Flashback about 16,000 years ago. During this time, the Southern Ocean was experiencing a sudden rise in atmospheric CO2 and temperatures in a period of less than 100 years. "During this earlier period, known as Heinrich stadial 1, atmospheric CO2 increased by a total of ~40ppm, Antarctic surface atmospheric temperatures increased by around 5°C and Southern Ocean temperatures increased by 3°C," said lead author of the new study published in Nature Communications, Dr. Laurie Menviel. Does any of that sound at all familiar?
According to Science Daily, Heinrich events like the one Dr. Menviel mentions, refer to rapid increases in atmospheric carbon dioxide occur over a very short period of time. Many scientists have used Heinrich event 1 as a case study in previous investigations because it is relatively easy to decipher the changes in ocean currents, temperature, ice and sea levels within the region’s geology. Yet nonetheless, scientists hadn’t been able to figure out why Heinrich event 1 saw such a strong spike in atmospheric CO2 concentrations. This new research suggests that the spike the region experienced from this particular Heinrich event could have been caused by strong westerly winds.
Westerly winds refer to winds that blow from the west. During Heinrich event 1, these winds moved toward Antarctica, getting stronger as they went. This, in turn, created a chain of events: stronger winds meant greater ocean circulation, which meant more transport of carbon-rich waters from the deep Pacific Ocean to the surface of the Southern Ocean. This resulted in a release of about 100Gt of carbon dioxide from the Southern Ocean into the atmosphere.
The most harrowing part of this discovery is the similarity that the natural release of carbon dioxide during Heinrich event 1 has with our current crisis from human-driven climate change. "The carbon exchange in particular between the Southern Ocean and the atmosphere matter deeply for our climate. It is estimated the Southern Ocean absorbs around 25% of our atmospheric carbon emissions and that ~43% of that carbon is taken up by the Ocean south of 30S," Dr. Menviel commented.
However, the scientists urge that more research is needed in order to fully understand the complexity of the systems involved. "For this reason, it is vital to bring more observational networks into the Southern Ocean to monitor these changes. We need a clear warning if we are approaching a point in our climate system where we may see a spike in atmospheric carbon dioxide and the rapid temperature rise that inevitably follows,” said Dr. Menviel