Ecology, Climate Change and Related News

Conservation Science for a Healthy Planet

Tag Archive: GHG

  1. Can Responsible Grazing Make Beef Climate-Neutral?

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    • New research found that the greenhouse gases sequestered in one grass-fed system balanced out those emitted by the cows, but some meatless advocates are skeptical.
     

    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 study that 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.”

    Paige L. Stanley, Jason E.Rowntree, David K.Beede, Marcia S.DeLonge, Michael W.Hamm. Impacts of soil carbon sequestration on life cycle greenhouse gas emissions in Midwestern USA beef finishing systems.  Agricultural Systems Volume 162, May 2018, Pages 249-258 https://doi.org/10.1016/j.agsy.2018.02.003

    See previous post on this here. 

    And related NPR story:

    A Grass-Roots Movement For Healthy Soil Spreads Among Farmers

    April 9 2018 America’s farmers are digging soil like never before. A movement for “regenerative agriculture” is dedicated to building healthier soil and could even lead to a new eco-label on food.

  2. Climate change threatens world’s largest seagrass carbon stores

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    • Seagrass meadows are CO2 sinks, known as ‘Blue Carbon ecosystems’. They take up and store carbon dioxide in their soils and biomass through biosequestration.
    • we need to advance our understanding of how seagrass ecosystems, especially those living close to their thermal tolerance, will respond to global change threats, both direct and through interactive effects with local pressures.

    March 19, 2018 Universitat Autònoma de Barcelona  read full ScienceDaily article here

    In the summer of 2010-2011 Western Australia experienced an unprecedented marine heat wave that elevated water temperatures 2-4°C above average for more than 2 months. The heat wave resulted in defoliation of the dominant Amphibolis antarctica seagrass species across the iconic Shark Bay World Heritage Site…

    ….Over the three years following the event, the loss of seagrass released up to nine million metric tons of carbon dioxide (CO2) into the atmosphere. This amount is roughly the equivalent to the annual CO2 output of 800,000 homes, two average coal-fired power plants, or 1,600,000 cars driven for 12 months. It also potentially raised Australia’s annual estimate of national land-use change CO2 emissions by up to 21%….

    …”This is significant, as seagrass meadows are CO2 sinks, known as ‘Blue Carbon ecosystems’. They take up and store carbon dioxide in their soils and biomass through biosequestration. The carbon that is locked in the soils is potentially there for millennia if seagrass ecosystems remain intact,” explains Professor Pere Masqué, co-author of the study and researcher at ICTA-UAB and the UAB Department of Physics….

    …”We need to advance our understanding of how seagrass ecosystems, especially those living close to their thermal tolerance, will respond to global change threats, both direct and through interactive effects with local pressures….

    A. Arias-Ortiz, O. Serrano, P. Masqué, P. S. Lavery, U. Mueller, G. A. Kendrick, M. Rozaimi, A. Esteban, J. W. Fourqurean, N. Marbà, M. A. Mateo, K. Murray, M. J. Rule & C. M. Duarte. A marine heatwave drives massive losses from the world’s largest seagrass carbon stocks. Nature Climate Change, 2018 DOI: 10.1038/s41558-018-0096-y

  3. 20% of Americans responsible for 46% of US food-related greenhouse gas emissions

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    • 20 percent of Americans account for nearly half of U.S. diet-related greenhouse gas emissions, and high levels of beef consumption are largely responsible
    • The researchers did not look specifically at how the beef was produced, which can influence its carbon footprint. “That information is not available on the dietary side,” Heller said [in a related Inside Climate News article]. “People aren’t saying where their beef is coming from or how it was raised. It was just beef.”
      • [Ellie’s note: this likely reflects CAFO cattle (cattle in concentrated agriculture feeding operations) in this national study as opposed to specific grass fed, grass finished beef which also provides other ecological benefits; note that leaks from natural gas and oil production are a more significant contributor of atmospheric methane than cattle; see more on methane, cows and rotational grazing here, here, here, and here]
    • the highest-impact quintile consumed more than twice as many calories on a given day — 2,984 versus 1,323 — than those in the bottom 20 percent

    March 20, 2018 University of Michigan  Read full ScienceDaily article here

    See also InsideClimateNews article on this here

    On any given day, 20 percent of Americans account for nearly half of U.S. diet-related greenhouse gas emissions, and high levels of beef consumption are largely responsible, according to a new study from researchers at the University of Michigan and Tulane University.

    ….If Americans in the highest-impact group shifted their diets to align with the U.S. average — by consuming fewer overall calories and relying less on meat — the one-day greenhouse-gas emissions reduction would be equivalent to eliminating 661 million passenger-vehicle miles, according to the researchers—  nearly 10 percent of the emissions reductions needed for the United States to meet its targets under the Paris climate accord, the authors wrote…

    The highest-impact group was responsible for about eight times more emissions than the lowest quintile of diets. And beef consumption accounted for 72 percent of the emissions difference between the highest and lowest groups, according to the study.

    …Emissions related to the processing, packaging, distribution, refrigeration and cooking of those foods were not part of the study but would likely increase total emissions by 30 percent or more, Heller said….

    …. cows don’t efficiently convert plant-based feed into muscle or milk, so they must eat lots of feed. Growing that feed often involves the use of fertilizers and other substances manufactured through energy-intensive processes. And then there’s the fuel used by farm equipment.

    In addition, cows burp lots of methane, and their manure also releases this potent greenhouse gas.

    …They found that Americans in the highest-impact quintile consumed more than twice as many calories on a given day — 2,984 versus 1,323 — than those in the bottom 20 percent. But even when the findings were adjusted for caloric intake, the highest-impact quintile was still responsible for five times more emissions than the lowest-impact group.,,,

    Martin C Heller, Amelia Willits-Smith, Robert Meyer, Gregory A Keoleian, Donald Rose. Greenhouse gas emissions and energy use associated with production of individual self-selected US diets. Environmental Research Letters, 2018; 13 (4): 044004 DOI: 10.1088/1748-9326/aab0ac

  4. Cities Emit 60% More Carbon Than Thought

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    The carbon footprint of some of the world’s biggest cities is 60 percent larger than previously estimated when all the products and services a city consumes is included, according to a new analysis.

    The report was released Tuesday at the IPCC Cities and Climate Change Science Conference in Edmonton, Canada, and estimated the carbon emissions for the food, clothing, electronics, air travel, construction materials, and so on consumed by residents but produced outside city limits.

    The world’s cities emit 70 percent of the world’s carbon dioxide—and that’s likely higher when consumption emissions are included, says report author Michael Doust, program director at C40 Cities, a network of the world’s megacities committed to addressing climate change….

    …Wealthy “consumer cities” such as London, Paris, New York, Toronto, or Sydney that no longer have large industrial sectors have significantly reduced their local emissions. However, when the emissions associated with their consumption of goods and services are included, these cities’ emissions have grown substantially and are among the highest in the world on a per person basis, the report says. Meanwhile, “producer” cities in India, Pakistan, or Bangladesh generate lots of industrial pollution and carbon emissions in the manufacture of products that will be sold and consumed in Europe and North America….

    ..Cities that have high consumption-based GHG emissions are recommended to use consumption-based GHG inventories alongside their sector-based GHG inventories, or incorporate key supply chains into the latter. This would encourage more
    holistic GHG emissions assessments; enable decision-makers to consider a wider range of opportunities to reduce global GHG emissions; and provide an additional perspective with which to engage other stakeholders in climate action….

    C40 Cities. Consumption-based GHG emissions of C40 cities. March 2018.

     

  5. California’s water saving brings bonus effects- electricity savings and GHG reductions

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    • The decrease in water usage translated into a significant electricity saving of 1,830 gigawatt hours (GWh) resulting in GHG emissions saved of 524,000 metric tons of carbon dioxide equivalent (CO2e), the equivalent of taking 111,000 cars off the road for a year.
    • water conveyance and use accounts for 19 per cent of total electricity demand and 32 per cent of total non-power plant natural gas demand state-wide

    January 11, 2018 IOP Publishing read full ScienceDaily article here

    Water-saving measures in California have also led to substantial reductions in greenhouse gas (GHG) emissions and electricity consumption in the state.

    Measures to cut water use by 25 per cent across California were implemented in 2015, following a four-year drought in the state that caused the fallowing of 542,000 acres of land, total economic costs of $2.74 billion, and the loss of approximately 21,000 jobs.

    The UC Davis researchers found that, while the 25 per cent target had not quite been reached over the one-year period — with 524,000 million gallons of water saved — the measures’ impact had positive knock-on effects for other environmental objectives.

    In California, the water and energy utility sectors are closely interdependent. The energy used by the conveyance systems that move water from the wetter North to the drier and more heavily populated South — combined with utility energy use for treatment and distribution, end-user water consumption for heating, and additional pumping and treatment — accounts for 19 per cent of total electricity demand and 32 per cent of total non-power plant natural gas demand state-wide….

    Edward S Spang, Andrew J Holguin, Frank J Loge. The estimated impact of California’s urban water conservation mandate on electricity consumption and greenhouse gas emissions. Environmental Research Letters, 2018; 13 (1): 014016 DOI: 10.1088/1748-9326/aa9b89

  6. Transformation to wind and solar achievable with lower full life cycle GHG emissions compared to other energy technologies

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    • Electricity production from biomass, coal, gas and hydropower for instance induces much higher indirect greenhouse gas emissions than nuclear electricity, or wind and solar-based power supply
    • Scaling up wind and solar technologies would induce only modest indirect GHG emissions compared to other energy power technologies
    December 8, 2017 Potsdam Institute for Climate Impact Research (PIK)  read full ScienceDaily article here
    Different low carbon technologies from wind or solar energy to fossil carbon capture and sequestration (CCS) differ greatly when it comes to indirect GHG emissions in their life cycle. The new study finds that wind and solar energy belong to the more favorable when it comes to life-cycle emissions and scaling up these technologies would induce only modest indirect GHG emissions — and hence not impede the transformation towards a climate-friendly power system….

    “Both fossil and non-fossil power technologies still come with a certain amount of greenhouse gas emissions within their life cycle — on the one hand because it needs energy to construct and operate them, on the other hand because of methane emissions, e.g. from coal and gas production,” explains lead author Michaja Pehl. “However, we found there are substantial differences across technologies regarding their greenhouse gas balance. Electricity production from biomass, coal, gas and hydropower for instance induces much higher indirect greenhouse gas emissions than nuclear electricity, or wind and solar-based power supply.”….

    ….”When it comes to life cycle greenhouse gas emissions, wind and solar energy provide a much better greenhouse gas balance than fossil-based low carbon technologies, because they do not require additional energy for the production and transport of fuels, and the technologies themselves can be produced to a large extend with decarbonized electricity,” states Edgar Hertwich, an industrial ecologist from Yale University who co-authored the study. Due to technological innovation, less and less energy will be needed to produce wind turbines and solar photovoltaic systems….

    Michaja Pehl, Anders Arvesen, Florian Humpenöder, Alexander Popp, Edgar G. Hertwich, Gunnar Luderer. Understanding future emissions from low-carbon power systems by integration of life-cycle assessment and integrated energy modelling. Nature Energy, 2017; 2 (12): 939 DOI: 10.1038/s41560-017-0032-9

  7. California Considers Following China With Combustion-Engine Car Ban

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    Ryan Beene and John Lippert

    The internal combustion engine’s days may be numbered in California, where officials are mulling whether a ban on sales of polluting autos is needed to achieve long-term targets for cleaner air…. The earliest such a ban is at least a decade away… replicating similar moves by China, France and the U.K.

    …Embracing such a policy would send shockwaves through the global car industry due to the heft of California’s auto market. More than 2 million new passenger vehicles were registered in the state last year, topping France, Italy or Spain. If a ban were implemented, automakers from General Motors Co. to Toyota Motor Corp. would be under new pressure to make electric vehicles the standard for personal transportation in the most populous U.S. state, casting fresh doubts on the future of gasoline- and diesel-powered autos elsewhere.…California has set a goal to cut carbon dioxide emissions by 80 percent from 1990 levels by 2050. Rising emissions from on-road transportation has undercut the state’s efforts to reduce pollution, according to Next 10, San Francisco-based non-profit.

    To reach the ambitious levels of reduction in greenhouse gas emissions, we have to pretty much replace all combustion with some form of renewable energy by 2040 or 2050,” Nichols said. “We’re looking at that as a method of moving this discussion forward.”…China will likely order an end to sales of all polluting vehicles by 2030, the chairman of electric-carmaker BYD Co. said Thursday. France and the U.K. have announced 2040 as their end date for sales of fossil fuel-powered cars….

  8. Ozone treaty taking significant bite out of US greenhouse gas emissions

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    • Reducing ozone-depleting substances from 2008 to 2014 eliminated the equivalent of 170 million tons of carbon dioxide emissions each year– equivalent of 50% of US CO2 and other GHG over same period.
    August 14, 2017 American Geophysical Union see full ScienceDaily article here
    The Montreal Protocol, the international treaty adopted to restore Earth’s protective ozone layer in 1989, has significantly reduced emissions of ozone-depleting chemicals from the United States. In a twist, a new study shows the 30-year old treaty has had a major side benefit of reducing climate-altering greenhouse gas emissions from the US.
    That’s because the ozone-depleting substances controlled by the treaty are also potent greenhouse gases, with heat-trapping abilities up to 10,000 times greater than carbon dioxide over 100 years.The new study is the first to quantify the impact of the Montreal Protocol on U.S. greenhouse gas emissions with atmospheric observations.

    .Hu added that the benefits of the Montreal Protocol on greenhouse gas emissions would likely grow in the future. By 2025, she projects that the effect of the Montreal Protocol will be to reduce U.S. greenhouse gas emissions by the equivalent of 500 million tons of carbon dioxide per year compared with 2005 levels. This reduction would be equivalent to about 10 percent of the current U.S. emissions of carbon dioxide.

    Lei Hu et al. Considerable contribution of the Montreal Protocol to declining greenhouse gas emissions from the United States. Geophysical Research Letters, 2017; DOI: 10.1002/2017GL074388

  9. US cats and dogs cause 25-30 percent of the environmental impact of meat consumption in this country

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    The truth about cats’ and dogs’ environmental impact

    • Researcher finds that feeding pets creates the equivalent of 64 million tons of carbon dioxide a year

    Posted: 02 Aug 2017 11:28 AM PDT  UCLA

    US cats and dogs cause 25-30 percent of the environmental impact of meat consumption in this country. The nation’s 163 million cats and dogs eat as much food as all the people in France. People should keep their pets — and keep feeding them meat — but there may be steps pet owners can take to reduce their environmental impact, says a researcher.

    …”A dog doesn’t need to eat steak,” Okin said. “A dog can eat things a human sincerely can’t. So what if we could turn some of that pet food into people chow?”

    A commitment to snout-to-tail consumption, where as much rendered product as possible is produced for human use, could significantly reduce national meat consumption. Okin estimates that if even a quarter of the meat in pet food could be consumed by humans, it would equal the amount of meat consumed by 26 million Americans, nearly the population of Texas…

    Gregory S. Okin. Environmental impacts of food consumption by dogs and cats. PLOS ONE, 2017; 12 (8): e0181301 DOI: 10.1371/journal.pone.0181301

  10. Climate change solutions – the role of healthy soils

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    There’s too much carbon in the atmosphere and not enough in the ground where it’s useful. Healthy soil can help flip the picture.  Full article here

    May 17 2017 UC Davis via Washington Post

    …Scow—a microbial ecologist and director of this experimental farm at the University of California, Davis—sees a living being brimming with potential. The soil beneath this field doesn’t just hold living things—it is itself alive. Scow likens soil to the human body with its own system of “organs” working together for its overall health. And, like us, it needs good food, water and care to live up to its full potential...

    …Soil can potentially store between 1.5 and 5.5 billion tons of carbon a year globally. That’s equivalent to between 5 and 20 billion tons of carbon dioxide. While significant, that’s still just a fraction of the 32 billion tons of carbon dioxide emitted every year from burning fossil fuels. Soil is just one of many solutions needed to confront climate change. But the nice thing about healthy soils, Scow said, is that creating them not only helps fight climate change—it also brings multiple benefits for agricultural, human and environmental health….

    there are more microbes in one teaspoon of soil than there are humans on Earth. Many of them lie dormant, just waiting to be properly fed and watered. A well-fed army of microbes can go to work strengthening the soil so it can grow more food, hold more water, break down pollutants, prevent erosion and, yes, sequester carbon….

    Soil sequesters carbon through a complex process that starts with photosynthesis. A plant draws carbon out of the atmosphere and returns to the soil what isn’t harvested in the form of residue and root secretions. This feeds microbes in the soil. The microbes transform the carbon into the building blocks of soil organic matter and help stabilize it, sequestering the carbon….

    …There’s too much carbon in the atmosphere and not enough in the ground where it can be used. A new effort in California aims to flip that picture. The state’s Healthy Soils Incentives Program is considered the first in the nation to provide state funding to help farmers and ranchers enhance their soils to reduce greenhouse gas emissions. The $7.5 million program, expected to launch this summer, encourages farming practices known to boost microbial communities underground and sequester carbon….

    …Stone is as much a natural resources manager as a rancher, with a protective eye on the ranch’s watersheds, trees, pasture and grass-fed cattle, and a genuine desire to leave the land better than he found it. He rotates his cattle frequently across the pasture to avoid overgrazing. Most of the ranch—7,000 acres—is in a conservation easement. He avoids fertilizer. And, increasingly, he composts.

    ….California loses about 20,000 acres of rangeland each year, much of which become greenhouse-gas-emitting housing developments, shopping centers, roads and parking lots. The remaining 63 million acres of rangeland in the state—part of the 770 million acres nationwide—represent significant opportunities for additional carbon storage, and can help offset some of the emissions for which the meat industry is often criticized.

    Scientists estimate that U.S. rangelands could potentially sequester up to 330 million metric tons of carbon dioxide in their soils, and croplands are estimated to lock up more than twice that amount—up to 770 million metric tons. That’s the CO2 emissions equivalent of powering 114 million homes with electricity for a year.

    When you look at the cow, you think of emissions,” Stone said. “But the whole system is actually sequestering carbon. There are so many opportunities in agriculture to move the needle on climate change.”