When giant icebergs drift off into the ocean, it's not usually something that we TreeHuggers celebrate. Indeed sea level rise alone cased by melting ice is enough reason to not keep warming our planet.
That said, it's not all bad news. We've reported before that by shedding nutrients and fertilizing the ocean, melting icebergs actually promote biological activity in the oceans. And as the krill and phytoplankton that feed on these bergs eventually die and sink, the process leads to increased carbon sequestration that may help slow the impact of climate change.
Now The Guardian reports on a new study led by Professor Grant Bigg at the University of Sheffield, published in the journal Nature Geoscience, that found plumes of plankton up to 1000km long trailing behind icerbergs in the Antarctic, and lasting for over a month after an iceberg had passed. The results are leading researchers to significantly scale up the contribution that this fertilization effect has on overall ocean carbon—with Biggs' team suggesting it may contribute up to 20% of all the carbon stored in the Southern Ocean.Now, none of this should be taken to suggest that nature will just fix itself. From methane released by melting permafrost to the awful pollution caused by forest fires, there are so many examples of "positive feedback loops" in which the impact of climate change leads to increased emissions, creating a vicious cycle that is hard to reverse. The impact of iceberg fertilization is, however, a very welcome example of the opposite effect—a negative feedback loop that may help to bury a little carbon and buy a little time.