Natural carbon sinks are faltering

The ocean has long provided a critical climate service by absorbing roughly 30% of human-caused carbon dioxide emissions and 90% of excess heat (Callaway Climate Insights, The Energy Collective). This capacity is under mounting pressure as rising temperatures and shifting chemistry weaken the ocean's ability to store carbon, with recent data showing a 6% reduction in this efficiency (Ocean Rising). Meanwhile, the global ocean heat content hit a record in 2025, with 89% of the ocean experiencing marine heatwaves. These feedback loops, including carbon release from thawing permafrost and wildfires, are largely absent from standard climate models (MIT Technology Review).

Global warming is accelerating, with the rate of temperature rise now double what it was at the turn of the century (Climate Uncovered). Major institutions now acknowledge that the target of limiting warming to 1.5°C is unreachable, with projections suggesting this threshold will be crossed by May 2029 (The Climate Casino, Climate Time). While some argue that natural feedbacks will eventually force thermal equilibrium, the current accumulation of energy in the system continues to drive extreme heat and rising sea levels (Evolutionshift). As the issue on Tuesday showed (an earlier story), effective action requires moving beyond individual choices to address these systemic physical realities.