A Source of CO2 That Might Surprise You

That babbling brook out back has been holding out on you

NASA

A satellite view of the Mississippi River shows a mosaic of riverbank land-use patterns.

Rivers and streams in the United States are releasing a lot more CO2 into the atmosphere than scientists previously thought, according to a new study by scientists at Yale. In fact, American waterways are discharging the gas into the atmosphere at a rate of 100 million metric tons per year, an amount equal to a car burning 40 billion gallons of gas, researchers say.

The study, conducted by David Butman and Peter Raymond of the Yale School of Forestry and Environmental Studies, looked at water chemistry data from more than 4,000 rivers and streams. The authors say identifying this significant source of CO2 could change the way scientists model the movement of carbon through ecosystems and the atmosphere.

“These rivers breathe a lot of carbon,” said Butman in a press release from the National Science Foundation, one of the study’s funders. “They are a source of carbon dioxide, just like we breathe out carbon dioxide and like smokestacks emit carbon dioxide.”

The study is published in the current issue of Nature Geoscience.

  • http://warming101.com Anna Haynes

    Gretchen, how about updating this blogpost to address 2 more points:
    1) Comparison of emissions as % of overall auto gas consumption, and 2) implications of this research (readers will form a view of its implications whether or not you address them; so you might as well help readers form an accurate view).

    > an amount equal to a car burning 40 billion gallons of gas

    See “Why They Are Called Numbers” –
    http://init.planet3.org/2011/10/07/why-they-are-called-numbers/
    (in gee-whiz fashion they numb, providing about as much helpful info as one of those text cloud images.)

    from wikianswers, How much gasoline is burned in the United Sates each year?
    Answer: 140 billion gallons in 2004, and it was growing.
    (so yes, the natural waterway emissions are a substantial % of this)

    Next point to make:
    Comparing natural to human emissions isn’t really relevant – natural emissions overall do dwarf human ones, we know that, but the former were in balance, the latter are what’s filling the atmospheric CO2 “bathtub”. See SkepticalScience argument #29 ( skepticalscience.com/fixednum.php )

    The press release also raises a disturbing prospect, that increased waterway co2 emissions could be a feedback of further human-caused warming:
    “The paper…also indicates that as the climate heats up there will be more rain and snow, and that an increase in precipitation will result in even more terrestrial carbon flowing into rivers and streams and being released into the atmosphere.”

  • Roger Pierno

    Gretchen, What surprised me is the shallowness of your article. Your piece left me with more questions and little useful information. What is the process for this carbon conversion to CO2 in rivers and streams? How does this 100 million metric tons per year compare as a percentage to the other know CO2 sources in the US? In order to provide “… in-depth coverage of climate-related science and policy issues….” you really need to go beyond the press release.

    • http://www.kqed.org/climatewatch Gretchen Weber

      Hi Anna and Roger,
      Thanks for you comments and for furthering the discussion here. Unfortunately, we don’t always have the resources to explore every topic as deeply and some might like. Sometimes, we post things to the Climate Watch blog that come across our desks that we think are interesting, and we want to alert our readers so they can take a look for themselves and explore should they choose. This is one of those instances.
      Thanks for raising some great questions.
      Gretchen