by Daniel Brouse
November 11, 2023
What do you know about the Rio Negro as it relates to climate change and carbon sinks? The Rio Negro gets its name from its color. The black water is caused by highly acidic and carbon rich water. One scientist that lives on the river called it similar to Coca-cola. In 2023, the Rio Negro recorded record low levels.
Most of the carbon discharged into the water helps the carbon to eventually sink in the ocean as a literal carbon sink. The lack of rain and drought conditions result in more vegetation dying and contribute to a feedback loop — more plants die from less rain… and there is less rain to wash the excess carbon to the bottom of the ocean… resulting in more global warming… resulting in more dead vegetation.
A study of Dissolved Organic Carbon (DOC) in South American rivers found, “Small and steep catchments hosting organic rich forest soils and peatlands were the most sensitive and showed the highest and fastest DOC release if evaluated on a per unit area basis. Here, rain events caused a rapid exponential increase in DOC release….”
The study Effects of natural light and depth on rates of photo-oxidation of dissolved organic carbon in a major black-water river, the Rio Negro, Brazil found under natural sunlight during the dry seasons rates of complete photo-oxidation and changes in absorbance indices decayed exponentially. The deeper the water the less CO2 created.
The Amazon river was also at record lows during 2023. The drought conditions in the Amazon rain forest are unusual. We are watching the Rio Negro and Amazon Rivers as a case study for the slowing and/or collapse of the AMOC. The tipping point for the collapse of AMOC (Atlantic Meridional Overturning Circulation) was thought to be centuries away, at the earliest. In July of 2023, the study Warning of a forthcoming collapse of the Atlantic meridional overturning circulation was published in the journal Nature Communications. “Here we provide statistical significance and data-driven estimators for the time of tipping. We estimate a collapse of the AMOC to occur around mid-century (2025-2095) under the current scenario of future emissions.” The collapse is likely to cause faster sea level rise on the east coast of the US, more severe storms in Europe, and increasing drought in the Sahel in Africa. “From the study of past climate, we know changes in the AMOC have been some of the most abrupt and impactful events in the history of climate,” said Prof. Stefan Rahmstorf, at the Potsdam Institute for Climate Impact Research in Germany and world leading oceanographer. During the last Ice Age, winter temperatures changed by up to 10C within three years in some places. “We are dealing with a system that in some aspects is highly non-linear, so fiddling with it is very dangerous, because you may well trigger some surprises,” he said. “I wish I knew where this critical tipping point is, but that is unfortunately just what we don’t know. We should avoid disrupting the AMOC at all costs. It is one more reason why we should stop global warming as soon as possible.” A feedback loop created by the AMOC tipping point would cause a disruption of weather systems and circulation. The result would be the loss of naturally occurring carbon sinks.
Conclusion
The carbon sequestration from dissolved organic carbon is only one of the many carbon sinks in the Amazon. It is likely Amazon droughts will become more frequent and intense resulting in decarbonization at an exponential rate. The collapse of the AMOC will hasten the collapse of the Amazon. The collapse of the Amazon will hasten the collapse of the AMOC.
A case study for: Toppled Tipping Points: The Domino Effect Brouse and Mukherjee (2023)
Climate Change: How Long Is “Ever”? Brouse (2023)
Climate Change: The End of Times Brouse and Mukherjee (2023)
The Reign of Violent Rain Brouse and Mukherjee (2023)
Climate Change: Rate of Acceleration Brouse and Mukherjee (2023)