Oceans and forests have absorbed roughly half our carbon emissions for decades, slowing climate change – but can they keep it up?

For decades, oceans and forests have been absorbing roughly half of the carbon emissions humans produce, thereby mitigating climate change. However, scientists now wonder if these natural carbon sinks can continue to keep up with the growing levels of carbon dioxide. A recent study, published in Science, sheds light on the future of these vital carbon sinks.

The ocean has been absorbing 35% of carbon dioxide emissions from fossil fuels since 1990, while the world's forests and other plants have absorbed an additional 13%. However, new research suggests that the rate of these absorptions may slow down in the coming decades.

Measuring the extent of these carbon sinks is a complex task due to the varying behaviors and unpredictable changes in land and ocean regions. The study utilized high-precision measurements of atmospheric oxygen and carbon dioxide to quantify the land and ocean carbon sinks. Contrary to most computer model simulations, the study found that the land carbon sink has not been increasing over time to keep pace with increasing fossil fuel emissions.

On the other hand, the study revealed a larger ocean carbon sink than predicted by most models, and it has been increasing as emissions grow. However, the increasing absorption may begin to slow down, leaving the oceans less effective at absorbing carbon dioxide in the coming decades. This discovery highlights the need for further research to understand the behavior of these crucial carbon sinks and their potential impact on climate change mitigation.