Auditing the Northwest Atlantic Carbon Sink
This research will create an auditing toolkit — a scientific balance sheet — for the Northwest Atlantic’s capacity to absorb carbon dioxide from the atmosphere, now and in the future. Measurement of how much of the carbon dioxide emitted by human activities is absorbed by the ocean is critical for design and assessment of policies required to mitigate climate change. The module will assemble a unique suite of measurements and models in order to assess the carbon dioxide strength regionally.
The ocean’s net uptake of carbon dioxide over the past 200 years is equivalent to 42-44% of the emissions due to fossil-fuel combustion and has mitigated climate change. Of that total uptake, 8 to 10% has been sequestered within the Northwest Atlantic, making that region the most intense sink for carbon on the planet. But, the ocean’s ability to absorb carbon is also susceptible to climate change. This research will develop a state-of-the-art combination of observations and models to measure the Northwest Atlantic’s carbon sink over five year periods. The carbon auditing toolkit will provide a means to validate global models of the ocean carbon sink and contribute to the global stocktaking of greenhouse gas sources and sinks required by the Paris climate accord of 2015.
Why is the Northwest Atlantic a globally important carbon sink?
The intense sequestration of carbon dioxide in the Northwest Atlantic is a consequence of the formation of deep and intermediate water masses that occurs there. Warm, salty water moves northward offshore of the eastern seaboard of North America. The northward-flowing warm, near-surface flow absorbs some of the “extra” atmospheric carbon dioxide associated with human activity. Especially within the Labrador Sea but also to the east of Greenland, this surface water becomes dense as a result of cooling, and in winter it can sink several thousand meters into the ocean interior, carrying its cargo of “extra” or carbon dioxide into the deep ocean as it sinks.
The deep ocean circulation transports the extra carbon dioxide southward, far into the ocean interior, via a cold, deep current that effectively sequesters the carbon for several hundred years or more. While this “overturning circulation” has been extraordinarily effective in removing carbon dioxide from the atmosphere, it is variable from year to year and subject to reduction or interruption as a result of climate change, especially if the release of large quantities of freshwater from melting ice were to slow the sinking process. The effectiveness of the ocean’s carbon sink must be assessed and monitored in order to plan the additional carbon mitigation measures that are required to meet international climate change targets.
More information about this project can be found here.
01 Jan 2020
Cold Ocean and Arctic, Science, Technology and Society
Strategic Research Theme
Arctic and Northern Regions
Environment, Energy and Natural Resources
Governance and Public Policy
Oceans, Fisheries and Aquaculture