There’s no denying Americans eat a lot of meat. In fact, the average U.S. citizen eats about 55 pounds of beef a year, including an estimated three hamburgers a week, and the United States Department of Agriculture (USDA) expects that amount to increase by about 3 percent by 2025. This heavy reliance on animal protein carries a big environmental footprint—livestock production contributes about 14.5 percent of global greenhouse gas (GHG) emissions, with beef constituting 41 percent of that figure, thanks to the methane cattle produce in the digestion process and the fact that overgrazing can release carbon stored in soils.
….A new five-year studythat will be published in the May 2018 issue of the journal Agricultural Systems suggests that they can. Conducted by a team of researchers from Michigan State University (MSU) and the Union of Concerned Scientists (UCS), the study suggests that if cattle are managed in a certain way during the finishing phase, grassfed beef can be carbon-negative in the short term and carbon-neutral in the long term….
….“it is possible that long-term [adaptive multi-paddock grazing] AMP grazing finishing in the Upper Midwest could contribute considerably more to climate change mitigation and adaptation than previously thought.”
Rather than using the common method of continuous grazing, in which cattle remain on the same pasture for an entire grazing season, the researchers used the more labor-intensive method of AMP, which entails moving the cattle at intervals ranging from days to months, depending on the type of forage, weather, time of year, and other considerations. A herd of adult cattle on MSU grazing land served as their test population.
Though the study’s finding that strategic grazing can make a dent in the overall environmental impact of cattle runs counter to the widespread opinion among other researchers and climate activists, it is welcome news for advocates of regenerative agriculture.
…. Tara Garnett, a food systems analyst and the founder of the Food Climate Research Network (FCRN) at the University of Oxford in England, calls the MSU work “a really useful study,” but also observes that it is “unclear how far this approach will lead to the same results elsewhere.” The study authors, too, are careful to stress that their results apply to Upper Midwestern conditions, and using a similar method in other ecosystem types will require further tailored study. They also acknowledge that while degraded land properly managed can take up large amounts of carbon, the soil will eventually reach equilibrium (meaning it will reach its carbon limit), and estimates of how long that takes vary widely.
In addition, soil types and the many other aspects of climate and ecosystems in different regions require detailed understanding and granular management of grazing—something many beef producers may be unwilling to undertake. And grazing requires twice as much land as feedlots….
…. One very promising practice, she said, is for ranchers to enlist farmers in the beef finishing phase. One farmer was initially very skeptical, but after he had grown a series of cover crops to rest his wheat fields and used cattle to “harvest” them, leaving the residue on the fields, he discovered that the soil was improving rapidly, Carman said. Reduced fertilizer and pesticide inputs, together with the income from the pasturage fees, makes the next wheat crop less expensive to grow.
…. said Rowntree, “I hope our paper can give our industry, combined with policymakers, a lens that can potentially help. We’re not trying to pit one group against another.”
Carman also acknowledges the complexity at hand, but feels the benefits to the soil she has seen are important to take into account. “Livestock are partly to blame for a lot of ecological problems we’ve got,” she said. “But we couldn’t repair these problems without livestock.”
U.S. power plant emissions averaged 967 lb. CO2 per megawatt-hour (MWh) in 2017, which was down 3.1 percent from the prior year and down 26.8 percent from the annual value of 1,321 lb CO2 per MWh in 2005.
Researchers have announced the release of the 2018 Carnegie Mellon Power Sector Carbon Index. The Index tracks the environmental performance of US power producers and compares current emissions to more than two decades of historical data collected nationwide. This release marks the one-year anniversary of the Index, developed as a new metric to track power sector carbon emissions performance trends.
….The latest data revealed the following findings: U.S. power plant emissions averaged 967 lb. CO2 per megawatt-hour (MWh) in 2017, which was down 3.1 percent from the prior year and down 26.8 percent from the annual value of 1,321 lb CO2 per MWh in 2005. The result for 2016 was initially reported as 1,001 lb/MWh, but was later revised downward to 998 lb/MWh.
Not all nitrogen comes from the atmosphere as previously thought. This study showed that~25% of all nitrogen on Earth comes from bedrock and helps explain how natural ecosystems like boreal forests are capable of taking up high levels of carbon dioxide.
Ecosystems need nitrogen and other nutrients to absorb carbon dioxide pollution, and there is a limited amount of it available from plants and soils.
When thinking about carbon sequestration, the geology of the planet can help guide our decisions about what we’re conserving.
This nitrogen may allow forests and grasslands to sequester more fossil fuel CO2 emissions than previously thought.
These results are going to require rewriting the textbooks.
For centuries, the prevailing science has indicated that all of the nitrogen on Earth available to plants comes from the atmosphere. But a study from the University of California, Davis, indicates that more than a quarter comes from Earth’s bedrock….
“Our study shows that nitrogen weathering is a globally significant source of nutrition to soils and ecosystems worldwide,” said co-lead author Ben Houlton, a professor in the UC Davis Department of Land, Air and Water Resources and director of the UC Davis Muir Institute. “This runs counter the centuries-long paradigm that has laid the foundation for the environmental sciences. We think that this nitrogen may allow forests and grasslands to sequester more fossil fuel CO2 emissions than previously thought.”
…”Geology might have a huge control over which systems can take up carbon dioxide and which ones don’t,” Houlton said. “When thinking about carbon sequestration, the geology of the planet can help guide our decisions about what we’re conserving.”
The work also elucidates the “case of the missing nitrogen.” For decades, scientists have recognized that more nitrogen accumulates in soils and plants than can be explained by the atmosphere alone, but they could not pinpoint what was missing….
….”These results are going to require rewriting the textbooks,” said Kendra McLauchlan, program director in the National Science Foundation’s Division of Environmental Biology, which co-funded the research. “While there were hints that plants could use rock-derived nitrogen, this discovery shatters the paradigm that the ultimate source of available nitrogen is the atmosphere. Nitrogen is both the most important limiting nutrient on Earth and a dangerous pollutant, so it is important to understand the natural controls on its supply and demand. Humanity currently depends on atmospheric nitrogen to produce enough fertilizer to maintain world food supply. A discovery of this magnitude will open up a new era of research on this essential nutrient.”
B. Z. Houlton, S. L. Morford, R. A. Dahlgren. Convergent evidence for widespread rock nitrogen sources in Earth’s surface environment. Science, 2018; 360 (6384): 58 DOI: 10.1126/science.aan4399
ABSTRACT: The magnitude of future climate change could be moderated by immediately reducing the amount of CO2 entering the atmosphere as a result of energy generation and by adopting strategies that actively remove CO2 from it.Biogeochemical improvement of soils by adding crushed, fast-reacting silicate rocks to croplands is one such CO2-removal strategy.This approach has the potential to improve crop production, increase protection from pests and diseases, and restore soil fertility and structure.
Managed croplands worldwide are already equipped for frequent rock dust additions to soils, making rapid adoption at scale feasible, and the potential benefits could generate financial incentives for widespread adoption in the agricultural sector. However, there are still obstacles to be surmounted. Audited field-scale assessments of the efficacy of CO2 capture are urgently required together with detailed environmental monitoring. A cost-effective way to meet the rock requirements for CO2 removal must be found, possibly involving the recycling of silicate waste materials. Finally, issues of public perception, trust and acceptance must also be addressed.
Atmospheric scientists report that suburban sprawl increases CO2 emissions more than similar population growth in a developed urban core…
…The research team concluded that population growth does not directly correlate with growth in CO2 emissions. Other factors, specifically the types of neighborhoods where population is growing, are much bigger factors.
“In the more urban area, there’s population growth there, but it’s in the mature part of the city, not associated with growth in CO2,” Mitchell says. But it’s this population growth in rural areas that is seeing an increase in CO2 emissions. If you add more people into downtown Salt Lake City, they’re going into an existing place.”…
Logan E. Mitchell, et al. Long-term urban carbon dioxide observations reveal spatial and temporal dynamics related to urban characteristics and growth. PNAS, 2018 DOI: 10.1073/pnas.1702393115
Bill Gates and others aim to clean up the planet by stripping CO2 from the air and use it to produce carbon-neutral fuel. But can it work on an industrial scale?
Carbon Engineering (CE) and Greyrock have begun directly synthesising a mixture of petrol and diesel, using only CO2 captured from the air and hydrogen split from water with clean electricity – a process they call Air to Fuels (A2F).
By the middle of the century, many of the models assume as much removal of CO2 from the atmosphere by negative emission technologies as is absorbed naturally today by all of the world’s oceans and plants combined. They are not an insurance policy; they are a high-risk gamble with tomorrow’s generations, particularly those living in poor and climatically vulnerable communities, set to pay the price if our high-stakes bet fails to deliver as promised.”
….The idea is grandiose yet simple: decarbonise the global economy by extracting global-warming carbon dioxide (CO2) straight from the air, using arrays of giant fans and patented chemical whizzery; and then use the gas to make clean, carbon-neutral synthetic diesel and petrol to drive the world’s ships, planes and trucks.
The hope is that the combination of direct air capture (DAC), water electrolysis and fuels synthesis used to produce liquid hydrocarbon fuels can be made to work at a global scale, for little more than it costs to extract and sell fossil fuel today. This would revolutionise the world’s transport industry, which emits nearly one-third of total climate-changing emissions. It would be the equivalent of mechanising photosynthesis.
The individual technologies may not be new, but their combination at an industrial scale would be groundbreaking. Carbon Engineering, the company set up in 2009 by leading geoengineer Keith, with money from Gates and Murray, has constructed a prototype plant, installed large fans, and has been extracting around one tonne of pure CO2 every day for a year. At present it is released back into the air.
But Carbon Engineering (CE) has just passed another milestone. Working with California energy company Greyrock, it has now begun directly synthesising a mixture of petrol and diesel, using only CO2 captured from the air and hydrogen split from water with clean electricity – a process they call Air to Fuels (A2F).
“A2F is a potentially game-changing technology, which if successfully scaled up will allow us to harness cheap, intermittent renewable electricity to drive synthesis of liquid fuels that are compatible with modern infrastructure and engines,” says Geoff Holmes of CE. “This offers an alternative to biofuels and a complement to electric vehicles in the effort to displace fossil fuels from transportation.”
Synthetic fuels have been made from CO2 and H2 before, on a small scale. “But,” Holmes adds, “we think our pilot plant is the first instance of Air to Fuels where all the equipment has large-scale industrial precedent, and thus gives real indication of commercial performance and viability, and leads directly to scale-up and deployment.”…
….4,500 miles away, in a large blue shed on a small industrial estate in the South Yorkshire coalfield outside Sheffield, the UK Carbon Capture and Storage Research Centre (UKCCSRC) is experimenting with other ways to produce negative emissions.
….It is researching different fuels, temperatures, solvents and heating speeds to best capture the CO2 for the next generation of CCS plants, and is capturing 50 tonnes of CO2 a year. And because Britain is phasing out coal power stations, the focus is on achieving negative emissions by removing and storing CO2 emitted from biomass plants, which burn pulverised wood. As the wood has already absorbed carbon while it grows, it is more or less carbon-neutral when burned. If linked to a carbon capture plant, it theoretically removes carbon from the atmosphere. Known as Beccs (bioenergy with carbon capture and storage), this negative emissions technology is seen as vital if the UK is to meet its long-term climate target of an 80% cut in emissions at 1990 levels by 2050…
“Direct air capture is no substitute for using conventional CCS,” says Gibbins. “Cutting emissions from existing sources at the scale of millions of tonnes a year, to stop the CO2 getting into the air in the first place, is the first priority.
“The best use for all negative emission technologies is to offset emissions that are happening now – paid for by the emitters, or by the fossil fuel suppliers. We need to get to net zero emissions before the sustainable CO2 emissions are used up. This is estimated at around 1,000bn tonnes, or around 20-30 years of global emissions based on current trends,” he says. “Having to go to net negative emissions is obviously unfair and might well prove an unfeasible burden for a future global society already burdened by climate change.”…
…the challenge is daunting. Worldwide manmade emissions must be brought to “net zero” no later than 2090, says the UN’s climate body, the Intergovernmental Panel on Climate Change (IPCC). That means balancing the amount of carbon released by humans with an equivalent amount sequestered or offset, or buying enough carbon credits to make up the difference.
…In a recent article in the journal Science, the two climate scientists said they were not opposed to research on negative emission technologies, but thought the world should proceed on the premise that they will not work at scale. Not to do so, they said, would be a “moral hazard par excellence”.
Instead, governments are relying on these technologies to remove hundreds of millions of tonnes of carbon from the atmosphere. “It is breathtaking,” says Anderson. “By the middle of the century, many of the models assume as much removal of CO2 from the atmosphere by negative emission technologies as is absorbed naturally today by all of the world’s oceans and plants combined. They are not an insurance policy; they are a high-risk gamble with tomorrow’s generations, particularly those living in poor and climatically vulnerable communities, set to pay the price if our high-stakes bet fails to deliver as promised.”…
Nearly 60% of US carbon pollution comes from power and transportation, and power is already decarbonizing fast
To fulfill its responsibility for helping the world stay below the 2°C temperature guardrail, the transportation sector is America’s next clear big target
All major automakers recognize that the shift from fossil-fueled cars to EV is inevitable, and are investing accordingly
In order to meet its share of the carbon pollution cuts needed to achieve the 2°C Paris international climate target, America’s policies are rated as “critically insufficient” by the Climate Action Tracker….
….Cost and battery range have been the two barriers to widespread EV adoption. However, both have rapidly improved over the past several years. In 1996, the GM EV1 was the first modern mass-produced EV. It had a range of approximately 100 miles (160 km) per charge at an estimated price of $34,000 ($50,000 in 2016 dollars), which amounts to $500 per mile of range. Tesla produced its first car – the Roadster – starting in 2008, with a range of 244 miles (393 km) at a price of around $100,000 ($410 per mile). Nissan first sold its electric Leaf in 2011 for $33,600 with an 84-mile (135 km) range ($400 per mile).
All three companies have since dramatically improved their EV prices per mile of range. The 2018 Nissan Leaf sells for $30,000 with a 150-mile (240 km) range ($200 per mile). The Tesla Model 3 will sell for $35,000 with a 220-mile (354 km) range or $44,000 with a 310-mile (500 km) range ($140–160 per mile). The Chevy Bolt sells for $36,620 with a 238-mile (383 km) range ($154 per mile)….
…American power generation is already rapidly decarbonizing. To fulfill its responsibility for helping the world stay below the 2°C temperature guardrail, the transportation sector is America’s next clear big target…..All major automakers recognize that the shift from fossil-fueled cars to EV is inevitable, and are investing accordingly.
A price on carbon pollution would accelerate the transition. US gasoline prices remain low at around $2.50 per gallon, which leads to more Americans buying cars with low fuel efficiency. 97% of US car sales are still purely gasoline-powered. The transition to EVs is proceeding slowly, but it’s coming, and it will be a big part of any future American efforts to meet climate targets.
….Is [freshwater] also soaking up atmospheric carbon?A new paper published in Current Biology presents some of the first evidence that the answer may be yes, but perhaps not the same way as occurs in the ocean.
In the new study researchers reported a significant increase of CO2 and a correlating pH decrease of about 0.3 in four reservoirs in Germany over 35 years. They analyzed data collected from 1981 to 2015 by the local Ruhr region agency that monitors drinking water, and were able to document the rising carbon dioxide levels over time by factoring in changes in temperature, water density, pH, ion species distribution and total inorganic content….
…A crucial reason why the study of freshwater acidification has lagged until now is because determining how atmospheric carbon affects these ecosystems requires complex modeling…
…The primary way freshwater ecosystems absorb CO2 created by humans burning fossil fuels is likely different than what happens in oceans. In lakes and reservoirs the extra atmospheric CO2 feeds the surrounding vegetation and the rising global temperature lengthens the growing season. As plants in and around the lake grow larger and/or proliferate, the amount of organic carbon available when they die and the rate at which they break down in soil increases. Precipitation then washes it into lakes and other freshwater systems….
Linda C. Weiss, Leonie Pötter, Annika Steiger, Sebastian Kruppert, Uwe Frost, Ralph Tollrian. Rising pCO 2 in Freshwater Ecosystems Has the Potential to Negatively Affect Predator-Induced Defenses in Daphnia. Current Biology, 2018; DOI: 10.1016/j.cub.2017.12.022
Soils hold the largest biogeochemically active terrestrial carbon pool on Earth and are critical for stabilizing atmospheric CO2 concentrations. Nonetheless, global pressures on soils continue from changes in land management, including the need for increasing bioenergy and food production
Soil organic matter (SOM) anchors global terrestrial productivity and food and fiber supply. SOM retains water and soil nutrients and stores more global carbon than do plants and the atmosphere combined. SOM is also decomposed by microbes, returning CO2, a greenhouse gas, to the atmosphere. Unfortunately, soil carbon stocks have been widely lost or degraded through land use changes and unsustainable forest and agricultural practices.
To understand its structure and function and to maintain and restore SOM, we need a better appreciation of soil organic carbon (SOC) saturation capacity and the retention of above- and belowground inputs in SOM. Our analysis suggests root inputs are approximately five times more likely than an equivalent mass of aboveground litter to be stabilized as SOM. Microbes, particularly fungi and bacteria, and soil faunal food webs strongly influence SOM decomposition at shallower depths, whereas mineral associations drive stabilization at depths greater than ∼30 cm. Global uncertainties in the amounts and locations of SOM include the extent of wetland, peatland, and permafrost systems and factors that constrain soil depths, such as shallow bedrock. In consideration of these uncertainties, we estimate global SOC stocks at depths of 2 and 3 m to be between 2,270 and 2,770 Pg, respectively, but could be as much as 700 Pg smaller. Sedimentary deposits deeper than 3 m likely contain > 500 Pg of additional SOC. Soils hold the largest biogeochemically active terrestrial carbon pool on Earth and are critical for stabilizing atmospheric CO2 concentrations. Nonetheless, global pressures on soils continue from changes in land management, including the need for increasing bioenergy and food production
Excerpts on future directions:
2.1. Emerging Research Questions for Plant Production, Allocation, and SOM:
1. What is the relative contribution of roots compared with that of litter inputs to the accumulation of SOM under different vegetation types, soil conditions, land uses, and climates?
2. Is the higher CUE of root litter compared with that of aboveground litter explained by differences in chemical composition or root-soil interactions?
3. What is the fate of nutrients such as nitrogen and phosphorus from aboveground and belowground organic matter respired during decomposition, and what is their role in SOM formation?
4. In consideration of trade-offs with production, how feasible is it to manage plant allocation patterns in managed landscapes to sequester SOM but maintain growth and yield?
3.1. Emerging Research Questions for Belowground Food Webs and Soil Ecology
Although it is well established that microbes and soil fauna exert strong controls on the rates and pathways of plant litter decay, their role in soil carbon stabilization is less clear. Mycorrhizae have a strong role in carbon stabilization in many ecosystems, but the relative role of fungi in soil carbon stabilization, compared with that of bacteria, is not well characterized. Several questions deserve particular attention:
1. How critical is understanding microbial physiology to predicting future changes in soil carbon stocks with climate change?
2. Will microbial CUE be altered by global warming, will thermal adaptation occur, or will broad changes in the microbial community lead to unexpected changes in soil carbon stabilization patterns?
3. How will changes in future vegetation patterns affect detrital inputs to soil and the stabilization of these inputs?
4. Do soil fauna need to be added to models of SOM that include microbes?
4.1. Emerging Research Questions for Biotic–Abiotic Interactions and SOM
1. How will interactions between biotic processes (e.g., NPP, detrital inputs, and microbial activity) and carbon retention on mineral surfaces be altered by climate change?
2. Do soil minerals and their interactions with biotic processes need to be included in future SOM models?
3. How can abiotic and biotic factors be incorporated into land surface and Earth system models to reduce future uncertainty?
5.3. Emerging Research Questions for Global SOM Stocks, Distributions, and Controls:
Answers to the following important research questions could help close the data gap:
1. How can we better constrain the distributions of peatland and permafrost systems, the amount of SOC and SON they contain, and their vulnerability to a warming climate?
2. How can computational approaches enhance our understanding of depth distributions for SOM and their biotic and abiotic controls?
3. How can we best improve and verify estimates of bedrock depth and its influence on the global content of SOC and SON?
Soil carbon is vulnerable to oxidation and release to the atmosphere through a variety of human activities (Figure 1), including land use disturbance and the effects of climate change. The greatest human-induced loss of SOC has come from the conversion of native forests and grasslands to annual crops (Paustian et al. 1997, Lal 2004). Understanding the role of agricultural management on SOC stocks is therefore critical both for predicting future carbon fluxes and for devising best-management strategies to mitigate and reverse soil loss…. Mitigating and even reversing these land use effects, however, are both possible and desirable (Minansy et al. 2017)….. The initial status of the land is critical to the interpretation of afforestation studies. A degraded system often gains SOM with afforestation or other management; a healthy, native ecosystem may sometimes lose it….
….The adoption of soil conservation practices such as reduced tillage, improved residue management, reduced bare fallow, and conservation reserve plantings has stabilized, and partially reversed, SOC loss in North American agricultural soils (Paustian et al. 2016)….Improved grazing management, fertilization, sowing legumes, and improved grass species are additional ways to increase soil carbon by as much as 1 Mg C ha−1year−1 (Conant et al. 2017)…
….Ecosystem and Earth system models can improve their representations of SOM by adding modifiers and microbial attributes that influence SOM formation and stabilization across scales….
….Over the next century, most projected land use change is expected to arise from repurposing existing agricultural land rather than clearing native forests (Watson et al. 2014). Emerging land use activities that combine carbon sequestration with crop production offer great promise to increase global SOM while sustainably meeting food and fiber production for an increasing human population (Francis et al. 2016).
….anthropogenic greenhouse gas emissions have altered the planet’s climate, including
temperatures, precipitation, and vapor pressure deficit, and will continue to do so. Additional changes are apparent in the patterns and extremes of weather and in the frequency, intensity, and severity of disturbances. All the factors, knowledge, and skill illustrated through the examples in this review will be needed to project the effects of climate change on SOM. Global pressures on soils are coming from continuing changes in land management, such as the need for increasing bioenergy and food production. For these reasons and more, furthering progress in experiments, synthesis, and modeling of SOM will remain a research priority for decades..
Other links to aggregated content on soil science, carbon sequestration and range science:
The climate change simulations that best capture current planetary conditions are also the ones that predict the most dire levels of human-driven warming, according to a statistical study released in the journal Nature on Wednesday.
The study, by Patrick Brown and Ken Caldeira of the Carnegie Institution for Science in Stanford, California, examined the high-powered climate change simulations, or models, that researchers use to project the future of the planet based on the physical equations that govern the behavior of the atmosphere and oceans….
….Lead study author Brown argued, though, that the results have a major real-world implication: They could mean the world can emit even less carbon dioxide than we thought if it wants to hold warming below the widely accepted target of 2 degrees Celsius (3.6 degrees Fahrenheit). This would mean shrinking the “carbon budget.”
The study “would imply that to stabilize temperature at 2 degrees Celsius, you’d have to have 15 percent less cumulative CO2 emissions,” he said.