Boron isotope evidence for oceanic carbon dioxide leakage during the last deglaciation by M. A. Martínez-Botí, G. Marino, G. L. Foster, P. Ziveri, M. J. Henehan, J. W. B. Rae, P. G. Mortyn & D. Vance. Nature 518, 219–222 (12 February 2015) doi:10.1038/nature14155. As far as I can tell, no-one has covered this yet (well, all right, ScienceDaily did).
Its not that wildly exciting (so much so that I’m a touch surprised it made over-excitable Nature); but it is interesting. Another step on the Mystery of Deglaciations; the kind of stuff SoD has been banging on about a bit. Here’s the abstract:
Atmospheric CO2 fluctuations over glacial–interglacial cycles remain a major challenge… to explain glacial–interglacial atmospheric CO2 variations invoke changes in deep-ocean carbon storage, probably modulated by processes in the Southern Ocean, where much of the deep ocean is ventilated. A central aspect of such models is that, during deglaciations, an isolated glacial deep-ocean carbon reservoir is reconnected with the atmosphere, driving the atmospheric CO2 rise observed in ice-core records. However… Radiocarbon activity tracks changes in ocean ventilation, but not in ocean carbon content, whereas proxies that record increased deglacial upwelling do not constrain the proportion of upwelled carbon that is degassed relative to that which is taken up by the biological pump. Here we apply the boron isotope pH proxy in planktic foraminifera to two sediment cores… as a more direct tracer of oceanic CO2 outgassing. We show that surface waters at both locations, which partly derive from deep water upwelled in the Southern Ocean, became a significant source of carbon to the atmosphere during the last deglaciation, when the concentration of atmospheric CO2 was increasing…
So in broad terms, this is the same story as before: to explain the level and speed of CO2 changes at deglaciations, you probably need CO2 to ventilate from deep-ocean reservoirs (this also comes into the T/CO2 lead/lags stuff). Exactly what might cause that to occur is no clearer; there’s just a little bit more evidence that this actually occurred, rather than the somewhat more process-of-elimination there was before.
Attribution of Arctic temperature change to greenhouse-gas and aerosol influences, Najafi et al.
This one has been reported elsewhere, e.g. Aerosols dampen pace of Arctic warming for now, say scientists by CarbonBrief, so I don’t think I need bother say much. Aerosols offset warming. Who’da guessed?
Unprecedented 21st century drought risk in the American Southwest and Central Plains, Cook et al.
I sometimes wonder if I should take Unprecedented 21st century drought risk in the American Southwest and Central Plains type stuff more seriously. But there are so many Americans who are already doing so, I hardly need to.
* UAB – Carbon release from ocean helped end the Ice Age.
* Meanwhile, back in the real world, Rotating Eyeballs with Eli.