In this enlightening episode, we're joined by Dr. Liu, a renowned climate scientist, to explore the potentially devastating consequences of the slowing Meridional Overturning Circulation (MOC). Earth system models (ESMs) predict a dramatic decrease in the Atlantic MOC and the Southern MOC by the year 2100. Moreover, we could be facing a complete shutdown of SMOC by 2300. What does this mean for the Earth's climate and ocean carbon uptake? Dr. Liu delves into how this slowdown can affect both the biological and solubility carbon pumps in the ocean, leading to uncertain impacts on oceanic carbon absorption.

Despite reducing anthropogenic carbon intake by the solubility pump, a slowing MOC might inadvertently increase the deep-ocean storage of carbon and nutrients via the biological pump. This surprising result paints a complex picture, leading to a net reduction in the ocean's ability to absorb anthropogenic CO2. Moreover, Dr. Liu brings to light the long-term implications of deep-ocean nutrient sequestration, which could depress global-scale, marine net primary production over time. The MOC slowdown, therefore, stands as a powerful feedback mechanism that could extend or intensify peak-warmth climate conditions on multi-century timescales. Listen in to understand this critical facet of climate change and its potential ripple effects on our planet's future.

Climate Change, Meridional Overturning Circulation, Earth System Models, Ocean Carbon Uptake, Solubility Pump, Biological Pump, Anthropogenic CO2, Dr. Liu, Nutrient Sequestration, Global Warming, Positive Feedback, Climate Scenarios.

Nutrient sequestration from slowing overturning circulation. Nat. Clim. Chang. 13, 83–90 (2023). https://doi.org/10.1038/s41558-022-01555-7