Inconvenient: Iceberg calving helps ‘carbon sequestration’ and is ‘helping to slow global warming’
Posted by Anthony Watts
From the UNIVERSITY OF SHEFFIELD and the department of “unknown negative feedbacks” comes this interesting study. While there have been numerous claims that warmer Polar temperatures (due to posited global warming effects) will cause more iceberg calving, I’m sure it will come as quite a shock to those same folks when they discover that there’s a negative feedback for CO2 in the process. Via Eurkealert.
Northern edge of Iceberg B-15A in the Ross Sea, Antarctica, 29 January 2001. Credit: NSF/Josh Landis
Giant icebergs play key role in removing CO2 from the atmosphere
Key points:
This activity, known as carbon sequestration, contributes to the long-term storage of atmospheric carbon dioxide, therefore helping to slow global warming.
During the study, which is the first of its kind on this scale, a team of scientists led by Professor Grant Bigg analysed 175 satellite images of ocean colour — which is an indicator of phytoplankton productivity at the ocean’s surface — from a range of icebergs in the Southern Ocean which were at least 18 km in length.
The images from 2003-2013 showed that enhanced phytoplankton productivity, which has a direct impact on carbon storage in the ocean, extends hundreds of kilometres from giant icebergs, and persists for at least one month after the iceberg passes.
Professor Grant Bigg from the University of Sheffield analysed 175 satellite images taken over an 11-year period from 2003 to 2013. He noticed blooms of phytoplankton stretching hundreds of miles. The giant iceberg C16 is seen in the center of the picture, with levels of plankton spreading southwest and northeast.
Professor Bigg said: “This new analysis reveals that giant icebergs may play a major role in the Southern Ocean carbon cycle.
“We detected substantially enhanced chlorophyll levels, typically over a radius of at least four-10 times the iceberg’s length.
“The evidence suggests that assuming carbon export increases by a factor of five-10 over the area of influence and up to a fifth of the Southern Ocean’s downward carbon flux originates with giant iceberg fertilisation.
“If giant iceberg calving increases this century as expected, this negative feedback on the carbon cycle may become more important than we previously thought.”
The Southern Ocean plays a significant part in the global carbon cycle, and is responsible for approximately 10 per cent of the ocean’s total carbon sequestration through a mixture of biologically driven and chemical processes, including phytoplankton growth.
Previous studies have suggested that ocean fertilization from icebergs makes relatively minor contributions to phytoplankton uptake of CO2.
However this research, published today (Jan. 11, 2016) in Nature Geoscience, shows that melting water from icebergs is responsible for as much as 20 per cent of the carbon sequestered to the depths of the Southern Ocean.
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Of course, this is old news, as WUWT carried the story back in 2011 that says exactly the same thing.
Posted by Anthony Watts
From the UNIVERSITY OF SHEFFIELD and the department of “unknown negative feedbacks” comes this interesting study. While there have been numerous claims that warmer Polar temperatures (due to posited global warming effects) will cause more iceberg calving, I’m sure it will come as quite a shock to those same folks when they discover that there’s a negative feedback for CO2 in the process. Via Eurkealert.
Northern edge of Iceberg B-15A in the Ross Sea, Antarctica, 29 January 2001. Credit: NSF/Josh Landis
Giant icebergs play key role in removing CO2 from the atmosphere
Key points:
- Giant icebergs leave trail of carbon sequestration in their wake — a month after they have passed
- Geographers analysed 175 satellite images of ocean colour which is an indicator of phytoplankton productivity at the ocean’s surface
- Giant icebergs are responsible for storing up to 20 per cent of carbon in the Southern Ocean, a new study has found.
This activity, known as carbon sequestration, contributes to the long-term storage of atmospheric carbon dioxide, therefore helping to slow global warming.
During the study, which is the first of its kind on this scale, a team of scientists led by Professor Grant Bigg analysed 175 satellite images of ocean colour — which is an indicator of phytoplankton productivity at the ocean’s surface — from a range of icebergs in the Southern Ocean which were at least 18 km in length.
The images from 2003-2013 showed that enhanced phytoplankton productivity, which has a direct impact on carbon storage in the ocean, extends hundreds of kilometres from giant icebergs, and persists for at least one month after the iceberg passes.
Professor Grant Bigg from the University of Sheffield analysed 175 satellite images taken over an 11-year period from 2003 to 2013. He noticed blooms of phytoplankton stretching hundreds of miles. The giant iceberg C16 is seen in the center of the picture, with levels of plankton spreading southwest and northeast.
Professor Bigg said: “This new analysis reveals that giant icebergs may play a major role in the Southern Ocean carbon cycle.
“We detected substantially enhanced chlorophyll levels, typically over a radius of at least four-10 times the iceberg’s length.
“The evidence suggests that assuming carbon export increases by a factor of five-10 over the area of influence and up to a fifth of the Southern Ocean’s downward carbon flux originates with giant iceberg fertilisation.
“If giant iceberg calving increases this century as expected, this negative feedback on the carbon cycle may become more important than we previously thought.”
The Southern Ocean plays a significant part in the global carbon cycle, and is responsible for approximately 10 per cent of the ocean’s total carbon sequestration through a mixture of biologically driven and chemical processes, including phytoplankton growth.
Previous studies have suggested that ocean fertilization from icebergs makes relatively minor contributions to phytoplankton uptake of CO2.
However this research, published today (Jan. 11, 2016) in Nature Geoscience, shows that melting water from icebergs is responsible for as much as 20 per cent of the carbon sequestered to the depths of the Southern Ocean.
###
Of course, this is old news, as WUWT carried the story back in 2011 that says exactly the same thing.
