Carbon cycle flaw could plunge Earth into a 'milder' Ice Age: Study

A recent study from the University of California, Riverside, reveals a previously underappreciated mechanism in Earth's carbon cycle that could cause rapid and extreme cooling, potentially triggering ice ages. Traditionally, rock weathering—a slow process where rain dissolves silicate rocks, capturing atmospheric CO2 and stabilizing climate over geological timescales—has been viewed as Earth's primary climate regulator. However, this "gentle" feedback loop does not fully explain geological evidence of past severe ice ages. The researchers propose an additional "erratic thermostat" involving ocean carbon burial, driven by interactions between warming, ocean nutrients, and oxygen levels. As atmospheric CO2 rises and warms the planet, increased nutrient runoff (notably phosphorus) stimulates plankton growth in oceans. These plankton absorb CO2 and, upon dying, sink to the seafloor, burying carbon. Yet, warming also reduces ocean oxygen, preventing permanent phosphorus burial and causing its recycling. This creates a positive feedback loop that boosts plankton growth and