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Tag Archive: emissions

  1. US power sector carbon emissions intensity drops to lowest on record

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    • 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.

    April 4, 2018 College of Engineering, Carnegie Mellon University Read full ScienceDaily article here

    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.

  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. Norway is building some of the world’s first battery-powered ferries. Will they lead the way in cutting maritime pollution?

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    • Norway wants two-thirds of all boats carrying both passengers and cars along its jagged and windy Atlantic coastline to be electrified by 2030

    Mikael Holter and Jeremy Hodges, Bloomberg 
    …While progress in electrifying the world’s excessively polluting shipping fleets is miles behind advances in automobiles, Europe is making initial strides as Paris Climate Accord goals to cut carbon dioxide emissions loom large. Dozens of battery-powered boats that can move through inland waterways in Norway, Belgium and the Netherlands are about to make their first voyages, including some able to run fully automatically without a crew.Nowhere is this push more prevalent than Norway, a country where almost all electricity produced is hydropower, the state oil company is expanding into offshore wind farming and people drive more electric cars, per capita, than any country in the world. Next up, Norway wants two-thirds of all boats carrying both passengers and cars along its jagged and windy Atlantic coastline to be electrified by 2030. 

    Without big changes, the International Council on Clean Transportation warns sea transport could be responsible for 17 percent of CO2 emissions by 2050, up from 2-3 per cent now. But shipping was omitted from the Paris deal and battery technologies haven’t evolved enough for long ocean voyages, according to the International Maritime Organization, which is set to reveal in April an initial set of guidelines for cutting greenhouse gases….

  5. 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.

     

  6. The World Is Embracing SUVs. That’s Bad News for the Climate.

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    By Hiroko Tabuchi Mar 3 2018 Read full NYTimes article here

    SUVs and “crossovers” made up more than one in three cars sold globally last year, nearly tripling their share from just a decade ago, according to a new report. Drivers in China, Australia and elsewhere are buying SUVs because of lower gas prices and higher incomes—which is slowing progress in reining in carbon emissions….

    …Between 2005 and 2008, the average fuel economy of new cars worldwide improved by about 1.8 percent a year, according to the United Nations’ Global Fuel Economy Initiative. But since then, that pace has slowed to 1.1 percent in 2015, the latest data available, far below the near 3-percent clip needed to simply stabilize emissions from the world’s car fleet….

  7. Suburban sprawl worse than urban growth for CO2 emissions

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    March 5, 2018 University of Utah Read full ScienceDaily article here

    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

  8. Fertilized soil in the Central Valley produces 40% of CA’s nitrogen oxides emissions

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    January 31, 2018 UCDavis read full ScienceDaily article here

    A previously unrecognized source of nitrogen oxide is contributing up to about 40 percent of the NOx emissions in California, according to a new study. The study traces the emissions to fertilized soils in the Central Valley region….

    …Fossil fuels have long been recognized as a major contributor to NOx pollution. Technologies like the catalytic converter have helped greatly reduce NOx emitted from vehicles in urban areas. But some of the state’s worst air quality problems are now in rural areas, particularly the Central Valley region, which is home to some of the poorest communities in California.

    The Central Valley is also one of the world’s most highly productive agricultural areas. Roughly half of the fruits and nuts produced in the United States are grown there. This includes nearly all the nation’s almonds, walnuts, raisins, avocados, and tomatoes….

    ….“Only about half of the nitrogen fertilizer applied to crops are used by the plant. But slow-release fertilizers that deliver nutrients in a way that more closely mimics nature have been shown to greatly improve nitrogen use efficiency of crops, reducing emissions of nitrogen in the environment. Healthy soils programs that restore carbon in the soil can also help fight climate change and are likely to increase nutrient retention and cycling to crops….

    ….The state also began a program this year in which growers work in coalitions to gather information on efficient uses of nitrogen so they can evaluate how and where the state needs to manage nitrogen in agricultural areas. This work aims to reduce nitrate in the groundwater but it may have a double benefit in reducing NOx emissions.”…

    Maya Almaraz, Edith Bai, Chao Wang, Justin Trousdell, Stephen Conley, Ian Faloona, Benjamin Z. Houlton. Agriculture is a major source of NO x pollution in California. Science Advances, 2018; 4 (1): eaao3477 DOI: 10.1126/sciadv.aao3477

  9. Microwave appliance usage could be as bad for the environment as cars, suggests new research

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    • Microwave appliance usage emits 7.7 million tonnes of carbon dioxide equivalent per year in the EU. This is equivalent to the annual emissions of 6.8 million cars.
    • Microwave appliance usage across the EU consumes an estimated 9.4 terawatts per hour (TWh) of electricity every year. This is equivalent to the annual electricity generated by three large gas power plants.

    January 17, 2018  University of Manchester read full ScienceDaily article here

    Microwave appliance usage across the EU alone emits as much carbon dioxide as nearly seven million cars, according to a new study by The University of Manchester.

    Researchers at the University have carried out the first ever comprehensive study of the environmental impacts of microwave appliances, considering their whole life cycle, from ‘cradle to grave’.

    The study found:

    • Microwave appliance usage emits 7.7 million tonnes of carbon dioxide equivalent per year in the EU. This is equivalent to the annual emissions of 6.8 million cars.
    • Microwave appliance usage across the EU consumes an estimated 9.4 terawatts per hour (TWh) of electricity every year. This is equivalent to the annual electricity generated by three large gas power plants.
    • Efforts to reduce consumption should focus on improving consumer awareness and behaviour to use appliances more efficiently…

    Alejandro Gallego-Schmid, Joan Manuel F. Mendoza, Adisa Azapagic. Environmental assessment of microwaves and the effect of European energy efficiency and waste management legislation. Science of The Total Environment, 2018; 618: 487 DOI: 10.1016/j.scitotenv.2017.11.064

  10. Uncertainty surrounds US livestock methane emission estimates

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    • Per the EPA the top three sources of anthropogenic methane in the US are the combined energy sector—natural gas, petroleum systems and coal mining 40%; livestock, 36%; and landfills, 18%.
    • research around the world has shown that variability in enteric methane emissions largely can be explained with variability in feed dry-matter intake

    November 30, 2017, Pennsylvania State University  read full phys.org article here

    A new study of methane emissions from livestock in the United States ….has challenged previous top-down estimates.

    The research was conducted because serious discrepancies exist between top-down estimates that suggest the U.S. Environmental Protection Agency is underestimating agricultural emissions by up to 90 percent, and bottom-up estimates accepted by the federal government showing lower emissions.

    Top-down emissions estimates involve monitoring atmospheric methane concentrations by satellites or from air samples collected at high altitude by planes, and using models to estimate the sources of emissions. Bottom-up estimates take into account populations and animal emission factors.

    In their detailed analysis, researchers used a spatially explicit, bottom-up approach, based on animal inventories and feed-intake-based emission factors, to estimate enteric methane emissions for and methane emissions for cattle, swine and poultry for the contiguous United States.

    The researchers estimated methane emissions using a “gridded” approach, dividing the U.S. into 0.1 by 0.1-degree GIS units, which created cells from 31 square miles in the northern United States to 42 square miles in the southern part of the country.

    ….According to the EPA, the top three sources of anthropogenic methane in the United States are the combined energy sector—natural gas, petroleum systems and coal mining—which makes up 40 percent of the total; livestock, 36 percent of the total; and landfills, 18 percent of the total.

    …Methane emissions from livestock operations are the result of microbial fermentation and methanogenesis in the forestomach of ruminants and similar fermentation processes in manure from both ruminant and non-ruminant farm .

    Methane is also produced from enteric fermentation in the digestive tract of non-ruminant herbivore species, such as horses, donkeys and mules, as a result of fermentation processes in their hindgut. However, “hindgut fermenters” do not produce nearly as much methane per unit of fermented feed as ruminants, so enteric or manure emissions from equine species were not included in this analysis. Neither were emissions from small ruminants such as sheep and goats, which are negligible in the U.S.

    …Overall, the research, which was published this month in Environmental Science and Technology, yielded total U.S. livestock methane emissions of 19.6 billion pounds per year. However, uncertainty surrounding that total is high, researchers acknowledged.

    …predicting methane emissions from manure is a more complex process and carries a larger uncertainty in the estimates, the researchers pointed out. Manure composition, type of storage facilities and manure retention time, and environment—particularly temperature—are among the factors that affect methane emissions from manure.

    There is great uncertainty in both enteric and manure methane emissions from livestock, Hristov conceded. He said that research around the world has shown that variability in enteric methane emissions largely can be explained with variability in feed dry-matter intake. Nutrient composition of the feed is also important but has a lesser impact on enteric methane production.

    Uncertainty surrounds US livestock methane emission estimates The researchers estimated methane emissions using a “gridded” approach, dividing the US into 0.1- by 0.1-degree GIS units, which created cells from 31 square miles in the northern United States to 42 square miles in the southern part of the country. The study pegged total U.S. livestock methane emissions of 19.6 billion pounds per year. This map shows where they are coming from. Credit: Penn State

    Read more at: https://phys.org/news/2017-11-methane-emissions-livestock.html#jCp