Diving robots find Antarctic winter seas exhale surprising amounts of carbon dioxide

Posted: August 15, 2018 by oldbrew in Carbon cycle, Ocean dynamics, research
Tags: , ,


Researchers describe this as ‘a major challenge to our current understanding’. The global carbon cycle model may have to be revisited.

More than 100 oceanic floats are now diving and drifting in the Southern Ocean around Antarctica during the peak of winter, reports Phys.org.

These instruments are gathering data from a place and season that remains very poorly studied, despite its important role in regulating the global climate.

A new study from the University of Washington, the Monterey Bay Aquarium Research Institute, Princeton University and several other oceanographic institutions uses data gathered by the floating drones over past winters to learn how much carbon dioxide is transferred by the surrounding seas.

Results show that in winter the open water nearest the sea ice surrounding Antarctica releases significantly more carbon dioxide than previously believed.

“These results came as a really big surprise, because previous studies found that the Southern Ocean was absorbing a lot of carbon dioxide,” said lead author Alison Gray, a UW assistant professor of oceanography. “If that’s not true, as these data suggest, then it means we need to rethink the Southern Ocean’s role in the carbon cycle and in the climate.”

The paper is published Aug. 14 in Geophysical Research Letters.

The data was gathered through the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) project based at Princeton University. The National Science Foundation, through its Office of Polar Programs, funded the $21 million effort to place dozens of floating robots to monitor the water around Antarctica and learn how it functions in the global climate system.

“This is science at its most exciting—a major challenge to our current understanding made possible by extraordinary observations from the application of new technologies to study previously unexplored regions of the ocean,” said co-author and SOCCOM director Jorge Sarmiento at Princeton University. Gray conducted the research as a postdoctoral researcher in Sarmiento’s research group.

“Our observations have important implications for our understanding of the global carbon cycle,” Sarmiento said. “We find that the Southern Ocean is currently near neutral with respect to removal of carbon from the atmosphere, contrary to previous studies which suggest there is a large uptake of carbon by the Southern Ocean. These results can be reconciled if there is a corresponding unobserved carbon uptake waiting to be discovered somewhere else in the ocean.”

Previous winter measurements in the region had come mainly from ships traveling across Drake Passage to supply Antarctic research stations. Those data were few and far between.

“After four years of SOCCOM, the vast majority of information about the chemistry of the Southern Ocean is coming from these floats,” Gray said. “We have more measurements from the past few years than all the decades that came before.”

Continued here.

Abstract and Plain Language Summary here.

  1. pochas94 says:

    The figure suggests that in winter, as seawater freezes, it leaves behind the Carbon Dioxide so that water under and near the edge of the ice shelf is enriched in CO2. The same thing happens with salt, so I would expect it also would be concentrated, but this would be more noticeable in bottom water. I don’t see a need to revise all of oceanography based on this.

  2. dennisambler says:

    Unfotunate that the article, in a Physics magazine, repeats the usual false mantra.

    “Learning the rate of these various transfers helps to predict the long-term levels of carbon dioxide, a molecule released by burning fossil fuels that, when it accumulates in the atmosphere, traps heat.”

    The science has been “settled” for decades, yet they still know nothing, but continue to claim the factual high ground.

    “Stabilising climate to avoid dangerous climate change”— a summary of relevant research at the Hadley Centre, January 2005

    “What constitutes ‘dangerous’ climate change, in the context of the UN Framework Convention on Climate Change, remains open to debate.

    Once we decide what degree of (for example) temperature rise the world can tolerate, we then have to estimate what greenhouse gas concentrations in the atmosphere should be limited to, and how quickly they should be allowed to change.

    These are very uncertain because we do not know exactly how the climate system responds to greenhouse gases.

    The next stage is to calculate what emissions of greenhouse gases would be allowable, in order to keep below the limit of greenhouse gas concentrations. This is even more uncertain, thanks to our imperfect understanding of the carbon cycle (and chemical cycles) and how this feeds back into the climate system.”

  3. oldbrew says:

    CO2 emits in all directions as fast as it absorbs, like any radiative gas. It’s also a tiny 0.04% of the atmosphere, so how they can get away with claiming it ‘traps heat’ is a mystery.

    Greenhouses are enclosed units – that’s the whole point of them – unlike the open atmosphere with its convective winds, thermals, changing weather etc. The whole thing is a nonsense.

  4. HM says:

    I’d like to know the isotope values. https://www.esrl.noaa.gov/gmd/outreach/isotopes/mixing.html says plants, fossil fuels, ocean and air all have measurably different value for (delta) carbon13
    Maybe it is just standard ocean carbon.

  5. Richard111 says:

    oldbrew says “CO2 emits in all directions as fast as it absorbs, like any radiative gas.”

    Exactly. Thus less than half the radiation from CO2 molecules can reach the surface.

    Reducing energy by half is called ‘heat trapping’. Amazing!

  6. cognog2 says:

    Yes oldbrew. I picked this up.
    This so called trapped heat gets mopped up by atmospheric water which the enables it to rise due to phase change way past the CO2 and up to the tropopause to dissipate it to space.
    In nature a force always has an opposing one and water does the job in this instance.

  7. gymnosperm says:

    If CO2 is rejected at freezing similarly to brine rejection, ice core data may need calibration. I’m wondering if wind and waves and spray may extract the CO2 mechanically. Cooling water want to absorb CO2.

  8. oldbrew says:

    gymnosperm says: Cooling water want to absorb CO2

    Yes, that looks like the challenge in ‘a major challenge to our current understanding’.

    Should they be considering volcanoes?

    Scientists found 91 volcanoes under Antarctica. Here’s what they might do
    Aug 25, 2017

    The scientists were unable to determine volcanic activity in the range, according their recent study in the Geological Society of London. But even inactive or dormant volcanoes can melt ice because of the high temperatures the volcanoes generate underground.

    – – –
    USGS Volcano Hazards Program says:
    By far the most abundant volcanic gas is water vapor, which is harmless. However, significant amounts of carbon dioxide, sulfur dioxide, hydrogen sulfide and hydrogen halides can also be emitted from volcanoes.


  9. BoyfromTottenham says:

    I am no chemist, but doesn’t ph buffering make it difficult (or invalid) to infer the amount of CO2 in seawater by measuring its ph?

  10. Graeme No.3 says:

    In theory colder water should absorb more CO2 (as soluble gas). A small proportion (about 2%) reacts to form bicarbonate but that reaction decreases with lower pH.
    In practice all the assumptions behind CO2 releases and “Global Warming” should be re-examined, but they won’t be because “The Science is settled” so it isn’t Science.

  11. dai davies says:

    I think you’re probably right about the volcanos. From my IPCC-CO2 article:

    Missing data: Volcanic emissions of CO2

    The IPCC gives CO2 emissions from volcanos as 0.1 GtC/y. It has apparently based this on the assumption that volcanos are evenly distributed across the Earth’s crust. Geologists disagree. The Earth’s crust is much thinner under the oceans. Recent thinking is that the numbers of sea floor volcanos may be several orders of magnitude greater than assumed, and CO2 diffuses from a large surrounding area even when a volcano is otherwise inactive.

    Casey (16) summarised the state of our understanding of volcanic emissions. He takes an estimate of 3,500,000 submarine volcanos (17) and, assuming 4% of these as active, calculates possible emissions of 120 GtC/y. He gives a conservative minimum of 24 GtC/y. My reading of his analysis is that his high figure is already conservative because he is knowingly leaving out diffusion from around the inactive volcanos. Either way, these figures dwarf our 9 GtC/y making it quite irrelevant. They also imply the existence of unaccounted rapid sink capacity 3 to 10 times larger than our annual emissions.

  12. oldbrew says:

    Interesting Dai. This looks like the article:

    Click to access IPCC-CO2.pdf

    From the article:
    Casey provides many journal references confirming that volcanic CO2 emissions can also be 13C depleted, so can’t be isotopically distinguished from fossil fuels. There is no isotope ‘signature’ pointing to anthropogenic fossil fuel use.

  13. pochas94 says:

    “no isotope ‘signature’ ”

    Which leaves us to wonder why the continued 2.7 ppm/yr increase. Subsea volcanism? Ocean storage from a past cold spell? I suspect the rate of increase will persist for a long time.

  14. BoyfromTottenham says:

    Dai Davies – if true, could the vast number of undersea volcanoes explain the massive amount of chalk forming the sea floor in various parts?

  15. Graeme No.3 says:

    I don’t know but quite possibly. The White Cliffs of Dover (with the South Downs) are the remains of marine deposits formed in the Cretaceous, when it was warmer than the Jurassic despite a lower CO2 concentration. The increased warmth has been blamed on ocean circulation changes caused by increased geothermal action, esp. in the Caribbean. There were also deposits formed in the Jurassic such as the Jurassic coast (around Lyme Regis) with encapsulation of Mesozoic reptiles (Plesiosaurs, Ichthyosaurs). There are massive deposits from the Cretaceous age in the Kansas ‘badlands’ also encapsulating things like Mosasaurs. The risen sea level would have been open to the Caribbean as the seaway continued up to the Arctic.

  16. stpaulchuck says:

    Not to worry. Just give them a couple of months to create some “adjustments” to the data and this will all go away.

  17. oldbrew says:

    pochas94 says: August 16, 2018 at 9:47 am
    Which leaves us to wonder why the continued 2.7 ppm/yr increase.

    Assuming such data is accurate.