to about 1.6 ppm per year during the 1980s and 1.5 ppm per year in the 1990s. During the last decade, we’ve seen an average growth rate of atmospheric CO2 concentrations of 2.2 ppm. And, according to Tans (and pretty much every scientist out there), there is no doubt that this rate is increasing because we’re generating more and more emissions.

Monthly average readings are recorded during May of each year, just before plants start to suck up large quantities of CO2 from the atmosphere during the northern hemisphere growing season. In the northern fall, winter, and early spring, plants and soils give off CO2, which cause levels to rise through May. Charles Keeling was the first to observe this seasonal rise and subsequent fall in CO2 levels embedded within annual increases, a cycle now known as the Keeling Curve.

It’s important to take these measurements at the same time each year so as to control as many variables as possible, making the data useful for establishing reliable trends. The Mauna Loa data, together with measurements from other sampling stations around the world, are collected by NOAA’s Global Greenhouse Gas Reference Network and produce a foundational research dataset for international climate science.

NOAA’s report can be accessed here.

Limestone.

New method of CO2 capture is cheaper, more effective, and “a key step toward closing the carbon loop”

Researchers from the University of Toronto (U of T) Faculty of Applied Science & Engineering plan to make CO2 capture even more appealing — they’ve developed a process that allows for atmospheric CO2 to be recycled into fuel or plastics for much lower costs than before.

Limestone.

Limestone, a carbonate rock. CO2 capture methods often convert the gas into similar rocks.
Image via Pixabay.

Direct-air carbon capture is an emerging technology that uses CO2 already in the atmosphere as raw material to make a range of commercial products such as fuel or plastics. It’s a promising alternative to the traditional approach, environmentally speaking, because it substitutes carbon compounds found in oil, coal, or natural gas with the one that’s floating around in (and heating up) the air we breathe. However, it’s also the more expensive approach between the two.

The team, led by Professor Ted Sargent from the U of T, aims to drive its cost down.

Cutting out the middleman

“Today, it is technically possible to capture CO2 from air and, through a number of steps, convert it to commercial products,” says Prof. Sargent.

“The challenge is that it takes a lot of energy to do so, which raises the cost and lowers the incentive. Our strategy increases the overall energy efficiency by avoiding some of the more energy-intensive losses.”

The team worked on a new electrochemical process that can capture and transform that CO2 for a fraction of the cost (compared to currently-available approaches).

Up to now, the most common approach involved pumping air through a liquid, alkaline solution. This substance dissolves CO2 in the air, chemically-tying it into carbonate compounds. To retrieve the useful carbon, these compounds need to then be turned back into CO2 gas. Commonly, chemical agents are used to convert the carbonate solution into a solid salt which is then baked at temperatures in excess of 900ºC to release the gas. This is then hoovered up and used to synthesize other carbon compounds.

It takes a lot of energy — and thus, a lot of money — to generate all that heat. And that’s just not a very effective way of doing it, the team believes. Their alternative method involves the use of an electrolyzer, a device that uses electricity to drive chemical reactions. They got the idea from previous work which involved the use of electrolyzers to produce hydrogen from water. The process, they say, does away with the heating step, allowing for the carbonate solution to be turned directly back into CO2.

The new electrolyzer also employs a silver-based catalyst that immediately turns the released CO2 into syngas. Syngas (synthesis gas) is a mixture of hydrogen, and CO, with some CO2, and is a very common feedstock material for the chemical industry. Syngas is involved in processes ranging from plastic to jet fuel production.

“We used a bipolar membrane, a new electrolyzer design that is great at generating protons,” says Geonhui Lee, co-lead author of the paper describing the technique. “These protons were exactly what we needed to convert the carbonate back into CO2 gas.”

“This is the first known process that can go all the way from carbonate to syngas in a single step,” Sargent adds.

Another advantage this process has over conventional CO2 retrieval processes is better yields and higher efficiency. Furthermore, it solves a major problem regarding existing electrolyzing technologies: these cannot actually work with carbonate.

“Once the CO2 turns into carbonate, it becomes inaccessible to traditional electrolyzers,” says Li. “That’s part of the reason why they have low yields and low efficiencies. Our system is unique in that it achieves 100% carbon utilization: no carbon is wasted. It also generates syngas as a single product at the outlet, minimizing the cost of product purification.”

Lab tests showed that the new electrolyzer can convert carbonate to syngas with an overall efficiency of 35%, with stable operations confirmed for over six days at a time. There’s still work to be done in upscaling the process to industrial scales, according to Sargent, but the proof-of-concept device shows the new method is viable.

“It goes a long way toward answering the question of whether it will ever be possible to use air-captured CO2 in a commercially compelling way,” he says. “This is a key step toward closing the carbon loop.”

The paper “CO2 Electroreduction from Carbonate Electrolyte” has been published in the journal ACS Publications.

Leaf.

Researchers create fuel from water, CO2, and artificial photosynthesis

New research at the University of Illinois is bringing working artificial photosynthesis one step closer to reality.

Leaf.

Image via Pixabay.

The team has successfully produced fuel from water, carbon dioxide, and visible light through artificial photosynthesis. Their method effectively converts carbon dioxide into longer, more complex molecules, like propane. When fully developed, artificial photosynthesis of this kind could be used to store solar energy in chemical bonds (i.e. fuel) for peak-demand times.

Sunfuel

“The goal here is to produce complex, liquefiable hydrocarbons from excess CO2 and other sustainable resources such as sunlight,” said Prashant Jain, a chemistry professor and co-author of the study.

“Liquid fuels are ideal because they are easier, safer and more economical to transport than gas and, because they are made from long-chain molecules, contain more bonds — meaning they pack energy more densely.”

Plants use photosynthesis to capture energy from sunlight in the form of glucose. Glucose is a relatively energy-dense compound (it’s a sugar), so plants can effectively use it as a type of chemical energy that they assemble from (relatively energy-poor) CO2. Researchers have long strived to recreate this process in the lab, with various degrees of success, as it holds great promise for clean energy applications.

The new study reports on probably the most successful attempt to emulate photosynthesis so far. The artificial process the team developed draws on the same green light that powers photosynthesis in plants. It mixes CO2 and water into fuel with a little help from gold nanoparticles that serve as a catalyst. The electron-rich particles of gold absorb green light and handle the transfer of protons and electrons between water and CO2 — in broad lines, playing the same role as the pigment chlorophyll in natural photosynthesis.

Gold nanoparticles work particularly well in this role, says Jain, because their surfaces interact with CO2 molecules in just the right way. They’re also pretty efficient at absorbing light and do not break down or degrade like other metals do.

While the resulting fuel can simply be combusted to retrieve all that energy, it wouldn’t be the best approach, the team writes. Simply burning it re-releases all the CO2 back into the atmosphere, which is counterproductive to the notion of harvesting and storing solar energy in the first place, says Jain.

“There are other, more unconventional potential uses from the hydrocarbons created from this process,” he says.

“They could be used to power fuel cells for producing electrical current and voltage. There are labs across the world trying to figure out how the hydrocarbon-to-electricity conversion can be conducted efficiently.”

Exciting though the development might be, the team acknowledges that their artificial photosynthesis process is nowhere near as efficient as it is in plants.

“We need to learn how to tune the catalyst to increase the efficiency of the chemical reactions,” he said.

“Then we can start the hard work of determining how to go about scaling up the process. And, like any unconventional energy technology, there will be many economic feasibility questions to be answered, as well.”

The paper “Plasmonic photosynthesis of C1–C3 hydrocarbons from carbon dioxide assisted by an ionic liquid” has been published in the journal Nature Communications.

Methane.

One research team proposes swapping atmospheric methane for CO2, and it might be a good idea

A relatively simple but counterintuitive approach aims to fight climate change — by actually increasing CO2 emissions.

Methane.

Image via Pixabay.

Fighting climate warming with greenhouse emissions might sound like it won’t work, because it wouldn’t. The team that authored this study, however, doesn’t just aim to increase CO2 levels in the atmosphere. Rather, it proposes that we degrade methane, a much more potent greenhouse gas, into CO2 — the swap, they write, would be a net benefit for world climate.

The study proposes zeolite, a crystalline material that consists primarily of aluminum, silicon, and oxygen, as a key material to help us scrub methane emissions.

The lesser of two evils

“If perfected, this technology could return the atmosphere to pre-industrial concentrations of methane and other gases,” said lead author Rob Jackson, the Michelle and Kevin Douglas Provostial Professor in Earth System Science in Stanford’s School of Earth, Energy & Environmental Sciences.

Much more relevant to the current situation, the team notes, is that this process is also profitable. Boiled down, the idea is to take methane from sources where it’s difficult or expensive to eliminate — from cattle farms or rice paddies, for example — and degrade it into CO2.

Methane concentrations in the atmosphere are almost two-and-a-half times higher today than before the Industrial Revolution, the team explains. There’s a lot less methane than CO2 in the air, granted, but methane is 84 times more potent than CO2 as a climate-warming gas over the first 20 years after its release. Finally, some 60% of atmospheric methane today is directly generated by human activity.

Most climate strategies today focus on CO2, which is understandable. It’s the largest (by quantity) greenhouse gas we emit, and it’s easy to relate to — we breathe out CO2, cars belch out CO2, factories do too, and plants like to munch on it. But scrubbing other greenhouse gases, particularly methane due to its enormous greenhouse effect, could be useful as a complementary approach, the team explains. Furthermore, there’s just so much CO2 already floating around — and we keep pumping it out with such gusto — that CO2-removal scenarios often call for billions of tons to be removed, over decades, which would still not get us to pre-industrial levels

“An alternative is to offset these emissions via methane removal, so there is no net effect on warming the atmosphere,” said study coauthor Chris Field, the Perry L. McCarty Director of the Stanford Woods Institute for the Environment.

Methane levels could be brought back down to pre-industrial levels by removing about 3.2 billion tons of the gas from the atmosphere, the team notes. Converting all of it into CO2 would be equivalent to a few months of global industrial emissions, which is relatively little, but would have an outsized effect: it would eliminate approximately one-sixth of all causes of global warming to date.

So why then didn’t anybody think of this before? Well, the thing is that methane is hard to scrub from the air because its overall concentrations are so low. However zeolite, the team explains, is really really good at capturing the gas due to its “porous molecular structure, relatively large surface area and ability to host copper and iron,” explains coauthor Ed Solomon, the Monroe E. Spaght Professor of Chemistry in the School of Humanities and Sciences. The whole process could be as simple as using powerful fans to push air through reactors full of zeolite and catalysts. This material can then be heat-treated to form and release carbon dioxide gas.

Now let’s talk money. If market prices for carbon offsets rise to $500 or more per ton this century as predicted by most relevant assessment models, the team writes, each ton of methane removed from the atmosphere could be worth more than $12,000. A zeolite reactor the size of a football field could thus produce millions of dollars a year in income while removing harmful methane from the air. This is very fortunate as, in my experience, nothing motivates people to care about the environment quite like making money from saving it.

In principle, the researchers add, the approach of converting a more harmful greenhouse gas to one that’s less potent could also apply to other greenhouse gases.

The paper “Methane removal and atmospheric restoration” has been published in the journal Nature Sustainability.

Atmospheric CO2 reaches record 415ppm — the highest it’s been in millions of years

In less than a century, humans have managed the ignoble feat of raising atmospheric CO2 levels by more than 100 parts per million (ppm). Like every year, weather stations are measuring new record levels of CO2 in the atmosphere and according to data from the Mauna Loa Observatory in Hawaii, the concentration of CO2 in the atmosphere is now over 415 ppm, which is higher than at any point during the existence of our lineage.

Some believe that global warming, which is responsible for at least 1ºC (1.8ºF) of warming compared to pre-Industrial Age levels, has already triggered an irreversible feedback loop that will see much of the polar ice sheets melt. Whatever the case, the effects of man-made climate change are sorely felt around the world now. The Arctic, which warms twice as fast than the global average, lost nearly one million square kilometers (620,000 square miles) of winter sea ice cover since 1979 — that’s an area twice as large as Texas. Heat waves and droughts are more common and every new year seems like it’s the warmest on record. 

Scientists at the National Oceanic and Atmospheric Administration and the Scripps Institution of Oceanography have been measuring atmospheric carbon since 1958 when the program was started by the late Charles David Keeling. The famous, constantly updated graph that shows the accelerated rise of CO2 in the atmosphere, known as the Keeling Curve (shown above), is named after him.

The latest recorded figure, which stands at 415.26 ppm of CO2, is unprecedented in millions of years. The last time this happened, during the Pliocene Epoch, the Arctic was covered in trees and global sea levels were 25 meters higher than today.

The year’s increase in CO2 in the atmosphere has been partly fueled by El Niño conditions — changes in the sea-surface temperature of the tropical Pacific Ocean. This warms and dries tropical ecosystems, reducing their uptake of carbon, and exacerbating forest fires. However, the main factor responsible for the upward trend is, by far, the burning of fossil fuels.

According to a 2017 study, if the world continues on this business as usual route, by 2050 CO2 levels could rise beyond anything the Earth’s atmosphere has seen in the last 50 million years (600ppm). That’s not a death sentence in and of itself — life has flourished in those conditions before — but the shift is too fast and brutal for animals to adapt. A lot of today’s species will find it difficult (if not impossible) to adapt to those conditions in such a short time. As for humans, climate change threatens communities through rising sea levels, more frequent extreme weather, heat waves, and food shortages.

All the signs are pointing to an impending disaster if we don’t do something about it. This means moving to zero-emission energy generation as fast as possible. But that’s not enough — we also need to increase carbon capture and sequestration by planting more forests and developing new technologies that can safely lock excess carbon from the atmosphere.

The notion that the climate change we’re experiencing today is mainly driven by a natural climate cycle is silly and not rooted in scientific reality.

Iceland researchers trap CO2 into rocks — but there’s a catch

Iceland’s volcanoes might hold the key to sucking CO2 out of the atmosphere but the process requires huge amounts of water.

If we want to ensure a sustainable future for our planet’s climate, reducing our emissions is paramount, but ultimately, it would be really good if we could also remove existing CO2 from the atmosphere — otherwise, the inertia of the warming will still continue long after we have reduced our emissions (than in itself is a gargantuan challenge, but that’s a different story).

While the roadmap to cutting emissions is fairly clear, eliminating CO2 from the atmosphere is a whole other beast, and scientists are only now starting to test ways through which this could be done. A project in Iceland seems like the most promising approach so far.

The technique starts from a natural event in which basaltic rocks absorb carbon dioxide and mineralize it, storing it forever — but this geological process happens over great periods of time. In order to accelerate this process, scientists developed a way to first absorb the CO2 into water, and then inject the carbonated water into porous basaltic rocks. The bubbly liquid is then pumped under high pressure into the rock 1,000 meters (3,300 feet) under the ground. The CO2 produced by the injection itself is also absorbed.

“So basically we are just making soda water out of the CO2,” says project director Edda Sif Aradottir.

The solution infiltrates into the rock pores and starts to solidify, reacting with the calcium, magnesium, and iron inside the rock, beginning an accelerated mineralization process. It’s not the first time something like this has been attempted, but researchers weren’t sure just how quick this process was. It took only two years for the carbon to solidify.

“With this method we have actually changed the time scale dramatically,” says geologist Sandra Osk Snaebjornsdottir, who also worked on the project called CarbFix. “Almost all of the injected CO2 was mineralized within two years in our pilot injection,” Snaebjornsdottir says.

For Iceland, a true land of ice and fire, the method is perfect. Virtually all of the country consists of volcanic, basaltic rocks, and the country generates more than half of its energy from clean geothermal sources. The country is also an island, so it has access to what is essentially limitless supply of water — because the method uses huge quantities of water. Around 25 ton of water are needed for each ton of carbon dioxide injected into the ground, something which Snaebjornsdottir calls the “Achilles heel” of the method. Furthermore, the method hasn’t yet been adapted to use saltwater instead of freshwater — which could make a huge difference. Providing hundreds or thousands of tons of freshwater is not something many places can readily do.

Scalability is another concern. The CarbFix project, which was implemented at a power plant, reduced the plant’s emissions by a third, amounting to 12,000 tons of CO2 captured and stored at a cost of about $25 a ton. Considering that Iceland alone, a country of less than 400,000 people, emits over 4 million tons a year, that’s a hefty price tag — but not one beyond affordability. The United States, for instance, produces around 5,000 million tons of CO2 a year which, at the current price tag, would cost $125 billion, which is still only a fraction of the country’s military budget — and that’s enough to offset all of the country’s emission. Of course, having the money is only a part of the problem, you also need to invest in the injection facilities, and have access to proper basaltic rocks in the first place, but since this is still the early stages of the carbon injecting technology, there are reasons to hope that the efficiency and price will improve in the not-too-distant future. Judging by the world’s current climate trajectory, we may need this technology sooner rather than later.

According to the Paris Agreement, Iceland has agreed to cut its emissions by 40% by 2030. However, the country’s CO2 emissions have increased significantly in recent years, largely due to the transportation sector, which is vital for the country’s tourism sector. For this reason, despite the fact that most of the country’s energy is renewable, Iceland’s CO2 emissions per capita are way over the European average.

Iceland’s Environment and Natural Resources Minister Gudmundur Ingi Gudbrandsson has encouraged the project, which might be vital for Iceland’s — and the world’s — climate objectives.

Wall fans.

New paper proposes we use air conditioners to make fuel out of thin air

Cool down your home and the climate at the same time.

Wall fans.

Image credits Sławomir Kowalewski.

New research from the Karlsruhe Institute of Technology and the University of Toronto wants to put your air conditioning unit to work on fighting climate change. The idea is to outfit air conditioners — devices which move huge amounts of air per day — with carbon-capture technology and electrolyzers, which would turn the gas into fuel.

Crowd oil

“Carbon capture equipment could come from a Swiss ‘direct air capture’ company called Climeworks, and the electrolyzers to convert carbon dioxide and water into hydrogen are available from Siemens, Hydrogenics or other companies,” said paper co-author Geoffrey Ozin for Scientific American.

Air-conditioner units are very energy-thirsty. As most of our energy today is derived from fossil fuels, this means that air conditioners can be linked to a sizeable quantity of greenhouse emissions. It’s estimated that, by the end of the century, we’ll be using enough energy on air conditioning to push the average global temperature up by half a degree. Which is pretty ironic.

The team’s idea is pretty simple — what if heating, ventilation, and air conditioning (or HVAC) systems could act as carbon sinks, instead of being net carbon contributors? Carbon-capture devices need to be able to move and process massive quantities of air in order to be effective. HVAC systems already do this, being able to move the entire volume of air in an average office building five to ten times every hour. So they’re ideally suited for one another. The authors propose “retrofitting air conditioning units as integrated, scalable, and renewable-powered devices capable of decentralized CO2 conversion and energy democratization.”

“It would be not that difficult technically to add a CO2 capture functionality to an A/C system,” the authors write, “and an integrated A/C-DAC unit is expected to show favourable economics.”

Modular attachments could be used to add CO2-scrubbing filters to pre-existing HVAC systems. After collection, that CO2 can be mixed with water to make, basically, fossil fuels. As Ozin told Scientific American, the required technology is commercially available today.

But, in order to see if it would also be effective, the team used a large office tower in Frankfurt, Germany, as a case study. HVAC systems installed on this building could capture enough CO2 to produce around 600,000 gallons of fuel in a year. They further estimate that installing similar systems on all the city’s buildings could generate in excess of 120 million gallons of (quite wittily-named) “crowd oil” per year.

“Renewable oil wells, a distributed social technology whereby people in homes, offices, and commercial buildings all around the world collectively harvest renewable electricity and heat and use air conditioning and ventilation systems to capture CO2 and H2O from ambient air, by chemical processes, into renewable synthetic oil — crowd oil — substituting for non-renewable fossil-based oil — a step towards a circular CO2 economy.”

Such an approach would still take a lot of work and polish before it could be implemented on any large scale. Among some of the problems is that it would, in effect, turn any HVAC-equipped system into a small, flammable oil refinery. The idea also drew criticism as it could potentially distract people from the actual goal — reducing emission levels.

“The preliminary analysis […] demonstrates the potential of capturing CO2 from air conditioning systems in buildings, for making a substantial amount of liquid hydrocarbon fuel,” the paper reads.

“While the analysis considers the CO2 reduction potential, carbon efficiency and overall energy efficiency, it does not touch on spatial, or economic metrics for the requisite systems. These have to be obtained from a full techno-economic and life cycle analysis of the entire system.”

The paper “Crowd oil not crude oil” has been published in the journal Nature Communications.

Ocean.

Climate change may make the oceans belch out CO2, study warns

As oceans warm up due to climate change, they’ll likely start generating a lot of CO2.

Ocean.

Image via Pixabay.

Despite being the largest carbon sink active today, oceans might become net emitters under warmer climates, a new study reports. The paper reports that warmer oceans lose some of their ability to store carbon, which will accelerate the rate of CO2 regeneration in many areas of the world. This will further reduce the ocean’s ability to store carbon, the authors explain.

Positive carbon loop

“The results are telling us that warming will cause faster recycling of carbon in many areas, and that means less carbon will reach the deep ocean and get stored there,” said study coauthor Robert Anderson, an oceanographer at Columbia University’s Lamont-Doherty Earth Observatory.

Ocean water soaks up roughly 25% of our carbon dioxide emissions year after year. While this process also involves abiotic chemical and physical processes, the lion’s share of that CO2 is gobbled up by plankton through photosynthesis. But, all plankton must die eventually, and when they do, these tiny marine plants sink to the bottom of the ocean — and the carbon they ‘ate’ goes down with them. It’s estimated that plankton produces around 40 to 50 billion tons of dry, solid organic carbon each year.

Some of this organic matter (and the carbon therein) gets locked into the depths for centuries at a time, but part of it gets consumed by aerobic bacteria before sinking into oxygen-free waters, the team writes. Those bacteria then expel it as carbon dioxide, pushing it back into the atmosphere. Only about 15% of plankton-derived carbon sinks to the bottom of the sea, the authors estimate. They further report that the environmental conditions that allow bacteria to recycle carbon are spreading as water temperatures rise.

The team used data from a 2013 research cruise from Peru to Tahiti. They focused on two distinct regions: nutrient-rich, highly productive waters off South America, and the largely infertile bodies of water that form the South Pacific Gyre. Instead of using traditional sampling methods — simple devices that trap particles as they sink — the team pumped large amounts of water from different depths and isolated particles and thorium isotopes. This approach allowed them to calculate the quantity of carbon sinking at different depth intervals, they explain, and much more reliably so — the technique yielded far more data than the traditional traps.

Deeply worrying

In the oxygenated upper waters layers off South America, the team reports, oxygen gets used up very quickly. It is consumed completely at about 150 meters of depth, halting aerobic activity. Organic matter that reaches this layer (called the oxygen minimum zone, OMZ) will sink to the bottom of the ocean. In the depths, oxygen levels do increase again, and aerobic bacteria start breaking down organic matter. However, any CO2 produced down that far will take centuries to get back into the air via upwelling currents.

The OMZ thus forms a sort of protective cap over any organic matter that sinks past it, according to the team. The common wisdom of today, held that organic matter produced near the surface makes it through the OMZ, and that most CO2 regeneration takes place in the deep ocean. However, only about 15% of this matter sinks past the OMZ, the team shows.

“People did not think that much regeneration was taking place in the shallower zone,” said the study’s lead author, Frank Pavia, a graduate student at Lamont-Doherty. “The fact that it’s happening at all shows that the model totally doesn’t work in the way we thought it did.”

As mean water temperatures in the ocean increase, OMZs will spread both horizontally and vertically, covering larger areas of ocean at shallower depths, the team estimates. At the same time, higher temperatures will drive bacterial activity above the OMZs. On one hand, this would allow more organic matter to sink undegraded into the deep. However, the increased rate of CO2 regeneration near the surface will counteract this increased trapping, the team says. Whether near surface regeneration or the cap provided by the OMZ might have a stronger effect is still something we need to look into, they explain. However, this shift in OMZs is definitely not good news, as they are not at all suitable for most marine life — and this shift will affect a lot of today’s key fishing areas.

In the South Pacific Gyre, the results were less ambiguous. There is far more regeneration near the warmer surface than previously estimated in this area. The South Pacific Gyre and similar current systems in other parts of the oceans are projected to grow as the oceans warm. The gyres will divide waters into warmer layers (on the surface) and colder ones (deeper down). Because much of the CO2 regeneration will take place in the warm, shallower waters, CO2 regeneration will pick up over wide spans of ocean, the team explains. And, unlike below the nearer-shore OMZs, “there is no counterbalancing effect in the gyres,” said Anderson.

“The story with the gyres is that over wide areas of the ocean, carbon storage is going to get less efficient.” (There are four other major gyres: the north Pacific, the south and north Atlantic, and the Indian Ocean.)

These are only parts of the ocean carbon cycle, the team notes. Abiotic reactions are responsible for significant exchanges of carbon between atmosphere and oceans, and these processes could interact with the biology in complex and unpredictable ways.

“This [the study] gives us information that we didn’t have before, that we can plug into future models to make better estimates,” said the study’s lead author, Frank Pavia, a graduate student at Lamont-Doherty.

The paper “Shallow particulate organic carbon regeneration in the South Pacific Ocean,” has been published in the journal PNAS.