Auditing the Northwest Atlantic Carbon Sink

OFI Large Research Module B

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.

About the research

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.

The research team

The team of researchers on this collaborative project come from Dalhousie University, the University of Alberta and Memorial University of Newfoundland as well as international OFI partners in Germany and the USA. The team lead is Doug Wallace of Dalhousie University, who holds the Canada Excellence Research Chair in Ocean Science and Technology.  

Team members include Kumiko Azetsu-Scott, Eric Oliver, Dariia Atamanchuk, Paul Myers, Brad deYoung, Thomas Trappenberg, Mike Dowd, Aldo Chircop and Meinhard Doelle.

An international expert on maritime law, OFI researcher, Aldo Chircop answers questions from the Clear Seas Centre about the impacts of greenhouse gas emissions on shipping.

Partners

• The Department of Fisheries and Oceans, Bedford Institute of Oceanography
• Environment and Climate Change Canada
• GEOMAR of Germany
• Woods Hole Oceanographic Institution of the United States
• Lamont-Doherty Earth Observatory of Columbia University in the United States.
• Pro-Oceanus Ltd. of Bridgewater
• Atlantic Towing Ltd.

Ocean breathing - Watch this VITALS video and learn how the deep ocean connects with the atmosphere and the role of deep breathing in climate change. The video was produced by OFI researchers, Paul Myers (University of Alberta), Doug Wallace (Dalhousie University) and Brad deYoung (Memorial University) along with their colleagues Roberta Hamme (University of Victoria), Jean-Eric Tremblay (Univesite Laval) and Jaime Palter (University of Rhode Island).  

Taking the Pulse and Temperature of the North Atlantic Ocean

‍Observation is fundamental to understanding the ocean and forecasting its future and improving ocean health and promoting sustainable management. The Journal of Ocean Technology 2017 has published The GO-SHIP A02 Survey written by Evin McGovern, Caroline Cusack, Peter Croot, and OFI researcher and Dalhousie University professor, Doug Wallace.