Carbon dioxide in atmosphere has spiked to record-setting new level

https://thehill.com/changing-america/sustainability/climate-change/546653-carbon-dioxide-in-atmosphere-has-spiked-to

Observatory data confirms a returned trend of increasing atmospheric carbon dioxide levels.ByAlexandra Kelley | April 6, 2021https://imasdk.googleapis.com/js/core/bridge3.448.1_en.html#goog_130977516200:00 of 00:55Volume 20%Next Up 

Story at a glance

  • As travel returns worldwide, carbon dioxide levels are increasing.
  • Carbon dioxide and other greenhouse gases are key contributors to climate change.

One of the U.S.’s premier observatories for measuring carbon dioxide emissions released into the atmosphere reported a record-breaking figure on April 3, noting a total of 421.21 particulate matter (ppm) of carbon dioxide in the Earth’s atmosphere — the highest daily average ever recorded.https://platform.twitter.com/embed/Tweet.html?dnt=false&embedId=twitter-widget-0&features=eyJ0ZndfZXhwZXJpbWVudHNfY29va2llX2V4cGlyYXRpb24iOnsiYnVja2V0IjoxMjA5NjAwLCJ2ZXJzaW9uIjpudWxsfSwidGZ3X2hvcml6b25fdHdlZXRfZW1iZWRfOTU1NSI6eyJidWNrZXQiOiJodGUiLCJ2ZXJzaW9uIjpudWxsfX0%3D&frame=false&hideCard=false&hideThread=false&id=1378912724323819523&lang=en&origin=https%3A%2F%2Fthehill.com%2Fchanging-america%2Fsustainability%2Fclimate-change%2F546653-carbon-dioxide-in-atmosphere-has-spiked-to&sessionId=100290235f060f3d79ff00989bcef6c7fa9b029c&theme=light&widgetsVersion=1ead0c7%3A1617660954974&width=550px

Based on data collected at the Mauna Loa laboratory in Hawaii, the peak comes after relatively low readings throughout March and early April, aside from a single uptick recorded between March 19 to 21.

Notably, however, when observing annual trends, this record-breaking volume represents a return to pre-pandemic levels. 

Carbon dioxide emissions have gradually increased since hitting record low levels during September and October of 2020, in the middle of the ongoing COVID-19 pandemic. This is broadly due to less travel by car, plane and other modes of transportation during lockdowns. 


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Prior to these record drops, emissions had posted steady declines since May 2020, with decreasing carbon dioxide levels occurring monthly from June to September of 2020.

The holiday months of November and December of 2020 saw burgeoning increases as a travel boom gave way to another surge of COVID-19 infections. This trend of rising carbon dioxide levels continues to persist.

A silver lining of the mass economic shutdowns spurred by the COVID-19 pandemic were widespread decreases in carbon dioxide and other greenhouse gas emissions, the main factors in anthropomorphic climate change.

As travel begins to resume, levels of carbon dioxide in the atmosphere are also increasing to comparable pre-pandemic levels. 

Since the 1960s, per Mauna Loa station data, atmospheric carbon dioxide has increased dramatically each decade.

Environmental advocates have underscored the need for sustainable policies of a government level to reduce the effects of climate change. 

One of Earth’s giant carbon sinks may have been overestimated – study

https://www.theguardian.com/environment/2021/mar/24/soils-ability-to-absorb-carbon-emissions-may-be-overestimated-study

The potential of soils to slow climate change by soaking up carbon may be less than previously thought

Grassland in RussiaGrassland in Russia
Grassland in Russia. The study suggests that plans to plant trees is such areas to combat climate change may be counterproductive. Photograph: Valery Matytsin/TASS

Damian Carrington Environment editor@dpcarringtonWed 24 Mar 2021 12.00 EDT

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The storage potential of one of the Earth’s biggest carbon sinks – soils – may have been overestimated, research shows. This could mean ecosystems on land soaking up less of humanity’s emissions than expected, and more rapid global heating.

Soils and the plants that grow in them absorb about a third of the carbon emissions that drive the climate crisis, partly limiting the impact of fossil-fuel burning. Rising carbon dioxide levels in the atmosphere can increase plant growth and, until now, it was assumed carbon storage in soils would increase too.

But the study, based on over 100 experiments, found the opposite. When plant growth increases, soil carbon does not. The finding is significant because the amount of organic carbon stored in soils is about three times that in living plants and double that in the atmosphere. Soils can also store carbon for centuries, whereas plants and trees rot quickly after they die.

It is not yet known how big the effect of lower carbon storage in soils might be on the speed of climate change, and experts cautioned that other impacts of the climate emergency such as drought would also affect how well plants and soils store carbon.

“We found that when rising CO2 increases plant growth, there is a decrease in soil carbon storage. That’s a very important conclusion,” said César Terrer, who led the research while at Stanford University in the US. He said that if soils do absorb less in future, “the speed of global warming could be higher”.

Terrier said soils, plants and trees were important for carbon levels, but that ending the burning of fossil fuels remains essential. “If we really want to stop global warming, we need to stop emissions, because ecosystems only take up a fraction of all the CO2 emissions,” he said.

The study, published in the journal Nature, analysed more than 100 experiments from across the world in which soils, plants and trees were exposed to higher CO2 levels than in today’s atmosphere. The biomass growing in forests rose by 23% in experiments where the CO2 level used was double pre-industrial atmospheric levels. It is 50% higher today. But the forest soils did not store any more organic carbon at all.Advertisementhttps://d26e136dff2c28f9f8743ab959918f44.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html

It was thought that biomass and soil carbon would increase in tandem, as more plant biomass falls to the ground and turns into organic matter. But increased plant and tree growth requires more nutrients from the soil, which may explain the new finding, the scientists said. Extracting the extra nutrients requires the plants to increase the symbiotic microbial activity in their roots, which then releases CO2 to the atmosphere that might otherwise have remained locked in the soil.

The researchers found that in grasslands, elevated CO2 led to 9% plant growth – less than forests – but soil carbon rose by 8%. Terrier said there has been a lot of discussion about tree planting as a way to tackle the climate crisis. “What I found very concerning in that debate is that people were suggesting planting trees in natural grasslands, savannah, and tundra,” he said. “I think that would be a terrible mistake because, as our results imply, there is a very large potential to increase soil carbon storage in grasslands.”

Prof Simon Lewis, at University College London, who was not part of the research team, said: “Given that the land absorbs 30% of the carbon emitted from fossil fuels and deforestation, understanding if that will change in the future matters.”

He said the change would be determined by the balance between rising CO2 boosting plant growth and the negative effects of climate change itself, including drought, heatwaves and fires. The evidence to date suggests the biggest change will be the negative effects of global heating on ecosystems, he said.

Prof Pete Smith at the University of Aberdeen said: “The combined effect of CO2 on plants and soils and on climate change is what matters in terms of the real world response.”

Insatiable demand for cannabis has created a giant carbon footprint

MARCH 8, 2021

https://phys.org/news/2021-03-insatiable-demand-cannabis-giant-carbon.html

by Colorado State University

Insatiable demand for cannabis has created a giant carbon footprint
The life cycle greenhouse gas emissions from indoor cannabis cultivation modeled across the U.S. Credit: Hailey Summers/Colorado State University

It’s no secret that the United States’ $13 billion cannabis industry is big business. Less obvious to many is the environmental toll this booming business is taking, in the form of greenhouse gas emissions from commercial, mostly indoor production.https://36c7bdb571aa01a80f815b11f82ad0e1.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.html

A new study by Colorado State University researchers provides the most detailed accounting to date of the industry’s carbon footprint, a sum around which there is only limited understanding. What is clear, though, is that consumer demand for cannabis is insatiable and shows no signs of stopping as more states sign on to legalization.

The study, published in Nature Sustainability, was led by graduate student Hailey Summers, whose advisor, Jason Quinn, is an associate professor in the Department of Mechanical Engineering. Summers, Quinn and Evan Sproul, a research scientist in mechanical engineering, performed a life-cycle assessment of indoor cannabis operations across the U.S., analyzing the energy and materials required to grow the product, and tallying corresponding greenhouse gas emissions.

They found that greenhouse gas emissions from cannabis production are largely attributed to electricity production and natural gas consumption from indoor environmental controls, high-intensity grow lights, and supplies of carbon dioxide for accelerated plant growth.

“We knew the emissions were going to be large, but because they hadn’t been fully quantified previously, we identified this as a big research opportunity space,” Summers said. “We just wanted to run with it.”

The CSU group’s efforts update previous work by Lawrence Berkeley National Laboratory researchers, which quantified small-scale grow operations in California and predated the cascade of state-by-state legalization since Colorado was first to legalize in 2012. To date, 36 states have legalized medical use of cannabis, and 15 have legalized recreational use.

Mapping variable emissions

The CSU team surmised there would be substantial variability in emissions depending on where the product was being grown, due to climate as well as electric grid emissions. Their recently published work captures the potential cross-country spread of large commercial warehouses for growing cannabis, and it models emissions for several high-growth locations around the country. Their results include a map that shows relative emissions anywhere in the U.S., as defined as emissions per kilogram of cannabis flower. They’ve also developed a GIS map that allows users to enter a county name and find local emissions estimates.https://googleads.g.doubleclick.net/pagead/ads?client=ca-pub-0536483524803400&output=html&h=280&slotname=5350699939&adk=3784993980&adf=780081655&pi=t.ma~as.5350699939&w=753&fwrn=4&fwrnh=100&lmt=1615231349&rafmt=1&psa=1&format=753×280&url=https%3A%2F%2Fphys.org%2Fnews%2F2021-03-insatiable-demand-cannabis-giant-carbon.html&flash=0&fwr=0&rpe=1&resp_fmts=3&wgl=1&tt_state=W3siaXNzdWVyT3JpZ2luIjoiaHR0cHM6Ly9hZHNlcnZpY2UuZ29vZ2xlLmNvbSIsInN0YXRlIjozfSx7Imlzc3Vlck9yaWdpbiI6Imh0dHBzOi8vYXR0ZXN0YXRpb24uYW5kcm9pZC5jb20iLCJzdGF0ZSI6N31d&dt=1615231348180&bpp=44&bdt=1452&idt=959&shv=r20210303&cbv=r20190131&ptt=9&saldr=aa&abxe=1&cookie=ID%3D5d55f89f953c9743-22199107c8c6003e%3AT%3D1615230132%3ART%3D1615230132%3AS%3DALNI_MadDCWOeUiPeZ8t0BqGk4vZokqQFA&correlator=6963473544776&frm=20&pv=2&ga_vid=185394846.1565457508&ga_sid=1615231349&ga_hid=1000505025&ga_fc=0&u_tz=-480&u_his=1&u_java=0&u_h=640&u_w=1139&u_ah=607&u_aw=1139&u_cd=24&u_nplug=3&u_nmime=4&adx=263&ady=2098&biw=1123&bih=538&scr_x=0&scr_y=300&eid=42530671%2C21066435%2C21067496&oid=3&pvsid=2771790257571091&pem=466&rx=0&eae=0&fc=896&brdim=0%2C0%2C0%2C0%2C1139%2C0%2C1139%2C607%2C1139%2C537&vis=1&rsz=%7C%7CpEebr%7C&abl=CS&pfx=0&fu=8320&bc=31&ifi=1&uci=a!1&btvi=1&fsb=1&xpc=wmKdTPVEMg&p=https%3A//phys.org&dtd=1047

Their research shows that U.S. indoor cannabis cultivation results in life-cycle greenhouse gas emissions of between 2,283 and 5,184 kilograms of carbon dioxide per kilogram of dried flower. Compare that to emissions from electricity use in outdoor and greenhouse cannabis growth, which is 22.7 and 326.6 kilograms of carbon dioxide, respectively, according to the New Frontier Data 2018 Cannabis Energy Report. Those outdoor and greenhouse numbers only consider electricity, while the CSU researchers’ estimate is more comprehensive, but the comparison still highlights the enormously larger footprint of indoor grow operations.

The researchers were surprised to find that heating, ventilation and air conditioning systems held the largest energy demand, with numbers fluctuating depending on the local climate—whether in Florida, which requires excessive dehumidifying, or Colorado, where heating is more important.

The high energy consumption of cannabis is due in part to how the product is regulated, Quinn said. In Colorado, many grow operations are required to be in close proximity to retail storefronts, and this has caused an explosion of energy-hungry indoor warehouses in urban areas like Denver. According to a report from the Denver Department of Public Health and Environment, electricity use from cannabis cultivation and other products grew from 1% to 4% of Denver’s total electricity consumption between 2013 and 2018.

The team is seeking more funding for continuing their modeling work, with hopes of extending it to a comparison between indoor and potential outdoor growth operations. Ultimately, they would like to help the industry tackle environmental concerns while legal cannabis is still relatively new in the U.S.

“We would like to try and improve environmental impacts before they have become built into the way of doing business,” Sproul said.


Explore furtherNovel research accounts for future impacts of greenhouse gas emissions

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Warming already baked in will blow past climate goals, study finds

A study in the journal Nature Climate Change figures the carbon pollution already put in the air will push global temperatures to about 2.3 degrees Celsius.

https://www.nbcnews.com/science/environment/warming-already-baked-will-blow-climate-goals-study-finds-rcna216

Smoke billows from the Jeffrey Energy Center coal-fired power plant on Sept. 12, 2020, near Emmet, Kan.

Smoke billows from the Jeffrey Energy Center coal-fired power plant on Sept. 12, 2020, near Emmet, Kan.Charlie Riedel / AP fileJan. 5, 2021, 6:15 AM PST / Updated Jan. 5, 2021, 6:17 AM PSTBy Associated Press

The amount of baked-in global warming, from carbon pollution already in the air, is enough to blow past international agreed upon goals to limit climate change, a new study finds.

But it’s not game over because, while that amount of warming may be inevitable, it can be delayed for centuries if the world quickly stops emitting extra greenhouse gases from the burning of coal, oil and natural gas, the study’s authors say.

For decades, scientists have talked about so-called “committed warming” or the increase in future temperature based on past carbon dioxide emissions that stay in the atmosphere for well over a century. It’s like the distance a speeding car travels after the brakes are applied.

But Monday’s study in the journal Nature Climate Change calculates that a bit differently and now figures the carbon pollution already put in the air will push global temperatures to about 2.3 degrees Celsius (4.1 degrees Fahrenheit) of warming since pre-industrial times.

Previous estimates, including those accepted by international science panels, were about a degree Celsius (1.8 degrees Fahrenheit) less than that amount of committed warming.

International climate agreements set goals of limiting warming to 2 degrees Celsius (3.6 degrees Fahrenheit) since pre-industrial times, with the more ambitious goal of limiting it to 1.5 degrees Celsius (2.7 degrees Fahrenheit) added in Paris in 2015. The world has already warmed about 1.1 degrees Celsius (2 degrees Fahrenheit).

“You’ve got some … global warming inertia that’s going to cause the climate system to keep warming, and that’s essentially what we’re calculating,” said study co-author Andrew Dessler, a climate scientist at Texas A&M University. “Think about the climate system like the Titanic. It’s hard to turn the ship when you see the icebergs.”

Dessler and colleagues at the Lawrence Livermore National Lab and Nanjing University in China calculated committed warming to take into account that the world has warmed at different rates in different places and that places that haven’t warmed as fast are destined to catch up.

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Places such as the Southern Ocean, surrounding Antarctica are a bit cooler, and that difference creates low-lying clouds that reflect more sun away from earth, keeping these places cooler. But this situation can’t keep going indefinitely because physics dictates that cooler locations will warm up more and when they do, the clouds will dwindle and more heating will occur, Dessler said.

Previous studies were based on the cooler spots staying that way, but Dessler and colleagues say that’s not likely.

Outside experts said the work is based on compelling reasoning, but want more research to show that it’s true. Breakthrough Institute climate scientist Zeke Hausfather said the new work fits better with climate models than observational data.

Just because the world is bound to get more warming than international goals, that doesn’t mean all is lost in the fight against global warming, said Dessler, who cautioned against what he called “climate doomers.”

If the world gets to net zero carbon emissions soon, 2 degrees of global warming could be delayed enough so that it won’t happen for centuries, giving society time to adapt or even come up with technological fixes, he said.

“If we don’t, we’re going to blow through (climate goals) in a few decades,” Dessler said. “It’s really the rate of warming that makes climate change so terrible. If we got a few degrees over 100,000 years, that would not be that big a deal. We can deal with that. But a few degrees over 100 years is really bad.”

Could we ever pull enough carbon out of the atmosphere to stop climate change?

By Donavyn Coffey a day ago

Planting trees helps, but what are other ways?

Planting 1 trillion trees is one way to store unwanted carbon.Planting 1 trillion trees is one way to store unwanted carbon.(Image: © Shutterstock)

Nature has equipped Earth with several giant “sponges,” or carbon sinks, that can help humans battle climate change. These natural sponges, as well as human-made ones, can sop up carbon, effectively removing it from the atmosphere. 

But what does this sci-fi-like act really entail? And how much will it actually take — and cost — to make a difference and slow climate change

Sabine Fuss has been looking for these answers for the last two years. An economist in Berlin, Fuss leads a research group at the Mercator Research Institute on Global Commons and Climate Change and was part of the original Intergovernmental Panel on Climate Change (IPCC) — established by the United Nations to assess the science, risks and impacts of global warming. After the panel’s 2018 report and the new Paris Agreement goal to keep global warming to 2.7 degrees Fahrenheit (1.5 degrees Celsius) or less, Fuss was tasked with finding out which carbon removal strategies were most promising and feasible. 

Related: What is a carbon sink?Click here for more Space.com videos…CLOSEhttps://imasdk.googleapis.com/js/core/bridge3.432.0_en.html#goog_167488136Volume 0% PLAY SOUND

Afforestation and reforestation — planting or replanting of forests, respectively — are well known natural carbon sinks. Vast numbers of trees can sequester the greenhouse gas carbon dioxide (CO2) from the atmosphere for photosynthesis, a chemical reaction that uses the sun’s energy to turn carbon dioxide and water into sugar and oxygen. According to a 2019 study in the journal Science, planting 1 trillion trees could store about 225 billion tons (205 billion metric tons) of carbon, or about two-thirds of the carbon released by humans into the atmosphere since the Industrial Revolution began. 

Agriculture land management is another natural carbon removal approach that’s relatively low risk and already being tested out, according to Jane Zelikova, terrestrial ecologist and chief scientist at Carbon180, a nonprofit that advocates for carbon removal strategies in the U.S. Practices such as rotational grazing, reduced tilling and crop rotation increase carbon intake by photosynthesis, and that carbon is eventually stored in root tissues that decompose in the soil. The National Academy of Sciences found that carbon storage in soil was enough to offset as much as 10% of U.S. annual net emissions — or about 632 million tons (574 million metric tons) of CO2 — at a low cost. 

But nature-based carbon removal, like planting and replanting forests, can conflict with other policy goals, like food production, Fuss said. Scaled up, these strategies require a lot of land, oftentimes land that’s already in use. 

This is why more tech-based approaches to carbon removal are crucial, they say. With direct air capture and carbon storage, for instance, a chemical process takes carbon dioxide out of the air and binds it to filters. When the filter is heated, the CO2 can be captured and then injected underground. There are currently 15 direct air capture plants worldwide, according to the International Energy Agency. There’s also bioenergy with carbon capture. With this method, plants and trees are grown, creating a carbon sink, and then the organic material is burned to produce heat or fuel known as bioenergy. During combustion, the carbon emissions are captured and stored underground. Another carbon capture trick involves mineralization; in this process, rocks get ground up to increase the surfaces available to chemically react with, and crystallize, CO2. Afterward, the mineralized CO2 is stored underground. 

However, none of these technologies have been implemented on a large scale. They’re extremely expensive, with estimates as high as $400 per ton of CO2 removed, and each still requires a lot of research and support before being deployed. But the U.S. is a good example of how a mix of carbon removal solutions could work together, Zelikova said: Land management could be used in the agricultural Midwest; basalt rocks in the Pacific Northwest are great for mineralization; and the oil fields in the Southwest are already primed with the right technology and skilled workers for underground carbon storage, she said. 

Related: Why does the Earth rotate?

Ultimately, every country will have to put together its own unique portfolio of CO2 removal strategies because no single intervention will be successful on its own. “If we scaled up any of them exclusively, it would be a disaster,” Fuss said. “It would use a lot of land or be prohibitively expensive.” Her research has shown that afforestation and reforestation will be most productive in tropical regions, whereas solar radiation differences in the more northern latitudes with more albedo (reflection of light back into space) mean those countries will likely have better luck investing in the more technological interventions, such as carbon capture and biomass extraction.

The need to deploy these solutions is imminent. The global carbon budget, the amount of CO2 humans can emit before the global temperature rises 2.7 F (1.5 C) above preindustrial levels, is about 300 gigatons of CO2, Fuss said. RELATED MYSTERIES

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“In recent years, we’ve emitted 40 gigatons,” she said. Put another way, only a few years are left in that budget. A recent study in the journal Scientific Reports suggests that waiting even a few years from now may be too late if we are to meet the goal set in the Paris Agreement. Based on their climate model, the authors predict that even if we stop emitting greenhouse gases entirely, “global temperatures will be 3 C [5.4 F] warmer and sea levels 3 meters [10 feet] higher by 2500 than they were in 1850.” To reverse climate change’s effects, 33 gigatons of existing greenhouse gases must be removed this year and every year moving forward, the researchers said.  

The reality, however, is these approaches are not ready and there’s not a consensus on how to pay for them. There is a consensus among scientists on the next step: We need to stop further emissions immediately. But, “since emissions are embedded in our daily lives and infrastructure,” Fuss said, “[carbon] removal comes more to the forefront.”

Originally published on Live Science.

Carbon Capture Is Not a Climate Savior

December 24, 2020

The promise of negative emissions is baked into most “net zero” pledges. But putting that into practice is easier said than done.

Algae at the wastewater biofuel system at the San Francisco Public Utilities Commission's Southeast Water Pollution Control Plant (shown here in 2012) capture carbon dioxide and produce biofuel.SARAH RICE/GETTY IMAGESAlgae at the wastewater biofuel system at the San Francisco Public Utilities Commission’s Southeast Water Pollution Control Plant (shown here in 2012) capture carbon dioxide and produce biofuel.

https://newrepublic.com/article/160754/carbon-capture-not-climate-savior

In December, the Vatican became one of the latest entities to unveil a plan to reach net-zero emissions by 2050, joining far less pious actors like BP, Shell, and President-elect Joe Biden. Net-zero plans have become all the rage as public concern about the climate crisis has grown. But approving coverage of these wide-ranging announcements rarely question what the “net” of net-zero actually means. 

Meeting climate targets means releasing fewer fumes into the sky, for starters. And those plans include that. But they also include something else. The way they get to “zero” isn’t by cutting all greenhouse gas emissions by mid-century but by sucking carbon dioxide out of the atmosphere afterward through a suite of methods known collectively as “negative emissions.” And there’s a problem with that: Existing “carbon capture” technologies and techniques can today capture only 0.1 percent of global emissions. Banking on them to pick up the slack amounts to a big gamble. It’s not clear these techniques are scalable or that the countries and companies behind net-zero pledges have thought through what trying to scale them would mean.

Talking up carbon capture is good for fossil fuel companies—it makes the next few decades look profitable for them. Companies from ExxonMobil to Shell to Occidental Petroleum have all boasted about investments in carbon capture while continuing to double down on their core business model of finding and digging up as much oil and gas as possible. Whether they’re making meaningful investments in carbon capture is a different matter entirely. Exxon recently nixed its $1 billion investment to store carbon under a gas operation it owns in Wyoming. It moved ahead with a $9 billion expansion of its crude oil drilling operations off the coast of Guyana. All the while, Exxon, like its competitors, continues to advertise its token investments in carbon capture as proof that they’ve enlisted in good faith in the climate fight, despite all evidence to the contrary.Special OfferPostelection updates:
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The approach is eerily reminiscent of the climate denial playbook. When companies like Exxon and General Motors funded climate denial, the effect wasn’t to convince the world that more carbon dioxide is a good thing or that the earth just naturally gets really hot sometimes, but it was to muddy the waters, casting enough doubt on the scientific consensus to stymie policymaking that might threaten their profits. Now, such companies’ lavish advertising budgets are being used to spread a new kind of doubt in the face of a new consensus about how to deal with that problem: Phase out fossil fuel use as quickly as possible while phasing in renewables. Negative emissions are one among several vague talking points being thrown out by polluters to suggest that isn’t necessary. What if we could suck up a whole lot of carbon dioxide at some point? What if the timeline for decarbonization could be pushed back as a result? The jury’s still out on how much carbon dioxide we can take out of the atmosphere after 2050, they argue. And renewables can’t yet meet the world’s energy needs. So it’s probably safest to let us keep making the earth hotter while our best researchers work to find a technological fix to this problem that’s just around the corner. 

Here’s the sticky bit: Negative emissions are needed if the world’s governments are indeed serious about keeping warming to “well below” 2 degrees Celsius, per the text of the Paris Agreement. Anything higher than 1.5 degrees may well amount to a death sentence for potentially millions across the global south, and the lack of zero-carbon alternatives on offer in big sectors of the economy mean it’d be all too possible to sail past that threshold in the decades to come. Carbon capture is necessary. But fossil fuel executives are the last people who should get to define how much of it’s needed, what it should look like, and who benefits.https://ee9607a1e788642f9a8db0d1678b9c19.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.html


“It’s important to know how many gigatons we can take out of the air and the economic efficiency,” Georgetown University’s Olúfẹ́mi Táíwò, whose research explores the intersections of climate justice and colonialism, told me. In a forthcoming primer on carbon dioxide removal, or CDR, Harvard University researchers Andrew Bergman and Toly Rinberg suggest that around 1 metric gigaton of removal per year, worldwide,is consistent with a pathway toward capping warming at 1.5 degrees Celsius—far less than the 5 to 15 metric gigatons suggested by the models used by the Intergovernmental Panel on Climate Change, or IPCC. 

Even more modest targets will require technology that is currently quite expensive, probably in addition to large quantities of land for carbon sinks. The Integrated Assessment Models, or IAMs, used by the IPCC to design net-zero pledges pose deceptively simple answers to this challenge. In assuming a continued annual GDP growth of around 2 percent, year on year, carbon capture technologies that are expensive to deploy now will get cheaper in the future. So long as our future selves and countries are richer, it’ll be cheaper and easier to suck up carbon at evermore impressive scales down the line—more so, say, than phasing out fossil fuels and deploying lots of renewables in the next 20 years. We don’t actually know, though, if societies getting richer means they’ll be able to capture more carbon—particularly given the stubborn fact that GDP and emissions tend to rise together.

Carbon capture, or negative emissions, can mean many different things. So-called “natural climate solutions” involve things like tree planting, grassland and wetland restoration, or (controversially) agriculture-based soil sequestration. The Green New Deal resolution introduced to Congress last year backed this approach, citing the need for “removing greenhouse gases from the atmosphere and reducing pollution by restoring natural ecosystems through proven low-tech solutions that increase soil carbon storage, such as land preservation and afforestation.” But there are other approaches, too. Among the most frequently invoked in climate modeling is Bioenergy with Carbon Capture and Storage, or BECCS. This relies on harvesting new carbon-sucking crops like switchgrass for fuel, then capturing the resulting emissions through machines that filter out emissions from where the power is generated. And in direct air capture, machines that look like air conditioners suck carbon down from the sky and inject it into rock formations or soft drinks, among other uses. Special OfferPostelection updates:
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In some industries, carbon capture makes intuitive sense—for example, in aviation, where sustainable fuel solutions are going to take a while to develop. In others, carbon capture can serve to reduce emissions from activities that should be eliminated outright. A good example of this are so-called “scrubbers” on gas and coal-fired power plants. These lessen the amount of carbon they’re spewing into the atmosphere with the help of a recently bolstered federal tax credit known as 45Q. This isn’t a negative emissions technology, since pollution is still happening. Such poorly targeted subsidies for carbon capture and storage, or CCS, could even extend the life of already uneconomical power stations that should be among the first things phased out as part of any earnest decarbonization agenda.  https://ee9607a1e788642f9a8db0d1678b9c19.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.html

“If you’re doing aggressive mitigation, the coal for CCS option essentially falls off the table,” Glen Peters, research director at the Center for International Climate Research, says. “You need both to happen: aggressive mitigation, while starting to figure out the technologies you’ll need for the last 20 to 30 percent.” Despite platitudes from Republicans, former energy secretaries, and even some parts of organized labor about the supposed promise of “clean coal,” no amount of tax credits will change the fact that coal remains a bad investment in just about every sense. 


Innovation is a seductive concept. Given that Republicans are particularly keen on it, investing in negative emissions technologymight seem like low-hanging fruit for climate policy in a divided government; just this week, $35 billion in research funding—including roughly $6 billion for carbon capture—made it into the broad spending bill now sitting on Trump’s desk. 

Much of the policy support for negative emissions on offer now, though—and that can garner bipartisan support—tends to take the form of sloppily designed corporate subsidies for polluters like 45Q. The vast majority of the carbon captured on earth today is poured back into extraction. Enhanced Oil Recovery, or EOR, utilizes carbon by injecting it underground to help unearth more fossil fuels from wells. 45Q—created to spur on a domestic carbon capture and storage industry—furnishes generous subsidies on “clean coal” and EOR alike. Unsurprisingly, fossil fuel interests have consistently sought to degrade the reporting requirements for such credits. A 2018 study by Clean Water Action found that just three of the 60 million metric tons worth of 45Q tax credits claimed as of that spring had been reported to the EPA’s verification process.  

“Moving forward, we have to completely change how we’re tackling this type of technology,” Shuchi Talati, a senior policy adviser at Carbon 180, told me. “We really need to have more broad participatory conversations on what infrastructure means for these kinds of projects. Things like carbon dioxide pipelines will be needed at scale. I think having conversations that include labor, environmental justice, and community groups and local governments need to be had at the beginning,” she added, noting the need in particular for international governance. https://ee9607a1e788642f9a8db0d1678b9c19.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.html

“Land use, respecting the rights of indigenous peoples and low-income communities, questions of community benefits agreements, who’s going to get the jobs these projects create … These are all things we should know. I just don’t think ExxonMobil is going to ask those questions, much less answer them in any kind of serious way,” said Táíwò.

Carbon dioxide removal projects, wrote Táíwò, Talati, and several other researchers across disciplines in a recent paper in One Earth, need to be evaluated “on a case-specific basis rather than just as abstract technologies.” In a country where rural, mostly white landowners can still stymie vital wind farm and transmission line projects, comparatively little attention is paid to potential resistance to negative emissions. Removing just a single metric gigaton of carbon per yearwould require a land area bigger than Texas. Stabilizing temperatures at the same level through BECCS alone, per many IAMs, is estimated to require a landmass five times the size of India. And a recent Nature Climate Change study finds that relying primarily on more “natural” negative emissions to stabilize warming at 1.5 degrees could trigger a five-fold increase in staple food crop price. 

Already, troubling patterns have emerged. As Táíwò has pointed out, Africa—where land ownership is increasingly concentrated—now accounts for 75 percent of the land pledged under the “Bonn Challenge” to restore 350 million hectares of forest. Having the “net” of “net-zero” pledges happen out of sight and out of mind for global north countries could see the dynamics of capturing carbon look a lot like those that were erected to dig it out of the ground. Making matters worse is the fact that decades of multilateral programs, from REDD+ to the Bonn Challenge, have treated large swathes of the global south as an inexhaustible carbon sink. Having contributed just 3 percent of global emissions since 1751, Táíwò says, it’s “absurd that the African continent should have to deal with the land use costs of carbon removal.” 

“Carbon removal in particular is one of the most direct forms of climate reparations,” he added. “Global north countries taking on carbon removal is obviously not exhaustive of their responsibilities from a justice perspective, but in a lot of ways is the most direct thing they can do conceptually speaking.” A more just approach would be for global north countries to fund carbon removal and site much of it in their own backyards.

But while less land-use intensive, direct-air capture technologies have their own feasibility and affordability issues. For one, they depend on an enormous amount of electricity; if the grid powering DAC is still carbon-intensive, its carbon savings look a lot more ambiguous. Andif such technologies are patented by private companies, onerous intellectual property statutes could make it virtually impossible for them to proliferate widely, particularly to low- and middle-income countries that lack the capacity to pay the rents that might be demanded by patent holders. Wealthy countries’ recent refusals to waive intellectual property rights for publicly funded Covid-19 vaccines, Táíwò notes, could offer a preview for how IP rules may stymie a new generation of life-saving technologies. 

True negative emissions—mostly, capturing carbon and keeping it buried—aren’t neatly compatible with the profit motive. Even if captured carbon is used to make building materials, acknowledging that negative emissions are critical to ward off climate catastrophe means making sure that installing them quickly doesn’t depend on their ability to turn a profit. Lavishing private companies with subsidies and tax incentives, that is, will only go so far. Instead, we might need to treat carbon like sewage, as science fiction writer Kim Stanley Robinson recently proposed: an essential but basically boring public service that nobody expects to get rich off of unless there’s something illicit happening. 

As fossil fuel companies look to capture the field of captured carbon with schemes for EOR and pernicious academic funding, there’s a dire need for democratic governance models for carbon dioxide removal that prioritize equity and emissions reductions over shareholders. Environmental sociologist Holly Jean Buck argues that carbon capture could fall under the mandate of nationalized fossil fuel companies, which could keep union workers on the payroll as they build out the vast amount of infrastructure needed to store carbon. As the One Earth paper coauthored by Buck also notes, “We might need to stretch our imaginations to envision economic and political futures in which CDR fits into the world we want rather than delaying or undermining it.”


The proliferation of net-zero plans in 2020 is clearly good news insofar as it indicates that governments are now taking the climate crisis more seriously. But they also belie the need for concrete plans to reduce emissions much sooner. “The scenarios are performative in a sense that they show us one way but not all the ways to 1.5 or 2 degrees,” Glen Peters explained. Earlier climate models, he said, were designed around stabilizing atmospheric concentrations of carbon dioxide, say around 450 or 550 parts per million. “But many models couldn’t get to this,” he said. “So what they did is change that target to only apply in 2100, so you could go over and come back down. All the models could do this if they used BECCS.” Such models can be useful reference points but don’t need to dictate what’s possible. 

What caused the ice ages? Tiny ocean fossils offer key evidence

DECEMBER 10, 2020

https://phys.org/news/2020-12-ice-ages-tiny-ocean-fossils.html?fbclid=IwAR3Yvv5PsX9bObsuEYXRS1eyffwir99o93K-yXW9g9mAfeZAoFZDAzbbpXw

by Liz Fuller-Wright, Princeton University

What caused the ice ages? Tiny ocean fossils offer key evidence
This diatom species, Fragilariopsis kerguelensis, is a floating algae that is abundant in the Antarctic Ocean and was the major species in the samples collected for the study by Princeton University and the Max Planck Institute for Chemistry. These microscopic organisms live near the sea surface, then die and sink to the sea floor. The nitrogen isotopes in their shells vary with the amount of unused nitrogen in the surface water. The researchers used that to trace nitrogen concentrations in Antarctic surface waters over the past 150,000 years, covering two ice ages and two warm interglacial periods. Credit: Philipp Assmy (Norwegian Polar Institute) and Marina Montresor (Stazione Zoologica Anton Dohrn)

The last million years of Earth history have been characterized by frequent “glacial-interglacial cycles,” large swings in climate that are linked to the growing and shrinking of massive, continent-spanning ice sheets. These cycles are triggered by subtle oscillations in Earth’s orbit and rotation, but the orbital oscillations are too subtle to explain the large changes in climate.https://8b4a283b4123076bbb082c6b0c4e1d40.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.html

“The cause of the ice ages is one of the great unsolved problems in the geosciences,” said Daniel Sigman, the Dusenbury Professor of Geological and Geophysical Sciences. “Explaining this dominant climate phenomenon will improve our ability to predict future climate change.”

In the 1970s, scientists discovered that the concentration of the atmospheric greenhouse gas carbon dioxide (CO2) was about 30% lower during the ice ages. That prompted theories that the decrease in atmospheric CO2 levels is a key ingredient in the glacial cycles, but the causes of the CO2 change remained unknown. Some data suggested that, during ice ages, CO2 was trapped in the deep ocean, but the reason for this was debated.

Now, an international collaboration led by scientists from Princeton University and the Max Planck Institute for Chemistry (MPIC) have found evidence indicating that during ice ages, changes in the surface waters of the Antarctic Ocean worked to store more CO2 in the deep ocean. Using sediment cores from the Antarctic Ocean, the researchers generated detailed records of the chemical composition of organic matter trapped in the fossils of diatoms—floating algae that grew in the surface waters, then died and sank to the sea floor. Their measurements provide evidence for systematic reductions in wind-driven upwelling in the Antarctic Ocean during the ice ages. The research appears in the current issue of the journal Science.

For decades, researchers have known that the growth and sinking of marine algae pumps CO2 deep into the ocean, a process often referred to as the “biological pump.” The biological pump is driven mostly by the tropical, subtropical and temperate oceans and is inefficient closer to the poles, where CO2 is vented back to the atmosphere by the rapid exposure of deep waters to the surface. The worst offender is the Antarctic Ocean: the strong eastward winds encircling the Antarctic continent pull CO2-rich deep water up to the surface, “leaking” CO2 to the atmosphere.https://googleads.g.doubleclick.net/pagead/ads?guci=2.2.0.0.2.2.0.0&client=ca-pub-0536483524803400&output=html&h=280&slotname=5350699939&adk=3784993980&adf=780081655&pi=t.ma~as.5350699939&w=753&fwrn=4&fwrnh=100&lmt=1607891776&rafmt=1&psa=1&format=753×280&url=https%3A%2F%2Fphys.org%2Fnews%2F2020-12-ice-ages-tiny-ocean-fossils.html%3Ffbclid%3DIwAR3Yvv5PsX9bObsuEYXRS1eyffwir99o93K-yXW9g9mAfeZAoFZDAzbbpXw&flash=0&fwr=0&rpe=1&resp_fmts=3&wgl=1&tt_state=W3siaXNzdWVyT3JpZ2luIjoiaHR0cHM6Ly9hZHNlcnZpY2UuZ29vZ2xlLmNvbSIsInN0YXRlIjowfSx7Imlzc3Vlck9yaWdpbiI6Imh0dHBzOi8vYXR0ZXN0YXRpb24uYW5kcm9pZC5jb20iLCJzdGF0ZSI6MH1d&dt=1607891775727&bpp=226&bdt=1314&idt=999&shv=r20201203&cbv=r20190131&ptt=9&saldr=aa&abxe=1&cookie=ID%3D5d55f89f953c9743-22e6569e4cc5006c%3AT%3D1607721097%3ART%3D1607721097%3AS%3DALNI_MYEkuf_Iee2xDN3kq44UdtznCjh2Q&correlator=3168947984516&frm=20&pv=2&ga_vid=185394846.1565457508&ga_sid=1607891777&ga_hid=1178168891&ga_fc=0&u_tz=-480&u_his=1&u_java=0&u_h=640&u_w=1139&u_ah=607&u_aw=1139&u_cd=24&u_nplug=3&u_nmime=4&adx=263&ady=1965&biw=1123&bih=538&scr_x=0&scr_y=0&eid=42530671%2C21066435%2C21068084&oid=3&pvsid=2470879372500863&pem=466&ref=https%3A%2F%2Fl.facebook.com%2F&rx=0&eae=0&fc=896&brdim=0%2C0%2C0%2C0%2C1139%2C0%2C1139%2C607%2C1139%2C537&vis=1&rsz=%7C%7CpEebr%7C&abl=CS&pfx=0&fu=8320&bc=31&ifi=1&uci=a!1&btvi=1&fsb=1&xpc=O8lYBHvjyS&p=https%3A//phys.org&dtd=1090

The potential for a reduction in wind-driven upwelling to keep more CO2 in the ocean, and thus to explain the ice age atmospheric CO2 drawdown, has also been recognized for decades. Until now, however, scientists have lacked a way to unambiguously test for such a change.

The Princeton-MPIC collaboration has developed such an approach, using tiny diatoms. Diatoms are floating algae that grow abundantly in Antarctic surface waters, and their silica shells accumulate in deep sea sediment. The nitrogen isotopes in diatoms’ shells vary with the amount of unused nitrogen in the surface water. The Princeton-MPIC team measured the nitrogen isotope ratios of the trace organic matter trapped in the mineral walls of these fossils, which revealed the evolution of nitrogen concentrations in Antarctic surface waters over the past 150,000 years, covering two ice ages and two warm interglacial periods.

“Analysis of the nitrogen isotopes trapped in fossils like diatoms reveals the surface nitrogen concentration in the past,” said Ellen Ai, first author of the study and a Princeton graduate student working with Sigman and with the groups of Alfredo Martínez-García and Gerald Haug at MPIC. “Deep water has high concentrations of the nitrogen that algae rely on. The more upwelling that occurs in the Antarctic, the higher the nitrogen concentration in the surface water. So our results also allowed us to reconstruct Antarctic upwelling changes.”

What caused the ice ages? Tiny ocean fossils offer key evidence
This diatom species, Fragilariopsis kerguelensis, is a floating algae that is abundant in the Antarctic Ocean and was the major species in the samples collected for the study by Princeton University and the Max Planck Institute for Chemistry. These microscopic organisms live near the sea surface, then die and sink to the sea floor. The nitrogen isotopes in their shells vary with the amount of unused nitrogen in the surface water. The researchers used that to trace nitrogen concentrations in Antarctic surface waters over the past 150,000 years, covering two ice ages and two warm interglacial periods. Credit: (c) Michael Kloster, Alfred-Wegener-Institute

The data were made more powerful by a new approach for dating the Antarctic sediments. Surface water temperature change was reconstructed in the sediment cores and compared with Antarctic ice core records of air temperature.

“This allowed us to connect many features in the diatom nitrogen record to coincident climate and ocean changes from across the globe,” said Martínez-García. “In particular, we are now able to pin down the timing of upwelling decline, when climate starts to cool, as well as to connect upwelling changes in the Antarctic with the fast climate oscillations during ice ages.”

This more precise timing allowed the researchers to home in on the winds as the key driver of the upwelling changes.

The new findings also allowed the researchers to disentangle how the changes in Antarctic upwelling and atmospheric CO2 are linked to the orbital triggers of the glacial cycles, bringing scientists a step closer to a complete theory for the origin of the ice ages.

“Our findings show that upwelling-driven atmospheric CO2 change was central to the cycles, but not always in the way that many of us had assumed,” said Sigman. “For example, rather than accelerating the descent into the ice ages, Antarctic upwelling caused CO2 changes that prolonged the warmest climates.”

Their findings also have implications for predicting how the ocean will respond to global warming. Computer models have yielded ambiguous results on the sensitivity of polar winds to climate change. The researchers’ observation of a major intensification in wind-driven upwelling in the Antarctic Ocean during warm periods of the past suggests that upwelling will also strengthen under global warming. Stronger Antarctic upwelling is likely to accelerate the ocean’s absorption of heat from ongoing global warming, while also impacting the biological conditions of the Antarctic Ocean and the ice on Antarctica.

“The new findings suggest that the atmosphere and ocean around Antarctica will change greatly in the coming century,” said Ai. “However, because the CO2 from fossil fuel burning is unique to the current times, more work is needed to understand how Antarctic Ocean changes will affect the rate at which the ocean absorbs this CO2.”

“Southern Ocean upwelling, Earth’s obliquity, and glacial-interglacial atmospheric CO2 change” by Xuyuan Ellen Ai, Anja S. Studer, Daniel M. Sigman, Alfredo Martínez-García, François Fripiat, Lena M. Thöle, Elisabeth Michel, Julia Gottschalk, Laura Arnold, Simone Moretti, Mareike Schmitt, Sergey Oleynik, Samuel L. Jaccard and Gerald H. Haug appears in the Dec. 11 issue of Science.


Explore furtherCarbon ‘leak’ may have warmed the planet for 11,000 years, encouraging human civilization

Polestar points to “a disturbing lack of transparency” about EV carbon footprint

Polestar on Thursday said it would publish full details on the “climate impact” of its electric cars.

The move “sets new standards for other car makers to follow,” Polestar declared in a press release. Based on what Green Car Reports has seen released to consumers, that would indeed make it one of the first few automakers of any kind to do so.

“Polestar at the disturbing lack of transparency across the industry, as it is today impossible for a consumer to compare the climate impact of different cars,” the company said.

One issue Polestar highlighted was the differing methodologies used by various automakers to calculate the life-cycle carbon footprint of vehicles. That means emissions not only from driving, but from manufacturing as well.

Polestar has already published the methodology for its life-cycle emissions assessments, as well as results for the Polestar 2, its first all-electric production model. Similar reports will presumably be generated for each new Polestar EV.

Using its own methodology, the automaker calculated that the Polestar 2 actually has a higher manufacturing-phase carbon footprint than an internal-combustion Volvo XC40—based on the same Compact Modular Architecture (CMA) platform. That’s because of an energy-intensive battery production process, Polestar said.

However, once the car is delivered to the customer, and charged using renewable energy, emissions virtually disappear, Polestar noted. After 50,000 kilometers (31,000 miles), the XC40 surpasses the Polestar 2 in total emissions, the company said.

 

2021 Polestar 22021 Polestar 2

That conclusion neatly lines up with other research on the carbon footprint of electric cars. One persistent myth that has been repeatedly debunked is that electric cars have higher lifetime emissions due to the manufacturing process, or from using coal-fired electricity grids for charging.

As a peer-reviewed process from the Union of Concerned Scientists has attested for years, electric cars have had a far lower lifetime carbon footprint than internal combustion vehicles—and recently, in nearly every set of conditions.

A study recently pointed out some of the errors in the data that some German automakers had been using to downplay the carbon gains of moving to EVs.

The most noteworthy of the studies that made some peculiar assumptions that don’t mirror the real world or the entire manufacturing ecosystem is a 2017 Swedish study.

Even outside of its lifetime carbon footprint, sustainability has been one of the hallmarks of the Polestar 2 and its materials choices and details.

Is having a certified number for lifetime carbon footprint an important part of your vehicle decision, and should other automakers follow suit? Let us know what you think in your comments below?

Ocean carbon uptake widely underestimated

https://phys.org/news/2020-09-ocean-carbon-uptake-widely-underestimated.html

ocean
Credit: CC0 Public Domain

The world’s oceans soak up more carbon than most scientific models suggest, according to new research.

Previous estimates of the movement of carbon (known as “flux”) between the atmosphere and oceans have not accounted for  differences at the water’s surface and a few metres below.

The new study, led by the University of Exeter, includes this—and finds significantly higher net flux of carbon into the oceans.

It calculates CO2 fluxes from 1992 to 2018, finding up to twice as much net flux in certain times and locations, compared to uncorrected models.

“Half of the carbon dioxide we emit doesn’t stay in the atmosphere but is taken up by the oceans and land vegetation ‘sinks’,” said Professor Andrew Watson, of Exeter’s Global Systems Institute.

“Researchers have assembled a  of near-surface carbon dioxide measurements—the “Surface Ocean Carbon Atlas” (http://www.socat.info) – that can be used to calculate the flux of CO2 from the atmosphere into the .

“Previous studies that have done this have, however, ignored small temperature differences between the surface of the ocean and the depth of a few metres where the measurements are made.

“Those differences are important because carbon dioxide solubility depends very strongly on temperature.

“We used  to correct for these temperature differences, and when we do that it makes a big difference—we get a substantially larger flux going into the ocean.

“The difference in ocean uptake we calculate amounts to about 10 per cent of global fossil fuel emissions.”

Dr. Jamie Shutler, of the Centre for Geography and Environmental Science on Exeter’s Penryn Campus in Cornwall, added: “Our revised estimate agrees much better than previously with an independent method of calculating how much carbon dioxide is being taken up by the ocean.

“That method makes use of a global ocean survey by research ships over decades, to calculate how the inventory of carbon in the ocean has increased.

“These two ‘big data’ estimates of the ocean sink for CO2 now agree pretty well, which gives us added confidence in them.”

The paper, published in Nature Communications, is entitled: “Revised estimates of ocean-atmosphere CO2 flux are consistent with ocean  inventory.”

Shockingly Simple: How Farmland Could Absorb an Extra 2 Billion Tonnes of CO2 From the Atmosphere Each Year

Rock Dust Farmland

Credit: Dr Dimitar Epihov

2 Billion Tonnes of CO2 Could be Absorbed From the Atmosphere Each Year by Applying Rock Dust to Farmland

Adding crushed rock dust to farmland could draw down up to two billion tonnes of carbon dioxide (CO2) from the air per year and help meet key global climate targets, according to a major new study led by the University of Sheffield.

  • Major new study shows adding rock dust to farmland could remove carbon dioxide (CO2) equivalent to more than the current total emissions from global aviation and shipping combined — or around half of Europe’s current total emissions
  • Research identifies the nation-by-nation potential for CO2 drawdown, as well as the costs and the engineering challenges involved
  • Findings reveal the world’s highest emitters (China, India and the US) also have the greatest potential to remove CO2 from the atmosphere using this method
  • Scientists suggest unused materials from mining and the construction industry could be used to help soils remove CO2 from the atmosphere

Adding crushed rock dust to farmland could draw down up to two billion tonnes of carbon dioxide (CO2) from the air per year and help meet key global climate targets, according to a major new study led by the University of Sheffield.

The technique, known as enhanced rock weathering, involves spreading finely crushed basalt, a natural volcanic rock, on fields to boost the soil’s ability to extract CO2 from the air.

In the first nation-by-nation assessment, published in Nature, scientists have demonstrated the method’s potential for carbon drawdown by major economies, and identified the costs and engineering challenges of scaling up the approach to help meet ambitious global CO2 removal targets. The research was led by experts at the University of Sheffield’s Leverhulme Centre for Climate Change Mitigation, and the University’s Energy Institute.

Meeting the Paris Agreement’s goal of limiting global heating to below 2C above pre-industrial levels requires drastic cuts in emissions, as well as the active removal of between two and 10 billion tonnes of CO2 from the atmosphere each year to achieve net-zero emissions by 2050. This new research provides a detailed initial assessment of enhanced rock weathering, a large-scale CO2 removal strategy that could make a major contribution to this effort.

The authors’ detailed analysis captures some of the uncertainties in enhanced weathering CO2 drawdown calculations and, at the same time, identifies the additional areas of uncertainty that future work needs to address specifically through large-scale field trials.

The study showed that China, the United States and India – the highest fossil fuel CO2 emitters – have the highest potential for CO2 drawdown using rock dust on croplands. Together, these countries have the potential to remove approximately 1 billion tonnes of CO2 from the atmosphere, at a cost comparable to that of other proposed carbon dioxide removal strategies (US$80-180 per tonne of CO2).

Indonesia and Brazil, whose CO2 emissions are 10-20 times lower than the US and China, were also found to have relatively high CO2 removal potential due to their extensive agricultural lands, and climates accelerating the efficiency of rock weathering.

The scientists suggest that meeting the demand for rock dust to undertake large-scale CO2 drawdown might be achieved by using stockpiles of silicate rock dust left over from the mining industry, and are calling for governments to develop national inventories of these materials.

Calcium-rich silicate by-products of iron and steel manufacturing, as well as waste cement from construction and demolition, could also be processed and used in this way, improving the sustainability of these industries. These materials are usually recycled as low value aggregate, stockpiled at production sites or disposed of in landfills. China and India could supply the rock dust necessary for large-scale CO2 drawdown with their croplands using entirely recycled materials in the coming decades.

The technique would be straightforward to implement for farmers, who already tend to add agricultural lime to their soils. The researchers are calling for policy innovation that could support multiple UN Sustainable Development Goals using this technology. Government incentives to encourage agricultural application of rock dust could improve soil and farm livelihoods, as well as reduce CO2, potentially benefiting the world’s 2.5 billion smallholders and reducing poverty and hunger.

Professor David Beerling, Director of the Leverhulme Centre for Climate Change Mitigation at the University of Sheffield and lead author of the study, said: “Carbon dioxide drawdown strategies that can scale up and are compatible with existing land uses are urgently required to combat climate change, alongside deep and sustained emissions cuts.

“Spreading rock dust on agricultural land is a straightforward, practical CO2 drawdown approach with the potential to boost soil health and food production. Our analyses reveal the big emitting nations – China, the US, India – have the greatest potential to do this, emphasizing their need to step up to the challenge. Large-scale Research Development and Demonstration programs, similar to those being pioneered by our Leverhulme Centre, are needed to evaluate the efficacy of this technology in the field.”

Professor Steven Banwart, a partner in the study and Director of the Global Food and Environment Institute, said: “The practice of spreading crushed rock to improve soil pH is commonplace in many agricultural regions worldwide. The technology and infrastructure already exist to adapt these practices to utilize basalt rock dust. This offers a potentially rapid transition in agricultural practices to help capture CO2 at large scale.”

Professor James Hansen, a partner in the study and Director of the Climate Science, Awareness and Solutions Program at Columbia University’s Earth Institute, said: “We have passed the safe level of greenhouse gases. Cutting fossil fuel emissions is crucial, but we must also extract atmospheric CO2 with safe, secure and scalable carbon dioxide removal strategies to bend the global CO2 curve and limit future climate change. The advantage of CO2 removal with crushed silicate rocks is that it could restore deteriorating top-soils, which underpin food security for billions of people, thereby incentivizing deployment.”

Professor Nick Pidgeon, a partner in the study and Director of the Understanding Risk Group at Cardiff University, said: “Greenhouse gas removal may well become necessary as we approach 2050, but we should not forget that it also raises profound ethical questions regarding our relationship with the natural environment. Its development should therefore be accompanied by the widest possible public debate as to potential risks and benefits.”

Reference: “Potential for large-scale CO2 removal via enhanced rock weathering with croplands” by David J. Beerling, Euripides P. Kantzas, Mark R. Lomas, Peter Wade, Rafael M. Eufrasio, Phil Renforth, Binoy Sarkar, M. Grace Andrews, Rachael H. James, Christopher R. Pearce, Jean-Francois Mercure, Hector Pollitt, Philip B. Holden, Neil R. Edwards, Madhu Khanna, Lenny Koh, Shaun Quegan, Nick F. Pidgeon, Ivan A. Janssens, James Hansen and Steven A. Banwart, 8 July 2020, Nature.
DOI: 10.1038/s41586-020-2448-9