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  • richardmitnick 10:42 am on September 7, 2016 Permalink | Reply
    Tags: , Carbon Dioxide, , ,   

    From MIT: “Study finds increased ocean acidification due to human activities” 

    MIT News
    MIT News
    MIT Widget

    September 7, 2016
    Jennifer Chu | MIT News Office

    1
    “The ocean has been the only true sink for anthropogenic emissions since the industrial revolution,” says MIT graduate student Sophie Chu, pictured here. “Right now, it stores about 1/4 to 1/3 of the anthropogenic emissions from the atmosphere. We’re expecting at some point the storage will slow down.” Photo: Zhaohui Aleck Wang/Woods Hole Oceanographic Institution

    Oceanographers from MIT and Woods Hole Oceanographic Institution report that the northeast Pacific Ocean has absorbed an increasing amount of anthropogenic carbon dioxide over the last decade, at a rate that mirrors the increase of carbon dioxide emissions pumped into the atmosphere.

    The scientists, led by graduate student Sophie Chu, in MIT’s Department of Earth, Atmospheric, and Planetary Sciences, found that most of the anthropogenic carbon (carbon arising from human activity) in the northeast Pacific has lingered in the upper layers, changing the chemistry of the ocean as a result. In the past 10 years, the region’s average pH has dropped by 0.002 pH units per year, leading to more acidic waters. The increased uptake in carbon dioxide has also decreased the availability of aragonite — an essential mineral for many marine species’ shells.

    Overall, the researchers found that the northeast Pacific has a similar capacity to store carbon, compared to the rest of the Pacific. However, this carbon capacity is significantly lower than at similar latitudes in the Atlantic.

    “The ocean has been the only true sink for anthropogenic emissions since the industrial revolution,” Chu says. “Right now, it stores about 1/4 to 1/3 of the anthropogenic emissions from the atmosphere. We’re expecting at some point the storage will slow down. When it does, more carbon dioxide will stay in the atmosphere, which means more warming. So it’s really important that we continue to monitor this.”

    Chu and her colleagues have published their results in the Journal of Geophysical Research: Oceans.

    Tipping the scales

    The northeast Pacific, consisting of waters that flow from Alaska’s Aleutian Islands to the tip of southern California, is considered somewhat of a climate canary — sensitive to changes in ocean chemistry, and carbon dioxide in particular. The region sits at the end of the world’s ocean circulation system, where it has collected some of the oldest waters on Earth and accumulated with them a large amount of dissolved inorganic carbon, which is naturally occurring carbon that has been respired by marine organisms over thousands of years.

    “This puts the Pacific at this already heightened state of high carbon and low pH,” Chu says.

    Add enough atmospheric carbon dioxide into the mix, and the scales could tip toward an increasingly acidic ocean, which could have an effect first in sea snails called pteropods, which depend on aragonite (a form of calcium carbonate) to make their protective shells. More acidic waters can make carbonate less available to pteropods.

    “These species are really sensitive to ocean acidification,” Chu says. “It’s harder for them to get enough carbonate to build their shells, and they end up with weaker shells, and have reduced growth rates.”

    Protecting shells

    Chu and her colleagues originally set out to study the effects of ocean acidification on pteropods, rather than the ocean’s capacity to store carbon. In 2012, the team embarked on a scientific cruise to the northeast Pacific, where they followed the same route as a similar cruise in 2001. During the month-long journey, the scientists collected samples of pteropods, as well as seawater, which they measured for temperature, salinity, and pH.

    Upon their return, Chu realized that the data they collected could also be used to gauge changes in the ocean’s anthropogenic carbon storage. Ordinarily, it’s extremely difficult to tease out anthropogenic carbon in the ocean from carbon that naturally arises from breathing marine organisms. Both types of carbon are classified as dissolved inorganic carbon, and anthropogenic carbon in the ocean is miniscule compared to the vast amount of carbon that has accumulated naturally over millions of years.

    To isolate anthropogenic carbon in the ocean and observe how it has changed through time, Chu used a modeling technique known as extended multiple linear regression — a statistical method that models the relationships between given variables, based on observed data. The data she collected came from both the 2012 cruise and the previous 2001 cruise in the same region.

    She ran a model for each year, plugging in water temperature, salinity, apparent oxygen utilization, and silicate. The models then estimated the natural variability in dissolved inorganic carbon for each year. That is, the models calculated the amount of carbon that should vary from 2001 to 2012, only based on natural processes such as organic respiration. Chu then subtracted the 2001 estimate from the 2012 estimate — a difference that accounts for sources of carbon that are not naturally occurring, and are instead anthropogenic.

    Sinking carbon

    The researchers found that since 2001, the northeast Pacific has stored 11 micromoles per kilogram of anthropogenic carbon, which is comparable to the rate at which carbon dioxide has been emitted into the atmosphere. Most of this carbon is stored in surface waters. In the northern part of the region in particular, anthropogenic carbon tends to linger in shallower waters, within the upper 300 meters of the ocean. The southern region of the northeast Pacific stores carbon a bit deeper, within the top 600 meters.

    Chu says this shallow storage is likely due to a subpolar gyre, or rotating current, that pushes water up from the deep, preventing surface waters from sinking. In contrast, others have observed that similar latitudes in the Atlantic have stored carbon much deeper, due to evaporation and mixing, leading to increased salinity and density, which causes carbon to sink.

    The team calculated that the increase in anthropogenic carbon in the upper ocean caused a decrease in the region’s average pH, making the ocean more acidic as a result. This acidification also had an effect on the region’s aragonite, decreasing its saturation state over the last decade.

    Richard Feely, a senior scientist at the National Oceanic and Atmospheric Administration, says that the group’s results show that this particular part of the ocean is “highly sensitive to ocean acidification.”

    “Our own work with pteropods, and that of others, indicate that some marine organisms are already being impacted by ocean acidification processes in this region,” says Feely, who did not contribute to the study. “Laboratory studies indicate that many species of corals, shellfish, and some fish species will be impacted in the near future. As this study, and others, have shown, the region will soon become undersaturated with respect to aragonite later this century.”

    While the total amount of anthropogenic carbon appears to be increasing with each year, Chu says the rate at which the northeast Pacific has been storing carbon has remained relatively the same since 2001. That means that the region could still have a good amount of “room” to store carbon, at least for the foreseeable future. But already, her team and others are seeing in the acidification trends the ocean’s negative response to the current rate of carbon storage.

    “It would take hundreds of thousands of years for the ocean to absorb the majority of CO2 that humans have released into the atmosphere,” Chu says. “But at the rate we’re going, it’s just way faster than anything can keep up with.”

    This research was supported in part by the National Science Foundation Ocean Acidification Program, the National Institute of Standards and Technology, and the National Science Foundation Graduate Research Fellowship Program.

    See the full article here .

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  • richardmitnick 5:54 pm on December 7, 2014 Permalink | Reply
    Tags: , Carbon Dioxide, , ,   

    From Huff Post: “These 6 Countries Produce Nearly 60 Percent Of Global Carbon Dioxide Emissions” 

    Huffington Post
    The Huffington Post

    12/05/2014
    DINA CAPPIELLO

    Six countries produce nearly 60 percent of global carbon dioxide emissions. China and the United States combine for more than two-fifths. The planet’s future will be shaped by what these top carbon polluters do about the heat-trapping gases blamed for global warming.

    How they rank, what they’re doing:

    CHINA

    s
    A general view shows residential and commercial buildings on a hazy day in Shanghai on November 21, 2014. AFP PHOTO / JOHANNES EISELE

    It emits nearly twice the amount of greenhouse gases as the United States, which it surpassed in 2006 as the top emitter of carbon dioxide. China accounts for about 30 percent of global emissions. U.S. government estimates show China doubling its emissions by 2040, barring major changes. Hugely reliant on fossil fuels for electricity and steel production, China until recently was reluctant to set firm targets for emissions, which continue to rise, although at a slower rate. That changed when Beijing announced last month in a deal with Washington that it would stem greenhouse gas emission growth by 2030. About a week later, China’s Cabinet announced a coal consumption cap by 2020 at about 62 percent of the energy mix. While politically significant, the U.S.-China deal alone is expected to have little effect on the global thermostat.

    2013 CO2 emissions: 11 billion tons

    2013 Population: 1.36 billion

    UNITED STATES

    2
    In this March 8, 2014 photo, steam from the Jeffrey Energy Center coal-fired power plant is silhouetted against the setting sun near St. Mary’s, Kansas. (AP Photo/Charlie Riedel, File)

    It has never entered into a binding treaty to curb greenhouse gases. Nevertheless, it has cut more carbon pollution than any other nation. It is on pace to meet a 2009 Obama administration pledge to reduce emissions 17 percent from 2005 levels by 2020. Carbon emissions are up, though, as the U.S. rebounds from recession. President Barack Obama has largely leaned on existing laws, not Congress, to make progress — boosting automobile fuel economy and proposing to reduce carbon pollution from new and existing power plants. The White House vowed in the China deal to double the pace of emissions reductions, lowering carbon pollution 26 percent to 28 percent from 2005 levels by 2025. Expect resistance when Republicans control Congress in January.

    2013 CO2 emissions: 5.8 billion tons

    2013 Population: 316 million

    INDIA

    3
    In this Tuesday, Sept. 23, 2014 photo, smoke rises from chimneys of brick kilns on the outskirts of New Delhi, India. (AP Photo/Altaf Qadri, File)

    The U.S.-China agreement puts pressure on the Indian government, which could announce new targets during a planned Obama visit in January. Meantime, India plans to double coal production to feed a power grid still suffering blackouts. Its challenge: to curb greenhouse gases as its population and economy grow. In 2010, India voluntarily committed to a 20 percent to 25 percent cut in carbon emissions relative to economic output by 2020 against 2005 levels. It has made recent strides installing solar power, which it is expected to increase fivefold to 100 gigawatts by 2030. Under current policies, its carbon dioxide emissions will double by then, according to the International Energy Agency.

    2013 CO2 emissions: 2.6 billion tons

    2013 population: 1.2 billion

    RUSSIA

    4
    Electrical light illuminates a petroleum cracking tower at the Lukoil-Nizhegorodnefteorgsintez oil refinery, operated by OAO Lukoil, in Nizhny Novgorod, Russia, on Thursday, Dec. 4, 2014. (Andrey Rudakov/Bloomberg via Getty Images)

    It never faced mandatory cuts under the 1997 Kyoto Protocol because its emissions fell so much after the Soviet Union collapsed. A major oil and gas producer, Russia in 2013 adopted a domestic greenhouse gas target that would trim emissions 25 percent from 1990 levels by 2020. Russia’s carbon dioxide emissions today average 35 percent lower than 1990 levels. To meet its goal, Russia has set a goal for 2020 of boosting energy efficiency 40 percent and expanding renewable energy 4.5 percent. The state-owned gas company Gazprom has energy conservation plans, as has the federal housing program. But in 2006, Russia announced a move to more coal- and nuclear-fired electricity to export more oil and natural gas.

    2013 CO2 emissions: 2 billion tons

    2013 population: 143.5 million

    JAPAN

    5
    A passenger jet flies over factory facilities in the Keihin Industrial Zone in Kawasaki City, near Tokyo, Japan, on Thursday, Nov. 13, 2008. (Toshiyuki Aizawa/Bloomberg via Getty Images)

    The shuttering of its nuclear power plants after the 2011 Fukushima nuclear disaster forced a drastic change in plans to curb carbon pollution. In November, Japanese officials said they would now reduce greenhouse gases 3.8 percent from 2005 levels by 2020. With more fossil fuels in the mix, Japan’s emissions will be up 3 percent from 1990 levels, its benchmark for its pledge at a 2009 United Nations summit in Copenhagen to reduce emissions 25 percent. Beginning in 2012, Japan placed a carbon tax based on emissions of fossil fuels, with the proceeds going to renewable energy and energy-saving projects.

    2013 CO2 emissions: 1.4 billion tons

    2013 population: 127 million

    GERMANY

    6
    In this picture taken Thursday, April 3, 2014, giant machines dig for brown coal at the open-cast mining Garzweiler near the city of Grevenbroich, western Germany. (AP Photo/Martin Meissner)

    It has outperformed the 21 percent reduction in greenhouse gases it agreed to in 1997. Emissions are down 25 percent against 1990 levels. To comply with 2020 European Union-set goals, Germany must reduce greenhouse gases 40 percent by 2020. On Wednesday, it boosted subsidies for energy efficiency to help it get there. Germany has in recent years seen back-to-back emissions increases due to higher demand for electricity and a switch to coal after Fukushima, which prompted a nuclear power phase-out. Coal use is down this year and renewables continue to gain electricity market share. Renewables already account for a quarter of Germany’s electrical production. The country plans to boost that share to 80 percent by 2050 — and put a million electric cars on the road by 2020.

    2013 CO2 emissions: 836 million tons

    2013 population: 80.6 million

    ___

    See the full article here.

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